期刊
CHEMOSPHERE
卷 280, 期 -, 页码 -出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.chemosphere.2021.130566
关键词
Sewage sludge; Rice husk; Co-pyrolysis; Phosphorus; Heavy metals
资金
- National Natural Science Foundation of China [51908233]
This study investigated the effects of rice husk dose and pyrolysis temperature on the phosphorus fractions and environmental risk of heavy metals in biochar co-pyrolyzed from sewage sludge and rice husk. The results showed that co-pyrolysis could improve biochar-P bioavailability, and the P species mainly existed as orthophosphate in biochar. Additionally, the toxicity and mobility of heavy metals decreased with increasing rice husk dose and pyrolysis temperature, indicating that co-pyrolysis of sewage sludge and rice husk could be a promising P reuse strategy.
This study investigated the effects of rice husk dose and pyrolysis temperature on the phosphorus (P) fractions and environmental risk of heavy metals in biochar co-pyrolyzed from sewage sludge and rice husk. Biochar properties were analyzed, and the transformation of P and heavy metals speciation during co-pyrolysis were also discussed. Co-pyrolysis of raw sludge and rice husk (10-50 wt%) could increase the carbonization degree and stability of biochar at 500 degrees C. The organic P (OP) in raw sludge (68 wt%) was transformed to inorganic P (IP) during co-pyrolysis, indicating that the addition of rice husk could improve biochar-P bioavailability by promoting the transformation of IP. The IP content increased from 71.5 wt% of sludge biochar to 92 wt% of blended biochar (50 wt% sludge and 50 wt% rice husk) at a pyrolysis temperature of 500 degrees C. With the mass ratio of sludge to rice husk of 5:5, the OP content decreased from 3 mg g(-1) to 0.75 mg g(-1) as the pyrolysis temperature increased from 300 degrees C to 700 degrees C. The P-31 nuclear magnetic resonance spectra and X-ray photoelectron spectroscopy results showed that P species in biochar mainly existed as orthophosphate, which can be directly taken up by plants. After co-pyrolysis, the toxicity and mobility of heavy metals gradually decreased with increasing rice husk dose and pyrolysis temperature. The study indicates that co-pyrolysis of sewage sludge and rice husk could be a promising P reuse strategy. (C) 2021 Elsevier Ltd. All rights reserved.
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