Photooxidative Degradation of Pesticides in Water; Response Surface Modeling Approach

Abstract

Abstract:The conventional water treatment technologies, mostly relying on physical and biological processes, seem to be inadequate for effective removal of priority substances such as pesticides, while advanced oxidation processes showed a good performance for the same purpose. The aim of the study was to evaluate UV-C/H 2 O 2 and UV-C/S 2 O 8 2-processes for treating seven pesticides listed as priority substances (PS-Ps) within the EU Water Framework directive; alachlor, atrazine, chlorfenvinphos, cybutryne, diuron, isoproturon and simazine. The influence of pH and pollutant/oxidant ratio ([PS-P]:[OX]) on the degradation kinetics was evaluated using full factorial plan and response surface modeling. The degradation of PS-Ps by both photooxidation processes obeyed first-order kinetics. Degradation kinetics of PS-Ps is highly depended on [PS-P]: [OX], while pH has minor significance, particularly in UV-C /S 2 O 8 2-process. In most cases degradation kinetics by UV-C /S 2 O 8 2-was several times faster in comparison to UV-C /H 2 O 2 process. In addition, the inhibitory influence of NOM on the degradation of PSs in the mixture was determined.

Biodegradation kinetics of diuron by Pseudomonas aeruginosa FN and optimization of biodegradation using response surface methodology

“…The Table 2 summarizes the full experimental matrix and the apparent rate constants for diuron. The significance of the model, its accuracy and significance of the independent variables in relationship with dependent variable (biodegradation of diuron) are described by standard statistical parameters (Cvetnic et al , 2017) by analysis of variance (ANOVA) ( F , t , p , R 2 , R adj 2 , R pre 2 and adequate precision). Results of ANOVA showed that all variables are significant with p < 0.050.…”

“…RSM is found to be a useful tool to study the interactions of two or more independent variables using mathematical and statistical techniques considering affecting factors in an optimum manner. The power of RSM is that even in the presence of complex interactions it can be used to evaluate the relative significance of several contributing factors (Wang et al ., 2017; Cvetnic et al , 2017; Toolabi et al , 2017).…”

Photochemical processes in surface water bodies and their potential impacts on the chemical composition of water: A review

“…The increased pesticide photolysis occurred with the participation of hydroxyl radicals generated by FA. Cvetnic et al (2017) studied photochemical degradation of some pesticides (alachlor, atrazine, chlorfenvinphos, cibutrin, diuron, isoproturon and simazine) was studied during UV-C irradiation exposure with the presence of Н 2 О 2 or sodium persulfate (Na 2 S 2 O 8 ).…”

“…Cvetnic et al (2017) studied photochemical degradation of some pesticides (alachlor, atrazine, chlorfenvinphos, cibutrin, diuron, isoproturon and simazine) was studied during UV‐C irradiation exposure with the presence of Н 2 О 2 or sodium persulfate (Na 2 S 2 O 8 ). In most cases, the kinetics of pesticide degradation by UV–C/S 2 O 8 2− was several times faster than by UV–C/H 2 O 2 .…”

Untitled

“…The complete degradation of fipronil contaminated waste water is a very challenging task. Various innovative technologies have been proposed for the removal of pesticides namely photocatalytic oxidation [1], ultrasonic radiation [2], bioremediation [3] and thermal desorption [4]. They are neither cost effective, nor ecofriendly, nor involving low concentrations.…”