CUED Publications database

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

Shen, Z and Hou, D and Jin, F and Shi, J and Fan, X and Tsang, DCW and Alessi, DS (2019) Effect of production temperature on lead removal mechanisms by rice straw biochars. Science of the Total Environment, 655. pp. 751-758. ISSN 0048-9697

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Abstract

© 2018 Elsevier B.V. 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: Article
Uncontrolled Keywords: Adsorption Biochar Lead immobilization Precipitation Production temperature Soil remediation
Subjects: UNSPECIFIED
Divisions: Div D > Geotechnical and Environmental
Depositing User: Cron Job
Date Deposited: 08 Dec 2018 20:04
Last Modified: 15 Oct 2020 04:19
DOI: 10.1016/j.scitotenv.2018.11.282