Effect of production temperature on lead removal mechanisms by rice straw biochars

Shen, Z., Hou, D., Jin, F. , Shi, J., Fan, X., Tsang, D. C.W. and Alessi, D. S. (2019) Effect of production temperature on lead removal mechanisms by rice straw biochars. Science of the Total Environment, 655, pp. 751-758. (doi:10.1016/j.scitotenv.2018.11.282)

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Production temperature significantly affects biochar properties and consequently the removal mechanisms of heavy metals. In this study, rice straw biochars were produced at 300, 500 and 700 °C (RSB300, RSB500 and RSB700). The influence of production temperature on the adsorption characteristics and removal mechanisms of lead on this set of rice straw biochars were investigated by batch adsorption tests, micro-structural analyses and sequential metal extractions. Biochars produced at higher temperatures had significantly higher pH values and surface areas, resulting in higher metal removal capacities and faster uptake kinetics. Precipitation was a key mechanism for lead removal from solution for all biochars: lead oxalate was precipitated on RSB300, and hydrocerussite was precipitated on RSB500 and RSB700. The immobilized lead fraction on the biochars could be divided into exchangeable, acid soluble and non-available fractions. RSB300 had 11.34% of the total immobilized Pb attributed to the exchangeable fraction, whereas for RSB500 and RSB700, it was <1%. Immobilized Pb on RSB500 and RSB700 was almost exclusively attributable to the acid soluble and non-available fractions (>99%). Based on our results, RSB500 and RSB700 are likely much more appropriate for soil remediation of Pb as compared with RSB300.

Item Type:Articles
Additional Information:This work was supported by the Opening Fund of National Engineering Laboratory for Site Remediation Technologies (No. NEL-SRT201702), and the National Water Pollution Control and Treatment Science and Technology Major Project (No. 2018ZX07109-003). Moreover, this study was partly funded by the Thousand Talents Program of the Chinese government and Tsinghua University. The first author would like to thank the Killam Trusts of Canada for kindly providing the Izaak Walton Killam Memorial Postdoctoral Fellowship.
Glasgow Author(s) Enlighten ID:Jin, Dr Fei
Authors: Shen, Z., Hou, D., Jin, F., Shi, J., Fan, X., Tsang, D. C.W., and Alessi, D. S.
College/School:College of Science and Engineering > School of Engineering > Infrastructure and Environment
Journal Name:Science of the Total Environment
ISSN (Online):1879-1026
Published Online:20 November 2018
Copyright Holders:Copyright © 2018 Elsevier B.V.
First Published:First published in Science of the Total Environment 655:751-758
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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