Natural Sorbent’s Bio-Sorption Efficiency for Liquid Phase Scavenging of Pesticides from Wastewater

Abstract

The removal of pesticides from waste water is a major concern of today and poses a great threat to the human and environmental health hence this research study aimed at assessing the efficiency of the used tea residue as a low-cost bio-adsorbent for the treatment of waste water containing pesticides. Therefore, to carry out the intended research project, initially the adsorbent was activated in order to increase its efficiency or adsorption capacity. Moreover, batch experiments were conducted with three pesticides (2,4-D, Carbaryl and Imidacloprid) at variable parameters (pH, contact time, adsorbent dose and initial concentration) and the effects of these variables on the adsorption capacity was assessed.

UV-spectroscopy was put into service for obtaining the concentrations of pesticide after the contact between the adsorbate (pesticide) and adsorbent (activated tea residue) while the characterization of the adsorbent was performed using the FTIR spectroscopy. The non-activated tea-residue removed suitable amounts of pesticides from aqueous solution but the activation process enhanced the natural adsorbent's efficiency. The optimum adsorbent dose for the removal of all two pesticides (2,4-D and impidacloprid) was same, that is 10mg while, the optimum adsorbent dose for carbaryl was 30mg. Whereas, the optimal pH and pesticide concentration varied for all three pesticide. Firstly, large amount of 2,4-D was removed at acidic pH with 10 ppb pesticide concentration, secondly, carbaryl at basic pH with 1ppb and lastly, imidacloprid at neutral pH with 1 ppb. Under optimal conditions the activated tea residue removed 99.99% of 2,4-D, 99.5% of carbaryl and 99.7% of imidacloprid.