Title: Novel determination method for chemical oxygen demand in water based on sulphate radical digestion and turbidimetry

Authors: Fukang Ji; Yongxiang Li; Xinbo Zhang; Fengyi Zhao; Mengdi Zhang; Juncheng Wang; Xiaofang Sun

Addresses: College of Chemical Engineering, Zhejiang University of Technology, Hangzhou City, Zhejiang Province, China ' College of Chemical Engineering, Zhejiang University of Technology, Hangzhou City, Zhejiang Province, China ' College of Chemical Engineering, Zhejiang University of Technology, Hangzhou City, Zhejiang Province, China ' College of Chemical Engineering, Zhejiang University of Technology, Hangzhou City, Zhejiang Province, China ' College of Chemical Engineering, Zhejiang University of Technology, Hangzhou City, Zhejiang Province, China ' College of Chemical Engineering, Zhejiang University of Technology, Hangzhou City, Zhejiang Province, China ' College of Chemical Engineering, Zhejiang University of Technology, Hangzhou City, Zhejiang Province, China

Abstract: Sulphate radical-based advanced oxidation processes (SR-AOPs) have gained considerable popularity in the fields of organic contaminant degradation and industrial wastewater treatment. However, there are few reports focusing on study and application of such promising technology in determination or online monitoring of chemical oxygen demand (COD) in water quality. Herein, a novel determination method of COD based on photoactivated SR-AOPs and barium sulphate turbidimetry is proposed, in which, sulphate radicals (SO₄^•-) are mainly responsible for the digestion of organic pollutants, not hydroxyl radicals (^•OH). For improving the precision and accuracy of this determination method, all the parameters affecting on the digestion and detection were investigated. Performance verification results showed that this method has a good linearity (R² = 0.9988), precision (2.26%), accuracy (0.43%) and low method detection limit (2.4431 mg/L) within a range of 5~200 mg/L, under the optimised process conditions.

Keywords: chemical oxygen demand; determination method; sulphate radical; turbidimetry.

DOI: 10.1504/IJEP.2024.142565

International Journal of Environment and Pollution, 2024 Vol.74 No.1/2/3/4, pp.154 - 171

Received: 03 Oct 2023
Accepted: 29 Feb 2024
Published online: 08 Nov 2024 *

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