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| Quantitative analysis of the adsorption of cadmium on wheat straw and pig manure biochar |
| Received:August 19, 2020 |
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| KeyWord:wheat straw;pig manure;biochar;cadmium;adsorption mechanism;quantitative analysis |
| Author Name | Affiliation | E-mail | | CHEN Qiao | School of Environment Science and Engineering, Shaanxi University of Science & Technology, Xi'an 710021, China | | | REN Xin-hao | School of Environment Science and Engineering, Shaanxi University of Science & Technology, Xi'an 710021, China | renxinhao@sust.edu.cn | | HE Fei | School of Environment Science and Engineering, Shaanxi University of Science & Technology, Xi'an 710021, China | | | YANG Shu-yuan | School of Environment Science and Engineering, Shaanxi University of Science & Technology, Xi'an 710021, China | | | GUO Jun-kang | School of Environment Science and Engineering, Shaanxi University of Science & Technology, Xi'an 710021, China | |
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| Abstract: |
| To quantitatively analyze the adsorption of cadmium(Cd) on biochar, four types of biochar(WBC300, WBC700, PBC300 and PBC700) derived from wheat straw and pig manure were prepared by pyrolysis at 300℃ and 700℃. The adsorption of cadmium by biochar was investigated. The results showed that the treatment by acid washing decreased the sorption capacity of biochar by 38.5%~83.0%, and the effect of ash washing of BC700 was greater than that of BC300. The inorganic components of biochar adsorbed Cd in solution mainly through precipitation and ion exchange, whereas the organic components adsorbed Cd by complexing with oxygencontaining functional groups. Under the experimental conditions(pH=5.0, the initial concentration of Cd was 200 mg·L-1), for PBC300, the contribution of precipitation, ion exchange and complexation to the adsorption of Cd were 52.1%, 32.2% and 15.5%, respectively; for PBC700, they were 91.9%, 5.10% and 2.96%, respectively; for WBC300, they were 23.9%, 36.2% and 39.9%, respectively; and for WBC700, they were 63.5%, 21.8% and 14.7%, respectively. With the increase in biochar pyrolysis temperature, the contribution rate of precipitation in Cd adsorption increases, while the contribution rate of ion exchange and complexation decreases. Inorganic precipitation and ion exchange are the main mechanisms of Cd adsorption by biochar prepared at high temperature with high ash content. |
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