Enhanced adsorption properties of polyoxometalates/coal gangue composite:The key role of kaolinite-rich coal gangue

As a kind of solid waste, kaolinite-rich coal gangue (CG) occupies many lands and brings great pollution to the environment. Ciprofloxacin (CIP), as a widely used antibiotic, can not only easily lead to bacterial resistance, but also cause serious impacts on the environment and thus threaten human health. Therefore, the comprehensive utilization of kaolinite-rich CG and removal of CIP are definitely imminent. In this study, a series of adsorbents ammonium phosphotungstate/CG (NH4-PW/CG) were synthesized through a simple precipitation method using kaolinite-rich CG as a support for the removal of CIP. The obtained NH4-PW/CG displayed the excellent adsorption efficiency (82%) toward CIP within 10 min, which was much higher than NH4-PW (25%) and CG (10%), respectively. The presence of kaolinite-rich CG made the surface charges of composite NH4-PW/CG more negative and the particle size of NH4-PW smaller, both of which contributed to the enhanced adsorption efficiency of NH4-PW/CG. This work offers a new strategy for the comprehensive utilization of kaolinite-rich CG and provides an efficient adsorbent for the removal of positively charged pollutants.