Biochar and Biochar Composites: Preparation, Modification and Environmental Application

A special issue of Processes (ISSN 2227-9717). This special issue belongs to the section "Materials Processes".

Deadline for manuscript submissions: closed (20 October 2023) | Viewed by 8623

Special Issue Editors


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Guest Editor
Department of Agronomy, Federal University of Viçosa, Viçosa 36.570-900, Brazil
Interests: weed management; behavior of herbicides in the soil using radioisotopes
Special Issues, Collections and Topics in MDPI journals

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Guest Editor
Department of Chemistry, Federal University of Viçosa, Viçosa 36.570-900, MG, Brazil
Interests: nanomaterials; biochar; hydrogen; green chemistry
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Biochar is a new and promising material used for various environmental applications, such as soil amendment, organic and inorganic pollutants removal, and as catalysts. Biochar is produced from the carbonization of a given biomass by different processes, and their physical-chemical characteristics are influenced by several factors, such as the chemical composition of the precursor raw material. In order to improve the properties of the produced biochars, chemical or physical activation methods for this material can be used.

This Special Issue will focus mainly on the feedstocks of raw materials for the production of biochar, the production processes (pyrolysis and hydrothermal method) and their parameters, as well as the physical-chemical characteristics of the biochar produced are discussed, as this is a material of great economic feasibility, and the application of biochar being viable in large scale and environmentally safe.

Prof. Dr. Kassio Ferreira Mendes
Prof. Dr. Renata Pereira Lopes
Guest Editors

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Keywords

  • thermochemical conversion
  • biochar
  • hydrochar
  • bonechar
  • pyrolysis
  • hydrothermal
  • X-ray fluorescence
  • scanning electron microscopy
  • Fourier transform infrared spectroscopy
  • sorption isotherms
  • degradation process
  • CO2 mitigator
  • nutrient source
  • leaching pote

Published Papers (5 papers)

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Research

17 pages, 2280 KiB  
Article
Ruthenium Catalysts Supported on Hydrothermally Treated Carbon from Rice Husk: The Effect of Reduction Temperature on the Hydrogenation Reaction of Levulinic Acid to γ-Valerolactone
by Virginia I. Rodríguez, Gustavo Mendow, Bárbara S. Sánchez, Juan Rafael García, Richard A. Pujro, Sergio R. de Miguel and Natalia S. Veizaga
Processes 2023, 11(5), 1421; https://doi.org/10.3390/pr11051421 - 8 May 2023
Viewed by 1485
Abstract
Ru catalysts supported on activated carbon obtained by hydrothermal treatment of rice husk were evaluated in the hydrogenation reaction of levulinic acid to γ-valerolactone. The hydrothermally treated carbon was characterized by nitrogen physisorption, elemental analysis, and thermogravimetric analysis, and the catalysts were [...] Read more.
Ru catalysts supported on activated carbon obtained by hydrothermal treatment of rice husk were evaluated in the hydrogenation reaction of levulinic acid to γ-valerolactone. The hydrothermally treated carbon was characterized by nitrogen physisorption, elemental analysis, and thermogravimetric analysis, and the catalysts were characterized by FTIR spectroscopy, X-ray photoelectron spectroscopy, temperature-programmed reduction, and temperature-programmed desorption of pyridine (acidic properties). Prior to the reaction, the catalysts were reduced at different temperatures in the range of 100–350 °C to evaluate the effect of the reduction temperature on the performance in the hydrogenation of levulinic acid. The reaction was carried out in a batch reactor at 70 °C and 1.5 MPa. The results of conversion and selectivity to γ-valerolactone showed that the catalyst with the best performance was the sample reduced at 200 °C. After 2 h of reaction, a γ-valerolactone yield of 74% was achieved. This catalyst presented the lowest acidity value, and the ruthenium-containing phase consisted mainly of RuO2, with a small portion of Ru0. The solid catalyst can be recovered and successfully reused for three runs with the GVL yield at 56%. Full article
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17 pages, 7674 KiB  
Article
Experimental Study on Small-Strain Elastic Parameters of Biochar–Methanotroph–Clay Mixture
by Shuyun Zhang, Wenjing Sun, Kun Xu and Deyang Liu
Processes 2023, 11(4), 982; https://doi.org/10.3390/pr11040982 - 23 Mar 2023
Viewed by 1063
Abstract
During the service of a landfill, uneven soil settlement and earthquakes can cause changes to the pore structure and cracks in the covering layer. The use of a biochar–methanotroph–clay mixture as a new landfill covering layer, can improve its engineering properties. The biochar–methanotroph–clay [...] Read more.
During the service of a landfill, uneven soil settlement and earthquakes can cause changes to the pore structure and cracks in the covering layer. The use of a biochar–methanotroph–clay mixture as a new landfill covering layer, can improve its engineering properties. The biochar–methanotroph–clay mixture’s shear-wave velocity and compression-wave velocity were measured by the bender–extender element test, and the elastic parameters under small-strain conditions, such as maximum shear modulus, Gmax, maximum constrained modulus, Mmax, and Poisson’s ratio, ν, were obtained. The parameters showed that the elastic characteristics and lateral deformation capacity were of great significance for settlement, seismic field, and stress–strain analysis. Based on the bender–extender element test, the effects of different compaction degrees, and biochar content on Gmax, Mmax, and ν of the biochar–clay mixture, and different methane cultivation days on the biochar–methanotroph–clay mixture, were investigated. The results showed that the Gmax, Mmax, and ν of the biochar–clay mixture increased with the increase in biochar content and dry density. When the biochar content was 15%, and the dry density was 1.64 g/cm3, the ν increased significantly. The Gmax and Mmax of the biochar–methanotroph–clay mixture tended to increase with the increase in methane cultivation days, and the higher the biochar content, the more obvious the increasing trend. The ν showed a decreasing trend with the increase in methane cultivation days, and the resistance to lateral deformation was stronger. Full article
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13 pages, 4745 KiB  
Article
Effect of Dry and Wet Cycles on the Strength Characteristics of Biochar–Clay Mixture
by Deyang Liu, Wenjing Sun, Yi Kong and Shuyun Zhang
Processes 2023, 11(3), 970; https://doi.org/10.3390/pr11030970 - 22 Mar 2023
Cited by 5 | Viewed by 1616
Abstract
Biochar is an economical and environmentally friendly “green material” with potential benefits in greenhouse gas emission reduction, soil performance improvement, and environmental restoration. Mixing biochar with clay and using it as a landfill cover can effectively reduce the escape of greenhouse gases into [...] Read more.
Biochar is an economical and environmentally friendly “green material” with potential benefits in greenhouse gas emission reduction, soil performance improvement, and environmental restoration. Mixing biochar with clay and using it as a landfill cover can effectively reduce the escape of greenhouse gases into the air, which is important for environmental protection. It is suggested that biochar should be mixed with clay and used as a landfill covering layer. In this study, the shear strength was obtained by direct shear test, and the shear strength characteristics of biochar–clay mixture under the influence of different dry and wet cycles, biochar contents, and moisture conditions were studied. The results show that the shear strength of the biochar–clay mixture in the saturated state decreases with increasing wet and dry cycles, with shear strength decreases ranging from 6% to 19%. The cohesion and internal friction angles of the clays and mixtures show a decreasing trend under wet and dry cycles, with the cohesion and internal friction angles decreasing in the range of 2% to 16%. The shear stress–shear displacement curve for the biochar–clay mixture in the saturated state shows strain hardening after wet and dry cycles; the curve in the dry state shows strain softening with a distinct peak and a platform at the front end of the curve. The shear strength of clay in a dry state is larger than that of biochar–clay mixture and always larger than that of clay in a saturated state. The shear strength difference of the mixture between dry and saturated states is obviously smaller than that of pure clay. This paper, therefore, provides theoretical guidance for the application of biochar–clay mixtures to landfill covers. Full article
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14 pages, 1316 KiB  
Article
Jack Bean Development in Multimetal Contaminated Soil Amended with Coffee Waste-Derived Biochars
by Ruan Carnier, Aline Renée Coscione, Douglas Delaqua, Aline Peregrina Puga and Cleide Aparecida de Abreu
Processes 2022, 10(10), 2157; https://doi.org/10.3390/pr10102157 - 21 Oct 2022
Cited by 2 | Viewed by 1492
Abstract
Coffee waste-derived biochar was found to immobilize heavy metals in contaminated soil, although there are few studies involving these materials. Given the large amount of waste generated in the coffee industry, this presents a relevant opportunity to contribute to the circular economy and [...] Read more.
Coffee waste-derived biochar was found to immobilize heavy metals in contaminated soil, although there are few studies involving these materials. Given the large amount of waste generated in the coffee industry, this presents a relevant opportunity to contribute to the circular economy and environmental sustainability. Therefore, the objective of this study was to evaluate the effects of the application of biochars derived from coffee grounds and coffee parchment in the remediation of a Cd, Zn and Pb contaminated soil and at the development of jack beans (Canavalia ensiformis) in this area’s revegetation. The biochars were pyrolyzed at 700 °C, and the treatments were: contaminated soil (CT); contaminated soil + calcium carbonate (CaCO3); contaminated soil + 5% (weight (w)/weitght (w)) coffee ground biochar and contaminated soil + 5% (w/w) coffee parchment biochar. These treatments were incubated for 90 days, followed by the cultivation of jack beans for 60 days. Soil samples, soil solution and plants were analyzed for nutrients and heavy metals. The addition of coffee grounds and coffee parchment biochars significantly reduced the contents of heavy metals in the soil compared to the Control (32.13 and 42.95%, respectively, for Zn; 26.28 and 33.06%, respectively, for Cd and 28.63 and 29.67%, respectively, for Pb), all of which had a superior performance than the CaCO3 treatment. Thus, following the observed reduction in the soil soluble fraction of metals, its uptake by the plants was also reduced, especially limiting Cd and Pb accumulation in plant dry matter. In addition, coffee parchment biochar promoted a greater accumulation of nutrients in the shoots, i.e., for K and P (1450 and 21.5 mg pot−1, respectively, dry matter basis) compared to the control (54.4 and 9.3 mg pot−1, respectively). Therefore, coffee parchment biochar use in association with jack beans may represent a viable tool for the remediation of metal contamination concomitantly with revegetation of the contaminated area. Full article
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19 pages, 1107 KiB  
Article
Pyrolysis Temperature and Application Rate of Sugarcane Straw Biochar Influence Sorption and Desorption of Metribuzin and Soil Chemical Properties
by Kamila C. Mielke, Ana Flávia S. Laube, Tiago Guimarães, Maura Gabriela da S. Brochado, Bruna Aparecida de P. Medeiros and Kassio F. Mendes
Processes 2022, 10(10), 1924; https://doi.org/10.3390/pr10101924 - 23 Sep 2022
Cited by 8 | Viewed by 2206
Abstract
Pyrolysis temperature and application rate of biochar to soil can influence herbicide behavior and soil fertility. The objective was to investigate the effect of soil amendments with application rates of sugarcane straw biochar, produced at different pyrolysis temperatures, on the sorption–desorption of metribuzin [...] Read more.
Pyrolysis temperature and application rate of biochar to soil can influence herbicide behavior and soil fertility. The objective was to investigate the effect of soil amendments with application rates of sugarcane straw biochar, produced at different pyrolysis temperatures, on the sorption–desorption of metribuzin in soil. The analysis was performed using high-performance liquid chromatography (HPLC). The treatments were three pyrolysis temperatures (BC350, BC550 and BC750 °C) and seven application rates (0, 0.1, 0.5, 1, 1.5, 5 and 10% w w−1). Amended soil with different application rates decreased H + Al and increased pH, OC, P, K, Ca, Mg, Fe, Mn, CEC and BS contents. Kf values of sorption and desorption of metribuzin were 1.42 and 0.78 mg(1−1/n) L1/n Kg−1, respectively, in the unamended soil. Application rates < 1% of biochar sorbed ~23% and desorbed ~15% of metribuzin, similar to unamended soil, for all pyrolysis temperatures. Amended soil with 10% of BC350, BC550 and BC750 sorbed 63.8, 75.5 and 89.4% and desorbed 8.3, 5.8 and 3.7% of metribuzin, respectively. High pyrolysis temperature and application rates of sugarcane straw biochar show an ability to immobilize metribuzin and improve soil fertility, which may influence the effectiveness in weed control. Full article
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