Biopolymer-Based Nanohydroxyapatite Composites for the Removal of Fluoride, Lead, Cadmium, and Arsenic from Water

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

doi:10.1021/acsomega.1c00316

Biopolymer-Based Nanohydroxyapatite Composites for the Removal of Fluoride, Lead, Cadmium, and Arsenic from Water

ACS Omega. 2021 Mar 18;6(12):8517-8530. doi: 10.1021/acsomega.1c00316. eCollection 2021 Mar 30.

Authors

M Shanika Fernando¹, A K D V K Wimalasiri¹, Karolina Dziemidowicz², Gareth R Williams², K R 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, U.K.
³ Faculty of Technology, Sabaragamuwa University of Sri Lanka, P.O. Box 02, Belihuloya 70140, Sri Lanka.

Abstract

In this study, hydroxyapatite (HAP) nanocomposites were prepared with chitosan (HAP-CTS), carboxymethyl cellulose (HAP-CMC), alginate (HAP-ALG), and gelatin (HAP-GEL) using a simple wet chemical in situ precipitation method. The synthesized materials were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, Brunauer-Emmett-Teller surface area analysis, and thermogravimetric analysis. This revealed the successful synthesis of composites with varied morphologies. The adsorption abilities of the materials toward Pb(II), Cd(II), F^-, and As(V) were explored, and HAP-CTS was found to have versatile adsorption properties for all of the ions, across a wide range of concentrations and pH values, and in the presence of common ions found in groundwater. Additionally, X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy confirmed the affinity of HAP-CTS toward multi-ion mixture containing all four ions. HAP-CTS was hence engineered into a more user-friendly form, which can be used to form filters through its combination with cotton and granular activated carbon. A gravity filtration study indicates that the powder form of HAP-CTS is the best sorbent, with the highest breakthrough capacity of 3000, 3000, 2600, and 2000 mL/g for Pb(II), Cd(II), As(V), and F^-, respectively. Hence, we propose that HAP-CTS could be a versatile sorbent material for use in water purification.