Ascorbic acid/Fe0 composites as an effective persulfate activator for improving the degradation of rhodamine B
Abstract
An ascorbic acid/Fe0 composite (H2A/Fe0)-activated persulfate (PS) process was provided for rhodamine B (RhB) removal. Experimental results demonstrated that the H2A/Fe0–PS system exhibits a rapid and continuous oxidation of organic contaminants, and shows great advantages over the conventional Fe0–PS system by significantly improving removal efficiency. This H2A induced dramatic enhancement for RhB degradation could be attributed to both the reduction and chelating ability of H2A. The H2A/Fe0 composites were characterized using TEM, FE-SEM, FTIR and XPS, indicating that the obtained H2A/Fe0 composites were prepared successfully. Key factors affecting the treatment were determined for the H2A/Fe0–PS system, including H2A/Fe0 dosage, PS dosage, initial solution pH and temperature. Moreover, radical quenching tests revealed that sulfate radicals (SO4˙−), hydroxyl radicals (˙OH) and superoxide radicals (O2˙−) were generated in the H2A/Fe0–PS system, and SO4˙− was the main radical species responsible for RhB degradation. Finally, possible degradation pathways are proposed. These findings prove that the H2A/Fe0–PS system may provide a simple and effective technology for improving the degradation of refractory organic pollutants.