A comparative study on behavior of heavy metals in pyrochar and hydrochar from sewage sludge

ABSTRACT

Behavior of heavy metals in biochar obtained from sewage sludge with the pyrolysis and hydrothermal processes was comparatively studied. Increase of reaction temperature resulted in increased pH of pyrochar (7.75 ~ 8.96) and hydrochar (5.94 ~ 7.00), while yields of pyrochar and hydrochar were both decreased. For hydrochar, temperature higher than 300 was found to be adverse to the immobilization of Cu and Zn. In comparison with hydrothermal process, increase of reaction temperature in the pyrolysis process was beneficial to the immobilization of Cu and Pb, while adverse effect was found on Cd and Zn.

KEYWORDS:

• Biochar
• heavy metal
• hydrothermal
• pyrolysis
• sewage sludge

Acknowledgments

We are also grateful to Professor Yunbo Zhai and Doctor Chuan Peng of Hunan University for their help with the laboratory aspects of this study.

Funding

This work was supported by the Research Project of Hubei Provincial Department of Education (Q20162702).

Additional information

Funding

This work was supported by the Research Project of Hubei Provincial Department of Education (Q20162702).