A kinetic and mechanistic study of the degradation of 1, 2-dichloroethane and methyl tert-butyl ether using alkaline-activated persulfate oxidation. Issue 79 (9th August 2016)

• Record Type: Journal Article
• Authors: Chen, Ku-Fan; Chang, Yu-Chen; Liu, Kuan-Yu
• Is Part Of: RSC advances. Volume 6:Issue 79(2016)
• Page Start: 75578
• Page End: 75587
• Publication Date: 2016-08-09
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c6ra16050f
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : Alkaline-activated persulfate accelerates the degradation of 1, 2-dichloroethane (1, 2-DCA) while the rate of degradation of methyl tert -butyl ether (MTBE) in alkaline-activated persulfate system is decreased. Abstract : In this study, alkaline-activated persulfate is used to treat groundwater that is contaminated with 1, 2-dichloroethane (1, 2-DCA)- and methyl tert -butyl ether (MTBE). The results show that alkaline-activated persulfate accelerates the degradation of 1, 2-DCA. Vinyl chloride is produced because there is dehydrochlorination of 1, 2-DCA at high pH. Although the rate of degradation of MTBE in alkaline-activated persulfate systems is decreased, there is a significant reduction in the accumulation of MTBE-degrading byproducts, tert -butyl alcohol and tert -butyl formate. Alkaline-activated persulfate degrades 1, 2-DCA via the mechanisms of oxidation and dehydrochlorination, but oxidation alone contributes to the removal of MTBE. The use of low-cost basic oxygen furnace (BOF) slag increases the pH of the solution (>12) and allows the alkaline-activated persulfate reaction to proceed. No detectable heavy metals are released from the BOF slag in the persulfate system that is activated by BOF slag. The degradation of 1, 2-DCA and MTBE follows the pseudo-first-order kinetics for all persulfate systems. Alkaline-activated persulfate causes a decrease in ORP because there is a high pH, which adversely affects the removal of contaminants if the contaminants do not undergo base-mediated degradation. Therefore, the performance in terms of contaminant removal must be evaluated before alkaline-activated persulfate is used for different compounds. This novel, slag-activated persulfate system is an environmentally friendly and cost-effective alternative to the remediation of groundwater.