Municipal solid waste incineration fly ash (MSWI-FA) is a hazardous by-product of the incineration process, characterized by elevated levels of heavy metals, chlorides, and dioxins. With a composition high in calcium but low in silicon/aluminum, MSWI-FA exhibits a poor immobilization effect, high energy demands, and limited pozzolanic activity when it is disposed of or reutilized alone. Conversely, alumina-/silica-containing waste (ASW) presents a chemical composition rich in SiO₂ and/or Al₂O₃, offering an opportunity for synergistic treatment with MSWI-FA to facilitate its harmless disposal and resource recovery. Despite the growing interest in co-treatment of MSWI-FA and ASW in recent years, a comprehensive evaluation of ASW's roles in this process remains absent from the existing literature. Therefore, this study endeavors to examine the advancement in the co-treatment of MSWI-FA and ASW, with the focus on three key aspects, i.e., elucidating the immobilization mechanisms by which ASW improves the solidification/stabilization of MSWI-FA, exploring the synergies between MSWI-FA and ASW in various thermal and mechanochemical treatments, and highlighting the benefits of incorporating ASW in the production of MSWI-FA-based building materials. Additionally, in the pursuit of sustainable solid waste management, this review identifies research gaps and delineates future prospects for the co-treatment of MSWI-FA and ASW.

A coal fly ash/CoFe₂O₄ (CFA/CFO) magnetic composite was synthesized by a facile hydrothermal synthesis method, and then used as an adsorbent for the removal of malachite green (MG) dye from water. The structure, morphology, and properties of the composite were characterized by XRF, SEM, XRD, FT-IR, BET and VSM techniques. A batch adsorption experiment on the removal of MG was performed with CFA/CFO, and the effect of various experimental parameters, such as the adsorbent dosage and contact time of MG at 25 °C, were investigated. Three isotherm models, namely the Langmuir, Freundlich, and Dubinin–Kaganer–Radushkevich (DKR) models, were applied to describe the adsorption process. The results indicated that the Freundlich and DKR models fit quite well with the experimental data. Thermal and microwave methods were used and compared in the regeneration experiment. All the results indicated that the as-prepared composite should be considered as a potential low-cost adsorbent for easy and efficient removal of MG from water.