Experimental-design-guided approach for the removal of atrazine by sono-electrochemical-UV-chlorine techniques

Abstract

The aim of the present study was to investigate the electrochemical formation of free chlorine species (HOCl/ClO) and their subsequent use for the degradation of the pesticide atrazine. Initially, the process of electrochemical-free chlorine production was investigated using a bench-scale electrochemical flow-cell. The most significant variables (electrolyte concentration ([NaCl]) and inter-electrode gap) of the process were obtained using a 2 factorial design and the optimum process conditions (1.73 mol L and 0.56 cm) were determined by a central composite design. Following optimization of free chlorine production, three degradation techniques were investigated, individually and in combination, for atrazine degradation: electrochemical, photochemical and sonochemical. The method using the techniques in combination was denominated sono-photo-assisted electrochemical degradation. Constant current assays were performed and the sono-photo-assisted electrochemical process promoted more efficient removal of atrazine, achieving total organic carbon removal of ∼98% and removal of atrazine to levels below the detection limit (>99%) in under 30 min of treatment. Furthermore, the combination of three techniques displayed lower energy consumption, and phytotoxicity tests (Lactuca sativa) showed that there was no increase in toxicity.

Electrochemical degradation of aqueous alachlor and atrazine: products identification, lipophilicity, and ecotoxicity

“…One can observe that from 0.4 to 1.2 V vs. NHE, no significant increase of the density current occurs; however, for potentials above 1.2 V, there was a fast increase in density current, characterized by the oxygen evolution reaction (OER) and chlorine evolution (Eqs. 1 and 2) 27 In Figure 2a, it can be observed that oxygen and chlorine evolution reactions became more evident with increasing concentrations of NaCl. However, when the herbicides were added to the 0.15 mol L -1 NaCl solution (Fig.…”

“…In electrochemical oxidations, the choice of the material with which the anode is made is of fundamental importance, because the efficiency and selectivity of the process depends on it. Among the most frequently used anodes for the removal of organic compounds is the dimensionally stable anode (DSA) with a nominal composition Ti/Ru0.3Ti0.7O2 27 . It has been used in the chloralkali industry for several years due to its mechanical stability and catalytic activity 28,29 .…”

DEGRADAçãO DA CITARABINA PELO MéTODO SONO ELETROQUíMICO FOTO-ASSISTIDO EM MEIO DE URINA ARTIFICIAL

“…Entre as técnicas de degradação apresentadas na literatura se destacam a eletroquímica foto-assistida e sonoeletroquímica. Um estudo mostrou a eficácia da técnica eletroquímica foto-assistida com energia ultrassônica para a remoção de pesticidas (Pinto et al,2017;Antonelli et al;2017). Com base em informações coletadas nos hospitais da cidade de Uberaba -MG (Hospital de Clínicas da UFTM e Hospital Dr. Hélio Angotti), dentre a gama de quimioterápicos existentes, a citarabina está entre os mais utilizados.…”

Adsorption of Atrazine from Aqueous Solution onto Peanut Shell Activated Carbon: Kinetics and Isotherms Studies

“…Atrazine residues were also found in the treated soils and surface water [3]. Thus, several methods such as oxidation [4], photocatalysis [5], electrochemical [6] and adsorption [7] are used for herbicide residues removal from polluted water. Among these methods, adsorption is widely used because of its low-cost and easily application.…”