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Advanced Biomass-Derived Carbon Materials

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A topical collection in Materials (ISSN 1996-1944). This collection belongs to the section "Carbon Materials".

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Editor

Prof. Dr. Andrea Kruse

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Institute of Agricultural Engineering, Conversion Technologies of Biobased Resources, Universität Hohenheim / University of Hohenheim, Stuttgart, Germany
Interests: hydrothermal carbonization; carbon materials; platform-chemicals from biomass; nutrient recovery; hydrothermal conversion; hydrothermal liquefaction; hydrothermal gasification; hydrothermal pretreatment
Special Issues, Collections and Topics in MDPI journals

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Dear Colleagues,

Fossil oils are a limited resource, not only for energy production, but also as basis for the production of materials. On the other hand, what really provokes research in biomass-derived carbon materials, is the following goal: The development of novel, sustainable materials produced based on the molecular structures available in nature. The materials should be produced in sustainable way and independent on fossil resources. We need new materials, e.g., in view of e-mobility, with better properties and not too high price. For this we need fundamental knowledge about the chemical basics, about the formation and structure-properties relation, but also about the production of such materials.

This Special Issue should include the most recent and innovative work in the field of biomass-derived carbon materials and cover fundamental to applied research.

Prof. Andrea Kruse
Guest Editor

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Keywords

Carbonization
activation
activated carbon
biochar
biocoal
pyrolysis
hydrothermal
carbon materials
hydrochar

Published Papers (32 papers)

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2023

Jump to: 2022, 2021, 2020, 2019, 2018

12 pages, 3531 KiB

Open AccessArticle

Enzymolytic Lignin-Derived N-S Codoped Porous Carbon Nanocomposites as Electrocatalysts for Oxygen Reduction Reactions

by Zheng Li, Xia Qu, Yuwei Feng, Lili Dong, Yantao Yang, Tingzhou Lei and Suxia Ren

Materials 2023, 16(24), 7614; https://doi.org/10.3390/ma16247614 - 12 Dec 2023

Cited by 1 | Viewed by 702

Currently, the development of nonmetallic oxygen reduction reaction (ORR) catalysts based on heteroatomic-doped carbon materials is receiving increaseing attention in the field of fuel cells. Here, we used enzymolytic lignin (EL), melamine, and thiourea as carbon, nitrogen, and sulfur sources and NH₄ [...] Read more.

Currently, the development of nonmetallic oxygen reduction reaction (ORR) catalysts based on heteroatomic-doped carbon materials is receiving increaseing attention in the field of fuel cells. Here, we used enzymolytic lignin (EL), melamine, and thiourea as carbon, nitrogen, and sulfur sources and NH₄Cl as an activator to prepare N- and S-codoped lignin-based polyporous carbon (ELC) by one-step pyrolysis. The prepared lignin-derived biocarbon material (ELC-1-900) possessed a high specific surface area (844 m² g⁻¹), abundant mesoporous structure, and a large pore volume (0.587 cm³ g⁻¹). The XPS results showed that ELC-1-900 was successfully doped with N and S. ELC-1-900 exhibited extremely high activity and stability in alkaline media for the ORR, with a half-wave potential (E_1/2 = 0.88 V) and starting potential (E_onset = 0.98 V) superior to those of Pt/C catalysts and most non-noble-metal catalysts reported in recent studies. In addition, ELC-1-900 showed better ORR stability and methanol tolerance in alkaline media than commercial Pt/C catalysts. Full article

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12 pages, 2561 KiB

Open AccessArticle

Characterization of Magnetic Biochar Modified Using the One-Step and Electrochemical Methods and Its Impact on Phosphate Adsorption

by Changgen Mei, Lulu Wang and Wei Tao

Materials 2023, 16(22), 7092; https://doi.org/10.3390/ma16227092 - 09 Nov 2023

Viewed by 578

The properties and phosphate adsorption capability of the one-step method and electrochemical method in modifying peanut shell biochar have been determined. The one-step method deposits MgO and Fe₃O₄ onto biochar through chemical impregnation and regularly affects the functional groups and [...] Read more.

The properties and phosphate adsorption capability of the one-step method and electrochemical method in modifying peanut shell biochar have been determined. The one-step method deposits MgO and Fe₃O₄ onto biochar through chemical impregnation and regularly affects the functional groups and magnetic separation of biochar, thereby enhancing its ability to adsorb phosphate. In contrast, the electrochemical method is not favorable for modifying functional groups of biochar but can promote phosphate adsorption because of the formation of MgFe₂O₄ and Fe₃O₄ using electrolysis. The adsorption isotherm and kinetics data suggest that adsorption is monolayer onto a homogeneous surface and phosphate adsorption could be controlled by chemical processes. Biochar with the addition of both Fe²⁺ and Mg²⁺ shows better phosphate adsorption capability than those with barely any Fe²⁺ additions. It was concluded that the one-step method is a better modification method than the electrochemical method for enhancing the phosphate adsorption capability of biochars. Full article

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12 pages, 2584 KiB

Open AccessArticle

“Sweetwoods” Lignin as Promising Raw Material to Obtain Micro-Mesoporous Carbon Materials

by Ance Plavniece, Galina Dobele, Dmitrijs Djachkovs, Lilija Jashina, Oskars Bikovens, Aleksandrs Volperts and Aivars Zhurinsh

Materials 2023, 16(17), 6024; https://doi.org/10.3390/ma16176024 - 01 Sep 2023

Cited by 1 | Viewed by 799

Biorefineries with the significant amounts of lignin as a by-product have a potential to increase business revenues by using this residue to produce high value-added materials. The carbon materials from biomass waste increases the profitability of the production of porous carbon used for [...] Read more.

Biorefineries with the significant amounts of lignin as a by-product have a potential to increase business revenues by using this residue to produce high value-added materials. The carbon materials from biomass waste increases the profitability of the production of porous carbon used for sorbents and energy production. The purpose of this research is to study the chemical properties of lignin from “Sweetwoods” biorefinery as well as to characterize lignin carbonizates and activated carbons synthesized from them. This paper describes the effect of carbonization conditions (thermal or hydrothermal) on the properties of activated carbon material. It can be concluded that, depending on the carbonization method, the three-dimensional hierarchical porous structure of activated carbon materials based on “Sweetwoods” lignin, has micro- and mesopores of various sizes and can be used for number of purposes: both for high-quality sorbents, catalysts for electrochemical reduction reactions, providing sufficient space for ion mass transfer in electrodes for energy storage and transfer. Full article

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15 pages, 3822 KiB

Open AccessArticle

Hydrothermal Pretreatment of KOH for the Preparation of PAC and Its Adsorption on TC

by Shouqi Wang, Linkai Wu, Liangcai Wang, Jianbin Zhou, Huanhuan Ma and Dengyu Chen

Materials 2023, 16(14), 4966; https://doi.org/10.3390/ma16144966 - 12 Jul 2023

Cited by 1 | Viewed by 742

The environment has been heavily contaminated with tetracycline (TC) due to its excessive use; however, activated carbon possessing well-developed pores can effectively adsorb TC. This study synthesized pinecone-derived activated carbon (PAC) with high specific surface area (1744.659 cm²/g, 1688.427 cm² [...] Read more.

The environment has been heavily contaminated with tetracycline (TC) due to its excessive use; however, activated carbon possessing well-developed pores can effectively adsorb TC. This study synthesized pinecone-derived activated carbon (PAC) with high specific surface area (1744.659 cm²/g, 1688.427 cm²/g) and high adsorption properties (840.62 mg/g, 827.33 mg/g) via hydrothermal pretreatment methods utilizing pinecones as precursors. The results showed that PAC treated with 6% KOH solution had excellent adsorption properties. It is found that the adsorption process accords with the PSO model, and a large amount of C=C in PAC provides the carrier for π-πEDA interaction. The results of characterization and the isothermal model show that TC plays a key role in the adsorption process of PAC. It is concluded that the adsorption process of TC on PAC prepared by hydrothermal pretreatment is mainly pore filling and π-πEDA interaction, which makes it a promising adsorbent for TC adsorption. Full article

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13 pages, 3982 KiB

Open AccessArticle

Synthesis of Carbon Microspheres from Inedible Crystallized Date Palm Molasses: Influence of Temperature and Reaction Time

by Mohanad El-Harbawi, Saeed Alhawtali, Abdulrhman S. Al-Awadi, Lahssen El Blidi, Maher M. Alrashed, Abdulrahman Alzobidi and Chun-Yang Yin

Materials 2023, 16(4), 1672; https://doi.org/10.3390/ma16041672 - 16 Feb 2023

Cited by 3 | Viewed by 1313

In this work, carbon microspheres (CMs) were prepared by hydrothermal carbonization (HTC) of inedible crystallized date palm molasses. The effects of temperature and reaction time on the prepared materials were studied. Experiments were carried out at different temperatures (180, 200, 230 and 250 [...] Read more.

In this work, carbon microspheres (CMs) were prepared by hydrothermal carbonization (HTC) of inedible crystallized date palm molasses. The effects of temperature and reaction time on the prepared materials were studied. Experiments were carried out at different temperatures (180, 200, 230 and 250 °C) with reaction times ranging from 2 to 10 h. It was found that temperature had the greatest influence on the mass yield of the CMs. No solid products were observed at a temperature of 180 °C and a reaction time less than 2 h. The highest yield was found to be 40.4% at 250 °C and a reaction time of 6 h. The results show that the CMs produced were approximately 5–9 μm in diameter. The results also show that the largest diameter of the CMs (8.9 μm) was obtained at a temperature of 250 °C and a reaction time of 6 h. Nonetheless, if the reaction time was extended beyond 6 h at 250 °C, the CMs fused and their shapes were deformed (non-spherical shapes). The synthesized materials were characterized using Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR), Branuer-Emmett-Teller (BET) and thermogravimetric analysis (TGA). BET surface areas for the four samples were found to be less than 1 m²/g. The methylene blue adsorption studies indicated that the equilibrium adsorption capacity was reached after 15 min, with a maximum adsorption capacity of 12 mg/g. The recycling of date palm molasses (a known processed waste) to generate a useable carbon microsphere represents a beneficial step in the application of sustainable processing industries in the Middle East. Full article

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2022

Jump to: 2023, 2021, 2020, 2019, 2018

10 pages, 2469 KiB

Open AccessCommunication

Waste-Coffee-Derived Activated Carbon as Efficient Adsorbent for Water Treatment

by Hong-Ming Chen, Woon-Ming Lau and Dan Zhou

Materials 2022, 15(23), 8684; https://doi.org/10.3390/ma15238684 - 06 Dec 2022

Cited by 3 | Viewed by 1469

Activated carbon prepared from waste coffee was utilized as a potential low-cost adsorbent to remove Rhodamine B from aqueous solution. A series of physical characterizations verify that the obtained activated carbon possesses a layered and ordered hexagonal structure with a wrinkled and rough [...] Read more.

Activated carbon prepared from waste coffee was utilized as a potential low-cost adsorbent to remove Rhodamine B from aqueous solution. A series of physical characterizations verify that the obtained activated carbon possesses a layered and ordered hexagonal structure with a wrinkled and rough surface. In addition, high specific surface area, appropriate pore distribution, and desired surface functional groups are revealed, which promote the adsorption properties. Various adsorption experiments were conducted to investigate the effect on the absorption capacity (e.g., of initial dye concentration, temperature and solution pH) of the material. The results showed that the waste-coffee-derived activated carbon with a large surface area of approximately 952.7 m² g⁻¹ showed a maximum uptake capacity of 83.4 mg g⁻¹ at the pH of 7 with the initial dye concentration of 100 mg L⁻¹ under 50°C. The higher adsorption capacity can be attributed to the strong electrostatic attraction between the negatively charged functional groups in activated carbon and the positively charged functional groups in RB. The kinetic data and the corresponding kinetic parameters were simulated to evaluate the mechanism of the adsorption process, which can fit well with the highest R². The adsorption results confirmed the promising potential of the as-prepared waste-coffee-derived activated carbon as a dye adsorbent. Full article

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13 pages, 5458 KiB

Open AccessArticle

Sustainable Kapok Fiber-Derived Carbon Microtube as Broadband Microwave Absorbing Material

by Aichun Long, Pengfei Zhao, Lusheng Liao, Rui Wang, Jinlong Tao, Jianhe Liao, Xiaoxue Liao and Yanfang Zhao

Materials 2022, 15(14), 4845; https://doi.org/10.3390/ma15144845 - 12 Jul 2022

Cited by 11 | Viewed by 1633

The design of hierarchical structures from biomass has become one of the hottest subjects in the field of microwave absorption due to its low cost, vast availability and sustainability. A kapok-fiber-derived carbon microtube was prepared by facile carbonization, and the relation between the [...] Read more.

The design of hierarchical structures from biomass has become one of the hottest subjects in the field of microwave absorption due to its low cost, vast availability and sustainability. A kapok-fiber-derived carbon microtube was prepared by facile carbonization, and the relation between the structure and properties of the carbonized kapok fiber (CKF) was systematically investigated. The hollow tubular structures afford the resulting CKF composites with excellent microwave-absorbing performance. The sample with a 30 wt.% loading of CKF in paraffin demonstrates the strongest microwave attenuation capacity, with a minimum reflection loss of −49.46 dB at 16.48 GHz and 2.3 mm, and an optimized effective absorption bandwidth of 7.12 GHz (10.64–17.76 GHz, 2.3 mm) that covers 34% of the X-band and 96% of the Ku-band. Further, more than 90% of the incident electromagnetic wave in the frequency from 4.48 GHz to 18.00 GHz can be attenuated via tuning the thickness of the CKF-based absorber. This study outlines a foundation for the development of lightweight and sustainable microwave absorbers with a high absorption capacity and broad effective absorption bandwidth. Full article

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19 pages, 5911 KiB

Open AccessEditor’s ChoiceArticle

Activated Carbon Preparation from Sugarcane Leaf via a Low Temperature Hydrothermal Process for Aquaponic Treatment

by Kanyanat Tawatbundit and Sumrit Mopoung

Materials 2022, 15(6), 2133; https://doi.org/10.3390/ma15062133 - 14 Mar 2022

Cited by 3 | Viewed by 2641

The effects of hydrothermal treatment, 0–5% KMnO₄ content, and 300–400 °C pyrolysis temperature, were studied for activated carbon preparation from sugar cane leaves in comparison with non-hydrothermal treatment. The percent yield of activated carbon prepared by the hydrothermal method (20.33–36.23%) was higher [...] Read more.

The effects of hydrothermal treatment, 0–5% KMnO₄ content, and 300–400 °C pyrolysis temperature, were studied for activated carbon preparation from sugar cane leaves in comparison with non-hydrothermal treatment. The percent yield of activated carbon prepared by the hydrothermal method (20.33–36.23%) was higher than that prepared by the non-hydrothermal method (16.40–36.50%) and was higher with conditions employing the same content of KMnO₄ (22.08–42.14%). The hydrothermal and pyrolysis temperatures have the effect of increasing the carbon content and aromatic nature of the synthesized activated carbons. In addition, KMnO₄ utilization increased the O/C ratio and the content of C-O, Mn-OH, O-Mn-O, and Mn-O surface functional groups. KMnO₄ also decreases zeta potential values throughout the pH range of 3 to 11 and the surface area and porosity of the pre-hydrothermal activated carbons. The use of the pre-hydrothermal activated carbon prepared with 3% KMnO₄ and pyrolyzed at 350 °C as a filter in an aquaponic system could improve the quality of water with pH of 7.2–7.4, DO of 9.6–13.3 mg/L, and the turbidity of 2.35–2.90 NTU. It could also reduce the content of ammonia, nitrite, and phosphate with relative removal rates of 86.84%, 73.17%, and 53.33%, respectively. These results promoted a good growth of catfish and red oak lettuce. Full article

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2021

Jump to: 2023, 2022, 2020, 2019, 2018

19 pages, 5768 KiB

Open AccessArticle

Biomass Porous Carbons Derived from Banana Peel Waste as Sustainable Anodes for Lithium-Ion Batteries

by Fernando Luna-Lama, Julián Morales and Alvaro Caballero

Materials 2021, 14(20), 5995; https://doi.org/10.3390/ma14205995 - 12 Oct 2021

Cited by 14 | Viewed by 3480

Disordered carbons derived from banana peel waste (BPW) were successfully obtained by employing a simple one-step activation/carbonization method. Different instrumental techniques were used to characterize the structural, morphological, and textural properties of the materials, including X-ray diffraction, thermogravimetric analysis, porosimetry and scanning electron [...] Read more.

Disordered carbons derived from banana peel waste (BPW) were successfully obtained by employing a simple one-step activation/carbonization method. Different instrumental techniques were used to characterize the structural, morphological, and textural properties of the materials, including X-ray diffraction, thermogravimetric analysis, porosimetry and scanning electron microscopy with energy-dispersive X-ray spectroscopy. The chemical activation with different porogens (zinc chloride, potassium hydroxide and phosphoric acid) could be used to develop functional carbonaceous structures with high specific surface areas and significant quantities of pores. The BPW@H₃PO₄ carbon exhibited a high specific surface area (815 m² g⁻¹), chemical stability and good conductivity for use as an anode in lithium-ion batteries. After 200 cycles, this carbon delivered a reversible capacity of 272 mAh g⁻¹ at 0.2 C, showing a notable retention capacity and good cycling performance even at high current densities, demonstrating its effectiveness and sustainability as an anode material for high-energy applications in Li-ion batteries. Full article

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21 pages, 5193 KiB

Open AccessArticle

CO₂ Capture by Low-Cost Date Pits-Based Activated Carbon and Silica Gel

by Mohd Danish, Vijay Parthasarthy and Mohammed K. Al Mesfer

Materials 2021, 14(14), 3885; https://doi.org/10.3390/ma14143885 - 12 Jul 2021

Cited by 5 | Viewed by 2291

The rising levels of CO₂ in the atmosphere are causing escalating average global temperatures. The capture of CO₂ by adsorption has been carried out using silica gel type III and prepared activated carbon. The date pits-based activated carbon was synthesized using [...] Read more.

The rising levels of CO₂ in the atmosphere are causing escalating average global temperatures. The capture of CO₂ by adsorption has been carried out using silica gel type III and prepared activated carbon. The date pits-based activated carbon was synthesized using a tubular furnace by physical activation. The temperature of the sample was increased at 10 °C/min and the biomass was carbonized under N₂ flow maintained continuously for 2 h at 600 °C. The activation was performed with the CO₂ flow maintained constantly for 2 h at 600 °C. The temperature, feed flow and adsorbate volume were the parameters considered for CO₂ adsorption. The success of CO₂ capture was analyzed by CO₂ uptake, efficiency based on column capacity, utilization factors and the mass transfer zone. The massively steep profiles of the breakthrough response of the AC demonstrate the satisfactory exploitation of CO₂ uptake under the conditions of the breakthrough. The SG contributed to a maximal CO₂ uptake of 8.61 mg/g at 298 K and C_o = 5% with F = 5 lpm. The enhanced CO₂ uptake of 73.1 mg/g was achieved with a column efficiency of 0.94 for the activated carbon produced from date pits at 298 K. The AC demonstrated an improved performance with a decreased mass transfer zone of 1.20 cm with an enhanced utilization factor f = 0.97 at 298 K. This finding suggests that a date pits-based activated carbon is suitable for CO₂ separation by adsorption from the feed mixture. Full article

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16 pages, 4357 KiB

Open AccessArticle

Straw-Based Activated Carbon: Optimization of the Preparation Procedure and Performance of Volatile Organic Compounds Adsorption

by Zhen Li, Yonghong Li and Jiang Zhu

Materials 2021, 14(12), 3284; https://doi.org/10.3390/ma14123284 - 14 Jun 2021

Cited by 18 | Viewed by 2615

Straw is one of the largest agricultural biowastes and a potential alternative precursor of activated carbon. Activated carbon prepared from different types of straw have great differences in structure and adsorption performance. In order to explore the performance of different straw-based activated carbon [...] Read more.

Straw is one of the largest agricultural biowastes and a potential alternative precursor of activated carbon. Activated carbon prepared from different types of straw have great differences in structure and adsorption performance. In order to explore the performance of different straw-based activated carbon in volatile organic compounds adsorption, five common straws were selected as potential source materials for the preparation of SAC. The straw-based activated carbons were prepared and characterized via a thermo-gravimetric analysis, scanning electron microscope and the Brunauer–Emmett–Teller method. Among the five straw-based activated carbons, millet straw-derived activated carbon exhibited superior properties in S_BET, S_mic and adsorption capacities of both toluene and ethyl acetate. Furthermore, the preparation process of millet straw activated carbon was optimized via response surface methodology, using carbonization temperature, carbonization time and impregnation ratio as variables and toluene adsorption capacity, ethyl acetate adsorption capacity and activated carbon yield as responses. The optimal preparation conditions include a carbonization temperature of 572 °C, carbonization time of 1.56 h and impregnation ratio (ZnCl₂/PM, w/w) of 1.60, which was verified experimentally, resulting in millet straw activated carbon with a toluene adsorption capacity of 321.9 mg/g and ethyl acetate adsorption capacity of 240.4 mg/g. Meanwhile, the adsorption isothermals and regeneration performance of millet straw activated carbon prepared under the optimized conditions were evaluated. The descriptive ability of the isothermals via the Redlich–Peterson equation suggests a heterogeneous surface on millet straw activated carbon. Recyclability testing has shown that millet straw activated carbon maintained a stable adsorption capacity throughout the second to fifth cycles. The results of this work indicate that millet straw activated carbon may be a potential volatile organic compound adsorbent for industrial application. Full article

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15 pages, 10636 KiB

Open AccessArticle

Effect of Fine Size-Fractionated Sunflower Husk Biochar on Water Retention Properties of Arable Sandy Soil

by Łukasz Gluba, Anna Rafalska-Przysucha, Kamil Szewczak, Mateusz Łukowski, Radosław Szlązak, Justína Vitková, Rafał Kobyłecki, Zbigniew Bis, Michał Wichliński, Robert Zarzycki, Andrzej Kacprzak and Bogusław Usowicz

Materials 2021, 14(6), 1335; https://doi.org/10.3390/ma14061335 - 10 Mar 2021

Cited by 23 | Viewed by 2766

Biochar application has been reported to improve the physical, chemical, and hydrological properties of soil. However, the information about the size fraction composition of the applied biochar as a factor that may have an impact on the properties of soil-biochar mixtures is often [...] Read more.

Biochar application has been reported to improve the physical, chemical, and hydrological properties of soil. However, the information about the size fraction composition of the applied biochar as a factor that may have an impact on the properties of soil-biochar mixtures is often underappreciated. Our research shows how sunflower husk biochar (pyrolyzed at 650 °C) can modify the water retention characteristics of arable sandy soil depending on the biochar dose (up to 9.52 wt.%) and particle size (<50 µm, 50–100 µm, 100–250 µm). For comparison, we used soil samples mixed with biochar passed through 2 mm sieve and an unamended reference. The addition of sieved biochar to the soil caused a 30% increase in the available water content (AWC) in comparing to the soil without biochar. However, the most notable improvement (doubling the reference AWC value from 0.078 m³ m⁻³ to 0.157 m³ m⁻³) was observed at the lowest doses of biochar (0.95 and 2.24 wt.%) and for the finest size fractions (below 100 µm). The water retention effects on sandy soil are explained as the interplay between the dose, the size of biochar particles, and the porous properties of biochar fractions. Full article

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2020

Jump to: 2023, 2022, 2021, 2019, 2018

21 pages, 4812 KiB

Open AccessArticle

Utilization of Jujube Biomass to Prepare Biochar by Pyrolysis and Activation: Characterization, Adsorption Characteristics, and Mechanisms for Nitrogen

by Di Zhang, Tongtong Wang, Jinhu Zhi, Qiangqing Zheng, Qiling Chen, Cong Zhang and Yalong Li

Materials 2020, 13(24), 5594; https://doi.org/10.3390/ma13245594 - 08 Dec 2020

Cited by 19 | Viewed by 2597

The rapid advancement of jujube industry has produced a large amount of jujube biomass waste, requiring the development of new methods for utilization of jujube resources. Herein, medium-temperature pyrolysis is employed to produce carbon materials from jujube waste in an oxygen-free environment. Ten [...] Read more.

The rapid advancement of jujube industry has produced a large amount of jujube biomass waste, requiring the development of new methods for utilization of jujube resources. Herein, medium-temperature pyrolysis is employed to produce carbon materials from jujube waste in an oxygen-free environment. Ten types of jujube biochar (JB) are prepared by modifying different pyrolysis parameters, followed by physical activation. The physicochemical properties of JB are systematically characterized, and the adsorption characteristics of JB for NO₃⁻ and NH₄⁺ are evaluated via batch adsorption experiments. Furthermore, the pyrolysis and adsorption mechanisms are discussed. The results indicate that the C content, pH, and specific surface area of JB increase with an increase in the pyrolysis temperature from 300 °C to 700 °C, whereas the O and N contents, yield, zeta potential, and total functional groups of JB decrease gradually. The pyrolysis temperature more significantly effects the biochar properties than pyrolysis time. JB affords the highest adsorption capacity for NO₃⁻ (21.17 mg·g⁻¹) and NH₄⁺ (30.57 mg·g⁻¹) at 600 °C in 2 h. The Langmuir and pseudo-second-order models suitably describe the isothermal and kinetic adsorption processes, respectively. The NO₃⁻ and NH₄⁺ adsorption mechanisms of JB may include surface adsorption, intraparticle diffusion, electrostatic interaction, and ion exchange. In addition, π–π interaction and surface complexation may also be involved in NH₄⁺ adsorption. The pyrolysis mechanism comprises the combination of hemicellulose, cellulose, and lignin decomposition involving three stages. This study is expected to provide a theoretical and practical basis for the efficient utilization of jujube biomass to develop eco-friendly biochar and nitrogenous wastewater pollution prevention. Full article

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12 pages, 4254 KiB

Open AccessArticle

Graphite Nanoplatelets from Waste Chicken Feathers

by Bryan Pajarito, Amelia Jane Belarmino, Rizza Mae Calimbas and Jillian Rae Gonzales

Materials 2020, 13(9), 2109; https://doi.org/10.3390/ma13092109 - 02 May 2020

Cited by 5 | Viewed by 3286

Graphite nanoplatelets (GNPs), a functional 2D nanofiller for polymer nanocomposites, utilize natural graphite as a raw material due to its stacked graphene layers and outstanding material properties upon successful exfoliation into nano-thick sheets. However, the increasing demand for natural graphite in many industrial [...] Read more.

Graphite nanoplatelets (GNPs), a functional 2D nanofiller for polymer nanocomposites, utilize natural graphite as a raw material due to its stacked graphene layers and outstanding material properties upon successful exfoliation into nano-thick sheets. However, the increasing demand for natural graphite in many industrial applications necessitates the use of graphite from waste resources. We synthesized GNPs from waste chicken feathers (WCFs) by graphitizing carbonized chicken feathers and exfoliating the graphitic carbon by high-speed homogenization and sonication. We then separated GNP from non-exfoliated carbon by centrifugation. This paper describes the morphology, chemical, and crystalline properties of WCF and its carbon derivatives, as well as the structural features of WCF-derived carbons. We obtained GNPs that have a 2D structure with huge variations in particle size and thickness. The GNP shows the presence of carbonyl groups, which are mostly attached at the edges of the stacked graphene sheets. Defects in the GNP are higher than in graphene synthesized from direct exfoliation of natural graphite but lower than in graphene oxide and reduced graphene oxide. To produce GNP of high quality from WCF, restacking of graphene sheets and concentration of carbonyls must be minimized. Full article

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14 pages, 463 KiB

Open AccessArticle

Characterization of Chemically Activated Carbons Prepared from Miscanthus and Switchgrass Biomass

by Beata Doczekalska, Monika Bartkowiak, Bogusława Waliszewska, Grażyna Orszulak, Joanna Cerazy-Waliszewska and Tomasz Pniewski

Materials 2020, 13(7), 1654; https://doi.org/10.3390/ma13071654 - 02 Apr 2020

Cited by 23 | Viewed by 2454

Lignocellulosic biomass, including that of energy crops, can be an alternative source to produce activated carbons (ACs). Miscanthus and switchgrass straw were used to produce ACs in a two-step process. Crushed plant material was carbonized at 600 °C and then obtained carbon was [...] Read more.

Lignocellulosic biomass, including that of energy crops, can be an alternative source to produce activated carbons (ACs). Miscanthus and switchgrass straw were used to produce ACs in a two-step process. Crushed plant material was carbonized at 600 °C and then obtained carbon was activated using NaOH or KOH at 750 °C. The content of surface oxygen groups was determined using Boehm’s method. The porosity of ACs was assayed using the nitrogen adsorption/desorption technique, while their thermal resistance using the thermogravimetric method. The ACs derived from miscanthus and switchgrass were characterized by surfaces rich in chemical groups and a highly developed porous structure. The highest specific surface areas, over 1600 m²/g, were obtained after carbon treatment with NaOH. High values of iodine number, 1200–1240 mg/g, indicate an extensive system of micropores and their good adsorption properties. The type of activator affected the contents of oxygen functional groups and some porosity parameters as well as thermal stability ranges of the ACs. Among obtained carbons, the highest quality was found for these derived from M. sacchariflorus followed by switchgrass, after activation with NaOH. Hence, while these crop species are not as effective biomass sources as other energy grasses, they can become valuable feedstocks for ACs. Full article

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13 pages, 2989 KiB

Open AccessArticle

Biochars from Lignin-rich Residue of Furfural Manufacturing Process for Heavy Metal Ions Remediation

by Baobin Wang, Miao Ran, Guigan Fang, Ting Wu and Yonghao Ni

Materials 2020, 13(5), 1037; https://doi.org/10.3390/ma13051037 - 25 Feb 2020

Cited by 14 | Viewed by 3354

The pentose/furfural industrial manufacturing process uses corn cob residue as a raw material, where such a process yields significant amount of lignin-rich residue (LCR) at the end, which is commonly disposed by burning. In this study, the conversion of LCR to biochars (BCs), [...] Read more.

The pentose/furfural industrial manufacturing process uses corn cob residue as a raw material, where such a process yields significant amount of lignin-rich residue (LCR) at the end, which is commonly disposed by burning. In this study, the conversion of LCR to biochars (BCs), and their subsequent applications for heavy metal ion removal, were investigated. The BCs were prepared through hydrothermal carbonization and post-activation, using either ZnCl₂ or H₃PO₄ treatment. The as-prepared activated BCs were characterized using N₂ adsorption–desorption isotherms, XRD, FT-IR, SEM and TEM, and their performance in removing heavy metal ions (Pb²⁺, Cu²⁺, Cd²⁺) from aqueous solutions was assessed. The ZnCl₂-activated BCs (BC-ZnCl₂) exhibit a higher adsorption capacity than the H₃PO₄-activated BCs (BC-H₃PO₄), mainly due to the differences in their chemical/physical characteristics. The related adsorption kinetics and isotherms were analyzed. Full article

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14 pages, 5969 KiB

Open AccessArticle

Synthesis of Fe/Mg-Biochar Nanocomposites for Phosphate Removal

by Xuefeng Tao, Tao Huang and Bo Lv

Materials 2020, 13(4), 816; https://doi.org/10.3390/ma13040816 - 11 Feb 2020

Cited by 27 | Viewed by 2747

Magnetic biochar derived from agricultural biomass has been recognized as a cost-effective biochar sorbent for phosphate removal. This study evaluated the use of novel Fe/Mg-biochar nanocomposites (WBC1x), prepared by impregnating ground walnut shell in a solution with a different molar ratio of Fe [...] Read more.

Magnetic biochar derived from agricultural biomass has been recognized as a cost-effective biochar sorbent for phosphate removal. This study evaluated the use of novel Fe/Mg-biochar nanocomposites (WBC1x), prepared by impregnating ground walnut shell in a solution with a different molar ratio of Fe²⁺ to Mg²⁺, then pyrolyzing slowly, at a temperature of 600 °C, to remove phosphate. The results showed that MgO and Fe₃O₄ were loaded onto the biochar successfully through the impregnation-pyrolysis method and the composites were able to be separated easily by magnetic field. Meanwhile, a higher surface area and point of zero charge on WBC1x were observed compared to the non-magnetic biochar (WBC). Moreover, the isothermal adsorption and kinetics data further suggested the that phosphate adsorption onto WBC1x resulted from chemisorption. Additionally, the maximum phosphate adsorption capacity of WBC1x was 6.9 mg.g⁻¹, obtained though the Langmuir–Freundlich model, which was threefold higher than WBC, where MgO addition could enhance the adsorption capacity of WBC1x markedly by improving the surface charge. Full article

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2019

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26 pages, 9427 KiB

Open AccessArticle

Oxytree Pruned Biomass Torrefaction: Mathematical Models of the Influence of Temperature and Residence Time on Fuel Properties Improvement

by Kacper Świechowski, Marek Liszewski, Przemysław Bąbelewski, Jacek A. Koziel and Andrzej Białowiec

Materials 2019, 12(14), 2228; https://doi.org/10.3390/ma12142228 - 10 Jul 2019

Cited by 19 | Viewed by 3680

Biowaste generated in the process of Oxytree cultivation and logging represents a potential source of energy. Torrefaction (a.k.a. low-temperature pyrolysis) is one of the methods proposed for the valorization of woody biomass. Still, energy is required for the torrefaction process during which the [...] Read more.

Biowaste generated in the process of Oxytree cultivation and logging represents a potential source of energy. Torrefaction (a.k.a. low-temperature pyrolysis) is one of the methods proposed for the valorization of woody biomass. Still, energy is required for the torrefaction process during which the raw biomass becomes torrefied biomass with fuel properties similar to those of lignite coal. In this work, models describing the influence of torrefaction temperature and residence time on the resulting fuel properties (mass and energy yields, energy densification ratio, organic matter and ash content, combustible parts, lower and higher heating values, CHONS content, H:C and O:C ratios) were proposed according to the Akaike criterion. The degree of the models’ parameters matching the raw data expressed as the determination coefficient (R²) ranged from 0.52 to 0.92. Each model parameter was statistically significant (p < 0.05). Estimations of the value and quantity of the produced torrefied biomass from 1 Mg of biomass residues were made based on two models and a set of simple assumptions. The value of torrefied biomass (€123.4·Mg⁻¹) was estimated based on the price of commercially available coal fuel and its lower heating value (LHV) for biomass moisture content of 50%, torrefaction for 20 min at 200 °C. This research could be useful to inform techno-economic analyses and decision-making process pertaining to the valorization of pruned biomass residues. Full article

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33 pages, 4689 KiB

Open AccessArticle

Conductive Carbon Materials from the Hydrothermal Carbonization of Vineyard Residues for the Application in Electrochemical Double-Layer Capacitors (EDLCs) and Direct Carbon Fuel Cells (DCFCs)

by Viola Hoffmann, Dennis Jung, Joscha Zimmermann, Catalina Rodriguez Correa, Amal Elleuch, Kamel Halouani and Andrea Kruse

Materials 2019, 12(10), 1703; https://doi.org/10.3390/ma12101703 - 26 May 2019

Cited by 47 | Viewed by 6623

This study investigates the production of bio-based carbon materials for energy storage and conversion devices based on two different vineyard residues (pruning, pomace) and cellulose as a model biomass. Three different char categories were produced via pyrolysis at 900 °C for 2 h [...] Read more.

This study investigates the production of bio-based carbon materials for energy storage and conversion devices based on two different vineyard residues (pruning, pomace) and cellulose as a model biomass. Three different char categories were produced via pyrolysis at 900 °C for 2 h (biochars, BC), hydrothermal carbonization (HTC) (at 220, 240 or 260 °C) with different reaction times (60, 120 or 300 min) (hydrochars, HC), or HTC plus pyrolysis (pyrolyzed hydrochars, PHC). Physicochemical, structural, and electrical properties of the chars were assessed by elemental and proximate analysis, gas adsorption surface analysis with N₂ and CO₂, compression ratio, bulk density, and electrical conductivity (EC) measurements. Thermogravimetric analysis allowed conclusions to be made about the thermochemical conversion processes. Taking into consideration the required material properties for the application in electrochemical double-layer capacitors (EDLC) or in a direct carbon fuel cell (DCFC), the suitability of the obtained materials for each application is discussed. Promising materials with surface areas up to 711 m² g⁻¹ and presence of microporosity have been produced. It is shown that HTC plus pyrolysis from cellulose and pruning leads to better properties regarding aromatic carbon structures, carbon content (>90 wt.%), EC (up to 179 S m⁻¹), and porosity compared to one-step treatments, resulting in suitable materials for an EDLC application. The one-step pyrolysis process and the resulting chars with lower carbon contents and low EC values between 51 and 56 S m⁻¹ are preferred for DCFC applications. To conclude, biomass potentials can be exploited by producing tailored biomass-derived carbon materials via different carbonization processes for a wide range of applications in the field of energy storage and conversion. Full article

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14 pages, 4594 KiB

Open AccessArticle

Effect of Air Oxidation on Texture, Surface Properties and Dye Adsorption of Wood-Derived Porous Carbon Materials

by Suhong Ren, Liping Deng, Bo Zhang, Yafang Lei, Haiqing Ren, Jianxiong Lv, Rongjun Zhao and Xiufang Chen

Materials 2019, 12(10), 1675; https://doi.org/10.3390/ma12101675 - 23 May 2019

Cited by 12 | Viewed by 2887

Hierarchical porous carbon materials made from cork were fabricated using a facile and green method combined with air activation, without any templates and chemical agents. The influence of air activation on the texture and other surface characteristics of the carbon materials were evaluated [...] Read more.

Hierarchical porous carbon materials made from cork were fabricated using a facile and green method combined with air activation, without any templates and chemical agents. The influence of air activation on the texture and other surface characteristics of the carbon materials were evaluated by various characterization techniques. Results indicate that air oxidation can effectively improve the surface area and the hierarchical porous structure of carbon materials, as well as increase the number of oxygen-containing functional groups on the carbon surface. The specific surface area and the pore volume of the carbon material activated by air at 450 °C (C800-M450) can reach 580 m²/g and 0.379 cm³/g, respectively. These values are considerably higher than those for the non-activated material (C800, 376 m²/g, 0.201 cm³/g). The contents of the functional groups (C–O, C=O and O–H) increased with rising activation temperature. After air activation, the adsorption capacity of the carbon materials for methylene blue (MB) and methyl orange (MO) was increased from 7.7 and 6.4 mg/g for C800 to 312.5 and 97.1 mg/g for C800-M450, respectively. The excellent dye removal of the materials suggests that the porous carbon obtained from biomass can be potentially used for wastewater treatment. Full article

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11 pages, 6902 KiB

Open AccessArticle

Preparation of Lignin-Based Carbon Materials and Its Application as a Sorbent

by Ling-Yan Meng, Ming-Guo Ma and Xing-Xiang Ji

Materials 2019, 12(7), 1111; https://doi.org/10.3390/ma12071111 - 03 Apr 2019

Cited by 17 | Viewed by 4039

The purpose of this article was to explore the influences of synthetic methods on the lignin-based carbon materials. In this paper, the lignin-based activated carbon materials were comparatively researched in ZnCl₂ solution using various methods, including the microwave-assisted method, ultrasound method, and [...] Read more.

The purpose of this article was to explore the influences of synthetic methods on the lignin-based carbon materials. In this paper, the lignin-based activated carbon materials were comparatively researched in ZnCl₂ solution using various methods, including the microwave-assisted method, ultrasound method, and UV irradiation method, respectively. Scanning electron microscopy (SEM), Fourier transform infrared spectrometry (FT-IR), thermogravimetric analysis (TGA), and differential thermal analysis (DTA) were used to characterize the as-prepared samples. The effects of the synthetic parameters including the types of lignin, activated solution concentration, types of activated solution, and synthetic methods on the morphologies, thermal stability, and specific surface area of samples were comparatively investigated in detail. The specific surface area of lignin-based activated carbon increased to 473.8, 765.3, and 211.2 m²∙g⁻¹ using the microwave-assisted method, ultrasound method, and UV irradiation method, respectively, compared with that of the control (113.4 m²∙g⁻¹). The lignin-based carbon materials displayed the enhanced absorptive capacity, compared with that of the control. These novel synthetic methods reported here maybe have a guiding significance for the synthesis of carbon materials using the lignin as precursors. Full article

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12 pages, 2053 KiB

Open AccessArticle

Accelerated Microbial Reduction of Azo Dye by Using Biochar from Iron-Rich-Biomass Pyrolysis

by Wenbing Tan, Lei Wang, Hanxia Yu, Hui Zhang, Xiaohui Zhang, Yufu Jia, Tongtong Li, Qiuling Dang, Dongyu Cui and Beidou Xi

Materials 2019, 12(7), 1079; https://doi.org/10.3390/ma12071079 - 02 Apr 2019

Cited by 12 | Viewed by 2736

Biochar is widely used in the environmental-protection field. This study presents the first investigation of the mechanism of biochar prepared using iron (Fe)-rich biomass and its impact on the reductive removals of Orange G dye by Shewanella oneidensis MR-1. The results show that [...] Read more.

Biochar is widely used in the environmental-protection field. This study presents the first investigation of the mechanism of biochar prepared using iron (Fe)-rich biomass and its impact on the reductive removals of Orange G dye by Shewanella oneidensis MR-1. The results show that biochars significantly accelerated electron transfer from cells to Orange G and thus stimulated reductive removal rate to 72–97%. Both the conductive domains and the charging and discharging of surface functional groups in biochars played crucial roles in the microbial reduction of Orange G to aniline. A high Fe content of the precursor significantly enhanced the conductor performance of the produced biochar and thus enabled the biochar to have a higher reductive removal rate of Orange G (97%) compared to the biochar prepared using low-Fe precursor (75%), but did not promote the charging and discharging capacity of the produced biochar. This study can prompt the search for natural biomass with high Fe content to confer the produced biochar with wide-ranging applications in stimulating the microbial reduction of redox-active pollutants. Full article

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19 pages, 5130 KiB

Open AccessArticle

Microwave Hydrothermal Carbonization of Rice Straw: Optimization of Process Parameters and Upgrading of Chemical, Fuel, Structural and Thermal Properties

by Sabzoi Nizamuddin, Sundus Saeed Qureshi, Humair Ahmed Baloch, Muhammad Tahir Hussain Siddiqui, Pooja Takkalkar, Nabisab Mujawar Mubarak, Deepa K. Dumbre, Gregory J. Griffin, Srinivasan Madapusi and Akshat Tanksale

Materials 2019, 12(3), 403; https://doi.org/10.3390/ma12030403 - 28 Jan 2019

Cited by 46 | Viewed by 6170

The process parameters of microwave-induced hydrothermal carbonization (MIHTC) play an important role on the hydrothermal chars (hydrochar) yield. The effect of reaction temperature, reaction time, particle size and biomass to water ratio was optimized for hydrochar yield by modeling using the central composite [...] Read more.

The process parameters of microwave-induced hydrothermal carbonization (MIHTC) play an important role on the hydrothermal chars (hydrochar) yield. The effect of reaction temperature, reaction time, particle size and biomass to water ratio was optimized for hydrochar yield by modeling using the central composite design (CCD). Further, the rice straw and hydrochar at optimum conditions have been characterized for energy, chemical, structural and thermal properties. The optimum condition for hydrochar synthesis was found to be at a 180 °C reaction temperature, a 20 min reaction time, a 1:15 weight per volume (w/v) biomass to water ratio and a 3 mm particle size, yielding 57.9% of hydrochar. The higher heating value (HHV), carbon content and fixed carbon values increased from 12.3 MJ/kg, 37.19% and 14.37% for rice straw to 17.6 MJ/kg, 48.8% and 35.4% for hydrochar. The porosity, crystallinity and thermal stability of the hydrochar were improved remarkably compared to rice straw after MIHTC. Two characteristic peaks from XRD were observed at 2θ of 15° and 26°, whereas DTG peaks were observed at 50–150 °C and 300–350 °C for both the materials. Based on the results, it can be suggested that the hydrochar could be potentially used for adsorption, carbon sequestration, energy and agriculture applications. Full article

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17 pages, 4805 KiB

Open AccessArticle

Preparation and Characterization of Nanoporous Activated Carbon Derived from Prawn Shell and Its Application for Removal of Heavy Metal Ions

by Jian Guo, Yaqin Song, Xiaoyang Ji, Lili Ji, Lu Cai, Yaning Wang, Hailong Zhang and Wendong Song

Materials 2019, 12(2), 241; https://doi.org/10.3390/ma12020241 - 12 Jan 2019

Cited by 77 | Viewed by 7044

The aim of this study was to optimize the adsorption performance of activated carbon (AC), derived from the shell of Penaeus vannamei prawns, on heavy metal ions. Inexpensive, non-toxic, and renewable prawn shells were subjected to carbonization and, subsequently, KOH-activation to produce nanoporous [...] Read more.

The aim of this study was to optimize the adsorption performance of activated carbon (AC), derived from the shell of Penaeus vannamei prawns, on heavy metal ions. Inexpensive, non-toxic, and renewable prawn shells were subjected to carbonization and, subsequently, KOH-activation to produce nanoporous K-Ac. Carbonized prawn shells (CPS) and nanoporous KOH-activated carbon (K-Ac) from prawn shells were prepared and characterized by FTIR, XRD, BET, SEM, and TEM. The results showed that as-produced K-Ac samples were a porous material with microporous and mesoporous structures and had a high specific surface area of 3160 m²/g, average pore size of about 10 nm, and large pore volume of 2.38 m³/g. Furthermore, batches of K-Ac samples were employed for testing the adsorption behavior of Cd²⁺ in solution. The effects of pH value, initial concentration, and adsorption time on Cd²⁺ were systematically investigated. Kinetics and isotherm model analysis of the adsorption of Cd²⁺ on K-Ac showed that experimental data were not only consistent with the Langmuir adsorption isotherm, but also well-described by the quasi-first-order model. Finally, the adsorption behaviors of as-prepared K-Ac were also tested in a ternary mixture of heavy metal ions Cu²⁺, Cr⁶⁺, and Cd²⁺, and the total adsorption amount of 560 mg/g was obtained. Full article

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2018

Jump to: 2023, 2022, 2021, 2020, 2019

15 pages, 4588 KiB

Open AccessArticle

Synthesis and Characterization of Novel Fe-Mn-Ce Ternary Oxide–Biochar Composites as Highly Efficient Adsorbents for As(III) Removal from Aqueous Solutions

by Xuewei Liu, Guogang Zhang, Lina Lin, Zulqarnain Haider Khan, Weiwen Qiu and Zhengguo Song

Materials 2018, 11(12), 2445; https://doi.org/10.3390/ma11122445 - 03 Dec 2018

Cited by 14 | Viewed by 3450

The widespread pollution of water bodies with arsenic (As) necessitates the development of efficient decontamination techniques. To address this issue, we herein prepare Fe-Mn-Ce ternary oxide-biochar composites (FMCBCs) using impregnation/sintering methods and examined their physicochemical properties, morphologies, and As(III) removal performances. The specific [...] Read more.

The widespread pollution of water bodies with arsenic (As) necessitates the development of efficient decontamination techniques. To address this issue, we herein prepare Fe-Mn-Ce ternary oxide-biochar composites (FMCBCs) using impregnation/sintering methods and examined their physicochemical properties, morphologies, and As(III) removal performances. The specific surface area of FMCBCs increased with increasing Ce content and enhanced the quantity of surface functional groups (–OH, –COOH). The adsorption of As(III) on FMCBCs was well represented by pseudo-second-order kinetics, and the As(III) adsorption capacity of the best-performing FMCBCs (8.47 mg g⁻¹ for FMCBC₃) exceeded that of BC by a factor of 2.9. At pH = 3, the amount of adsorption of As(III) by FMCBCs reached a maximum, and the increased ionic strength could enhance adsorption capacity of FMCBCs. Moreover, an As(III) removal efficiency of ~99% was observed for FMCBC₃ at a dosage of 8 g L⁻¹, which highlighted its great potential as an absorbent for As(III) removal from contaminated water. Full article

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34 pages, 3964 KiB

Open AccessReview

Biobased Functional Carbon Materials: Production, Characterization, and Applications—A Review

by Catalina Rodriguez Correa and Andrea Kruse

Materials 2018, 11(9), 1568; https://doi.org/10.3390/ma11091568 - 31 Aug 2018

Cited by 59 | Viewed by 7734

Even though research on porous carbon materials from biomass dates back to at least hundred years, it is still an extremely relevant topic. These materials can be found in applications that range from those that are widely known, such as water treatment, to [...] Read more.

Even though research on porous carbon materials from biomass dates back to at least hundred years, it is still an extremely relevant topic. These materials can be found in applications that range from those that are widely known, such as water treatment, to others that are newer and indispensable for the transition towards environmentally friendly technologies, such as lithium- and sodium-ion batteries. This review summarizes some of the most relevant research that has been published concerning production technologies, insights on the chemical reaction mechanisms, characterization techniques, as well as some examples of the applications and the properties that the carbon materials must fulfil to be used in those applications. Full article

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15 pages, 2250 KiB

Open AccessArticle

Almond Shell as a Microporous Carbon Source for Sustainable Cathodes in Lithium–Sulfur Batteries

by Almudena Benítez, Marcos González-Tejero, Álvaro Caballero and Julián Morales

Materials 2018, 11(8), 1428; https://doi.org/10.3390/ma11081428 - 14 Aug 2018

Cited by 42 | Viewed by 8893

A microporous carbon derived from biomass (almond shells) and activated with phosphoric acid was analysed as a cathodic matrix in Li–S batteries. By studying the parameters of the carbonization process of this biomass residue, certain conditions were determined to obtain a high surface [...] Read more.

A microporous carbon derived from biomass (almond shells) and activated with phosphoric acid was analysed as a cathodic matrix in Li–S batteries. By studying the parameters of the carbonization process of this biomass residue, certain conditions were determined to obtain a high surface area of carbon (967 m² g⁻¹) and high porosity (0.49 cm³ g⁻¹). This carbon was capable of accommodating up to 60% by weight of sulfur, infiltrated by the disulphide method. The C–S composite released an initial specific capacity of 915 mAh g⁻¹ in the Li–S cell at a current density of 100 mA g⁻¹ with a high retention capacity of 760 mAh g⁻¹ after 100 cycles and a coulombic efficiency close to 100%. The good performance of the composite was also observed under higher current rates (up to 1000 mA g⁻¹). The overall electrochemical behaviour of this microporous carbon acting as a sulfur host reinforces the possibility of using biomass residues as sustainable sources of materials for energy storage. Full article

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15 pages, 5440 KiB

Open AccessArticle

Sequential Production of Levulinic Acid and Porous Carbon Material from Cellulose

by Shimin Kang, Jiaming Pan, Guoting Gu, Chong Wang, Zepan Wang, Jionghao Tan and Guiheng Liu

Materials 2018, 11(8), 1408; https://doi.org/10.3390/ma11081408 - 11 Aug 2018

Cited by 8 | Viewed by 3512

A sequential production of levulinic acid (LA) and porous carbon material (CM) from cellulose was conducted by a two-step process. The cellulose was first acid hydrolyzed, and the preferred reaction conditions required a severity factor of 4.0–4.5, in which the yields of LA, [...] Read more.

A sequential production of levulinic acid (LA) and porous carbon material (CM) from cellulose was conducted by a two-step process. The cellulose was first acid hydrolyzed, and the preferred reaction conditions required a severity factor of 4.0–4.5, in which the yields of LA, formic acid, and solid residue were 38 ± 3 wt%, 17 ± 3 wt%, and 15 ± 3 wt%, respectively. The solid residue was further used for CM preparation through pyrolysis, with or without ZnCl₂ activation. The ZnCl₂ activation promoted the formation of CMs with improved thermal stability, high surface area (1184–2510 m²/g), and excellent phenol adsorption capacity (136–172 mg/g). The used CM can be easily regenerated by a simple methanol Soxhlet extraction process, and a comparable phenol adsorption capacity of 97 mg/g was maintained for the 5th reusing. Finally, 100 g cellulose produced 40.5 g LA, 18.9 g formic acid and 8.5 g porous CM, with a total carbon utilization ratio reaching 74.4%. Full article

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11 pages, 2229 KiB

Open AccessArticle

Biomass-Derived Nitrogen-Doped Carbon Aerogel Counter Electrodes for Dye Sensitized Solar Cells

by Mira Tul Zubaida Butt, Kathrin Preuss, Maria-Magdalena Titirici, Habib Ur Rehman and Joe Briscoe

Materials 2018, 11(7), 1171; https://doi.org/10.3390/ma11071171 - 09 Jul 2018

Cited by 23 | Viewed by 4585

Dye sensitized solar cells have emerged as an attractive alternative to conventional solar cells due to their easy processing and the abundance and low cost of their materials. However, the counter electrode in these cells employs platinum which significantly impacts their cost. Here, [...] Read more.

Dye sensitized solar cells have emerged as an attractive alternative to conventional solar cells due to their easy processing and the abundance and low cost of their materials. However, the counter electrode in these cells employs platinum which significantly impacts their cost. Here, we report biomass-derived, nitrogen-doped carbon aerogel as an effective alternative to conventional platinum-based counter electrodes for dye sensitized solar cells. A stable suspension of biomass-derived, nitrogen-doped carbon aerogel was prepared in DMF by using oleylamine as a binder. The nitrogen-doped carbon aerogel electrode was annealed at different temperatures, and its impact on photovoltaic performance is investigated. I-V measurements confirm that the annealing temperature substantially enhances the photovoltaic parameters of these devices; these enhancements are linked to the removal of the organic binders. Electrochemical impedance spectra of the counter electrodes confirm that removal of oleylamine in nitrogen-doped carbon aerogels reduces the series resistance of the resulting electrodes. The power conversion efficiency of the solar cells from optimized nitrogen-doped carbon aerogel exhibited comparable efficiency to that of a cell fabricated using a platinum-based counter electrode. This study demonstrates the potential of biomass-derived carbon aerogels as a cheap and sustainable replacement of platinum in DSSCs. Full article

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15 pages, 30722 KiB

Open AccessArticle

Wheat Straw-Derived N-, O-, and S-Tri-doped Porous Carbon with Ultrahigh Specific Surface Area for Lithium-Sulfur Batteries

by Feng Chen, Lulu Ma, Jiangang Ren, Mou Zhang, Xinyu Luo, Bing Li, Zhiming Song and Xiangyang Zhou

Materials 2018, 11(6), 989; https://doi.org/10.3390/ma11060989 - 11 Jun 2018

Cited by 28 | Viewed by 4272

Recently, lithium-sulfur (Li-S) batteries have been greeted by a huge ovation owing to their very high theoretical specific capacity (1675 mAh·g⁻¹) and theoretical energy density (2600 Wh·kg⁻¹). However, the full commercialization of Li-S batteries is still hindered by dramatic [...] Read more.

Recently, lithium-sulfur (Li-S) batteries have been greeted by a huge ovation owing to their very high theoretical specific capacity (1675 mAh·g⁻¹) and theoretical energy density (2600 Wh·kg⁻¹). However, the full commercialization of Li-S batteries is still hindered by dramatic capacity fading resulting from the notorious “shuttle effect” of polysulfides. Herein, we first describe the development of a facile, inexpensive, and high-producing strategy for the fabrication of N-, O-, and S-tri-doped porous carbon (NOSPC) via pyrolysis of natural wheat straw, followed by KOH activation. The as-obtained NOSPC shows characteristic features of a highly porous carbon frame, ultrahigh specific surface area (3101.8 m²·g⁻¹), large pore volume (1.92 cm³·g⁻¹), good electrical conductivity, and in situ nitrogen (1.36 at %), oxygen (7.43 at %), and sulfur (0.7 at %) tri-doping. The NOSPC is afterwards selected to fabricate the NOSPC-sulfur (NOSPC/S) composite for the Li-S batteries cathode material. The as-prepared NOSPC/S cathode delivers a large initial discharge capacity (1049.2 mAh·g⁻¹ at 0.2 C), good cycling stability (retains a reversible capacity of 454.7 mAh·g⁻¹ over 500 cycles at 1 C with a low capacity decay of 0.088% per cycle), and superior rate performance (619.2 mAh·g⁻¹ at 2 C). The excellent electrochemical performance is mainly attributed to the synergistic effects of structural restriction and multidimensional chemical adsorptions for cooperatively repressing the polysulfides shuttle. Full article

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10 pages, 4463 KiB

Open AccessArticle

Fabrication of α-Fe/Fe₃C/Woodceramic Nanocomposite with Its Improved Microwave Absorption and Mechanical Properties

by Weihong Zhou, Yunshui Yu, Xueliang Xiong and Sicong Zhou

Materials 2018, 11(6), 878; https://doi.org/10.3390/ma11060878 - 24 May 2018

Cited by 22 | Viewed by 3718

Furan resin and fir powder pretreated by FeCl₃ and aqueous ammonia solution were used to fabricate α-Fe/Fe₃C/woodceramic nanocomposite. The bands of the pretreated wood powder were characterized by Fourier transform infrared spectroscopy (FTIR). The structural characterization of the nanocomposites was [...] Read more.

Furan resin and fir powder pretreated by FeCl₃ and aqueous ammonia solution were used to fabricate α-Fe/Fe₃C/woodceramic nanocomposite. The bands of the pretreated wood powder were characterized by Fourier transform infrared spectroscopy (FTIR). The structural characterization of the nanocomposites was performed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The microwave absorption of the nanocomposites was measured by a vector network analyzer in the range of 2–18 GHz. The mechanical properties of the composites were also investigated. XRD and SEM results show that the α-Fe and Fe₃C nanoparticles are in-situ generated and disperse in the matrix of the woodceramic. The diameters of these nanoparticles increase with the increasing of concentration of FeCl₃ solution. The experimental results show that both the complex permittivity and the complex permeability of α-Fe/Fe₃C/woodceramic nanocomposites increase as the concentration of FeCl₃ solution increases. The composites pretreated with 0.60 mol·L⁻¹ FeCl₃ have the best absorption properties. The maximum value of reflection loss (RL) at 3 mm thickness reaches −25.60 dB at 10.16 GHz and the bandwidth below −10 dB is about 2.5 GHz. Compared to woodceramic, the bending strength and compressive strength of α-Fe/Fe₃C/woodceramic nanocomposites increase by 22.5% and 18.7% at most, respectively. Full article

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8 pages, 3930 KiB

Open AccessArticle

Porous Structure Properties of Andropogon gerardi Derived Carbon Materials

by Natalia Howaniec and Adam Smoliński

Materials 2018, 11(6), 876; https://doi.org/10.3390/ma11060876 - 24 May 2018

Cited by 7 | Viewed by 2747

Various carbonaceous materials are valuable resources for thermochemical conversion processes and for production of materials of proven sorption properties, useful in environmental applications for gaseous and liquid media treatment. In both cases, the parameters of the porous structure of carbon materials are decisive [...] Read more.

Various carbonaceous materials are valuable resources for thermochemical conversion processes and for production of materials of proven sorption properties, useful in environmental applications for gaseous and liquid media treatment. In both cases, the parameters of the porous structure of carbon materials are decisive in terms of their physical and mechanical properties, having direct effects on heat and mass transport as well as on sorption capacity and selectivity. The physical activation of carbon materials produced from various precursors is widely discussed in literature. In this respect, the effects of temperature and partial oxidation of carbonaceous materials with steam or carbon dioxide are mostly considered. The reports on the effects of pressure on the development of porous structures of carbon materials are, however, extremely limited, especially when biomass as a precursor is concerned. In this paper, the results of an experimental study on the effects of pressure in the range of 1–4 MPa on the specific surface area, the total pore volume, average pore diameter, and microporosity of carbon materials prepared with the use of Andropogon gerardi biomass as a precursor are presented. The tested samples were prepared at the temperature of 1000 °C under an inert gas atmosphere in the high-pressure thermogravimetric analyzer. The most developed porous structure was reported for carbon materials produced under 3 MPa. The highest volume of narrow micropores was characteristic for materials carbonized under 2 MPa. Full article

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