Oxidation and reduction performance of 1,1,1-trichloroethane in aqueous solution by means of a combination of persulfate and zero-valent iron

Abstract

16In this study, the degradation performance of 1,1,1-trichloroethane (TCA) involving both 17 oxidation and reduction processes was investigated with an application of the persulfate-ZVI 18 (zero-valent iron) system, in which it is generally believed that SO4 −• -induced oxidation was 19 responsible for pollutants removal. The study was conducted with persulfate and 20 un-pretreated ZVI through batch experiments. The results showed that TCA was stable in the 21 presence of ZVI alone within 12 h and degraded with the addition of persulfate. TCA 22 degradation efficiency was found to increase with increasing persulfate concentrations, but to 23 decrease with increasing ZVI dosage. A two-stage process involving persulfate oxidation and 24 ZVI reduction was developed during TCA degradation. The addition of isopropanol and 25 tert-butyl alcohol proved the existence of sulfate and hydroxyl radicals during the 1st-stage 26 (0~2 h), which were absent in the 2-nd stage (2~12 h) when persulfate was exhausted. The 27 degradation performance of carbon tetrachloride, a reduction probe compound, was evidence 28 of the persulfate-ZVI system involving an enhanced ZVI reduction, and which was mainly 29 responsible for TCA degradation in the 2nd-stage. 1,1-Dichloroethane was the only 30 confirmed intermediate emerging during the 2nd-stage. 31

Systematic Performance Comparison of Fe3+/Fe0/Peroxymonosulfate and Fe3+/Fe0/Peroxydisulfate Systems for Organics Removal

“…•and • OH for efficient oxidation of arsenic(III) in water, while Gu et al [14] reported that efficient removal of 1,1,1-trichloroethane can be achieved using a similar system. For the PMS system, Ghanbari et al [15] reported that the ZVI/PMS system can be used to efficiently decolorize textile wastewater.…”

“…Previously, ZVI has been employed to activate both PMS and PDS to generate ROS for pollutant removal. For instance, Hussain et al [ 13 ] reported that the ZVI/PDS system can be used to generate SO 4 •– and • OH for efficient oxidation of arsenic(III) in water, while Gu et al [ 14 ] reported that efficient removal of 1,1,1-trichloroethane can be achieved using a similar system. For the PMS system, Ghanbari et al [ 15 ] reported that the ZVI/PMS system can be used to efficiently decolorize textile wastewater.…”

Role of inorganic ions and dissolved natural organic matters on persulfate oxidation of acid orange 7 with zero-valent iron

“…Among the various activation methods, zero-valent iron (ZVI) activation of PS has appeared to be a promising method. [14][15][16] ZVI activation is a cost-effective, efficient and environmentally friendly technology. 14,17 Additionally, ZVI not only serves as a slow-releasing source of dissolved Fe 2+ , but also avoids adding other anions that can lead to scavenging of SO 4 À c and possibly reducing the oxidation efficiency.…”