ACS ES&T engineering最新文献

Carbon-based adsorbents have been recently identified as advanced materials for the efficient removal of perfluorooctanoic acid (PFOA); however, the fundamental understanding of the selective adsorption of PFOA over competing contaminants/water matrix is still lacking. Herein, a novel honeycomb-like nitrogen-doped carbon nanosheet (HL-NC@Ni-800) material was reported for the rapid adsorption of PFOA. The PFOA selective adsorption was attributed to (i) favorable steric hindrance that allowed rapid and stable PFOA adsorption, (ii) abundant adsorption sites provided by the honeycomb-like mesoporous structure, (iii) electrostatic attraction between the PFOA anion and nickel cation, (iv) hydrophobic effect between the PFOA tail and nitrogen functional groups, and (v) Lewis acid–base effect. Consequently, PFOA was efficiently removed from the competing contaminants such as 1,4-dioxane and sulfamethoxazole by 94.6 and 89.6%, respectively, as well as the water matrix such as inorganic anions by ∼84–94% and real high-salinity seawater by 75.6–78.4%. The calculated maximum adsorption capacities (q_m) of HL-NC@Ni-800 for PFOA soared to 184.89 mg·g^–1. In addition, the thermodynamically favorable adsorption of PFOA with different steric conformations on HL-NC@Ni-800 provided theoretical explanations for its high-efficiency adsorption performance toward PFOA. This study provides a novel strategy for the synthesis method of efficient adsorbents for PFOA and also elucidates the mechanistic understandings of PFOA selective adsorption over competing contaminants/water matrix, for guiding the design of more efficient adsorbents to treat PFOA-contaminated water.

To improve the water resistance of manganese oxide (MnO_x) in the catalytic ozonation of dimethyl sulfide (DMS) under humid conditions, polymorphic MnO_x was synthesized based on δ-MnO₂ with reference to the in situ layer-to-tunnel (L–T) transition of minerals in a natural environment. The constructed polymorphic MnO_x(Mn–SH) possessed abundant α–δ (α(Mn)-O-δ(Mn)) interfaces and exhibited superior catalytic activity for the conversion of DMS, ensuring more than 91% of DMS removal under harsh conditions [relative humidity (RH) = 80%] and excellent stability after testing for 20 h (RH = 60–80%). In situ DRIFTS spectra and theoretical calculations demonstrated that α–δ interfaces facilitated the formation of active hydroxyl groups (−OH) through H₂O dissociation, which can participate in ozone (O₃) activation and avoid the deactivation caused by H₂O. Simultaneously, more Brønsted acid sites formed through H₂O dissociation, which promoted DMS adsorption and decomposition. This study gives an understanding of the role of α–δ interfaces in promoting activity for catalytic ozonation and provides a convenient strategy to construct polymorphic MnO_x with enhanced water resistance, which can be applied to existing MnO_x used for catalytic ozonation of sulfur-containing compounds from livestock farms and the petroleum industries.

Achieving high effective degradation of organic pollutants in sewage having adverse effects on human health and ecosystems remains a major challenge. In this study, an oxygen vacancy (O_v)-mediated Z-scheme Co₃O₄/O_v-TiO₂ heterojunction was first reported for simultaneous selective photoelectrocatalytic pollutant degradation and hydrogen production under visible light irradiation. The optimized Co₃O₄/O_v-TiO₂ exhibited excellent photoelectrocatalytic performance in the degradation of the organic pollutants under visible light irradiation due to the formation of a Z-scheme heterojunction for the utilization of highly reductive photogenerated electrons and oxidative holes. The mechanistic investigation suggested that the synergistic effects of hydroxyl radical and singlet oxygen as the dominant reactive species facilitated the ring-open reactions of the rhodamine B for the mineralization processes. This work provides a deep understanding of designing Z-scheme heterojunction photoelectrocatalysts through defect engineering technologies for sewage treatment.