A novel and green strategy for efficient removing Cr(VI) by modified kaolinite-rich coal gangue

In this study, a novel adsorbent CM/CTAB based on solid waste coal gangue (CG) and hexadecyltrimethyl ammonium bromide (CTAB) was successfully synthesized through intercalation and modification method for the first time. The adsorption experiment results indicated that the adsorbent displayed excellent removal performance and high selectivity toward Cr(VI). The maximum adsorption capacity of CM/CTAB toward Cr(VI) was 55.09 mg/g and the removal efficiency could reach 85% within 15 min, which were better than those of most reported mineral-based adsorbents. The enhanced adsorption performance was mainly related to the synergistic effect of Cr(VI) adsorption and reduction. The adsorption process was better fitted by pseudo-second-order and Langmuir isotherm model. This work provides an efficient adsorbent for Cr(VI) removal and contributes an idea for comprehensive utilizing of solid wastes.