Kinetic study of time-dependent fixation of UVI on biochar

Ashry, Ahmed and Bailey, Elizabeth H. and Chenery, Simon and Young, Scott D. (2016) Kinetic study of time-dependent fixation of UVI on biochar. Journal of Hazardous Materials, 320 . pp. 55-66. ISSN 0304-3894

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Abstract

Biochar, a by-product from the production of biofuel and syngas by gasification, was tested as a material for adsorption and fixation of UVI from aqueous solutions. A batch experiment was conducted to study the factors that influence the adsorption and time-dependent fixation on biochar at 20oC, including pH, initial concentration of UVI and contact time. Uranium (UVI) adsorption was highly dependent on pH but adsorption on biochar was high over a wide range of pH values, from 4.5 to 9.0, and adsorption strength was time-dependent over several days. The experimental data for pH > 7 were most effectively modelled using a Freundlich adsorption isotherm coupled to a reversible first order kinetic equation to describe the time-dependent fixation of UVI within the biochar structure. Desorption experiments showed that UVI was only sparingly desorbable from the biochar with time and isotopic dilution with 233UVI confirmed the low, or time-dependent, lability of adsorbed 238UVI. Below pH 7 the adsorption isotherm trend suggested precipitation, rather than true adsorption, may occur. However, across all pH values (4.5–9) measured saturation indices suggested precipitation was possible: autunite below pH 6.5 and either swartzite, liebigite or bayleyite above pH 6.5.

Item Type: Article
Keywords: Biochar, uranium, adsorption, pH, isotherm,kinetics
Schools/Departments: University of Nottingham UK Campus > Faculty of Science > School of Biosciences > Division of Agricultural and Environmental Sciences
Identification Number: https://doi.org/10.1016/j.jhazmat.2016.08.002
Depositing User: Bailey, Liz
Date Deposited: 12 Aug 2016 13:41
Last Modified: 13 Sep 2016 14:11
URI: http://eprints.nottingham.ac.uk/id/eprint/35815

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