Pumice-loaded rGO@MnO2 nanomesh photocatalyst with visible light response for rapid degradation of ciprofloxacin

Abstract

The agglomeration and recycling of nano-photocatalytic materials are still a big problem restricting the practical application of photocatalytic technology. Natural porous pumice with adsorption capacity provides an innovative approach to this challenge. Herein, the pumice supported reduced graphene oxide and MnO2 (PS@rGO@MnO2) was designed as a visible-light-driven solid photocatalyst. The PS@rGO@MnO2 possessed good photocatalytic performance, and the removal rate of ciprofloxacin (CFX) reached 80.00% with simulated solar irradiation for 6 h, and the degradation rate constant was 4.2 times that of blank pumice. The degradation rates of CFX in secondary effluent, lake water, and river water can reach 62.15%, 68.33%, and 67.63%, respectively. Hole (h+) and superoxide radical (O2−) are the main reactive oxygen species. The material test results revealed that the enhanced photocatalytic performance of PS@rGO@MnO2 was due to the improvement of light utilization rate, the reduction of electron-hole pair recombination rate, and the improvement of charge separation efficiency and transfer efficiency. ECOSAR model predictions indicate that CFX can effectively reduce toxicity in photocatalytic reactions. The removal performance of actual natural water verified that the material was of great practical application potential.