β-Bi₂O₃/BiVO₄/Mn_xZn_1−xFe₂O₄ (BV/MZF) composite magnetic photocatalyst was first synthesized using the hydrothermal and calcination method. BV/MZF was a mesoporous material with most probable pore size and specific surface area of 18 nm and 17.84 m²/g, respectively. Due to its high saturation magnetization (2.67 emu/g), the BV/MZF composite can be easily separated and recovered from solution under an external magnetic field. The results of photo-decomposition experiments show that the decomposition rate of Rhodamine B (RhB) by BV/MZF can reach 92.6% in 3 h under visible light. After three cycles, BV/MZF can still maintain structural stability and excellent pollutant degradation effect. In addition, analysis of the photocatalytic mechanism of BV/MZF for RhB shows that the p-n heterojunction formed in BV/MZF plays a vital role in its photocatalytic performance. This work has potential application in the future for solving environmental pollution.

This study aims to explore the solidification performance of municipal solid waste incineration fly ash (MSWIFA) through co-mechanical treatment with circulation fluidized bed combustion fly ash (CFBCFA). The mineral characterization, physical properties, and leaching resistance of the solidified bodies are investigated by X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FT-IR), Thermogravimetry-differential thermal analysis (TG-DTA), compressive strength, porosity, and leaching test, respectively. C–S–H, ettringite (AFt), and Friedel’s salt (FS) are the predominant hydrate products in the CFBCFA based solidified bodies, which are similar to the cement based solidified bodies. However, CFBCFA based solidified bodies exhibit higher compressive strength (36.7 MPa) than cement based solidified bodies (11.28 MPa), attributing to the three reasons: lower porosity and more compact internal structure of CFBCFA based solidified bodies; large amounts of Ca(OH)₂ originating from MSWIFA are conducive to promoting the hydration reaction extent and compressive strength of the CFBCFA based solidified bodies; excessive Ca(OH)₂ would cause compressive strength deterioration for the cement based solidified bodies. The heavy metals (Zn, Cu, Cr, Cd, and Pb) concentrations in the extraction solution of the CFBCFA based solidified bodies are far below the requirements of Chinese National Standard GB 5085.3-2007. The solidification of MSWIFA through co-mechanical treatment could be an ideal substitute for cement solidification technology.

This paper reports a novel magnetic composite photocatalyst ZnO/Bi₂₄O₃₁Br₁₀@SrFe₁₂O₁₉ (ZBBSF) fabricated via a hydrothermal method. The structural characteristics of ZBBSF and the probable photocatalytic mechanism for rhodamine-B (RhB) degradation under visible light were investigated. Application of ZBBSF in a primary treatment of landfill leachate was also evaluated. Crystal and microscopic structure analyses verified that SrFe₁₂O₁₉ successfully compounded with the ZnO/Bi₂₄O₃₁Br₁₀ composite (ZBB). The as-prepared ZBBSF composite displayed higher photocatalytic activity than ZBB for RhB degradation, and the decomposition level exceeded 95% after 30 min under visible light. Capturing experiments and electron spin resonance (ESR) analysis prove that •O₂ ^– and •OH are the dominant activated radicals in RhB degradation. ZBBSF exhibited considerable stability after five cycles. Furthermore, ZBBSF exhibited a notable decolourisation effect on landfill leachate, reaching 56% in 250 min under visible light. These findings suggest that ZBBSF is a new composite photocatalyst with high efficiency and recyclability for organic wastewater disposal.