Zirconium-modified Citrus limetta peel for effective removal of arsenic from ground water

Document Type

Article

Publication Date

2024

Abstract

The arsenic removal form ground water is an important global issue these days. In this study, raw Citrus limetta peel (RCLP), an agro biowaste, was saponified and loaded with Zr(IV) to develop anion exchange sites for the biosorption of As(V) ion. RCLP and Zr(IV)-modified saponified Citrus limetta peel [Zr(IV)-SCLP] were characterized by spectroscopic, thermo-gravimetric and microscopic techniques. Biosorption experiments at various pH showed that maximum excision of As(V) onto Zr(IV)-SCLP and RCLP occurred at pH 4.46 and 5.80 at an optimal contact time of 7 and 5 h, respectively. The biosorption kinetic data followed pseudo-second-order (PSO) model. Among the Freundlich, Langmuir and Temkin models, the experimental data followed the Langmuir model and yielded maximum As(V) biosorption capacities of 14.02 and 75.86 mg/g for RCLP and Zr(IV)-SCLP, respectively. The regeneration test showed that As(V) could be effectively desorbed using 1 M NaOH. It was demonstrated that the order of tested interfering ions for As(V) biosorption onto Zr(IV)-SCLP is PO43− > SO42− > CO32− > NO3− > Cl−. The dynamic biosorption of As(V) in a fixed bed column revealed that Zr(IV)-SCLP is effective also in continuous mode. Finally, the biosorbent was tested for As(V) removal in a field collected ground water sample. Interestingly, only 70 mg/L of the biosorbent was sufficient to decreased 74.60 μg/L of arsenic below tolerance limit of WHO (10 μg/L) for drinking water. These findings suggested that Zr(IV)-modified Citrus limetta peel can be an efficient, highly potential, economic and environmentally sustainable solution for the treatment of arsenic polluted ground water. © 2024 Elsevier B.V., All rights reserved.

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