Degradation of the insecticide propoxur by electrochemical advanced oxidation processes using a boron-doped diamond/air-diffusion cell

Abstract

A solution with 0.38 mM of the pesticide propoxur (PX) at pH 3.0 has been comparatively treated by electrochemical oxidation with electrogenerated HO (EO-HO), electro-Fenton (EF), and photoelectro-Fenton (PEF). The trials were carried out with a 100-mL boron-doped diamond (BDD)/air-diffusion cell. The EO-HO process had the lowest oxidation ability due to the slow reaction of intermediates with OH produced from water discharge at the BDD anode. The EF treatment yielded quicker mineralization due to the additionalOH formed between added Fe and electrogenerated HO. The PEF process was the most powerful since it led to total mineralization by the combined oxidative action of hydroxyl radicals and UVA irradiation. The PX decay agreed with a pseudo-first-order kinetics in EO-HO, whereas in EF and PEF, it obeyed a much faster pseudo-first-order kinetics followed by a much slower one, which are related to the oxidation of its Fe(II) and Fe(III) complexes, respectively. EO-HO showed similar oxidation ability within the pH range 3.0-9.0. The effect of current density and Fe and substrate contents on the performance of the EF process was examined. Two primary aromatic products were identified by LC-MS during PX degradation.

Determination of Carbamates and Thiocarbamates in Water, Soil and Sediment of the Formoso River, TO, Brazil

“…It is used in fruit, vegetable, corn, soybean, rice and other crops, as well as in food storage areas, households and domestic animals. [20][21][22] The results of the first campaign (C1), carried out in the rainy season, where rice cultivation predominates in the region, revealed the propoxur active principle in all sample points. In points 4, 6, and 7, they were quantified at a concentration of 0.025 μg L À 1 .…”

Assessment of 4‐Aminoantipyrine Degradation and Mineralization by Photoelectro‐Fenton with a Boron‐Doped Diamond Anode: Optimization, Treatment in Municipal Secondary Effluent, and Toxicity

“…The air-diffusion cathode was supplied by E-TEK (Somerset, NJ, USA) and was mounted as described elsewhere. [18] Compressed air at 1 L min À 1 was directly supplied to it for continuous H 2 O 2 production. The assays were made galvanostatically and the constant current was provided by an Instrutherm Fa-3003 power source.…”

“…It is a sequential or hybrid process in which the oxidation power of * OH generated on site is synergistically combined with the photolytic ability of UVA photons. [15][16][17][18] In this method, H 2 O 2 is continuously produced at a suitable cathode from two-electron reduction of O 2 gas via Reaction (1). Then, * OH is formed in the bulk upon catalyzed H 2 O 2 decomposition with added Fe 2 + via Fenton's Reaction (2): [19][20][21][22][23] O 2ðgÞ þ 2H þ þ 2e À !…”

Visible‐light‐driven photocatalytic degradation of fenpyroximate in rotating packed bed reactor using Fe3O4@PbS@Ni2P magnetic nanocomposite photocatalyst: Response surface modelling and optimization

“…Also, biodegradation, ozonation and chlorination are not suitable; thus, researchers are encouraged to apply alternative technologies . The advanced oxidation processes based on the generation of hydroxyl radicals are efficient and more applicable protocols for treating complex compounds such as pesticides, acaricides and herbicides . Amongst them, photocatalytic degradation based on semiconductors with a significant capability for the generation of highly reactive and nonselective hydroxyl radicals is a low‐cost, highly efficient and sustainable treatment technique .…”

“…[12][13][14][15] The advanced oxidation processes based on the generation of hydroxyl radicals are efficient and more applicable protocols for treating complex compounds such as pesticides, acaricides and herbicides. [16][17][18][19] Amongst them, photocatalytic degradation based on semiconductors with a significant capability for the generation of highly reactive and nonselective hydroxyl radicals is a low-cost, highly efficient and sustainable treatment technique. [20][21][22][23] In spite of the broad application of photocatalytic degradation as an efficient method for the degradation of various pollutants on a laboratory scale, few researches have been devoted to extending its usage in large-scale reactors due to some limitations such as poor light distribution inside the reactor and low photocatalyst surface area per unit volume of reactor.…”