LAUSR

Abstract Developing cost- effective green sorbents for enhanced removal of organophosphorus pesticides from contaminated water remains inspirational. In this study, a novel nanoscale Moringa olivera seeds waste (nMSW) was produced and applied for the first time as an effective bio-nanosrbent for chlorpyrifos (CPF) removal from contaminated wastewater. The nMSW sorbent was characterized and the parameters that affect the biosorption process like CPF concentration (10-80 μg/mL), biosrbent dose (0.05-0.5 g), solution pH (5-9), exposure time (10-1440 min) and temperature (25- 45°C) were optimized. The CPF adsorption by nMSW follows in order Langmuir > Temken > Kiselev adsorption models. The maximum adsorption capacity of nMSW for CPF has shown 2.75 folds increase (25 mg g-1) compared to that of the conventional bulk MSW and superior to most of the reported green sorbents. The sorption kinetics data fitted well to the power function and first-order models. Remarkable CPF removal efficiency of 81% was achieved using nMSW at pH 7 in contact time period of 30 min. The thermodynamic parameters revealed the spontaneous and the exothermic nature of CPF sorption process. The functional groups of nMSW and CPF, thermodynamics and bio-sorption data suggested that H-bonding, hydrophobicity, electrostatic and π–π interactions are the main driving forces in CPF removal mechanism by nMSW. The novel nano-biosorbent can be introduced as an effective green and low cost alternative for CPF removal from contaminated wastewater.