Impacts of inorganic anions and natural organic matter on thermally activated persulfate oxidation of BTEX in water. (January 2018)

• Record Type: Journal Article
• Authors: Ma, Jie; Yang, Yongqi; Jiang, Xianchenghao; Xie, Zhuoting; Li, Xiaoxuan; Chen, Changzhao; Chen, Hongkun
• Is Part Of: Chemosphere. Volume 190(2018)
• Page Start: 296
• Page End: 306
• Publication Date: 2018-01
• Subjects: Aromatic hydrocarbons -- Degradation -- Sulfate radical -- Peroxydisulfate -- Remediation -- Intermediate; Persulfate PS -- Peroxymonosufate PMS -- Advanced oxidation process AOP -- Sulfate radical-based advanced oxidation process SR-AOP -- Benzene, toluene, ethylbenzene, and xylene isomers BTEX -- Natural organic matter NOM -- Humic acid HA; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2017.09.148
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: The present study investigated the impacts of water matrix constituents (CO3 2−, HCO3 −, Cl −, Br −, PO4 3−, HPO4 2−, H2 PO4 −, NO3 −, SO4 2− and natural organic matters (NOM) on the oxidation of a mixture of benzene, toluene, ethylbenzene, and xylenes (BTEX) by thermally activated persulfate (PS). In the absence of matrix constituents, the BTEX oxidation rates decreased in the following order: xylenes > toluene ≈ ethylbenzene > benzene. HCO3 − /CO3 2− and NOM inhibited the BTEX oxidation and the inhibiting effects became more pronounced as the HCO3 − /CO3 2− /NOM concentration increased. SO4 2−, NO3 −, PO4 3− and H2 PO4 − did not affect the BTEX oxidation while HPO4 2− slightly inhibited the reaction. The impacts of Cl − and Br − were complex. Cl − inhibited the benzene oxidation while 100 mM and 500 mM of Cl − promoted the oxidation of m-xylene and p-xylene. Br − completely suppressed the benzene oxidation while 500 mM of Br − strongly promoted the oxidation of xylenes. Detailed explanations on the influence of each matrix constituent were discussed. In addition, various halogenated degradation byproducts were detected in the treatments containing Cl − and Br − . Overall, this study indicates that some matrix constituents such as NOM, HCO3 −, CO3 2−, H2 PO4 −, Cl − and Br − may reduce the BTEX removal efficiency of sulfate radical-based advanced oxidation process (SR-AOP) and the presence of Cl − and Br − may even lead to the formation of toxic halogenated byproducts. Graphical abstract: Image 1 Highlights: Impacts of 9 anions and NOM on PS oxidation of BTEX are experimentally studied. HCO3 − /CO3 2− and NOM inhibit BTEX oxidation due to scavenging of SO4 − by them SO4 2− /NO3 − /PO4 3− /H2 PO4 − do not affect BTEX oxidation but HPO4 2− slightly inhibit it. Cl − /Br − inhibit benzene oxidation but high concentrations promote xylene oxidation. Various halogenated byproducts are detected in treatments containing Cl − and Br − .