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| Influence of Low-temperature Pyrolysis Treatment on Bioavailability of Heavy Metals in Pig Manure |
| Received:December 13, 2014 |
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| KeyWord:pig manure;pyrolysis;pig manure-derived biochar;heavy metal;immobilization;bioavailability |
| Author Name | Affiliation | E-mail | | WANG Wei-jin | Institute of Resource, Ecosystem and Environment of Agriculture, Nanjing Agricultural University, Nanjing 210095, China | | | LI Bin | Institute of Resource, Ecosystem and Environment of Agriculture, Nanjing Agricultural University, Nanjing 210095, China | | | LI Lian-qing | Institute of Resource, Ecosystem and Environment of Agriculture, Nanjing Agricultural University, Nanjing 210095, China | lqli@njau.edu.cn | | PAN Gen-xing | Institute of Resource, Ecosystem and Environment of Agriculture, Nanjing Agricultural University, Nanjing 210095, China | | | YU Xin-yan | Institute of Resource, Ecosystem and Environment of Agriculture, Nanjing Agricultural University, Nanjing 210095, China | | | WANG Jia-fang | Institute of Resource, Ecosystem and Environment of Agriculture, Nanjing Agricultural University, Nanjing 210095, China | |
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| Abstract: |
| Animal wastes often contain heavy metals, thus posing environmental risks. Carbonization by pyrolysis is an important approach to reusing waste biomass. In this study, an experiment was designed to investigate the influence of low-temperature pyrolysis treatment on bioavailability of heavy metals in pig manure. Pig manure samples, collected from commercial pig farms across the China, were analyzed for heavy metal contents(arsenic, copper, zinc, cadmium, lead and nickel) and also subjected to pyrolysis at 350 ℃, 400 ℃ or 450 ℃。 The ranges and averages of heavy metal content(mg·kg-1) in pig manure were 261.6~2 564.5 and 928.2 for Zn, 87.98~700.6 and 294.7 for Cu, 2.19~7.17 and 4.80 for Ni, 0.45~19.57 and 3.60 for As, 1.69~4.02 and 2.39 for Pb, and 0.10~0.17 and 0.12 for Cd. The greatest variation was 155.7% for As. Metal content in the pig manure-derived biochar was increased by 57.7%~104.4%(Ni), 59.7%~99.4%(Cu), 50.7%~94.0%(Zn), 47.1%~73.5%(Pb), 30.8%~61.5%(Cd) and 17.1%~30.5%(As). However, the bioavailability of metals in the biochars decreased greatly. DTPA-extractable metals in the biochars were decreased by 94.4%~95.4% for Cu, 91.9%~95.1% for Ni, 91.3%~92.5% for Zn, 80.4%~81.0% for Pb and 76.6%~84.0% for As, as compared with the pig manures. It suggests that low-temperature pyrolysis could reduce the environmental risks of heavy metals in pig manures. |
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