Ascorbic acid/Fe0 composites as an effective persulfate activator for improving the degradation of rhodamine B

An ascorbic acid/Fe-0 composite (H(2)A/Fe-0)-activated persulfate (PS) process was provided for rhodamine B (RhB) removal. Experimental results demonstrated that the H(2)A/Fe-0-PS system exhibits a rapid and continuous oxidation of organic contaminants, and shows great advantages over the conventional Fe-0-PS system by significantly improving removal efficiency. This H(2)A induced dramatic enhancement for RhB degradation could be attributed to both the reduction and chelating ability of H(2)A. The H(2)A/Fe-0 composites were characterized using TEM, FE-SEM, FTIR and XPS, indicating that the obtained H(2)A/Fe-0 composites were prepared successfully. Key factors affecting the treatment were determined for the H(2)A/Fe-0-PS system, including H(2)A/Fe-0 dosage, PS dosage, initial solution pH and temperature. Moreover, radical quenching tests revealed that sulfate radicals (SO4-), hydroxyl radicals (OH) and superoxide radicals (O-2(-)) were generated in the H(2)A/Fe-0-PS system, and SO4- was the main radical species responsible for RhB degradation. Finally, possible degradation pathways are proposed. These findings prove that the H(2)A/Fe-0-PS system may provide a simple and effective technology for improving the degradation of refractory organic pollutants.