Qualitative and quantitative characterisation of adsorption mechanisms of lead on four biochars.
Sci Total Environ
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Shen, Z., Zhang, Y., Jin, F., McMillan, O., & Al-Tabbaa, A. (2017). Qualitative and quantitative characterisation of adsorption mechanisms of lead on four biochars.. Sci Total Environ, 609 1401-1410. https://doi.org/10.1016/j.scitotenv.2017.08.008
The adsorption mechanisms of lead (Pb2+) on four biochars (SB produced from British hardwood at 600°C and three standard biochars produced from wheat straw pellets at 700°C (WSP700), rice husk at 700°C (RH700) and soft wood pellets at 550°C (SWP550)) were characterised qualitatively and quantitatively, using a combination of chemical and micro-structural methods. Sequential extraction test results show that Pb2+ was predominantly adsorbed on SB (85.31%), WSP700 (75.61%) and RH700 (85.76%) as acidic soluble fraction, which was potentially bioavailable if applied in soil. The exchangeable fraction for SB, WSP700 and RH700 was low (1.38-4.29%) and their water soluble fraction was negligible (0-0.14%). Micro-structural analysis further investigated this fraction and confirmed the presence of cerussite (PbCO3) on SB and hydrocerussite (Pb3(CO3)2(OH)2) on WSP700, RH 700 and SWP550, suggesting a mechanism of surface precipitation for Pb2+ adsorption on the biochars. The percentages of Pb2+ in the form of PbCO3 on SB (82.24%) and Pb3(CO3)2(OH)2 on WSP700 (13.00%), RH 700 (19.19%) and SWP550 (29.70%) were quantified using thermogravimetric analysis (TGA). This study suggests that it is feasible to quantify different adsorption mechanisms of Pb2+ on biochars, which is important for the practical application of biochar in water and/or soil treatment.
External DOI: https://doi.org/10.1016/j.scitotenv.2017.08.008
This record's URL: https://www.repository.cam.ac.uk/handle/1810/286918