ACS Sustainable Chemistry & Engineering最新文献

This study advances the development of syngas fermentation by presenting the first industrial-scale process design for producing isopropanol (IPA) and acetone from steel mill off-gas, with a total production capacity of 46–50 ktonne per year. The process was rigorously developed in Aspen Plus, with a comprehensive techno-economic assessment and life-cycle analysis performed to evaluate the process performance. The developed process maximizes energy efficiency by utilizing the heat content of steel off-gas and implementing advanced heat pump systems. As a result, the process is thermally self-sufficient and can operate solely on renewable electricity. Efficient utilization of waste gases results in substantial reductions in global warming potential compared with petrochemical-based production (144–160% for IPA and 138–149% for acetone). The unit production cost of 0.58–0.74 $/kg_IPA/Ac and potential profit margins of 49–65% testify to the cost-effectiveness of the developed process. These findings demonstrate the environmental and economic sustainability of syngas fermentation from steel mill off-gas, establishing it as a potentially viable alternative to conventional petrochemical processes. This technology may hold great potential in reducing environmental impacts and carbon emissions in industrial chemical production.

The use of carbon-fiber reinforced thermoset polymers (CFRPs) is continuously growing in a wide range of manufacturing sectors, particularly when high performance, lightweight design, and corrosion resistance are required. However, their multimaterial cross-linked structure hinders their recyclability, resulting in the extensive generation of heterogeneous wastes. Nowadays, the correct management of end-of-life (EoL) thermosetting composites remains an open and unsolved issue. In this respect, this work presents a chemical recycling process of a model CFRP from an epoxy-amine network, operated at atmospheric pressure, relatively low temperature (≤200 °C), and mild pH (4–5), allowed by the modification of a Lewis acid catalyst. This process leads to complete liberation of the reinforcing carbon fibers without dimensional alteration, with mechanical characteristics fully comparable to the corresponding virgin fibers, and with the formation of a reusable oligomeric fraction. The recovered components are successfully upcycled by fabricating second-generation CFRPs. Finally, the solvolysis process is validated on real EoL composite parts from aerospace and sports equipment products. This work proposes an economically feasible, safe, and scalable approach to efficiently recycle amine-cured epoxy-based CFRPs, with reusability of all fractions and minimization of any secondary waste generation.

Crystallization is a key process in the chemical industry for manufacturing, separation, and purification. However, precise control over the crystal properties remains challenging. Ultrasound-assisted crystallization has been widely used to overcome these issues, but its continuous use can cause thermal degradation, reactor corrosion, and high energy consumption, limiting industrial scalability. Nanobubbles offer a green, sustainable alternative due to their high surface-to-volume ratio and strong negative surface charge, which promote nucleation and control crystal growth. This study compares ultrasound and nanobubbles in cooling crystallization. A theoretical analysis using a modified Gibbs free-energy equation showed that increased nanobubble surface charge reduces nucleation energy barriers by providing a relation of $\frac{\Delta G}{k_{B}T}\propto \frac{Q}{r^{*}}$. Experimentally, nanobubbles shortened induction times, increased yield, and reduced crystal size from 171 to 83 μm. The variation in operating parameters for nanobubble production resulted in optimum conditions for crystallization. Overall, nanobubbles present a viable, non-invasive alternative to ultrasound, offering effective crystallization control without significant energy input, making them suitable for industrial-scale applications.

Efficient extraction of biomolecules from high-moisture microalgae is constrained by the polarity mismatch between solvents and water. This study introduces a COSMO-RS-assisted computational–experimental framework for entrainer screening and mechanistic elucidation in subcritical dimethyl ether (DME)–water systems. A database of 1982 solvents was sequentially filtered by melting/boiling points, environmental, health, and safety (EHS) criteria, and COSMO-RS-predicted solubilities, followed by ternary-miscibility evaluation and targeted experiments. The integrated results reveal that extraction efficiency is primarily governed by ternary miscibility, with class-specific entrainers optimizing recovery across lipids, proteins, carbohydrates, and pigments. Excess-enthalpy (H^E) decomposition identifies hydrogen bonding as the principal favorable contribution, opposed by electrostatic misfit. Electrostatic potential (ESP), independent gradient model based on Hirshfeld partition (IGMH), and interaction region indicator (IRI) analyses clarify how selected entrainers increase DME–water miscibility and enhance solvation of representative biomolecules. The framework offers predictive guidance for designing efficient, selective, and environmentally sustainable extraction processes for wet biomass valorization.

Electrooxidation offers a sustainable alternative by utilizing renewable energy to convert biomass-derived cyclohexanol (CHA) to adipic acid (AA), a key industrial chemical for nylon-66 and polyurethane production. While bimetallic Ni-based catalysts enhance the conversion, the role of secondary metals in modulating Ni active-site reconstruction during operation remains unclear, limiting performance optimization. Here, we demonstrate that Cr-doping promoted the dynamic reconstruction of Ni(OH)₂ nanosheets to form NiOOH with abundant Ni³⁺ and oxygen vacancies (OVs), significantly boosting AA electrosynthesis. In situ characterizations reveal that Cr-doping accelerates OH^– adsorption and promotes NiOOH formation, while subsequent Cr³⁺ leaching generates OVs, thus, resolving the long-standing dilemma between stabilizing high-valence Ni and maintaining abundant defects. The optimized catalyst achieves 78.1% AA yield and 85.4% Faradaic efficiency at 1.45 V vs RHE, outperforming undoped Ni(OH)₂ and prior systems. Mechanistic studies identify surface Ni³⁺ and OVs-stabilized *OOH species as the keys for CHA dehydrogenation and cyclohexanone oxidation, respectively. Moreover, a membrane electrode assembly electrolyzer was designed for the efficient coproduction of AA (0.078 mmol h^–1 cm^–2) and H₂ (42.9 mL h^–1 cm^–2) at a current density of 100 mA cm^–2, demonstrating the scalability. This work clarifies the in situ reconstruction of bimetallic sites and provides a design strategy for the efficient electrosynthesis.

During succinic acid (SA) biosynthesis, increasing the utilization of CO₂ is beneficial for reducing greenhouse gas emissions and lowering production costs. In this study, amine-modified cellulose sponges (AMCS) were prepared, which could decrease more than 80% of CO₂ emissions in water by adsorption and chemical reaction. An external fibrous bed bioreactor was filled with AMCS, and the repeated-batch pressurized fermentation was supplied with CO₂ micronano bubbles (MNBs) without any carbonates or bicarbonates. In this process, Escherichia coli Suc260-CsgA could form stable biofilms on AMCS, which exhibited significantly enhanced resistance to free radicals. Compared with free-cell batch fermentation under atmospheric pressure, the average productivity of SA and yield were increased by 77.36 and 8.11%. The carbonic anhydrase activity of the biofilm was over 68% higher than that in free-cell fermentation mode, while the actual CO₂ utilization increased 2.88-fold. The results indicated that the microbial carbon sequestration was enhanced and the anabolic metabolism of SA was accelerated by the combination of the biofilm, AMCS, and MNBs.

Replacing the sluggish anodic oxygen evolution reaction (OER) with the value-added ethylene glycol oxidation reaction (EGOR) is a promising strategy for energy-efficient hydrogen production. However, achieving high Faradaic efficiency (FE) and selectivity, while elucidating the complex reaction kinetics and mass transport mechanisms coupled with the hydrogen evolution reaction (HER), remains challenging. Herein, a Mo-doped NiCo₂O₄ electrocatalyst, synthesized via a CTAB-assisted method, achieves >98% FE and >98% selectivity for ethylene glycol (EG) electrooxidation to formic acid (FA) at 100 mA/cm² in a three-electrode half-cell configuration. Density functional theory (DFT) reveals that Mo doping optimizes the electronic structure, thereby lowering the rate-determining step (RDS) energy barrier for selective FA production. An asymmetric flow field anion exchange membrane (AEM) flow electrolyzer was designed to overcome mass transport limitations, enabling a 143 mV reduction in cell voltage compared to conventional water electrolysis and stable operation over 30 h. In situ electrochemical impedance spectroscopy (EIS) with the distribution of relaxation times (DRT) quantitatively decouples ion transport, charge transfer, and mass transfer resistances under operational conditions. Systematic optimization of current density, flow rate, and EG concentration demonstrated synergistic regulation of kinetics and mass transport. This work provides a high-performance system for the co-production of green hydrogen and valuable chemicals and establishes a universal diagnostic framework for optimizing hybrid electrolysis systems.