Reinforcement in synergism of photocatalysis/persulfate activation for the removal of ciprofloxacin via coupling photoinduced electrons and FeOOH quantum dots

Abstract

Recently, the simultaneous photocatalysis/persulfate activation (SPPA) system is considered as a desirable strategy for the efficient decomposition of organic pollutants. In a SPPA system, an appropriate photocatalysts will play a vital role for achieving a high degradation efficiency. Herein, FeOOH quantum dots (QDs) were embedded on flower-like SnS₂ to develop a novel composite material FeOOH/SnS₂ (Fe-SS), and a SPPA system (named as Vis/Fe-SS/PS system) was constructed for the removal of ciprofloxacin (CIP). Compared with SnS₂ and FeOOH, the fabricated Fe-SS composites exhibit outstanding Visible light absorption, accelerated photocarriers transfer, and significantly boosted ability for sulfate activation, thus presenting high performance for the degradation of CIP. The optimum Vis/15Fe-SS/PS achieves 84 % of CIP degradation efficiency and 32 % of mineralization rates. The high performance of Vis/15Fe-SS/PS resulting from the synergism of photoinduced electrons and FeOOH QDs in persulfate activation. Combining the band position and the results from capture experiments and electron spin resonance (ESR) tests, the possible mechanism of Vis/15Fe-SS/PS system was proposed. The photoinduced electrons not only was captured by O₂ to generate ·O₂⁻ but also was accepted by FeOOH to activate PS to SO₄^·- for the removal of CIP via the successive redox circulation of Fe(III)/Fe(II). In addition, Vis/15Fe-SS/PS possesses good stability and higher removal rate toward other organic contaminants, showing the wide application in the organic wastewater treatment. This work is expected to offer ideas for the design of novel catalytic materials for the activation of PS.