Cerium oxide /Co-Co Prussian blue analogue composite catalyst for enhanced peroxymonosulfate activation for effective removal of tetracycline hydrochloride from water

Abstract

In this paper, a novel CeO₂/Co₃[Co(CN)₆]₂ (CeO₂/PBA_Co-Co) composite was prepared with co-precipitation and utilized to activate peroxymonosulfate (PMS) to eliminate tetracycline hydrochloride (TCH). Catalyst screening showed that the composite with a CeO₂:PBA_Co-Co mass ratio of 1:5 (namely, 0.2-CeO₂/PBA_Co-Co) had the best performance. The degradation efficiency of TCH in 0.2-CeO₂/PBA_Co-Co/Oxone system was investigated. The experimental results illustrated that 98% of 50 mg/L TCH and 48.5% of TOC were degraded by 50 mg/L 0.2-CeO₂/PBA_Co-Co and 400 mg/L Oxone within 120 min at 25 °C and initial pH 5.3. Recycling studies showed that the elimination rate of TCH can still achieve 85.8% after five cycles, suggesting that 0.2-CeO₂/PBA_Co-Co composite processes good reusability. Trapping experiments and EPR tests revealed that the reaction system produced multiple active species (¹O₂, O₂^•-, SO₄^•-, and ^•OH). We proposed the catalytic mechanism of 0.2-CeO₂/PBA_Co-Co for PMS activation, which mainly involves the promoted Co³⁺/Co²⁺ cycle by Ce³⁺ donated electrons. These results indicate that CeO₂/PBA_Co-Co composite is an effective catalyst for wastewater remediation.

Keywords: CeO2; Co–Co Prussian blue analogs; Heterogeneous catalysis; Peroxymonosulfate; Pollutant removal; Tetracycline hydrochloride.