Royal Society Open Science (Mar 2023)

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
https://doi.org/10.1098/rsos.221514
Journal volume & issue
Vol. 10, no. 3

Abstract

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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.

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