Superior arsenate adsorption and comprehensive investigation of adsorption mechanism on novel Mn-doped La2O2CO3 composites

Su, J, Lyu, T ORCID: https://orcid.org/0000-0001-5162-8103, Yi, H, Bi, L and Pan, G ORCID: https://orcid.org/0000-0003-0920-3018, 2019. Superior arsenate adsorption and comprehensive investigation of adsorption mechanism on novel Mn-doped La2O2CO3 composites. Chemical Engineering Journal: 123623. ISSN 1385-8947

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Abstract

A major challenge for effective decontamination of arsenate from aqueous solution is the development of adsorbent possessing enormous high-active sites with strong affinity to realize both high adsorption capacity and reduction of arsenate down to permissive levels. Here we demonstrate that this challenge may be overcome by doping Mn atoms into La2O2CO3 materials. The synthesized material (5.26%-MnL) achieved an arsenate capture ability superior to most other currently-reported adsorbents, with the maximum adsorption capacity of 555.6 mg/g. Additionally, this novel adsorbent could dramatically reduce the concentration of arsenate from 3775 μg/L to less than 4 μg/L, well below the acceptable value for drinking water (10 μg/L). The adsorption capacity of 5.26%-MnL was demonstrated to be >300 mg/g over a wide pH range from 4 to 9 and the efficiency was maintained >85% even after three cycles of adsorption/desorption. Through a series of characterizations, both surface complexation and ion exchange were proved to contribute to arsenate removal at low molar ratios of As(V)/5.26%-MnL while forming LaAsO4 precipitation played a greater role at higher As(V)/5.26%-MnL ratios. Density Functional Theory (DFT) calculations suggested that Mn atoms acted as active species by not only increasing lattice defects and adsorption sites, but also by activating La3+ in La2O2CO3, which lowered the adsorption energy and facilitated arsenate removal. Due to the high affinity and superior adsorption capacity towards arsenate, Mn-doped La2O2CO3 has been demonstrated to be a promising prospect for the remediation of arsenate-polluted water.

Item Type:	Journal article
Publication Title:	Chemical Engineering Journal
Creators:	Su, J., Lyu, T., Yi, H., Bi, L. and Pan, G.
Publisher:	Elsevier
Date:	29 November 2019
ISSN:	1385-8947
Identifiers:	Number Type 10.1016/j.cej.2019.123623 DOI 1249721 Other S1385894719330384 Publisher Item Identifier
Divisions:	Schools > School of Animal, Rural and Environmental Sciences
Record created by:	Jonathan Gallacher
Date Added:	05 Dec 2019 11:03
Last Modified:	31 May 2021 15:12
URI:	https://irep.ntu.ac.uk/id/eprint/38760

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