The 10th International Conference on Energy, Resources, Environment and Sustainable Development (ERESD 2024)

    Coal gasification fine slag (GFS), a difficult-to-dispose solid waste in the coal chemical industry, consists of minerals and residual carbon, which has great potential for resource utilization. However, due to the aggregate structure of minerals and its complex embedding patterns in the carbon matrix, the high-value utilization of GFS remains challenging. Based on the intrinsic characteristics of GFS, this study synthesized various porous carbon/minerals interwoven electrocatalysts for electrochemical oxidation of phenolic wastewater. Meanwhile, minerals were utilized to regulate the surface chemical and pore structure of electrocatalysts, turning disadvantages of minerals into advantages, which caused a sharp increase in wastewater treatment capacity. The positive effect of minerals on electrocatalyst properties was investigated by characterization techniques, electrochemical analyses and DFT calculations. It was found that silicate mediated iron conversion through strong interaction with H₂O₂, high work function gradient with electroactive iron, and excellent •O₂^- production capacity improved the reversibility and kinetics of the entire electrocatalytic reaction. Within the electrocatalytic system, the m-cresol removal rate reached 99.55±1.24%, surpassing most reported electrocatalysts. The adsorption and electrooxidation experiment confirmed that the carbon exhibited a hierarchical porous structure, facilitating the entry of H₂O₂ into the catalytic sites of minerals. Abundant catalytic sites in minerals accelerated adsorption and oxidation processes on carbon surfaces. More importantly, the synergy of carbon and minerals effectively shortened the diffusion path of short-lived radicals to degrade phenolic wastewater. Hence, this research provides new insights into the problem of mineral limitations and opens an innovative approach for GFS recycling and environmental remediation.

gasification fine slag,phenolic wastewater,composite electrocatalyst,electrochemical advanced oxidation,synergistic effect