Oxidation of clofibric acid in aqueous solution using a non-thermal plasma discharge or gamma radiation

Abstract

In this work, we study degradation of clofibric acid (CFA) in aqueous solution using either ionizing radiation from a 60 Co source or a non-thermal plasma produced by discharges in the air above the solution. The results obtained with the two technologies are compared in terms of effectiveness of CFA degradation and its by-products. In both cases the CFA degradation follows a quasi-exponential decay in time well modelled by a kinetic scheme which considers the competition between CFA and all reaction intermediates for the reactive species generated in solution as well as the amount of the end product formed. A new degradation law is deduced to explain the results. Although the end-product CO 2 was detected and the CFA conversion found to be very high under the studied conditions, HPLC analysis reveals several degradation intermediates still bearing the aromatic ring with the chlorine substituent. The extent of mineralization is rather limited. The energy yield is found to be higher in the gamma radiation experiments.

Kinetics and Products of Air Plasma Induced Oxidation in Water of Imidacloprid and Thiamethoxam Treated Individually and in Mixture

“…2 it is seen that both for I and T the efficiency of the process, expressed by the energy constant kE, depends linearly, in first approximation, on 1/C0. This behavior is consistent with previous reports in the literature showing that the pseudo-first order rate constant (k) of air non-thermal plasma induced oxidation of organic pollutants depends on the pollutant initial concentration, C0, and often increases linearly with increasing 1/C0 [32,47,48]. Such a dependence is predicted, under some approximations, by a simple kinetic model based on a mechanism of inhibition by products proposed by Slater and Douglas-Hamilton [49].…”

Can we remove tattoos with non‐thermal atmospheric plasma?

“…Several works focused on advanced oxidation processes for dyes and pollutant decomposition reported a linear dependence of the degradation constant with the inverse of the starting concentration. [22,23] By assuming the same behavior, on the basis of the half-life time that we measured in the experiment reported in Figure 2d for liquid gelatin samples (about 5 h), we can conclude that the discoloration of tattoo pigments by reaction of the oxidant species generated by plasma would be practically impossible (a treatment should last 20-200 days). To increase the NTP oxidative effect more energetic treatment would be required (higher applied power or treatment time), but this could also lead to the potentially harmful thermal effects observed in the solid gelatin disks (Figures 3 and S3).…”

Air non-thermal plasma, a green approach for the treatment of contaminated water: the case of sulfamethoxazole

“…It is evident that the rate of SMZ decomposition depends on its initial concentration, C 0 , the lower C 0 the faster its degradation. This phenomenon has been observed in many previous studies of NTPpromoted degradation of organic compounds in water (Madureira et al, 2017;Magureanu et al, 2021) including SMZ (Hu et al, 2023;Bilea et al, 2024), and attributed to competing reactions of the pollutant intermediate products with the reactive species generated by the discharge. A simple kinetic model accounting for these phenomena is described in the literature (Tomei et al, 2023 and references therein).…”

“…The experimental apparatus employed in this work is a dielectric barrier discharge (DBD) reactor, employing a wire/ plate electrode configuration, which was previously applied to the degradation of phenol (Marotta et al, 2011;Marotta et al, 2012), pharmaceuticals (Krishna et al, 2016;Madureira et al, 2017), pesticides (Giardina et al, 2018;Giardina et al, 2019), maleic and fumaric acids (Shapoval et al, 2023). The reactor is made of a glass vessel (i.d.…”