Removal of Tricyclazole and Total Organic Carbon in Real Pesticide Wastewater by Electro-Fenton

Ha Manh Bui,Loan Ngoc Huynh,Ibrahim H Alsohaimi

doi:10.1155/2022/6918063

Ha Manh Bui, Loan Ngoc Huynh + Show 1 more

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https://doi.org/10.1155/2022/6918063

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Abstract

In this study, electro-Fenton (EF) was employed for the removal of tricyclazole (TC) and total organic carbon (TOC) in real pesticide wastewater (RPW). The central composite design (CCD) with three parameters, that is, current density, Fe2+ concentration, and electrolysis time, has been conducted to predict the TOC and TC removal efficiency. The high correlation of the quadratic models of 0.9842 and 0.9781 for TC and TOC removal, respectively, indicates the significance of the models. The obtained results revealed that the high-efficiency removal of both TC and TOC in RPW. Approximately 99.6% of TC was decomposed under the optimum conditions of a current density of 2.2 mA/cm2 and an Fe2+ concentration of 0.2 mM during 188 min with an operating cost of 121.392 $/kg TC or ∼2.692 $/m3, while 84.2% TOC was eliminated at a current density of 2.2 mA/cm2 and an Fe2+ concentration of 0.2 mM during 217 min with an operating cost of 3.019 $/kg TOC or 3.916 $/m3. Acute toxicity tests at optimal condition revealed moderate exhibition toxicity of treated wastewater against Daphnia magna with LC50 values of 3.12%, 2.05%, 1.84%, and 1.36% at 24 h, 48 h, 72 h, and 96 h, respectively. The removal of TC and TOC followed pseudo-first-order kinetic with an R2 of ∼0.993 and 0.923, respectively.

Highlights

Agriculture is critical to the economies of Vietnam, in which export-oriented agricultural production is a significant source of foreign exchange earnings. e agricultural sector provides approximately 14.85% of the gross national product with over 18.8 million Vietnamese in 2019 [1]
With the increase in the reaction time from 30 to 150 min, the removal efficiency sharply increases, and with the further increase in the electrolysis time, the removal efficiency reaches a plateau. e increase in the rapid and slow removal of TC and total organic carbon (TOC) with the rise in the electrolysis time can be explained by the reaction between OH and TC or TOC in wastewater
Under saturated Fe2+ conditions (0.2 mM), fixed OH formation inadequate react with the pollutants; the TC and TOC removal efficiency slowly increase. is trend can be confirmed in some previous studies [20, 34]. e kinetics of the TOC and TC removal under fixed conditions (2.22 mA/cm2 of current density and 0.2 mM of Fe2+ dosage) give a better understanding of the relationship between TOC or TC concentrations and electrolysis times

Summary

Introduction

Agriculture is critical to the economies of Vietnam, in which export-oriented agricultural production is a significant source of foreign exchange earnings. e agricultural sector provides approximately 14.85% of the gross national product with over 18.8 million Vietnamese in 2019 [1]. The vast number of pesticides produced to prevent pests or diseases on crops resulting in threats to the environment and human health [2]. Extensive studies have reported that pesticides originating from agriculture factories are characterized by a high chemical oxygen demand (COD), total suspended solids (TSS), and toxicity. Pesticide application to rice paddies has been detected in surface water, groundwater, and soil [3]. Ese kinds of pesticides stand out in high production and worldwide distribution; tricyclazole (TC) is a unique fungicide among the most widely used pesticides for control of Pyricularia oryzae in rice fields [4, 5]. Biological processes are quite economical for the treatment of wastewaters. The COD is still high around 160 mg/L, and further treatment time has insignificant effect on the removal efficiency.

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