Search Results (2,768)

This work develops a novel phosphate-functionalized extraction resin (HEHEHP + Cyanex272)/SiO₂-P via the vacuum impregnation method for efficient separation of light rare earth element impurities from lanthanum (La³⁺) in nitric medium through synergistic extraction. Batch experiments have demonstrated superior adsorption selectivity toward impurity ions over La³⁺ in a pH 4 nitric acid solution. Column studies confirmed exceptional performance under ambient conditions, achieving a lanthanum treatment capacity of 120.6 mg/g and over 98% impurity removal, which surpasses most reported values. Notably, this purification process enables direct production of purified La³⁺ solutions through a single-column system without desorption, significantly enhancing efficiency and reducing costs. Mechanistic insights revealed combined ion exchange and coordination interactions between metal ions and P-OH/P=O groups, corroborated by advanced characterization and density functional theory calculations. These findings indicate a higher binding affinity of light rare earth compared with La³⁺. This strategy provides a scalable approach for ultra-high-purity lanthanum compound production in advanced optical and electronic applications. Full article

The contamination of water resources with heavy metals creates problems for using it as a source of drinking water. Adsorption is one of the most promising methods for heavy metal ion removal from natural and wastewater. The process of removing copper (II) from aqueous solutions using SiO₂ xerogel as an adsorbent has been studied. The xerogel was thoroughly characterized by transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and argon adsorption–desorption isotherms, revealing an amorphous structure with a high surface area (~347 m²/g) and uniform mesoporosity (2–14 nm pore size). The surface chemistry, dominated by silanol groups, was confirmed by XPS analysis. The adsorption process is influenced by electrostatic interactions between the positively charged Cu(II) ions and the negatively charged surface groups, with the optimal performance near neutral pH. Batch adsorption experiments demonstrated that the silica xerogel effectively removes Cu(II) ions from aqueous solutions, with removal efficiency exceeding 99% at pH values above 4.0. The maximum adsorption capacity of copper (II) ions on SiO₂ xerogel is 67.5 mg/L. Full article

Adsorption is a common method for solving the contamination of methylene blue (MB) in dyeing wastewater. Aerogel adsorbents with high porosity and specific surface areas have attracted increasing attention. However, the high costs of raw materials for aerogel preparation restrict their large-scale production and application. Fly ash (FA), a by-product of coal-fired power plants, is rich in silica and aluminum elements and has the potential to prepare aerogel adsorbents. This study proposed a modified recycling route for FA to synthesize silica–alumina composite aerogel with high specific surface area. FA was pretreated by three steps of alkali fusion, water leaching and acid leaching to obtain a solution rich in silicon and aluminum elements, with a total leaching efficiency of 96.92% and 91.36% for silicon and aluminum, respectively, under optimized alkaline fusion conditions of FA:NaOH mass ratio of 1:1.2, calcination time of 2 h, and calcination temperature of 550 °C. Silica–alumina aerogel with a specific surface area of 661.3 m²/g was then synthesized from the leaching solution through a sol–gel method, exhibiting well-developed mesopores and achieving an adsorption capacity of 52.22 mg/g for MB. The adsorption kinetics and isotherms of MB adsorption by FA-derived silica–alumina composite aerogel was investigated. FTIR characterization confirmed that the adsorption of MB by FA-derived aerogel was mainly physical adsorption. This study provides a new approach for the resource utilization of FA, and the high-specific-surface-area FA-derived aerogel holds potential as an alternative adsorbent for the removal of dyes in wastewater. Full article

The efficient purification of Pb(II)-containing wastewater is essential for safeguarding public health and maintaining the aquatic environment. In this study, novel hydrous ferric oxide (HFO) nanoparticle-embedded poly(vinylidene fluoride) (PVDF) composite adsorption membranes were developed through a simple blending method for efficient Pb(II) removal. This composite membrane (denoted as HFO-PVDF) combines the excellent selectivity of HFO nanoparticles for Pb(II) with the membrane’s advantage of easy scalability. The optimized HFO-PVDF_(1.5) membrane achieved adsorption equilibrium within 20 h and exhibited excellent adsorption capacity. Moreover, adsorption capacity markedly enhanced with increasing temperature, confirming the endothermic nature of the process. The developed HFO-PVDF membranes demonstrate significant potential for real-world wastewater treatment applications, exhibiting exceptional selectivity for Pb(II) in complex ionic matrices and could be effectively regenerated via a relatively straightforward process. Furthermore, filtration and dynamic regeneration tests demonstrated that at an initial Pb(II) concentration of 5 mg/L, the membrane operated continuously for 10–13 h before regeneration, treating up to 200 L/m² of wastewater before breakthrough, highlighting potential for cost-effective industrial wastewater treatment. This study not only demonstrates the high efficiency of the HFO-PVDF membrane for heavy metal ion removal but also provides a theoretical foundation and technical support for its practical application in water treatment. Full article

The safe and efficient capture of CO₂ in confined environments such as coal mine goafs remains a significant challenge, posing both environmental and safety risks. To address this issue, this study developed a novel biomass-based aerogel adsorbent using CNF-C and CS through sol–gel synthesis and freeze-drying. A series of composite aerogels with varying mass ratios were systematically characterized by SEM, BET, FTIR, and TG-DSC to analyze their microstructure, specific surface area, pore characteristics, chemical properties, and thermal stability. A constant temperature and humidity experimental setup was specially designed to explore the effects of various temperatures, humidity, and material ratios on CO₂ adsorption performance. FTIR analysis confirmed that -NH₂ served as the primary adsorption site, with its density increasing with higher chitosan content. The 1:3 ratio exhibited the optimal specific surface area (7.05 m²/g) and thermal stability, withstanding temperatures up to 350.0 °C, while the 1:1 ratio demonstrated the highest porosity (80.74%). Adsorption experiments indicated that 35.0 °C and 50% humidity were the optimal conditions, under which the 1:2 ratio biomass aerogel achieved an 18% increase in CO₂ adsorption capacity compared to room temperature. The sample with a 1:1 high cellulose ratio is primarily dominated by physical adsorption, making its performance susceptible to environmental fluctuations. The sample with a 1:3 high chitosan ratio is predominantly governed by chemical adsorption, exhibiting more stable adsorption characteristics. The 1:2 ratio achieved the best balance under 35.0 °C and 50% humidity. The biomass aerogel synergistically combined physical barriers from its three-dimensional network structure and chemical adsorption via active functional groups, enabling efficient CO₂ capture and stable sequestration. This study demonstrates the feasibility of biomass-derived aerogels for CO₂ adsorption under complex conditions and provides new insights into the design of sustainable materials for environmental remediation and carbon reduction applications. Full article

Elevated phosphorus levels in wastewater created significant environmental concerns, including the degradation of surrounding soil structure, inhibition of plant growth, and potential threats to human health. To address this issue, a self-standing nanofibrous composite membrane based on PA-66/PVA-15%La(OH)₃ was fabricated via electrospinning, followed by glutaraldehyde (GA) crosslinking and alkali hydrolysis to create an interpenetrating structure, where PA-66 provided the overall mechanical strength of the membrane, while La served as a functional component for the adsorption of phosphate. The chemical composition, surface morphology, thermal stability, and mechanical properties of the resulting membranes were characterized using ATR-FTIR, SEM, TGA, and tensile testing, respectively. Furthermore, the adsorption performance of the membranes was evaluated systematically through static and dynamic adsorption. The Langmuir isotherm model yielded a theoretical maximum adsorption capacity of 21.39 mg/g for phosphate ions. Notably, over 96% of this capacity was retained even in the presence of interfering ions. Moreover, dynamic adsorption experiments demonstrated that the membrane can deal with 1.74 L of phosphate-containing wastewater at a low flow rate of 1.0 mL/min and 1.46 L at a high flow rate of 2.0 mL/min, respectively, while consistently maintaining a phosphate removal efficiency exceeding 90%. A controlled release of phosphate ions from a phosphate-adsorbed membrane was successfully demonstrated using Mougeotia cultivation, implying the potential for phosphorus resource recovery. Full article

Boric acid/β-CD-based polymers (BA-CD) possess hierarchical porous structures and efficient functional groups for further molecular recognition, which are used for the adsorption of a series of cationic and anionic organic dyes. The effects of pH, contact time, initial concentration of solution, and temperature on the adsorption performance were experimentally investigated in detail. Surprisingly, the adsorption capacities of BA-CD towards RB exhibited a higher value of 733.2 mg g⁻¹ among a series of cationic and anionic dyes. The adsorption kinetics further indicated that the adsorption of dyes by BA-CD belonged to a quasi-second-order kinetic model, while the adsorption isotherms demonstrated the adsorption process as the Langmuir isotherm model. The characterization of the adsorption process was performed in the presence of monomolecular layer chemisorption. In addition, the reusability test showed that BA-CD had a high reusability rate of 90% in MG after five cycles, indicating its future potential for the treatment of dye wastewater. Full article

Many industries release untreated synthetic dye effluents into water bodies, harming ecosystems and human health. Therefore, an economical and sustainable solution for treating dye-contaminated water must be developed. In this study, mulberry leaves (Morus nigra L.), as a cost-effective and sustainable adsorbent, were prepared to remove Basic Yellow 28 (BY28) and Basic Blue 3 (BB3) cationic dyes from industrial dye wastewater using adsorption. Batch experiments with key variables such as initial dye concentration, adsorbent dosage, contact time, temperature, stirring speed, and pH were conducted to find optimal conditions. The effectiveness of mulberry leaves as an adsorbent after multiple regeneration cycles was examined. The adsorbent was characterized through various instrumental methods, including FTIR, SEM, XRD, and BET analysis. Adsorption performance was analyzed using the Langmuir and Freundlich isotherm models. The results showed that the mulberry leaf adsorbent best fits the Langmuir model, with R² values of 0.999 for BY28 and 0.973 for BB3. The maximum adsorption capacities were 0.15 mg/g for BY28 and 7.19 mg/g for BB3, indicating their upper limits for dye uptake. The optimal conditions achieving removal efficiencies of over 99% were 1.5 g, 50 mL, 15 min, 180 rpm, and 10 mg/L at 30 °C for BY28 in neutral pH (7) and 1.5 g, 50 mL, 45 min, 100 rpm, and 30 mg/L at 40 °C for BB3 in basic pH (10). The regeneration of mulberry leaves as an adsorbent through acid treatment with 0.1 M HCl and 0.1 M CH₃COOH solutions maintained a high performance, achieving up to 98% dye removal efficiency after two regeneration cycles. It has been observed that successful results can be achieved in terms of reusability. Additionally, the removals of BB3 and BY28 performed in an ultrasonic-bath-assisted environment successfully achieved removal efficiencies of 84.87% and 75.41%, respectively. According to the results, mulberry leaves can effectively be used in wastewater treatment to remove dyes, can be reused multiple times, and thus serve as an environmentally friendly and sustainable adsorbent. Full article

Fluoroquinolone antibiotics (FQs) are widely applied in veterinary practice and animal husbandry and frequently persist in organic waste liquids (OWLs), creating substantial environmental and health risks when untreated. A high-capacity mesoporous silica aerogel (SA-60) was produced via a cost-effective sol–gel route from water glass, followed by ambient pressure drying at 60 °C for 6 h. SA-60 exhibited pronounced selectivity, providing a maximum adsorption capacity of 630.18 mg·g⁻¹ for enrofloxacin (ENR) in acetonitrile. Adsorption efficiency was weakly dependent on pH. Mechanistic analysis indicated combined physical and chemical interactions, with intra-particle diffusion governing the overall rate. Thermodynamic evaluation showed a spontaneous and endothermic process for ENR adsorption. Organic solvent type and water content were major determinants of adsorption efficiency. Durable performance was observed, with capacity retention above 80% after five adsorption-desorption cycles. The mesoporous architecture (surface area 249.21 m²·g⁻¹; average pore diameter 10.81 nm) supported the high uptake. These results identify SA-60 as a sustainable adsorbent for removing hazardous FQs from OWLs, offering a simple, energy-efficient approach for the source-level control of antibiotic pollution and improved environmental management. Full article

This study focused on the comprehensive characterization of the adsorbent obtained from rice husk, which was selected for its high adsorption capacity in iodine solution (IS) and methylene blue solution (MBS). This was achieved with adsorbents prepared by a combined treatment involving calcium carbonate prior to carbonization and activation with phosphoric acid. Characterization was performed using advanced techniques, such as scanning electron microscopy (SEM), atomic force microscopy (AFM), laser light diffraction and energy-dispersive X-ray spectroscopy (EDS), which allowed for the evaluation of the adsorbent’s microstructure and composition. The results revealed a complex structure of the adsorbents with interconnected pores, which facilitates efficient adsorption in IS and MBS and the standard indicators to evaluate adsorption capacity. The novelty of this study lies in the application of advanced characterization techniques to optimize the adsorbent properties and understand how preparation conditions affect the adsorbent’s microstructure. The characterized adsorbent materials in this study presented great potential for applications in water treatment and industrial processes, offering an economical and environmentally sustainable solution. Promoting the use of rice husks in the production of adsorbents contributes to the circular economy, reducing production costs and environmental pollution. The results suggested that these materials are effective in the removal of pollutants, which make them relevant for practical applications in water and soil bioremediation. Full article

Nitrate pollution in water bodies has become a global environmental problem, and its excessive presence not only leads to eutrophication of water bodies but also threatens human health through the drinking water pathway. Therefore, it is urgent to develop new adsorbents with high adsorption capacity, good selectivity and excellent regeneration performance to solve the problem of nitrate pollution. In this study, reed straw (RS), trimethylamine-modified reed straw (MRS) and triethylamine-modified reed straw (ERS) were prepared by quaternary amination modification for nitrate removal. The adsorption performance, desorption performance, adsorption characteristics under disturbed environment and dynamic adsorption performance were investigated experimentally, and the adsorption mechanism was analyzed by various characterization means. The adsorption performance followed the order ERS (12.25 mg·g⁻¹) > MRS > RS, demonstrating that quaternary amination modification, particularly with triethylamine, significantly enhanced the NO₃⁻-N adsorption capacity. ERS exhibited excellent regeneration stability (over 80% after nine cycles) and high selectivity towards NO₃⁻-N in the presence of competing anions (Cl⁻, SO₄²⁻, humic acid). In the dynamic adsorption experiment, ERS had a breakthrough time of 290 min at a packing height of 3.3 cm, with an adsorption capacity of 10.74 mg·g⁻¹ and good adaptability to flow rate. In the actual wastewater application, the initial NO₃⁻-N removal rate was over 95%, the dynamic desorption rate reached 99.2% and the peak nitrate concentration of the desorbed solution reached 27 times of the initial value, confirming its high efficiency regeneration and enrichment ability. The study shows that the amine-modified reed straw adsorbent has a good potential for application and provides a new way for wastewater treatment plants to solve the problem of nitrate removal 12.25 mg·g⁻¹. Full article

Heteroatom doping is an effective strategy for improving the sodium storage performance of hard carbon. However, the use of sulfur and fluorine codoped carbon materials as anodes for sodium-ion batteries has not been reported. Here, an S-infused/S, F-codoped PVDF-derived carbon SFC5 was prepared by one-step carbonization of PVDF and synchronously used as an anode for a sodium-ion battery. The prepared SFC5 containing 10.11 at% S and 9.54 at% F is a short-range ordered amorphous carbon with a microporous structure. Owing to the structural advantages of S, F codoping, and the high specific capacity of S, SFC5 exhibited an outstanding sodium storage performance of 365 mAh g⁻¹ after 200 cycles at 50 mA g⁻¹ and 212 mAh g⁻¹ after 500 cycles at 400 mA g⁻¹. Moreover, theoretical calculations based on density functional theory (DFT) verify that S and F codoping can considerably reduce the Na⁺ adsorption energy and increase the electronic conductivity of SFC5. The current study presents a viable and facile approach to prepare high-performance, low-cost anode materials for SIBs, supported by empirical evidence and theoretical computations. Full article

Two nitrogen-modified mesoporous MCM-41-type silicas were synthesized by the sol–gel route and post-grafting surface modification procedure, obtaining an aminopropyl-modified MCM-41 (denoted MCM-41-N) and an aminoethyl-aminopropyl-modified MCM-41 (denoted MCM-41-NN). Hexavalent chromium removal from acidified water by adsorption and reduction to Cr(III) on the solid mesophases was analyzed. The modified silicas were characterized by powder X-ray diffraction (XRD), Fourier transformed infrared spectra (FT-IR), nitrogen adsorption–desorption measurements at −196 °C, X-ray photoelectron spectroscopy (XPS), ²⁹Si solid state Nuclear Magnetic Resonance (²⁹Si-RMN), and thermogravimetric analysis (TGA). Both samples exhibited very high capacities for decreasing Cr(VI) concentrations in water, according to the Langmuir isotherm model: 129.9 mg·g⁻¹ for MCM-41-N and 133.3 mg·g⁻¹ for MCM-41-NN. The chromium speciation in the supernatant after 24 h indicates that MCM-41-N had a higher capacity to reduce Cr(VI) to the less toxic Cr(III) species than MCM-41-NN: 92.9% vs. 72.5% when the initial Cr(VI) concentration was 10 mg·g⁻¹. These differences were related to the different capacity of nitrogen atoms in MCM-41-N and MCM-41-NN to interact with the surrounding surface silanols which are required for the chemical reduction in the hexavalent species to take place, as evidenced by FT-IR and XPS analysis. Also, the Cr(III)/Cr(VI) atomic ratios on the solid’s surfaces were higher for MCM-41-N. These results highlight the characteristics that nitrogen atoms incorporated into silica matrices must possess in order to maximize the transformation of Cr(VI) into the trivalent species, thereby reducing the generation of toxic waste harmful to living organisms. Full article

Aqueous zinc-ion batteries (AZIBs) have gained significant attention as promising candidates for next-generation energy storage systems, especially in mobile robotics, due to their inherent safety, environmental friendliness, and low cost. However, the practical application of AZIBs is often hindered by slow Zn²⁺ diffusion and the poor structural stability of the cathode materials under high-rate or long-term operation. To address these challenges, a defect-engineered, binder-free MnO₂ electrode, with a MnO₂ loading of 1.35 mg·cm⁻², is synthesized via in situ hydrothermal growth of ultrathin MnO₂ nanosheets directly on a 3D conductive nickel foam scaffold, followed by reductive annealing to introduce abundant oxygen vacancies. These oxygen-rich defect sites significantly enhance Zn²⁺ adsorption, improve charge transfer kinetics, and contribute to enhanced pseudocapacitive behavior, further improving overall electrochemical performance. The intimate contact between the MnO₂ and Ni substrate ensures efficient electron transport and robust structural integrity during repeated cycling. With this synergistic architecture, the MnO₂@Ni electrode achieves a high specific capacity of 122.9 mAh·g⁻¹ at 1 A·g⁻¹, demonstrating excellent cycling durability with 94.24% capacity retention after 800 cycles and nearly 99% coulombic efficiency. This study offers a scalable strategy for designing high-performance, structurally stable Zn-ion battery cathodes with improved rate capability, making it a promising candidate for energy-intensive mobile robotic and flexible electronic systems. Full article

Borophene, a two-dimensional (2D) allotrope of boron, has emerged as a highly promising material owing to its exceptional mechanical strength, electronic conductivity, and diverse structural phases. Unlike graphene and other 2D materials, borophene exhibits inherent anisotropy, flexibility, and metallicity, offering unique opportunities for advanced nanotechnological applications. This review presents a comprehensive summary of recent progress in borophene synthesis methods, highlighting both bottom–up strategies such as chemical vapor deposition (CVD) and molecular beam epitaxy (MBE), and top–down approaches, including liquid-phase exfoliation and sonochemical techniques. A key challenge discussed is the stabilization of borophene’s polymorphs, as bulk boron’s non-layered structure complicates exfoliation. The influence of substrates and doping strategies on structural stability and phase control is also explored. Moreover, the intrinsic physicochemical properties of borophene, including its high flexibility, oxidation resistance, and anisotropic charge transport, were examined in relation to their implications for electronic, catalytic, and sensing devices. Particular attention was given to borophene’s performance in hydrogen storage and hydrogen evolution reactions (HERs), where functionalization with alkali and transition metals significantly enhances H₂ adsorption energy and storage capacity. Studies demonstrate that certain borophene–metal composites, such as Ti- or Li-decorated borophene, can achieve hydrogen storage capacities exceeding 10 wt.%, surpassing the U.S. Department of Energy targets for hydrogen storage materials. Despite these promising characteristics, large-scale synthesis, long-term stability, and integration into practical systems remain open challenges. This review identifies current research gaps and proposes future directions to facilitate the development of borophene-based energy solutions. The findings support borophene’s strong potential as a next-generation material for clean energy applications, particularly in hydrogen production and storage systems. Full article