Effective Removal of Widely Applicable Pesticides Using Iron Pillared Clay (Fe/Bt): Adsorption Behaviour and Kinetics

Kelechi Emmanuel Onwuka; O. C. Atasie; C. I. Nosiri; N. E. Enenwa; P. O. Emole; C. A. Nwosu; Mohammed Akram

Abstract

The vast application of pesticides for agricultural purpose to enhance adequate plant growth is quite alarming, with its negative environmental influence increasing every day. The current study investigates the potential of iron pillared bentonite (Fe/Bt) for effective removal of three different widely applicable pesticides (Glyphosate, Bentazon and Diazinon) in aqueous solution. This adsorbent has been characterized ab initio by FT-IR spectroscopy. Adsorption parameters such as contact time, initial pesticide concentration and pH were applied to investigate the adsorption behaviour of individual pesticides onto Fe/Bt. Adsorption equilibrium and kinetics were investigated by subjecting data to both Langmuir and Freundlich isotherms, and pseudo first order and pseudo second order kinetic models respectively. Results showed that equilibrium sorption was achieved after 1080 minutes of contact time. Experimental data for adsorption of glyphosate and diazinon was well fitted to the Freundlich isotherm, while bentazon and also diazinon fitted excellently with the Langmuir isotherm. Among the two kinetic models exploited, Pseudo second order kinetic model gave best fit to the kinetic data, and increase in adsorbate pH at optimal experimental condition resulted to increased in the adsorption capacity of the adsorbent.