Pesticide degradation in water using atmospheric air cold plasma

Abstract

a b s t r a c tA high voltage dielectric barrier discharge plasma reactor using atmospheric air as the inducer gas was studied for the degradation of pesticides (dichlorvos, malathion, endosulfan) in water. The degradation kinetics of the pesticides were studied using GC-MS as a function of plasma control parameters. Electrical characterisation of the plasma revealed that the plasma discharge consisted of filamentary streamers. Excited nitrogen, reactive oxygen species and OH radicals generated in the dielectric barrier discharge (DBD) plasma reactor were identified using optical emission spectroscopy. Ozone, used as an indicator for metastable oxygen species, was quantified within the reactor at concentrations of 1600, 2200, 2800 ppm after 8 min of plasma treatment for applied voltages of 60, 70, and 80 kV respectively. The degradation efficacy of pesticides after 80 kV and 8 min of plasma treatment were found to be 78.98 ± 0.81% for dichlorvos, 69.62 ± 0.14% for malathion and 57.71 ± 0.58% for endosulfan. Degradation was found to follow first order kinetics. GC-MS analyses showed that the degraded compounds and intermediates formed were less toxic than the parent pesticide. A proposed mechanism of degradation of these pesticides is suggested.

Atmospheric cold plasma dissipation efficiency of agrochemicals on blueberries

“…Similar results were observed for the degradation of pesticides in water and on strawberries (N. Misra, S. K. Pankaj, et al, 2014;Sarangapani, Misra, et al, 2016) (Dojčinović, et al, 2011) which undergo several chain reactions to form metastables including ozone and hydrogen peroxide which have been identified as key species in the degradation of pesticides (N. N. Misra, Keener, Bourke, & Cullen, 2015;N.N. Misra, Ziuzina, Cullen, & Keener, 2013;Moiseev, et al, 2014;Sarangapani, Misra, et al, 2016). The increased efficacy found with applied voltage is attributed to the associated increase in intensity of discharge electric field leading to greater amounts of reactive species generated (Gao, Sun, Wan, Yu, & Li, 2013).…”

“…The removal efficiencies increased to 75% and 80% for boscalid and imidacloprid respectively, at 80 kV for 5 min of plasma treatment. Similar results were observed for the degradation of pesticides in water and on strawberries (N. Misra, S. K. Pankaj, et al, 2014;Sarangapani, Misra, et al, 2016) (Dojčinović, et al, 2011) which undergo several chain reactions to form metastables including ozone and hydrogen peroxide which have been identified as key species in the degradation of pesticides (N. N. Misra, Keener, Bourke, & Cullen, 2015;N.N. Misra, Ziuzina, Cullen, & Keener, 2013;Moiseev, et al, 2014;Sarangapani, Misra, et al, 2016).…”

“…Other studies have reported that the degradation of chemical contaminants yielded non-toxic intermediates and end products (Boehm, Heslin, Cullen, & Bourke, 2016;Gao, et al, 2013;Sarangapani, Misra, et al, 2016). It can also be noted that, ozone and other oxidants produced during plasma or post plasma treatment can speed up the mineralization process for complete degradation of the toxic intermediates and ultimately lead to the formation of CO2 (Reddy, Mahammadunnisa, & Subrahmanyam, 2014).…”

“…Recently, the potential of plasma discharges for pesticide degradation on food and in water was reported (N. Misra, Pankaj, Walsh, O'Regan, Bourke, & Cullen, 2014;Sarangapani, Misra, Milosavljevic, Bourke, O'Regan, & Cullen, 2016). Plasma is a partially or wholly ionised state of a gas consisting of positively and negatively charged ions, free electrons, free radicals and intermediate reactive atoms, molecules and UV photons with a net neutral charge (Kogelschatz, 2007).…”

Humic acid and trihalomethane breakdown with potential by-product formations for atmospheric air plasma water treatment

“…The use of atmospheric air as the inducer gas facilitates a potentially environmentally friendly and economically feasible approach. Atmospheric air plasma has been reported to be efficient in the breakdown of dyes [24], pesticides [25,26], aflatoxins [27] and for inactivation of pathogenic bacteria [28]. It is known that dielectric barrier discharge (DBD) plasma initiates several physical processes (UV light, shock waves) and chemical processes (O , O 3 , H 2 O 2 ) [29], processes which may directly or indirectly act on humic substances.…”