Research Articles
Adsorption of Cr(III) from aqueous solution on NaOH-treated scraped coconut waste
Authors:
T. M. P. D. M. Thennakoon,
University of Peradeniya, Peradeniya, LK
About T. M. P. D. M.
Department of Chemistry
A. P. G. M. V. Samaraweera,
University of Peradeniya, Peradeniya, LK
About A. P. G. M. V.
Department of Chemistry
N. Priyantha
University of Peradeniya, Peradeniya, LK
About N.
Department of Chemistry
Abstract
Scraped coconut waste left after coconut milk processing, is a low-cost, readily available natural substance in tropical countries, such as Sri Lanka. This study is based on the removal of Cr(III) ions using NaOH-treated scraped coconut waste (NSCW). Under optimized experimental conditions employed, treatment of the biosorbent with aqueous 0.10 mol L-1 NaOH solution provides much enhanced Cr(III) removal of 92.9%. As compared to the 53.6% removal in the absence of any modification, it is an increase by 73.3%. The extent of biosorption of Cr(III) by NSCW depends on experimental conditions, such as mass of NSCW, initial solution pH, shaking time and settling time. Fourier transform infrared spectroscopy provides information on functional groups, such as O-H, C-H, C=O and C-O present in NSCW, which possesses a relatively high surface area of 10.8 (±1.1) m2 g-1. Adsorption equilibrium studies demonstrate that the Langmuir isotherm is more suitable than the Freundlich isotherm in explaining the interaction of Cr(III) with NSCW, leading to the adsorption capacity of 14.28 mg g-1 for Cr(III) removal. Moreover, experiments conducted on kinetics provide the applicability of the pseudo first order model under low adsorbent dosage and ambient temperature conditions. Transfer of Cr(III) towards the NSCW surface is found to be controlled by intra-particle diffusion and boundary layer retarded diffusion, and the predominant mode depends on experimental conditions.
How to Cite:
Thennakoon, T. M. P. D. M., Samaraweera, A. P. G. M. V., & Priyantha, N. (2021). Adsorption of Cr(III) from aqueous solution on NaOH-treated scraped coconut waste. Ceylon Journal of Science, 50(5), 391–401. DOI: http://doi.org/10.4038/cjs.v50i5.7928
Published on
28 Oct 2021.
Peer Reviewed
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