ACS Sustainable Chemistry & Engineering最新文献

Enzyme catalysis and photocatalysis utilizing solar energy are both promising pathways in sustainable chemistry. Drawing inspiration from the integrated enzyme-photocoupled systems in thylakoids, thylakoid-inspired microreactors (TIMs) were prepared using modified SiO₂ nanoparticles as the building blocks, with g-C₃N₄-based photocatalysts encapsulated inside and CALB adsorbed on the surface. The thus designed TIMs result in exceptional catalytic efficiency in pyridine oxidation under visible light irradiation (>420 nm), achieving a rate 11.4 times greater than free enzymes and photocatalysts in a bulk solution. The increased contact area at the oil–water interface is the primary factor contributing to this enhancement, alongside the photocatalytic properties and enzyme loading. TIMs provide a robust platform for integrating functional components into a biomimetic, compartmentalized microreactor with spatially controlled organization and high-performance functionality.

This study investigates the effects of various chemical and physical treatments on the structural and surface properties of activated carbon and hydrochar. Both materials were subjected to treatments with hydrochloric acid, sodium hydroxide, and ethylenediaminetetraacetic acid solutions, as well as microwave irradiation and hydrothermal processing. The resulting changes were analyzed using scanning electron microscopy, energy-dispersive X-ray spectroscopy, nitrogen adsorption–desorption isotherms, and X-ray photoelectron spectroscopy. Results indicate that activated carbon exhibits remarkable chemical resistance, maintaining its intrinsic porous framework across all treatments. However, subtle modifications in surface chemistry were observed, with acid and base treatments slightly increasing the surface area, while ethylenediaminetetraacetic acid treatment decreased it. Hydrochar exhibited more significant changes, notably a drastic reduction in surface area and porosity following sodium hydroxide treatment, indicating low alkaline resistance. Microwave and hydrothermal treatments showed potential as regeneration methods for both materials, slightly increasing the specific surface area while preserving the physical structure. X-ray photoelectron spectroscopy revealed increases in oxygen-containing functional groups for activated carbon after treatments, while hydrochar showed more variable changes, notably in carbonyl functionalities. This comprehensive study provides crucial insights for optimizing the regeneration and modification processes of carbon-based adsorbents, potentially enhancing their performance and sustainability in water treatment applications.

Chemical and physical treatments enhance regeneration in water treatment, altering the structural and surface properties of activated carbon and sustainable hydrochar.

The conversion of CO₂ and H₂O into syngas by plasma is a desirable route for utilization of waste resources, energy conversion, and storage. However, it remains a great challenge to acquire satisfying conversion performance for an environmentally friendly and upscaling application. In this work, we propose a green strategy of synergizing nonthermal plasma with biochar for efficient conversion of high-flow CO₂–H₂O and reveal the reaction kinetics. Specifically, this work makes a breakthrough in that we achieve an energy efficiency of 23.6% at high flow rate (2000 mL/min) and H₂O content (50%), significantly outperforming other plasma reactors for CO₂–H₂O conversion. We find that the biochar surface reaction driven by plasma is the key for enhancing CO₂–H₂O conversion, where biochar reacts with OH and O radicals and suppresses recombination reactions of products, thus mitigating the quenching effect of H₂O. This work innovatively scales up CO₂–H₂O conversion, paving an avenue for its industrial application.

Isobutylene, a monomer for butyl rubber production, is traditionally obtained via the thermal cracking of natural gas. However, this route should be superseded by those that rely on the chemical or biological valorization of renewables to reduce our dependence on fossil resources. Despite extensive research on biobased butyl rubber, its economically viable large-scale production from bioisobutylene remains underexplored. This study develops a process for the microbial production of isobutanol and its conversion to isobutylene and butyl rubber. The fermentation of glucose by metabolically engineered Escherichia coli afforded isobutanol, which was removed from the culturing medium via absorptive vapor capture using water in a recovery tower to prevent cytotoxicity-related problems, concentrated via batch distillation and selectively dehydrated to isobutylene over γ-Al2O3/HCl. The low-temperature cationic copolymerization of isobutylene with isoprene afforded butyl rubber with properties suitable for commercial applications. Computational modeling validated the efficiency of the absorption tower and underscored the need for a multistage distillation tower for optimal isobutylene recovery. This study presents a framework for sustainable chemical production and contributes to the development of ecofriendly and commercially viable technologies.

This research promotes sustainability by developing an ecofriendly process to produce butyl rubber from renewable resources, thereby reducing dependence on fossil fuels.