Assessment of the UV/DCCNa and UV/NaClO oxidation process for the removal of diethyl phthalate (DEP) in the aqueous system

Shengnan Zhang; Junyan Wei; Nannan Wu; Ahmed A Allam; Jamaan S Ajarem; Saleh Maodaa; Zongli Huo; Feng Zhu; Ruijuan Qu

doi:10.1016/j.envpol.2023.122915

Assessment of the UV/DCCNa and UV/NaClO oxidation process for the removal of diethyl phthalate (DEP) in the aqueous system

Environ Pollut. 2024 Jan 15:341:122915. doi: 10.1016/j.envpol.2023.122915. Epub 2023 Nov 10.

Authors

Shengnan Zhang¹, Junyan Wei¹, Nannan Wu², Ahmed A Allam³, Jamaan S Ajarem⁴, Saleh Maodaa⁴, Zongli Huo⁵, Feng Zhu⁵, Ruijuan Qu⁶

Affiliations

¹ State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China.
² State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China; State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products & Institute of Agro-product Safety and Nutrition, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, PR China.
³ Zoology Department, Faculty of Science, Beni-Suef University, Beni-Suef, Egypt.
⁴ Zoology Department, College of Science, King Saud University, Riyadh, Saudi Arabia.
⁵ Jiangsu Provincial Center for Disease Control and Prevention, No. 172 Jiangsu Road, Nanjing, 210009, PR China.
⁶ State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China. Electronic address: quruijuan0404@nju.edu.cn.

PMID: 37952917
DOI: 10.1016/j.envpol.2023.122915

Abstract

In this work, the removal and transformation process of diethyl phthalate (DEP) in UV/dichloroisocyanurate (UV/DCCNa) and UV/sodium hypochlorite (UV/NaClO) systems were compared to evaluate the application potential of UV/DCCNa technology. Compared with UV/NaClO, UV/DCCNa process has the advantage of DEP removal and caused a higher degradation efficiency (93.8%) within 45 min of oxidation in ultrapure water due to the sustained release of hypochloric acid (HOCl). Fourteen intermediate products were found by high-resolution mass spectrometry, and the transformation patterns including hydroxylation, hydrolysis, chlorination, cross-coupling, and nitrosation were proposed. The oxidation processes were also performed under quasi-realistic environmental conditions, and it was found that DEP could be effectively removed in both systems, with yields of disinfection byproduct meeting the drinking water disinfection standard (<60.0 μg/L). Comparing the single system, the removal of DEP decreased in the mixed system containing five kinds of PAEs, which could be attributed to the regeneration of DEP and the competitive effect of •OH occurred among the Dimethyl phthalate (DMP), DEP, Dipropyl phthalate (DPrP), Diallyl phthalate (DAP) and Diisobutyl phthalate (DiBP). However, a greater removal performance presented in UV/DCCNa system compared with UV/NaClO system (69.4% > 62.1%). Further, assessment of mutagenicity and developmental toxicity by Toxicity Estimation Software Tool (T.E.S.T) software indicated that UV/DCCNa process has fewer adverse effects on the environment and is a more environmentally friendly chlorination method. This study may provide some guidance for selecting the suitable disinfection technology for drinking water treatment.

Keywords: Diethyl phthalate (DEP); Drinking water treatment; Removal efficiency; Transformation products; UV/Chlorine.

MeSH terms

Drinking Water* / analysis
Oxidation-Reduction
Phthalic Acids* / toxicity
Water Pollutants, Chemical* / analysis
Water Purification* / methods

Substances

diethyl phthalate
Drinking Water
Water Pollutants, Chemical
Phthalic Acids