SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3559-5
Polyamide (PA) membranes are promising for lithium extraction from spent lithium-ion battery (LIB) leachate but face a trade-off between selectivity and permeability. Here, we demonstrate that nascent PA membranes post-grafted with triaminoguanidinium (TAG) monomers (PA-TAG membranes) gain expanded ion passage channels (0.8–7.1 Å) and enhanced positive charge, achieving high-performance lithium separation. The PA-TAG membrane exhibits a pure water permeance (PWP) of 15.5 L m−2 h−1 bar−1, superior divalent ion rejection (~98%), and an excellent separation factor (~30), significantly outperforming pristine PA membranes. In a simulated acidic battery leachate, the PA-TAG membrane achieved a relative volumetric lithium recovery rate of 48.2% after a two-stage nanofiltration process, with the Li+/M2+ mass ratio of the second permeate reaching 53.35, 445 times that of the feed (0.12). The membrane maintained stable performance over 45 hours of nanofiltration and resisted acidic conditions (pH=2) for at least 20 days. These results highlight the potential of PA-TAG membranes for efficient lithium extraction from acidic battery leachate, addressing the critical need for sustainable recycling of spent LIBs.
The Chinese Journal of Process Engineering•2026•DOI: 10.12034/j.issn.1009-606X.225246
The development of efficient catalyst classification technologies is crucial for optimizing fluid catalytic cracking (FCC) and catalytic pyrolysis coupling processes, where distinct particle size distributions are required for different reaction pathways. In this study, a large-scale cold-model experimental platform of a multi-arm vortex separator is established to explore the influence of operating conditions on classification behavior. Systematic experiments are conducted by changing ejection gas velocity (8~20 m/s), inlet particle concentration (30~70 g/m3), and bed linear velocity (0.15~0.25 m/s). The results demonstrate that ejection gas velocity governs classification sharpness by controlling the entrainment of fines within the coarse fraction. The increase in ejection gas velocity enlarges the upward axial gas velocity inside the device, thereby enhancing the entrainment effect on particles near the vortex arm outlets. Increasing the ejection gas velocity from 12 to 16 m/s reduces proportion of fine particles in coarse components from 14% to 12%. The inlet particle concentration imposes competing effects on classification performance: while higher concentrations promote agglomeration and modify turbulence distribution, excessive loading intensifies fine-particle entrainment, thereby diminishing classification selectivity. The system maintains stable pressure drop characteristics under different bed linear velocities, with the pressure drop increasing by maximum of about 15% when the bed linear velocity is raised from 0.15 m/s to 0.25 m/s. Analysis of grade efficiency curves reveals classical S-shaped profiles with cut sizes (dc50) shifting under different operating regimes. Higher particle concentrations reduces dc50, favoring fine-particle removal, while higher ejection gas velocities enlarge dc50, moving the classification boundary toward larger sizes. These findings confirm the synergistic effect of ejection gas velocity and inlet concentration, highlighting that rational parameter matching can simultaneously improve efficiency and selectivity. Beyond the experimental findings, this work emphasizes the broader applicability of multi-arm vortex separators in refining and petrochemical processes. By enabling precise adjustment of particle size distribution, the system offers a promising pathway for enhancing catalyst utilization, extending catalyst lifetime, and facilitating process intensification in coupled FCC-pyrolysis units.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3889-6
Photocatalytic hydrogen production is fundamentally limited by inefficient charge separation and asynchronous supply of electrons and protons to active sites. Here, we designed a ZnIn2S4/ZnCo2S4 (ZIS/ZCS) heterojunction with an atomically coherent interface achieved via an ultralow lattice mismatch of 0.05%. This unique structure promotes rapid electron transfer through a built-in electric field and facilitates continuous proton migration via a hydrogen spillover effect, thereby synchronizing electron and proton delivery at the catalytic interface. This dual regulation of electrons and protons synergistically promotes proton-coupled electron transfer, resulting in a high hydrogen evolution rate of 70.3 mmol g−1 h−1 and selective oxidation of benzyl alcohol to aldehyde (39.3 mmol g−1 h−1) with 93.6% selectivity. This work demonstrates the critical importance of lattice match and dual charge-proton management in designing efficient photocatalysts for complex redox reactions.
Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2025040401
Conventional zero-valent iron (ZVI) suffers from limited electron transfer due to its dense surface oxide layer. This study introduces a mechanochemical ball-milling strategy incorporating sodium chloride (NaCl) with ZVI to fabricate chloride-modified ZVI (Cl-ZVIbm). Using hexavalent chromium (Cr(VI)) as a model pollutant, Cl-ZVIbm exhibited a 76.5-fold enhancement in removal kinetics (0.0306 min−1 vs. 0.0004 min−1) compared to ball-milled ZVI (ZVIbm), achieving complete removal of 2 mg·L−1 Cr(VI) within 120 min. Spectroscopic characterization and density functional theory (DFT) calculations revealed dual regulation mechanisms: (1) Cl− substitution of surface hydroxyl groups alters coordination environments, enabling Cr(VI) adsorption via a bidentate binuclear configuration with adsorption energy reduced from –0.28 eV to –1.64 eV; (2) The strong electron-withdrawing effect of Cl− drives directional electron migration from the iron core to the surface, increasing surface Fe(II) content by 26.9% (67.5% vs. 53.2%) and facilitating direct electron transfer to reduce 99.5% of Cr(VI) into low-toxicity Cr(III). Notably, chloride leaching during reactions was only 0.0126 mmol·L−1, far below industrial wastewater discharge standards, confirming environmental compatibility. This work provides atomic-scale insights into chloride-mediated electronic modulation on ZVI surfaces, offering novel principles for interfacial engineering of environmental functional materials and a theoretical basis for heavy metal remediation technologies.