Advances in the preparation and application of coal gasification slag-based adsorbent materials

With the development of the coal chemical industry, the emission of coal gasification slag (CGS) has grown rapidly, raising widespread concerns about environmental pollution and resource waste. The composition and structural characteristics of CGS, such as high contents of carbon, silicon, and aluminum and well-developed pores, enable the preparation of CGS-based adsorbent materials for wastewater treatment and gas purification, thus promoting high-value resource utilization of CGS and achieving the goal of “treating waste with waste.” On the basis of the compositional and structural characteristics of CGS being summarized in this review, the preparation methods of CGS-based adsorbent materials, such as activated carbon, zeolite, mesoporous silica, and carbon–silica composites, are systematically outlined as well as their preparation mechanisms are deeply elucidated. Then, the current application status and adsorption mechanisms of various types of CGS-based adsorbent materials in the fields of wastewater treatment and gas purification, such as heavy-metal removal, nitrate removal, ammonia–nitrogen removal, dye removal, CO 2 absorption, and pollutant adsorption–catalytic degradation, are fully discussed. Finally, bottlenecks and key research directions in the preparation of high-value-added adsorbent materials from CGS are summarized and prospected. This review is of significant relevance in promoting the product development and industrial application of CGS in the field of adsorption.