- Title
- Co-pyrolysis of sewage sludge and rice husk/ bamboo sawdust for biochar with high aromaticity and low metal mobility
- Creator
- Zhang, Jin; Jin, Junwei; Song, Chengfang; Shan, Shengdao; Wang, Minyan; Naidu, Ravi; Liu, Yanju; Man, Yu Bon; Liang, Xinqiang; Wong, Ming Hung; Christie, Peter; Zhang, Yan
- Relation
- Environmental Research Vol. 191, Issue December 2020, no. 110034
- Publisher Link
- http://dx.doi.org/10.1016/j.envres.2020.110034
- Publisher
- Academic Press
- Resource Type
- journal article
- Date
- 2020
- Description
- Blending waste biomass for co-pyrolysis is generally regarded as a promising method for reduced-volume, value-added, and hazard-free treatment of sewage sludge. Hence, a comparison was made of the co-pyrolysis of sewage sludge with rice husk and with bamboo sawdust (1:1, w/w) at 400 and 700℃ and the properties and behaviors of selected metals in the corresponding biochars. Biochar produced by co-pyrolysis with both biomass wastes had larger (5 x 5 rectangle) aromatic clusters than did the sewage sludge biochar (4 x 4 rectangle) using the rectangle-like model on the basis of biochar molar H/C ratio, indicating increased aromaticity of the co-pyrolyzed biochars. Moreover, the molar O/C ratio of the sewage sludge-bamboo biochar was much lower than that of the sewage sludge-husk biochar, especially after pyrolysis at 700 oC (0.02 vs 0.27), suggesting greater recalcitrance to ageing. Co-pyrolysis of sewage sludge with husk invariably resulted in a higher percentage of metals studied in the residual fraction than co-pyrolysis with sawdust at the same temperature, leading to a lower risk index (14.2) because of the maximum metal encapsulation in the sewage sludge-husk biochar at 700 oC. Overall, co-pyrolysis of sewage sludge with husk provided higher metal immobilization but apparently lower biochar stability than co-pyrolysis with sawdust. These results provide an alternatively practical strategy for the safe disposal of sewage sludge and biomass wastes.
- Subject
- sewage sludge; co-pyrolysis; waste biomass; biochar aromaticity; metal immobilization
- Identifier
- http://hdl.handle.net/1959.13/1431085
- Identifier
- uon:38915
- Identifier
- ISSN:0013-9351
- Language
- eng
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