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Co-pyrolysis of sewage sludge and Ca(H2PO4)2: heavy metal stabilization, mechanism, and toxic leaching.
Gu, Weihua; Guo, Jiangshan; Bai, Jianfeng; Dong, Bin; Hu, Jun; Zhuang, Xuning; Zhang, Chenglong; Shih, Kaimin.
Afiliación
  • Gu W; School of Resources and Environmental Engineering, Shanghai Polytechnic University, Shanghai, 201209, China; College of Environment, Zhejiang University of Technology, Hangzhou, 310014, China.
  • Guo J; School of Resources and Environmental Engineering, Shanghai Polytechnic University, Shanghai, 201209, China.
  • Bai J; School of Resources and Environmental Engineering, Shanghai Polytechnic University, Shanghai, 201209, China. Electronic address: jfbai@sspu.edu.cn.
  • Dong B; College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China. Electronic address: dongbin@tongji.edu.cn.
  • Hu J; College of Environment, Zhejiang University of Technology, Hangzhou, 310014, China.
  • Zhuang X; School of Resources and Environmental Engineering, Shanghai Polytechnic University, Shanghai, 201209, China.
  • Zhang C; School of Resources and Environmental Engineering, Shanghai Polytechnic University, Shanghai, 201209, China.
  • Shih K; Department of Civil Engineering University of Hongkong, Pokfulam Road, Hongkong, China.
J Environ Manage ; 305: 114292, 2022 Mar 01.
Article en En | MEDLINE | ID: mdl-34998065
The presence of unstable heavy metals in sewage sludge (SS) restricts its resource utilization. In this study, Ca(H2PO4)2 and SS were co-pyrolyzed to produce biochar, which contained relatively stable heavy metals. X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, and inductively coupled plasma atomic emission techniques were used to analyze the physical and chemical properties and heavy metal content of the biochar. The results indicated that co-pyrolysis of SS with Ca(H2PO4)2 resulted in the production of more stable heavy metals in the SS. The optimal co-pyrolysis conditions were a blended ratio of 15% Ca(H2PO4)2, 650 °C final temperature, 15 °C min-1, and 60 min retention time. The potential stabilization mechanisms of heavy metals were as follows: (1) organic decomposition and moisture (sourced from Ca(H2PO4)2 decomposition) evaporation resulted in greater biochar surface porosity; (2) phosphorous substances were complexed with heavy metals to form metal phosphates; and (3) the mixture reactions among inorganic substances, pyrolysis products of organics, and heavy metals resulted in the formation of highly aromatic metallic compounds. Additionally, the potential environmental risks posed by the heavy metals decreased from 65.73 (in SS) to 4.39 (in biochar derived from co-pyrolysis of SS and 15% of Ca(H2PO4)2). This study reports on a good approach for the disposal of SS and the reduction of its environmental risk.
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Texto completo: 1 Bases de datos: MEDLINE Asunto principal: Pirólisis / Metales Pesados Idioma: En Revista: J Environ Manage Año: 2022 Tipo del documento: Article País de afiliación: China

Texto completo: 1 Bases de datos: MEDLINE Asunto principal: Pirólisis / Metales Pesados Idioma: En Revista: J Environ Manage Año: 2022 Tipo del documento: Article País de afiliación: China