Enhanced water treatment with TEMPO-modified luffa cellulose-PVA nanofiber composite for removal of hexavalent chromium

Abstract

Water treatment has emerged as a global priority in recent years due to its direct impact on human health. To address this concern, the utilization of cost-effective, readily available, and efficient materials is imperative in overcoming associated challenges. In this study, cellulose derived from Luffa cylindrica (LC) underwent oxidation using (2,2,6,6-tetramethylpiperidine-1-yl)oxyl (TEMPO) and subsequently functionalized with amine groups from poly(ethylenimine) (PEI). The resulting material was then composited with polyvinyl alcohol (PVA) nanofiber. The modified membrane was employed for the adsorption of hexavalent chromium from wastewater using various pH, contact time, temperature, concentration, and composite dose. The findings revealed that the process is pH-dependent with a high optimal removal (93 %) observed at pH 2, (94 %) for the composite dose, and (90.3 %) for contact time. The Kinetics were studied by applying pseudo-first-order, pseudo-second-order, Elovich, and Intraparticle diffusion models. And the data suggested that the adsorption process adheres to the pseudo-second-order model (R2 = 0.9948). Moreover, the adsorption isotherm examined by Langmuir, Freundlich, Tempkin, and D-P equation and results exhibited a satisfactory fit to the Langmuir isotherm (R2 = 0.99193) and the maximum removable capacity was (52.91).

Keywords

• Water treatment
• Cellulose
• Nanofiber
• Adsorption
• Pollution