ACS Sustainable Chemistry & Engineering最新文献

Photocatalytic reduction of CO₂ is considered as a promising approach to achieving carbon neutrality and producing value-added chemicals in a sustainable way, utilizing CO₂ as a feedstock and solar energy as the driving force. Constructing novel photocatalysts with sufficient active sites and efficient charge separation efficiency is crucial for optimizing CO₂ conversion. Herein, the activated pinecone-derived biochar (APC) possesses a porous tubular carbon framework, a high degree of graphitization, and abundant oxygen-containing functional groups. NiO nanoparticles were successfully embedded in the APC supporter to manufacture NiO/APC composites. The obtained NiO/APC sample demonstrates remarkably enhanced photocatalytic properties and high selectivity (95.6%) for CH₄ production with respect to pure NiO. The coupling of APC and NiO can fully expose NiO nanoparticles, regulate the band structure of NiO, and establish a close interfacial interaction, which can significantly increase CO₂ adsorption, improve light absorption, prohibit charge recombination, and accelerate separation and migration of photoexcited charge carriers. Especially, the tubular APC framework not only serves as a supporter to inhibit the aggregation of NiO nanoparticles and as electron shuttles to accelerate the charge separation but also as a reactive site to realize the efficient conversion of CO₂ to CH₄. This work affords a paragon for the construction of highly efficient photocatalysts, which pave the way for practical applications in photocatalysis.

There has been numerous research focused on accelerating carbonation of recycled cement paste powder (RCPP). However, the carbonation rate is still low. This paper proposes an innovative utilization of triethanolamine (TEA) to accelerate carbonation of RCPP with sustainable solution recycling strategies. The results showed that the CO₂ uptake of RCPP increased and then decreased as the increased concentration of TEA. Calcite and silica gel were the main carbonation products in carbonated RCPP. On the other hand, TEA solution with concentration of 0.010 M was chosen for recycling experiment and the results showed that the CO₂ uptake of carbonated RCPP for 30 min decreased progressively with increasing number of cycles. Notably, by the 18th cycle, the CO₂ uptake was comparable to that of control sample. Furthermore, the mechanism of accelerating the carbonation of TEA was provided, proving the feasibility of accelerated carbonation of RCPP by using TEA solution.

Hydrothermal carbonization (HTC) is a thermal conversion process that has been widely studied in the field of waste biomass management. However, conventional HTC reactors require operation under high pressure, which leads to economic and safety issues during both manufacturing and operation processes. To address this challenge, a thermochemical treatment process with the assistance of sulfuric acid was adopted to promote carbonization of the typical lignocellulosic biomass Ceratophyllum demersum into carbon adsorbents at temperatures below 100 °C. After optimization by response surface method, the sample S80-8-70 obtained under a reaction temperature of 80 °C, 8 h of reaction time, and 70 wt % of sulfuric acid concentration showed excellent adsorption capacity (203.80 ± 17.88 mg/g), along with a higher mass yield (40.15 ± 0.69%). To explore the mechanism of low-temperature processes of biomass conversion, the characterizations of lignocellulosic components (cellulose, hemicellulose, and lignin) and their corresponding biochars under optimal conditions were also conducted. Scanning electron microscopy analysis showed that the surface morphology of cellulose and hemicellulose underwent significant changes during the thermochemical treatment process, while the lignin remained unchanged. The Brunauer–Emmett–Teller results indicated that sample S80-8-70 had well-developed mesoporous structures and a higher specific surface area compared to that of the biochars from lignocellulosic components. Fourier transform infrared spectroscopy showed that the functional groups of the S80-8-70 sample were similar to those of the biochars derived from cellulose and hemicellulose while retaining some characteristics of lignin. The ζ-potential analysis also indicated that the surface of the sample carried a negative charge, consistent with the biochars from cellulose and hemicellulose. These results demonstrate that lignocellulosic biomass was successfully converted into carbon adsorbent materials at temperatures below 100 °C. In the thermochemical process, cellulose and hemicellulose underwent carbonization, while the residual lignin had little impact on the carbonization and properties of the carbon materials. Moreover, by using a step-by-step washing method, high-concentration washing wastewater could be recovered and used for the next reaction.

Electrochemical generation of hydrogen peroxide (H₂O₂) through the two-electron oxygen reduction reaction (2e^– ORR) represents a sustainable development strategy for bulk H₂O₂ manufacturing, yet crafting efficient catalysts remains a substantial challenge. Carbon materials are particularly appealing as electrochemical catalysts, owing to their diverse nanostructures and adjustable electrochemical attributes. Nonetheless, the lack of structure–property understanding has hindered the progression of metal-free carbon electrocatalysts. In this study, we fabricated porous carbon with abundant edge sulfhydryl groups (−SH) and determined that the 2e^– ORR performance is roughly proportional to the edge −SH content, outperforming reported ORR catalysts in aspects such as H₂O₂ selectivity (90–98% over a broad potential of 0.30–0.70 V vs RHE) and stability (maintaining over 90% performance during 12 h testing) as measured in alkaline solution in a rotating ring-disk electrode setup. Furthermore, in a flow cell setup, both the H₂O₂ production rate (2910 mmol g_catalyst^–1 h^–1) and Faraday efficiency (over 80%) surpass most reported carbon- and metal-based electrocatalysts. Consequently, this research illuminates a straightforward pathway to design specific sulfur configurations in carbon-based catalysts for high-selectivity H₂O₂ production.

Traditional cotton textile dyeing processes are extensively dependent on electrolytes and auxiliaries, generating wastewater laden with hydrolyzed dyes and salts that present substantial environmental risks. This work developed a water-saving and less-salt dyeing method for cotton textiles by integrating deep eutectic solvent (DES) swelling pretreatment. This innovative approach alters the intra- and intermolecular hydrogen bonding of cellulose, inducing structural modifications, such as increased fiber diameter, enhanced amorphous cellulose content, and expanded porous architecture. These changes significantly improve dye accessibility and the uptake efficiency. Among the DES systems evaluated, K₂CO₃-glyceryl DES exhibited the highest S_w% in cotton fibers (59.5%). DES swelling method offers significant advantages over conventional processes, such as reduced environmental impact (e.g., lower water/energy consumption, fewer harsh chemicals), enhanced dye uptake efficiency, or improved fiber integrity. Furthermore, the DES retained its swelling efficacy after multiple recycling cycles, underscoring its reusability. This advancement not only aligns with eco-friendly textile manufacturing goals but also demonstrates economic viability.

In the quest for sustainable energy and environmental preservation, reductive catalytic fractionation (RCF) of lignocellulosic biomass has emerged as a powerful approach to valorize lignin. However, the precise mechanism driving the RCF process remains elusive due to analytical challenges. This study unlocks the mechanism by investigating the Pd/C-catalyzed RCF of birch wood using online high-resolution mass spectrometry (HRMS) for the first molecular-level insights. Real-time evolutions of various monomers, dimers, and oligomers bridged the gap between large lignin fragments and small phenolic products, revealing the stepwise nature of RCF. The process starts with lignin extraction into the liquid phase from the middle lamella to the secondary wall of the cell wall, followed by rapid catalytic depolymerization of the extracted lignin fragments to yield phenolic monomers and dimers. Intriguingly, the evolution of sugar-derived compounds highlights the holocellulose degradation with prolonged reaction times, posing challenges to lignin-first strategies. These findings underscore the importance of fine-tuning RCF conditions to enhance conversion efficiency and minimize side reactions. Moreover, this work highlights the application of advanced HRMS techniques for gaining mechanistic and kinetic insights into liquid-phase reactions, paving the way for more efficient biomass valorization technologies.

An environmentally friendly adsorbent for recovering nuclear energy source U(VI) from wastewater plays a crucial role in resource recovery and environmental preservation. In this work, a double-network aerogel adsorbent composite constructed from sodium alginate, poly(acrylic acid), and NH₂-MIL-125 (NM@SA) was fabricated by a mild method, which was adopted to remove and concentrate U(VI) in the corresponding simulated wastewater samples. According to the results of adsorption kinetic and isotherm models, the adsorption of U(VI) on NM@SA was a monolayer chemisorption process. The maximum adsorption capacity of NM@SA for U(VI) calculated from the Langmuir model was 703.6 mg·g^–1. In addition, the adsorbent maintained excellent adsorption capacity, recoverability, and reuse in large-scale operation. The same abilities can be demonstrated in real seawater environments. Finally, the potential adsorption mechanisms of U(VI) on NM@SA were discussed in conjunction with the experimental determination and characterization results. Overall, this study introduces an advantageous research approach for treating U(VI)-containing radioactive wastewater.

Nitrilase has attracted widespread attention due to its efficiency, specificity, and ecofriendliness in the hydrolysis reactions of nitrile compounds. These enzymes can catalyze various substrates, including aliphatic nitriles and aromatic nitriles. However, high substrate specificity is key to efficient catalysis and high-purity product synthesis. This study aims to enhance the preference of nitrilase for aliphatic nitriles through substrate channel engineering to expand its industrial applications. We developed a semirational design workflow that integrates extensive search and deep optimization strategies, relying on computational tools such as substrate channel modeling and molecular docking to systematically identify and optimize key amino acid residues related to substrate binding. Taking 3-chloropropionitrile as an example, the specific activity of the optimal mutant G191A/L194W increased from 2.47 to 58.35 U·mg^–1, with the substrate conversion rate approaching 100%, while the catalytic activity toward aromatic nitriles significantly decreased. Molecular dynamics simulations revealed the correlation between substrate specificity and channel morphology regulated by W194 and promoted the formation of a specificity-enhanced mutant network. This study provides a structural and mechanistic basis for substrate channel design and enzyme function modification and validates its potential for industrial applications.