Heterogeneous activation of peroxymonosulfate by Fe-Co layered doubled hydroxide for efficient catalytic degradation of Rhoadmine B

Nowadays, increasing attention has been paid to the sulfate radical (SO4−) due to its high oxidation efficiency for refractory organic pollutants. In this study, a novel heterogeneous catalyst, Fe-Co layered doubled hydroxide (FeCo-LDH) was prepared by co-precipitation method for the activation of peroxymonosulfate (PMS). The characterization results showed that FeCo-LDH with Fe:Co ratio of 1:2 had high purity and crystallographic structure. With Rhodmine B (RhB) as the model organic pollutant, FeCo-LDH (1:2)/PMS system exhibited much superior degradation performance, which was comparative to homogeneous Co(II)/PMS system. The effect of various parameters, such as temperature, initial pH, initial RhB concentration, PMS dosage and catalyst loading on the RhB degradation was discussed in detail. The RhB oxidation in FeCo-LDH/PMS system can be described well by pseudo-first-order kinetic and the activation energy was calculated as 59.71 kJ/mol. The quenching experiments using ethanol and tert-butyl alcohol (TBA) as radical scavengers indicated that both SO4− and OH radicals were generated in FeCo-LDH/PMS system and SO4− radicals acted as the predominant reactive species. The good stability and catalytic activity of as-prepared solid catalyst after used repeatedly as well as in different water sources revealed its potential in practical application.