In situ P‑functionalized geopolymer microspheres derived from Fe‑rich rubber sludge: A dual‑channel system for enhanced peroxymonosulfate activation and concurrent pollutant removal

The development of environmental and cost‑effective materials capable of simultaneously adsorbing heavy metals and degrading organic pollutants is essential for the safe treatment of industrial wastewater. In this study, porous rubber sludge‑based geopolymer microspheres (RS‑Ms) were fabricated from iron/phosphorus‑rich rubber sludge via alkali‑activation and suspension solidification. In a peroxymonosulfate (PMS) activation system, the RS‑Ms achieved complete degradation (100%) of tetracycline within 20 min, being 10.2 times faster than powdered rubber sludge, while simultaneously adsorbing Cu 2 + with a capacity of 24.5 mg·g⁻¹ . The high performance originates from the hierarchical porous structure that exposes abundant iron sites, and the intrinsic phosphorus that modulates the iron electronic structure, promoting electron transfer to PMS. Notably, Cu 2+ incorporated into the geopolymer framework via ion exchange acts as an “electron shuttle”, accelerating the Fe 3+ /Fe 2+ cycle and enhancing tetracycline degradation by 1.6‑fold in co‑pollutant systems. Mechanism studies indicate Cu 2+ removal occurs through complexation, hydrogen bonding, electrostatic adsorption, and ion exchange, while tetracycline degradation follows synergistic radical (•OH, SO 4 •− ) and non‑radical ( 1 O 2 ) pathways. The RS‑Ms/PMS system also demonstrated excellent stability, broad pH adaptability, and strong anti‑interference capacity in simulated real water. This work provides a feasible and safe strategy for valorizing industrial sludge into dual‑functional remediation materials, contributing to sustainable and hazard‑conscious wastewater treatment practices. Download: Download high-res image (224KB) Download: Download full-size image