Recent Advances and Perspectives of Industrial Solid Waste for Heavy Metal Wastewater Treatment: A Review

Heavy metal wastewater, characterized by high toxicity, poor biodegradability, and strong bioaccumulation potential, poses a serious threat to the ecological environment and human health. Conventional chemical treatment methods are costly and prone to secondary pollution. In contrast, using solid waste to prepare environmental functional materials for “waste control by waste” has emerged as a research hotspot in the field of synergistic water pollution control and resource recovery. This review systematically consolidates the sources, physicochemical properties, and compositional characteristics of typical industrial solid wastes—including red mud, electroplating sludge, fly ash, copper slag, and blast furnace slag—and elucidates how compositional variations constrain the selection of functionalization pathways. On this basis, key preparation techniques, namely hydrothermal synthesis, surface modification/impregnation, thermal treatment, geopolymerization, and sol–gel/polymerization, are critically reviewed and compared in terms of product structural regulation, process complexity, and engineering scale-up potential. Subsequently, the adsorption performance of the resultant materials toward heavy metals such as Pb2+, Cu2+, Cr(VI), As(VI), Cd2+, Ni2+, and Zn2+ is discussed, with particular emphasis on the pronounced effects of pH, temperature, initial concentration, coexisting ions, and adsorbent dosage on adsorption capacity. Notably, Pb2+ exhibits the highest adsorption capacity, whereas the removal of Cr(VI) and As(V) is strongly governed by the positive charge density and reduction efficiency of the material surface. In quinary heavy metal competitive systems, marked differences in the affinity of adsorption sites toward distinct metal ions have been observed. Mechanistic analysis identifies ion exchange, surface complexation, electrostatic attraction, and redox reactions as the predominant removal pathways. This review further incorporates engineering-oriented assessments, including multi-component competitive adsorption, fixed-bed column operation, and regeneration stability, and identifies the critical bottlenecks currently impeding the transition from laboratory-scale research to practical implementation—namely, performance instability arising from feedstock variability, attenuation of adsorption capacity during prolonged operation (with a 10–40% decline over 5–10 cycles), underdeveloped regeneration and recovery routes, and a systemic deficiency in techno-economic analysis and life-cycle assessment data. Finally, future research directions are proposed, emphasizing the development of low-carbon and energy-efficient preparation technologies, the promotion of synergistic valorization of multiple solid wastes alongside critical metal recovery, and the advancement of this field toward engineering applications through artificial intelligence-assisted design and life-cycle assessment, thereby furnishing theoretical references and technical support for the integrated management of industrial solid waste resource utilization and heavy metal wastewater treatment.