Enhanced adsorption removal of As(III) using MnOFe2O3 with the non-thermal atmospheric pressure plasma jet via the catalytic redox-adsorptive phenomenon

Abstract

In this study, redox adsorption of the heavy metal, As(III), was potentially removed using non–thermal plasma discharge by enhanced redox adsorption process in contaminated water as per the WHO level. The generated reactive species of O, OH•, and H2O2 produced by plasma interaction with water molecules at air ambient conditions were used to transform As(III) (H3AsO3) to As(V) (HAsO42−) and surface modification of adsorbent, MnOFe2O3 (Mn2+, Mn3+, Fe2+, and Fe3+). The maximum amount of reactive species, H2O2 was found to be 31.71 μM in the water. Also the catalyzing adsorption ability of adsorbent was enhanced by 30 % via the redox-adsorptive mechanism, when compared without plasma. Further, the batch kinetics of pseudo first order (PFO) model was shown to be well predicted for adsorption capacity qe (mg/g), in comparison with pseudo second order (PSO) under various As(III) concentrations. Also the maximum adsorption capacity qe was achieved by the isotherms studies based on the Langmuir model. The adsorption yield for As(III) to As(V) on the MnOFe2O3 were estimated with surface analysis of MnOFe2O3 by XRD, SEM, EDX, XPS, FTIR, and BET.