Graphitic carbon-encapsulated V2O5 nanocomposites as a superb photocatalyst for crystal violet degradation

Enhanced photocatalytic crystal-violet degradation performances of sonochemically-synthesized AC-CeO2 nanocomposites

Semiconductor-based photocatalysis is one of the favorable techniques for the wastewater treatment. Herein, we synthesized the activated carbon-decorated cerium dioxide (AC-CeO₂) nanocomposites via the facile ultrasonication method by using the biomass-derived AC nanoflakes and the sonochemically-synthesized CeO₂ nanoparticles. The AC-CeO₂ nanocomposites exhibited the aggregated morphology with the AC nanoflakes-anchored CeO₂ nanoparticles. Since the hybridization of conductive AC and semiconductive CeO₂ would lead to the increased photocarrier transport and the reduced photocarrier recombination, during the photocatalytic reaction, the AC-CeO₂ nanocomposites showed the enhanced crystal violet dye-degradation efficiency up to 97.9 % within 135 min. The results suggest that the AC-CeO₂ nanocomposites hold promise as a prominent photocatalyst for future green environmental technology.

Resource utilization of tannery sludge to prepare biochar as persulfate activators for highly efficient degradation of tetracycline

In this work, a low-cost carbon-based catalyst (TSBC) was prepared by the facile one-pot pyrolysis of tannery sludge (TS) and used to activate persulfate (PS) for tetracycline (TC) removal. The results showed that TSBC-500 exhibited optimal physicochemical properties and the best performance for PS activation to remove TC from drinking water. Approximately 99.1% of TC was removed in the TSBC-500/PS system, which was considerably higher than those in the TSBC-500 adsorption and pure PS systems. Radical quenching experiments indicated that •OH and SO₄•^- played major roles in the TC removal in the TSBC-500/PS system. In addition, transition metals, functional groups, and the high degree of carbon structural defects were beneficial for PS activation to degrade TC. This study not only newly contributes to high-value utilization of TS as a PS activator but also offers an efficient method for the removal of organic pollutants.

Recent advances in waste-derived functional materials for wastewater remediation

Water pollution is a major concern for public health and a sustainable future. It is urgent to purify wastewater with effective methods to ensure a clean water supply. Most wastewater remediation techniques rely heavily on functional materials, and cost-effective materials are thus highly favorable. Of great environmental and economic significance, developing waste-derived materials for wastewater remediation has undergone explosive growth recently. Herein, the applications of waste (e.g., biowastes, electronic wastes, and industrial wastes)-derived materials for wastewater purification are comprehensively reviewed. Sophisticated strategies for turning wastes into functional materials are firstly summarized, including pyrolysis and combustion, hydrothermal synthesis, sol-gel method, co-precipitation, and ball milling. Moreover, critical experimental parameters within different design strategies are discussed. Afterward, recent applications of waste-derived functional materials in adsorption, photocatalytic degradation, electrochemical treatment, and advanced oxidation processes (AOPs) are analyzed. We mainly focus on the development of efficient functional materials via regulating the internal and external characteristics of waste-derived materials, and the material's property-performance correlation is also emphasized. Finally, the key future perspectives in the field of waste-derived materials-driven water remediation are highlighted.

Honeycomb-like V2O5 Based Films: Synthesis, Structural, Thermal, and Optical Properties for Environmental Applications

In the present study, new composite films consisting of hierarchical nanobelt V2O5 and polymer mixture were prepared via a simple casting method. The incorporation of 30 wt.% of V2O5 into the polymer matrix yielded a honeycomb like structure with abundant micro-voids (5.5 μm), higher roughness average by 45.8%, and a higher root mean square roughness by 52%, which are beneficial for the enhancement of active surface area for dye adsorption. Furthermore, optical property studies have shown that the incorporation of V2O5 has made the nanocomposite film a suitable UV–visible light-sensitive material, and thus the application of films can be expanded towards photocatalytic degradation of various toxic pollutants such as nitrophenol, Cr(VI), antibiotects, and so on. Finally, the composite film exhibited enhanced thermostability in comparison to unmodified film, as confirmed by TGA and DSC analysis. The optimal film showed 96.3% removal efficiency and 27.02 mg/g adsorption capacity. The dye sorption performance of V2O5 based films is studied at various times, dosages, and initial dye concentrations. The experimental data more closely fit the Langmuir isotherm model (R2 = 0.997) than the Freundlich, Temkin, and Dubinin–Radushkevich isotherm models, demonstrating a monolayer adsorption mechanism. The MB adsorption process on V2O5 film was controlled by the chemical adsorption step, which was evidenced by the good-fitting of kinetic adsorption results to the pseudo second order model (R2 = 0.991). The obtained results indicated that the V2O5 based films in this work are hopeful candidates for environmental applications.