Decomposition of Perfluorooctanoic Acid (PFOA) in Water by Persulfate-induced via Microwave Irradiation

The perfluorinated compounds (PFCs) have the environmental persistence, bioaccumulation, and potential toxicity to humans. The PFCs has high stability that ascribed to their C-F bonds, have no known natural decomposition processes. Therefore, developing effective methods to degrade PFCs becomes F- and CO2 is important. Perfluorooctanoic acid (PFOA) is the main study pollutants of this research. With the methods of oxidizing PFCAs by using persulfate under microwave field, which increasing PFOA and perfluorooctane sulphonate (PFOS) decomposition rate. And we choose the activator as the persulfate of zero valent iron utilize it from ferrous ion, which could activate persulfate to from sulfate radicals. This study discusse the PFOA decomposition at different concentration of PS and dosage of ZVI under different temperature and pH. According to the experimental results, the PS/MW processes of degradation efficiency of the PFOA at 130℃. PFOA decomposition increased from 0% to 84.3% while pH value decreased from 11 to 2 for a half hour. The influence of persulfate concentration, the pseudo first-order rate constants (k) is 1.29 times higher at 5 mM and 4.31 times higher at 10 mM than at 1 mM. Within 1 hours, more than 98% of PFOA was decomposed at 140℃ with 5 mM persulfate. And the PS/ZVI/MW processes more effective degraded PFOA. The k value of MW, PS/MW, PS/ZVI/MW processes were 4.0×10-3 h-1, 9.7×10-2 h-1 and 2.3×102 M-1h-1(second order), respectively. The best optimum condition applies on PFOS. The result demonstrated that, more than 75.0% of PFOS was decomposed within 30 minute at PS/ZVI/MW processes.