The application of UV/PS oxidation for removal of a quaternary ammonium compound of dodecyl trimethyl ammonium chloride (DTAC): The kinetics and mechanism.

Author(s) Lee, M.Y.; Wang, W.L.; Bin Xu, Z.; Ye, B.; Wu, Q.Y.; Hu, H.Y.
Journal Sci Total Environ
Date Published 2019 Mar 10

Dodecyltrimethylammonium chloride (DTAC) is a quaternary ammonium compound (QAC) that is a widespread contaminant in environmental media and therefore of increasing concern. The synergistic effect with UV irradiation and persulfate (UV/PS) was used to degrade DTAC. The removal of DTAC was 91% with the PS dosage of 75.6 μM (UV/PS) and UV fluence of 870 mJ·cm. The second-order rate constants of DTAC with HO and SO were determined to be k (4.2 ± 0.18) × 10 M s and k (2.5 ± 0.27) × 10 M s, respectively. The contributions of HO and SO to DTAC degradation in the UV/PS were found to be 30% and 62% at pH 7, respectively. The contributions of SO and HO were not significantly influenced by acidic medium (pH 3-pH 7), whereas they were significantly affected by basic medium (pH 7-pH 11). The wastewater matrixes of HCO, Cl and humic acid inhibited the DTAC elimination, whereas NO and SO had no significant impact on its elimination. Moreover, the k in the reverse osmosis influent (ROI) and reverse osmosis concentrate (ROC) were examined to be 0.04 to 0.1 min and 0.02 to 0.05 min, respectively, as the PS dosage increased from 18.9 to 113.4 μM. The inhibitive effects of matrix in ROI and ROC was 70% and 81%, respectively. The contribution of radical scavenging effect by matrix ROI and ROC was more significant to DTAC degradation than UV scattering effect in ROI and ROC matrices. A UV fluence of 1305 mJ·cm was necessitated for complete detoxification and DTAC solution by UV/PS.

DOI 10.1016/j.scitotenv.2018.11.256
ISSN 1879-1026
Citation Sci Total Environ. 2019;655:12611269.

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