Response Surface Analysis of Fenobucarb Removal by Electrochemically Generated Chlorine

Giang Truong Le,Nguyen Thuy Ta,Yen Hai Dao,Trung Quoc Pham

doi:10.3390/w11050899

Giang Truong Le, Nguyen Thuy Ta + Show 2 more

Open Access

https://doi.org/10.3390/w11050899

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Journal: Water	Publication Date: Apr 29, 2019
Citations: 3	License type: CC BY 4.0

Affiliation: Vietnam Academy of Science and Technology

Abstract

The aim of the present study was to investigate the electrochemical formation of active chlorine and its subsequent use for the degradation of the pesticide fenobucarb. Initially, the process of electrochemical active chlorine production was investigated using an electrochemical flow-cell with a Ti/RuO2 plate electrode. The contribution of four main factors (chloride concentration, current density, the retention time of chloride in the cell (flow rate), and initial pH of inlet solution) to form active chlorine was determined by a central composite design (CCD). The influence of the four variables was statistically significant, and the contributions of flow rate, chloride concentration, pH, and current density were found to be 37.2%, 33.59%, 18.28%, and 10.93%, respectively. A mathematical model was established to predict and optimize the operating conditions for fenobucarb removal in the NaCl electrolysis process. The main transformation products (seven compound structures) were detected by liquid chromatography coupled with high-resolution mass spectrometry (LC–HRMS). The results of the model and transformation products indicated that fenobucarb was degraded due to direct oxidation on the electrode surface, and indirectly by active chlorine and other radicals present during the NaCl electrolysis process.

Highlights

In recent decades, electrochemical-based systems for water treatment have received considerable attention [1,2]
We know that chloride is transformed into active chlorine, chlorate, and perchlorate by an electrochemical and chemical reaction during the chloride electrolysis process
The results showed that the total amount of chloride, active chlorine, and chlorate in the outlet solution (0.176 mM)

Summary

Introduction

Electrochemical-based systems for water treatment have received considerable attention [1,2]. Electrochemical technologies provide several advantages for the prevention and remediation of pollution problems because the electron is a clean reagent. The electrochemical method can treat organic compounds non-selectively by both direct and indirect mechanisms based on the activity of free radicals and strong oxidants formed in the electrolysis process. A number of studies have shown that the electrochemical generation of chlorine, and the subsequent formation of active chlorine (AC), are interesting alternatives for in situ degradation of pollutants [4,5,6]. AC is produced via the anodic formation of chlorine (Cl2 )

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