Selective and efficient removal of emerging contaminants by sponge-like manganese ferrite synthesized using a solvent-free method: Crucial role of the three-dimensional porous structure

The recent advances of MnFe2O4-based nanoparticles in environmental application: A review

The manganese ferrite (MnFe2O4)-based nanoparticles showed a substantial potential to remediate the various pollutants in environmental application due to low cost, simple magnetic separation and high removal capacity. Herein, the functionalization of various MnFe2O4-based nanoparticles was briefly summarized; Then the recent advances concerning the removal of pollutants (i.e., organics, heavy metals and antibacterial activity) on different MnFe2O4-based nanoparticles were reviewed in details. The reactivity of MnFe2O4-based nanoparticles was significantly influenced by environmental factors. It is demonstrated that interaction mechanism of various pollutants on magnetic MnFe2O4-based nanoparticles included degradation, adsorption, coordination, redox and precipitation. Finally, the current problems and future perspective of MnFe2O4-based nanoparticles were proposed. The highlight of this review is to compare the removal performance of MnFe2O4-based nanoparticles with the different hybrids. This review is crucial for the application of MnFe2O4-based nanoparticles in the environmental remediation.

Overcoming metals redox rate limitations in spinel oxide-driven Fenton-like reactions via synergistic heteroatom doping and carbon anchoring for efficient micropollutant removal

The transition metals redox rate limitations of spinel oxides during Fenton-like reactions hinder its efficient and sustainable treatment of actual wastewater. Herein, we propose to optimize the electronic structure of Co-Mn spinel oxide (CM) via sulfur doping and carbon matrix anchoring synergistically, enhancing the radicals-nonradicals Fenton-like processes for efficient water decontamination. Activating peroxymonosulfate (PMS) with optimised spinel oxide (CMSAC) achieved near-complete removal of ofloxacin (10 mg/L) within 6 min, showing 8.4 times higher efficiency than CM group. Significantly higher yields of SO4·- and high-valent metal species in CMSAC/PMS system provided exceptional resistance to co-existing anions, enabling efficient removal of various emerging contaminants in high salinity leachate. Specifically, sulfur coordination and carbon anchoring-induced oxygen vacancy synergistically improved the electronic structure and electron transfer efficiency of CMSAC, thus forming highly reactive Co sites and significantly reducing the energy barrier for Co(IV)=O generation. The reductive sulfur species facilitated the conversion of Co(III) to Co(II), thereby maintaining the stability of the catalytic activity of CMSAC. This work developed a synergistic optimization strategy to overcome the metals redox rate limitations of spinel oxides in Fenton-like reactions, providing deep mechanistic insights for designing Fenton-like catalysts suitable for practical applications.

Advances in Inorganic Foam Materials Fabricated Via Blowing Strategy: A Comprehensive Review

Two-dimensional (2D) materials with excellent properties and widespread applications have been explosively investigated. However, their conventional synthetic methods exhibit concerns of limited scalability, complex purification process, and incompetence of prohibiting their restacking. The blowing strategy, characterized by gas-template, low-cost, and high-efficiency, presents a valuable avenue for the synthesis of 2D-based foam materials and thereby addresses these constraints. Whereas, its comprehensive introduction has been rarely outlined so far. This review commences with a synopsis of the blowing strategy, elucidating its development history, the statics and kinetics of the blowing process, and the choice of precursor and foaming agents. Thereafter, we dwell at length on across-the-board foams enabled by the blowing route, like BxCyNz foams, carbon foams, and diverse composite foams consisting of carbon and metal compounds. Following that, a wide-ranging evaluation of the functionality of the foam products in fields such as energy storage, electrocatalysis, adsorption, etc. is discussed, revealing their distinctive strength originated from the foam structure. Finally, after concluding the current progress, we provide some personal discussions on the existing challenges and future research priorities in this rapidly developing method.

Constructing High-Performance Cobalt-Based Environmental Catalysts from Spent Lithium-Ion Batteries: Unveiling Overlooked Roles of Copper and Aluminum from Current Collectors

Converting spent lithium-ion batteries (LIBs) cathode materials into environmental catalysts has drawn more and more attention. Herein, we fabricated a Co3O4-based catalyst from spent LiCoO2 LIBs (Co3O4-LIBs) and found that the role of Al and Cu from current collectors on its performance is nonnegligible. The density functional theory calculations confirmed that the doping of Al and/or Cu upshifts the d-band center of Co. A Fenton-like reaction based on peroxymonosulfate (PMS) activation was adopted to evaluate its activity. Interestingly, Al doping strengthened chemisorption for PMS (from -2.615 eV to -2.623 eV) and shortened Co-O bond length (from 2.540 Å to 2.344 Å) between them, whereas Cu doping reduced interfacial charge-transfer resistance (from 28.347 kΩ to 6.689 kΩ) excepting for the enhancement of the above characteristics. As expected, the degradation activity toward bisphenol A of Co3O4-LIBs (0.523 min-1) was superior to that of Co3O4 prepared from commercial CoC2O4 (0.287 min-1). Simultaneously, the reasons for improved activity were further verified by comparing activity with catalysts doped Al and/or Cu into Co3O4. This work reveals the role of elements from current collectors on the performance of functional materials from spent LIBs, which is beneficial to the sustainable utilization of spent LIBs.

A Sunlight-Driven Self-Cleaning CuCo-MOF Composite Membrane for Highly Efficient Emulsion Separation and Water Purification

The fouling phenomenon of membranes has hindered the rapid development of separation technology in wastewater treatment. The integration of materials into membranes with both excellent separation performance and self-cleaning properties still pose challenges. Here, a self-assembled composite membrane with solar-driven self-cleaning performance is reported for the treatment of complex oil-water emulsions. The mechanical robustness of the composite membrane is enhanced by the electrostatic attraction between chitosan and metal-organic frameworks (MOF) CuCo-HHTP as well as the crosslinking effect of glutaraldehyde. Molecular dynamics (MD) simulations also revealed the hydrogen bonding interaction between chitosan and CuCo-HHTP. The composite membrane of CuCo-HHTP-5@CS/MPVDF exhibits a high flux ranging from 700.6 to 2350.6 L∙m-2∙h-1∙bar-1 and excellent separation efficiency (>99.0%) for various oil-water emulsions, including crude oil, kerosene, and other light oils. The addition of CuCo-HHTP shows remarkable photothermal effects, thus demonstrating excellent solar-driven self-cleaning capability and antibacterial performance (with an efficiency of ≈100%). Furthermore, CuCo-HHTP-5@CS/MPVDF can activate peroxomonosulfate (PMS) under sunlight, quickly removing oil-fouling and dyes. Density functional theory (DFT) calculations indicate that the bimetallic sites of Cu and Co in CuCo-HHTP effectively promoted the activation of PMS. This study provides distinctive insights into the multifaceted applications of MOFs-derived photothermal anti-fouling composite membranes.

Selective removal of thiosulfate from coke oven gas desulfurization wastewater by catalytic wet air oxidation with manganese-based oxide from spent ternary lithium-ion batteries

Selective and efficient removal of thiosulfates (S2O32-) to recover high-purity and value-added thiocyanate products by fractional crystallization process is a promising route for the resource treatment of coke oven gas desulfurization wastewater. Herein, catalytic wet air oxidation (CWAO), with manganese-based oxide synthesized from spent ternary lithium-ion batteries (MnOx-LIBs), was proposed to selectively remove S2O32- from desulfurization wastewater. 98.0 % of S2O32- is selectively removed by the MnOx-LIBs CWAO system, which was 4.1 times that of the MnOx CWAO system. The synergistic effect among multiple metals from spent LIBs induces the enlarged specific surface area, increased reactive sites and formation of oxygen vacancy, promoting the adsorption and activation of O2, thereby realizing high-efficiency removal of S2O32-. The satisfactory selective removal efficiency can be maintained in the proposed system under complex environmental conditions. Notably, the proposed system is cost-effective and applicable to actual wastewater, in which 81.2 % of S2O32- is selectively removed from coke oven gas desulfurization wastewater. More importantly, compared with the typical processes, the proposed process is simpler and more environmentally-friendly. This work provides an alternative route to selectively remove S2O32- from coke oven gas desulfurization wastewater, expecting to drive the development of resource utilization of coke oven gas desulfurization wastewater.

Ce/N @BC prepared based on plant metallurgy strategy: A novel activator of peroxymonosulfate for the degradation of sulfamethoxazole

A novel carbon catalyst was created based on plant metallurgy strategy for organic pollutants removal. Plants rich in CeO2 NPs in water were used as carbon precursors and pyrolyzed with urea to obtain Ce/N co-doped carbon catalysts, which were used in the degradation of sulfamethoxazole (SMX) by active peroxymonosulfate (PMS). The results showed that the Ce/N @BC/PMS system achieved to 94.5% degradation of SMX in 40 min at a rate constant of 0.0602 cm-1. The activation center of PMS is widely dispersed Ce oxide nanocrystals, and CeO2 NPs promote the formation of oxygen centered PFR with enhanced catalytic ability and longer half-life. In addition, N-doping facilitates the transfer of π-electrons within the sp2 carbon of biochar, increasing active sites and thus improving PMS activation efficiency. The degradation process was contributed to by both radical and non-radical activation mechanisms including 1O2 and direct electron transfer, with O2•- serving as 1O2's precursor. Through the DFT calculations, LC-MS and toxicological analyses, the degradation pathway of pollutants and the toxicity changes throughout the entire degradation process were further revealed, indicating that the degradation of SMX could effectively reduce ecological toxicity.