TY - JOUR
T1 - UV/ peroxymonosulfate process for degradation of chloral hydrate
T2 - Pathway and the role of radicals
AU - Zhang, Xiaoxiao
AU - Chen, Zhonglin
AU - Kang, Jing
AU - Zhao, Shengxin
AU - Wang, Binyuan
AU - Yan, Pengwei
AU - Deng, Fengxia
AU - Shen, Jimin
AU - Chu, Wei
N1 - Funding Information:
The work was supported by the Hong Kong Polytechnic University (Grant No. 1-ZVH6), the National Key R&D Program of China (Grant No. 2017YFA0207203 and 2017YFA0207204), the State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology (Grant No. 2017TS02), and the National Natural Science Foundation of China (Grant No. 51608148).
Funding Information:
The work was supported by the Hong Kong Polytechnic University (Grant No. 1-ZVH6 ), the National Key R&D Program of China (Grant No. 2017YFA0207203 and 2017YFA0207204 ), the State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology (Grant No. 2017TS02 ), and the National Natural Science Foundation of China (Grant No. 51608148 ).
Publisher Copyright:
© 2020 Elsevier B.V.
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2021/1/5
Y1 - 2021/1/5
N2 - In this study, kinetics, influencing factors and potential mechanisms involved in the degradation of chloral hydrate (CH) by UV/peroxymonosulfate (PMS) process were demonstrated. The degradation rate of CH could reach 89.6% by UV254/PMS process, significantly exceeding UV300/PMS (0.7%), UV350/PMS (6.3%), UV254 direct photolysis (9.0%) and PMS alone (0.0%) processes. CH degradation in UV254/PMS system followed pseudo first-order degradation kinetics with an apparent rate constant of 0.186 min−1, which was suppressed by Cl− and HCO3−. The optimal pH for CH degradation was around 5.0. Direct mineralization accounted for the CH degradation in UV/PMS system. Interestingly, the addition of PMS at the neutral condition before UV irradiation transferred CH into trichloroacetic acid (TCAA). The transformation efficiency of CH into TCAA at 10 min was enhanced from 2.17%–40.38% with the elevation of initial pH from 7.0–8.0. The subsequent exposure of UV lamps ceased the transformation of CH into TCAA and facilitated the direct mineralization of CH, but it did not work in the refractory TCAA degradation. Finally, it was revealed that HO[rad] predominantly participated CH degradation in UV/PMS process, while O2[rad]− was responsible for the transformation of CH into TCAA by addition of PMS before UV irradiation.
AB - In this study, kinetics, influencing factors and potential mechanisms involved in the degradation of chloral hydrate (CH) by UV/peroxymonosulfate (PMS) process were demonstrated. The degradation rate of CH could reach 89.6% by UV254/PMS process, significantly exceeding UV300/PMS (0.7%), UV350/PMS (6.3%), UV254 direct photolysis (9.0%) and PMS alone (0.0%) processes. CH degradation in UV254/PMS system followed pseudo first-order degradation kinetics with an apparent rate constant of 0.186 min−1, which was suppressed by Cl− and HCO3−. The optimal pH for CH degradation was around 5.0. Direct mineralization accounted for the CH degradation in UV/PMS system. Interestingly, the addition of PMS at the neutral condition before UV irradiation transferred CH into trichloroacetic acid (TCAA). The transformation efficiency of CH into TCAA at 10 min was enhanced from 2.17%–40.38% with the elevation of initial pH from 7.0–8.0. The subsequent exposure of UV lamps ceased the transformation of CH into TCAA and facilitated the direct mineralization of CH, but it did not work in the refractory TCAA degradation. Finally, it was revealed that HO[rad] predominantly participated CH degradation in UV/PMS process, while O2[rad]− was responsible for the transformation of CH into TCAA by addition of PMS before UV irradiation.
KW - Chloral hydrate
KW - Degradation
KW - Radicals
KW - Trichloroacetic acid
KW - UV/PMS
UR - http://www.scopus.com/inward/record.url?scp=85090991502&partnerID=8YFLogxK
U2 - 10.1016/j.jhazmat.2020.123837
DO - 10.1016/j.jhazmat.2020.123837
M3 - Journal article
AN - SCOPUS:85090991502
SN - 0304-3894
VL - 401
JO - Journal of Hazardous Materials
JF - Journal of Hazardous Materials
M1 - 123837
ER -