Green low cost nanomaterial produced from Moringa oleifera seed waste for enhanced removal of chlorpyrifos from wastewater: Mechanism and sorption studies

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 mu g/mL), biosrbent dose (0.05-0.5 g), solution pH (5-9), exposure time (10-1440 min) and temperature (25-45 degrees 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 7C-7C 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.

Automated summary

The study developed a novel nanoscale Moringa olivera seeds waste (nMSW) as an effective bio-nanosrbent for enhanced removal of chlorpyrifos from contaminated wastewater. The nMSW exhibited superior adsorption capacity compared to conventional bulk MSW and most reported green sorbents, with remarkable removal efficiency achieved in a short contact time period. The thermodynamic parameters and bio-sorption data suggested the main driving forces in CPF removal mechanism by nMSW.