POTENTIAL EFFECT OF CHEMICAL AND THERMAL TREATMENT ON THE KINETICS, EQUILIBRIUM, AND THERMODYNAMIC STUDIES FOR ATRAZINE BIOSORPTION BY THE MORINGA OLEIFERA PODS

The effectiveness of chemical and thermal pretreatments on Moringa oleifera pods for the atrazine removal from water was investigated. The untreated pods (MOPun), the chemically treated pods (MOPC), and the chemically treated pods followed by the thermally treated pods (MOPT) were physico-chemically and morphologically characterized by elemental, pH(ZPC), N-2 physisorption, FTIR, and SEM analysis. The effect of modified pods was significant in increasing surface porosity, favouring the surface chemistry, and improving the atrazine biosorption capacity. Kinetics data were best explained by pseudo-second order model for all biosorbents. The equilibrium data for biosorption were analyzed by using Langmuir, Freundlich, Sips, and Polanyi-Manes (PMM) isotherm models to define the best correlation for atrazine biosorption capacity. Among the four isotherm models, both Sips and PMM were the models best fitted with the equilibrium isotherm for atrazine. The maximum atrazine adsorption capacities were 0.629, 1.580, and 7.47 mg . g (1) for MOPun, MOPC, and MOPT respectively with a maximum removal percentage of 65 %, 82 %, and 99 %. The thermodynamic studies showed that atrazine biosorption is favourable. The biosorption experiments demonstrated that Moringa oleifera pods have great potential for removing atrazine and other organic contaminants from water.