Removal of Cd and Pb with biochar made from dairy manure at low temperature
CHEN Zhi-liang1, ZHANG Jian-qiang1, HUANG Ling1, YUAN Zhi-hui2, LI Zhao-jun3, LIU Min-chao2
1 Guangdong Engineering Technology Research Center of Heavy Metal Pollution Control and Restoration in Farmland Soil, South China Institute of Environmental Sciences, Guangzhou 510635, P.R.China 2 School of Environment and Chemistry, Wuyi University, Jiangmen 529020, P.R.China 3 Key Laboratory of Plant Nutrition and Fertilizer, Ministry of Agriculture/China-New Zealand Joint Laboratory for Soil Molecular Ecology, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R.China
Biochar (BC) derived from waste products is a cost-effective sorbent for remediation of metal-contaminated soils. We studied the kinetics and adsorption mechanisms for removal of metal ions, such as lead (Pb2+) and cadmium (Cd2+) with biochar. The adsorption capacities of BC for Pb2+ and Cd2+ increased after alkaline treatment. The highest sorption capacities were 175.53 and 68.08 mg g–1, for Pb and Cd, respectively. The Langmuir adsorption isotherm and pseudo second kinetic equation could well fit the adsorption processes, revealing that the sorption mechanisms of Pb2+ and Cd2+ by BC are complex and predominantly controlled by chemisorption. BC has a higher affinity for Pb than Cd, due to easy hydrolysis of Pb at low pH. Furthermore, precipitation as carbonate minerals (2PbCO3·Pb(OH)2 and CdCO3) and complexation with functional groups (carboxyl and hydroxyl) were also important for adsorption of Pb and Cd by BC.
Fund: The authors wish to thank the National Key R&D Program of China (2017YFD0801300), the Guangdong Technology Program of China (2017B020203001), the Guangdong Natural Science Foundation of China (2017A030313245), and the Guangzhou Technology Program of China (201607010393, 2016201604030017 and 201707010484) for financial support.
CHEN Zhi-liang, ZHANG Jian-qiang, HUANG Ling, YUAN Zhi-hui, LI Zhao-jun, LIU Min-chao. 2019. Removal of Cd and Pb with biochar made from dairy manure at low temperature. Journal of Integrative Agriculture,