Prajitno, MY orcid.org/0000-0002-2944-1470, Harbottle, D orcid.org/0000-0002-0169-517X, Hondow, N orcid.org/0000-0001-9368-2538 et al. (2 more authors) (2020) The effect of pre-activation and milling on improving natural clinoptilolite for ion exchange of cesium and strontium. Journal of Environmental Chemical Engineering, 8 (1). 102991. ISSN 2213-3437
Abstract
Natural clinoptilolite, of relatively low-grade, was investigated for its capability to remove cesium and strontium ions from water and simulated seawater. To improve its capacity, the material was pre-activated with concentrated NaCl and HCl solutions. Additionally, it was milled to a number of < 300 μm size fractions, to expose exchange sites. Electron microscopy was used to characterise the naturally occurring impurities, where regions of high iron and potassium content was shown to correlate to lower levels of cesium adsorption. Adsorption kinetics for natural and activated resins with 5, 300 and 1500 ppm salt solutions were fitted with the Pseudo-Second Order (PSO) rate model. Activation led to clear increases in initial adsorption rate for both Cs+ and Sr2+, but only enhanced the overall rate constant for Cs+, due to the weaker interaction of the Sr2+. Equilibrium isotherms were compared with Langmuir and Freundlich monolayer models, where the adsorption capacity (Qc) for Cs+ was 67 mg/g which increased by over 100% with NaCl activation to 140 mg/g. Values for Sr2+ were significantly lower at 35 mg/g, with a considerably smaller enhancement with activation to 52 mg/g. Milling of the natural clinoptilolite was found to increase Cs+ uptake to similar levels as activation, in a linear correlation with specific surface area; although, improvements for Sr2+ were again lower, due to its weaker interaction with surface sites. In simulated seawater solutions, all materials gave considerably reduced performance due to K+ ion competition, with Sr2+ uptake decreased more extensively compared to Cs+. Overall, this work highlights that pre-activation and milling of clinoptilolite can be used to significantly enhance the grade of the ore for nuclear effluent treatment in low-salinity conditions.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2019 Elsevier Ltd. All rights reserved. This is an author produced version of a paper published in Journal of Environmental Chemical Engineering. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Cesium; clinoptilolite; ion exchange; milling; pre-activation; strontium |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemical & Process Engineering (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 10 Apr 2019 11:46 |
Last Modified: | 26 May 2022 10:46 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.jece.2019.102991 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:144778 |