The blending effect of natural polysaccharides with nano-zirconia towards the removal of fluoride and arsenate from water

M Shanika Fernando; A K D V K Wimalasiri; Karolina Dziemidowicz; Gareth R Williams; K Rasika Koswattage; D P Dissanayake; K M Nalin De Silva; Rohini M De Silva

doi:10.1098/rsos.221514

The blending effect of natural polysaccharides with nano-zirconia towards the removal of fluoride and arsenate from water

R Soc Open Sci. 2023 Mar 8;10(3):221514. doi: 10.1098/rsos.221514. eCollection 2023 Mar.

Authors

M Shanika Fernando¹, A K D V K Wimalasiri¹, Karolina Dziemidowicz², Gareth R Williams², K Rasika Koswattage³, D P Dissanayake¹, K M Nalin De Silva¹, Rohini M De Silva¹

Affiliations

¹ Centre for Advanced Materials and Devices (CAMD), Department of Chemistry, University of Colombo, Colombo 00300, Sri Lanka.
² UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London WCIN 1AX, UK.
³ Faculty of Technology, University of Sabaragamuwa, 70140 Belihuloya, Sri Lanka.

Abstract

Nano-zirconia (ZO) was synthesized using a microwave-assisted one-pot precipitation route. Two biopolymers, chitosan (CTS) and carboxymethyl cellulose were blended with ZO at different w/w ratios. The formulation with 30% w/w chitosan (ZO-CTS) was found to give enhanced uptake of F^- and As(V). ZO and the most effective ZO-CTS system were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. These confirmed the formation of a composite system containing nanoparticles of 50 nm in size, in which ZO was present in the amorphous form. It was observed that the combination of ZO with CTS improved the F^- and As(V) adsorption capacity most notably at pH 5.5. Fluoride adsorption by ZO-CTS followed the Freundlich isotherm model, with an adsorption capacity of 120 mg g^-1. Adsorption of As(V) by ZO-CTS could be fitted with both the Langmuir and Freundlich isotherm models and was found to have a capacity of 14.8 mg g^-1. Gravity filtration studies conducted for groundwater levels indicated the effectiveness of ZO-CTS in adsorbing As(V) and F^- at a pH of 5.5. The ability of the ZO-CTS in removing Cd(II) and Pb(II) was also investigated, and no such enhancement was observed, and found the neat ZO was the most potent sorbent here.

Keywords: adsorption; arsenate; chitosan; fluoride; zirconia.

Associated data

figshare/10.6084/m9.figshare.c.6444350
Dryad/10.5061/dryad.b8gtht7cv