Stability of dissolved percarbonate and its implications for groundwater remediation.

Efforts to improve the understanding of oxidant stability are of great practical significance to the design of an in-situ chemical oxidation (ISCO) system for soil and groundwater remediation. In this study, the stability of an emerging ISCO oxidant sodium percarbonate (SPC) was investigated. Although the dry solid form of SPC is relatively stable, dissolved SPC decomposes much faster than H2O2. SPC had higher oxidation efficiency for the dye Orange G than inactivated or alkaline-activated H2O2. Both OH− and HCO3−/CO3a2−, generated from SPC dissolution, activated the peroxide content of SPC and thus promoted its decomposition and pollutant oxidation. Higher incubation temperature and longer incubation period lead to faster SPC decomposition. Decomposed SPC had lower pollutant oxidation capability.