Degradation of trichloroethylene by zero-valent iron immobilized in cationic exchange membrane

Abstract

Zero-valent iron (ZVI) immobilized in cationic exchange membrane (CEM) was investigated for the degradation of trichloroethylene (TCE). Using a commercial CEM as a support, it was possible to immobilize ZVI conveniently. According to the surface analysis, the nanoparticles were formed on the surface of CEM after immobilization and the size of them was 30–40 nm. The ZVI-immobilized CEM (Fe(0)-CEM) contained 75 mg Fe/m 2 membrane. The removal of TCE was accomplished by sorption on the membrane matrix and degradation by the immobilized ZVI. About 36.2 mg/L of TCE was removed within initial 2 h and the observed rate constant ( k obs) was 0.44 h −1. The value of surface area normalized rate constant ( k SA) of Fe(0)-CEM was 35.77 L h −1 m −2. The obtained k SA was higher than other studies on the nanoparticles or the membrane-immobilized nanoparticles by 1–3 orders of magnitudes. The higher k SA resulted from low metal loading (ca. 6.5 mg/L) in this test. Moreover the released iron concentration to aqueous phase was very low (0.1–0.3 mg/L), In conclusion, the Fe(0)-CEM proposed in this study was effective in the TCE removal. And it would be possible to reuse the Fe(0)-CEM repeatedly after re-reducing it.