Journal of Inorganic Materials ›› 2021, Vol. 36 ›› Issue (10): 1083-1090.DOI: 10.15541/jim20200745

• RESEARCH ARTICLE • Previous Articles     Next Articles

Co-modification of Biochar and Bentonite for Adsorption and Stabilization of Pb2+ ions

XIAO Yao1(), WU Zhongjie2, CUI Mei3, SU Rongxin3,4, XIE Lianke2, HUANG Renliang4()   

  1. 1. School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
    2. Shandong Electric Power Research Institute of Chinese Power Company, Jinan 250002, China
    3. School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
    4. School of Marine Science and Technology, Tianjin University, Tianjin 300072, China
  • Received:2020-12-30 Revised:2021-01-25 Published:2021-10-20 Online:2021-03-12
  • Contact: HUANG Renliang, associate professor. E-mail: tjuhrl@tju.edu.cn
  • About author:XIAO Yao (1995-), female, Master candidate. E-mail: xiaoyao950827@gmail.com
  • Supported by:
    National Natural Science Fund of China(21976132);Science and Technology Project of State Grid Corporation of China(520626190015)

Abstract:

Heavy metals can seriously endanger human health and the ecological environment due to their toxicity, persistence, and bioaccumulative nature. In this study, an alkali-modified biochar-bentonite composite (CaO-Bent-CB) was prepared by alkali modification of corncob residues and bentonite mixture by calcium chloride and calcination at high temperature under anaerobic conditions. The CaO-Bent-CB composite has a specific surface area of ​​441.1 m2/g, which is significantly higher than CB (132.7 m2/g) and CaO-CB (177.2 m2/g). Meanwhile, the adsorption perfermance of CaO-Bent-CB to lead ions in water was evaluated. The results showed that the removal efficiency reached 98% after 6 h-adsorption, and the adsorption capacity was 109.6 mg/g when the concentration of lead ion was 120 mg/L, the weight ratio of bentonite to corncob residues was 1:5, and the dosage was 1 g/L. The adsorption capacity of CaO-Bent-CB was higher than that of CB (13.4 mg/g), bentonite (72.9 mg/g) and CaO-CB (86.9 mg/g). Moreover, the lead ion contaminated soil was stabilized by CaO-Bent-CB. When the concentration of lead ion in soil is 2200 mg/kg, and the loading of CaO-Bent-CB is 8% of soil, the concentration of lead ions in acid leachate (H2SO4-HNO3, pH=3.2, 12 h-soaking) is 4.5 mg/L, which is lower than the standard value of hazardous waste identification (5 mg/L). The results show that CaO-Bent-CB has a great potential in the water treatment and heavy metals removal in soil.

Key words: corncob residue, biochar, clay, heavy metal, soil remediation

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