Research progress of coal gangue-based modified materials and the sewage treatment field

Abstract

Coal has long been a significant component of China's energy system, and solid waste products from continuous mining, including coal gangue, have raised serious environmental issues. An exponential growth trend in the accumulation volume of coal gangue not only exacerbates the ecological carrying pressure of the mining area but also contributes to the cross-pollution of water, soil, and gas ecosystems through dust diffusion, heavy metal leaching, and other ways. Technical and financial limitations keep the resource conversion rate and added value at a low level, despite the current disposal technology system having established core application modes, such as ecological restoration in mining regions and substituting for building aggregate. The directional activation of coal gangue makes it highly promising for applications in sewage treatment, as it creates an abundance of active sites and unique porous structures on its surface. This review systematically summarizes the research progress on coal gangue-based modified materials in the field of sewage treatment, focusing on their physicochemical properties, adsorption, and photocatalytic reaction mechanisms. Research methods for modifying coal gangue include physical, chemical, biological, and other techniques. Modified materials derived from coal gangue encompass a range of composite materials, functional materials, and other types of materials. The text also addresses the limitations and challenges faced in the development of these modified materials. Furthermore, it provides recommendations for the future utilization of coal gangue resources, serving as a valuable reference for scholars in related fields.