Diethylamine functionalised Moringa oleifera leaves for the removal of chromium(VI) and bacteria from wastewater

The existence of heavy metals such as Cr(VI) in water is a threat to human and animal life. Herein, a novel method is reported, whereby, a low-cost adsorbent was prepared by reacting the cellulose ofMoringa Oleifera leaves with epichlorohydrin and triethylamine using diethylamine (DEA) as a modifying agent for Cr(VI) and bacterial removal. The functionalised Moringa Oleifera(FMO) was confirmed using XRD, FTIR, TGA, SEM, BET and Zeta potential. The FTIR results showed that the amino groups were successfully grafted on the surface of Moringa Oleifera (MO). Dosage, pH, contact time and initial concentrations were optimised to 2.5 g, 2, 85 min and 20 mg/L, respectively. The FMO removed 99% Cr(VI) at optimum conditions. Adsorption kinetics fitted well with pseudo second order, suggesting a chemisorption mechanism between Functionalisedcellulose ofMoringa Oleifera(FMO) and Cr(VI). The maximum adsorption capacity obtained from Langmuir Isotherm for Cr(VI) removal was 60.6061 mg/g. The correlation coefficient (R²) obtained from the linear calibration curve of Cr(VI) was 0.9999, with a limit of quantification (LOQ) and limit of detection (LOD) of 1.486 and 0.4461 mg/L, respectively. Reusability studies also displayed that the material could be used for up to 7 cycles, with a > 90% Cr (IV) removal. This bio adsorbent was highly selective towards chromium(VI) in the industrial waste water containing interfering ions. FMO was also tested for its antibacterial activity using pond, river, tap and sewage water against several bacterial strains. It was found that the FMO was most potent against E. coli, Staphylococcus aureus and total coliforms. Based on the data obtained, this study has shown that environmentally safe bioadsorbents can be used as multifunctional materials for the treatment of water.