Comparative study of oxidative degradation of Quinoline in aqueous solution by UV/PS, UV/PS/Fe2+ and UV/PS/Cu2+

The main aim of the present study was tofocus on Advanced Oxidation Processes (AOPs) based on the activation persulfate (PS) by metal ion and ultraviolet (UV) radiation, which effectively degrades organic pollutants by enhancing sulfate radical (SO4•−) generation. This study compared the three processes for degrading quinoline (Qu), namely,UV/PS,UV/PS/Fe2+ and UV/PS/Cu2+and indicated differing degradation kinetics among thesethree types of activation system.Activation of persulfate by Fe2+ ions generally resulted in rapid degradation in the early stage, but was accompanied by a dramatic decrease in efficiency due to the rapid depletion of Fe2+ by the sulfate radicals generated. In contrast, the Cu2+as persulfate activator, compared to Fe2+, had a longer-lasting effect on Qu degradation. In general, the degradation rate of Qu by UV/PS was slower than thoseof UV/PS/Fe2+and UV/PS/Cu2+. The effects of pH, initial concentration of the oxidants, initial concentration of Qu, and initial concentration of ferrous and copper on Qu degradation were also examined. Under the optimum conditions of pH = 6, [Qu]0= 40 mg/L,[Fe2+]= 1 mg/L, [Cu2+]= 1 mg/L and [PS] = 1000 mg/L for UV/PS,UV/PS/Fe2+ and UV/PS/Cu2+ , about 88.3%, 95.2% and 96.4% Qu degradations were achieved after 70 min treatment. Meanwhile, kinetics and the energy consumption per order were investigated. Similarly, total organic carbon (TOC) content removal were 31.2%, 36.1% and 82.2% respectively after 120 min.

Keywords:

Quinoline , persulfate activated , degradation , UV irradiation