Magnetically recoverable Fe3O4/graphene nanocomposite towards efficient removal of triazine pesticides from aqueous solution: Investigation of the adsorption phenomenon and specific ion effect. (February 2017) - Boruah, Purna K.
Abstract: Spillage of effluents containing high concentration levels of pesticides into water has been considered as one of the serious environmental problems. In this study Fe3 O4 /reduced graphene oxide (rGO) nanocomposite has been efficiently utilized for the adsorption of five harmful pesticides namely ametryn, prometryn, simazine, simeton and atrazine in an aqueous medium. Electrostatic interaction between the pesticides and Fe3 O4 /rGO nanocomposite was analyzed by the zeta potential analysis, which is strongly related to the adsorption capacity of the adsorbent. The kinetics parameters of adsorption followed the pseudo second-order linear model. The adsorption isotherm studies show that, the maximum adsorption capacity of 54.8 mg g −1 is achieved at pH 5 and it was enhanced in the presence of different ions (Mg 2+, Ca 2+, Na + and SO4 2 ) and maximum (63.7 mg g −1 ) for ametryn adsorption was found in seawater medium. Thermodynamic parameter shows that, the adsorption process is physisorption and spontaneity in nature. The mechanism of the adsorption process was established by the DRIFT spectroscopy analysis. Efficient adsorption (93.61%) of pesticides was observed due to electrostatic, hydrophobic and π–π interactions of composite towards the heterocyclic conjugation of pesticide molecules. Further, Fe3 O4 /rGO nanocomposite was easily and rapidly separated from an aqueous medium using the external magnet for reuse and 88.66% adsorption efficiency was observed up to seven cycles. Graphical abstract: Highlights: A feasible and eco-friendly route for the removal of five triazine pesticides. Magnetic Fe3 O4 /rGO shows efficient triazine pesticides removal property. Specific ion effect plays an important role in pesticide adsorption onto Fe3 O4 /rGO. The reusability and magnetic reparability of Fe3 O4 /rGO is added advantage.