Identification of intermediates, acute toxicity removal, and kinetics investigation to the Ametryn treatment by direct photolysis (UV254), UV254/H2O2, Fenton, and photo-Fenton processes

Abstract

This paper reports the degradation of 10 mg L Ametryn solution with different advanced oxidation processes and by ultraviolet (UV) irradiation alone with the main objective of reducing acute toxicity and increase biodegradability. The investigated factors included Fe and HO concentrations. The effectiveness of the UV and UV/HO processes were investigated using a low-pressure mercury UV lamp (254 nm). Photo-Fenton process was explored using a blacklight blue lamp (BLB, λ = 365 nm). The UV irradiation process achieved complete degradation of Ametryn solution after 60 min. The degradation time of Ametryn was greatly improved by the addition of HO. It is worth pointing out that a high rate of Ametryn removal was attained even at low concentrations of HO. The kinetic constant of the reaction between Ametryn and HO for UV/HO was 3.53 × 10 L mol s. The complete Ametryn degradation by the Fenton and photo-Fenton processes was observed following 10 min of reaction for various combinations of Fe and HO under investigation. Working with the highest concentration (150 mg L HO and 10 mg L Fe), around 30 and 70% of TOC removal were reached within 120 min of treatment by Fenton and photo-Fenton processes, respectively. Although it did not obtain complete mineralization, the intermediates formed in the degradation processes were hydroxylated and did not promote acute toxicity of Vibrio fischeri. Furthermore, a substantial improvement of biodegradability was obtained for all studied processes.

Bioleaching of iron from laterite soil using an isolated Acidithiobacillus ferrooxidans strain and application of leached laterite iron as Fenton’s catalyst in selective herbicide degradation

“…In the first four days of leaching drop in initial pH was observed. This might be due to ferrous oxidation resulting in more proton consumption [ 18 , 19 , 37 ]. Caranza and Paleneia (1996) claim that pH lower than 0.8 inhibits bacterial growth in spite of acidophilic mode of habitation in leaching studies which was supported by Marrero and team on their experimentation with Acidithiobacillus ferrooxidans later indicating the sensitivity of species to low pH [ 38 , 39 ].…”

The comparison of Fenton and photo‐Fenton oxidation as a primary unit process for the treatment of raw textile wastewaters

“…As can be seen in Figure 8, an increase of 13%, 10%, and 3%, respectively, was observed in the removal of COD, SS, and color from raw textile wastewater in the PFOP. It is possible to explain this increase with catalyst regeneration by Fe 3+ ‐Fe 2+ photoreduction in the presence of UV radiation and high rate and amount of HO• formation by direct photo‐lysis of H 2 O 2 (Babuponnusami & Muthukumar, 2014; Bousalah et al, 2020; de Oliveira et al, 2019; Pliego et al, 2015; Ramos et al, 2019; Roudi et al, 2020; Zhai et al, 2018). Compared to H 2 O 2 /catalyst system, the noticeable efficiency of PFOP suggests that the UV irradiation has a synergistic effect on the decomposition of H 2 O 2 with consequent formation of reactive species (i.e., HO) for pollutant degradation (Ahmadi et al, 2017).…”

“…In the PFOP, when UV radiation is used, HO• formation occurs with direct H 2 O 2 decomposition (Reactions 5-8). From this point of view, one of the important components affecting the process efficiency is the H 2 O 2 dose, and without H 2 O 2 , only the oxidation power of UV radiation is low (de Oliveira et al, 2019;Göde et al, 2019).…”

ZnO‐based composite catalysts for photocatalytic degradation of reactive black 5, and the optimization of process parameters

“…However, they have some limitations, including sludge production, inefficient mineralization, high‐energy consumption and the high costs of operation (da Silva et al, 2012; Luo et al, 2014; Richardson & Kimura, 2017). Therefore, other technologies with higher efficiencies are demanded for complete removal of synthetic dye contaminants from the wastewater discharged to the aquatic environment (Bhatt & Patel, 2021; De Oliveira et al, 2019).…”