Author(s): Siti Fairos Ab Shattar, Nor Azazi Zakaria, Keng Yuen Foo
Linked Author(s): Siti Fairos Ab Shattar
Keywords: Adsorption, metolachlor, natural clay, pesticide, water pollution
Abstract: Pesticide is a diverse group or mixture of chemical substances, intentially applied for selective attenuation against controlling pest, vectors and animal disease. Today, the presence of pesticide derivatives in the urban and suburban stormwater has attracted aesthetic attention among the scientific community. Among various available water treatment technologies, adsorption process, notably using low cost, renewable, eco-friendly, and natural adsorbent has gained important credibility. In this sense, in this study, a new route for the conversion of natural clay, into a functionalized adsorbent via simple chemical treatment has been presented. The treatment potential for the adsorptive removal of metolachlor was attempted. The physical and chemical properties were evaluated by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and nitrogen adsorption-desorption curve. The effects of adsorption behaviour as a function of initial concentration, contact time and solution pH were examined. Equilibrium data were fitted to the Langmuir, Freundlich, and Temkin isotherm models, while the kinetic data were simulated using the pseudo-first order, pseudo-second order model and Elovich kinetic equations. Thermodynamic parameters including the standard entalphy change (?H�), standard entropy change (?S�) and standard Gibbs free energy change (?G�) were computed. Results demonstrated that the equilibrium data was well fitted to the Langmuir isotherm model, with a maximum monolayer adsorption capacity of 38. 55 mg/g. The good correlation coefficient, R2 was found following closely to the pseudo-second order kinetic model, and the adsorption process was identified to be exothermic in nature. Morphological study provided a strong evidence support to the presumption that the intercalation of hexadecyltrimethylammonium bromide (HDTMA) with the natural clay was successfully obtained. The findings revealed the great feasibility of natural clay derivatives as a viable treatment technique for the effective remediation of pesticides contaminated stormwater
Year: 2017