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| Methylmercury adsorption characteristics of thiol-modified biochar in water |
| Received:June 11, 2021 |
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| KeyWord:biochar;sulfhydryl;complex;methylmercury |
| Author Name | Affiliation | E-mail | | XIE Tong | School of Environment and Resources, Zhejiang A &
F University, Hangzhou 311300, China | | | XUE Bingsong | School of Environment and Resources, Zhejiang A &
F University, Hangzhou 311300, China | | | WANG Shan | School of Environment and Resources, Zhejiang A &
F University, Hangzhou 311300, China | | | WU Shengchun | School of Environment and Resources, Zhejiang A &
F University, Hangzhou 311300, China
Key Laboratory of Soil Contamination Bioremediation of Zhejiang Province, Zhejiang A &
F University, Hangzhou 311300, China | | | LIANG Peng | School of Environment and Resources, Zhejiang A &
F University, Hangzhou 311300, China
Key Laboratory of Soil Contamination Bioremediation of Zhejiang Province, Zhejiang A &
F University, Hangzhou 311300, China | liangpeng@zafu.edu.cn |
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| Abstract: |
| Pyrolysis biochar was prepared from cow dung, sludge, and bamboo shavings and modified by 3-mercaptopropyltrimethoxysilane. Elemental analysis, scanning electron microscopy, and Fourier transform infrared spectrometry were used to characterize the biochar before and after thiol modification. Isothermal adsorption and adsorption kinetics experiments were used to conduct a comparative study of the different raw material-modified biochars and to discuss their methylmercurg(MeHg)adsorption mechanisms. The aim was to explore the MeHg adsorption characteristics and mechanisms of thiol-modified biochar. The results showed that O—Si groups were successfully introduced onto the biochar surface, which proved that the introduction of sulfhydryl groups was successful. Thiol-modified biochar has an enhanced ability to complex MeHg, which is mainly due to the stronger complexing ability of sulfur-containing groups(—SH, C—S)to MeHg. After modification, the adsorption of MeHg onto the three types of biochar conformed to the quasi-second-order adsorption kinetics and Langmuir isotherm adsorption equation. The maximum fitting adsorption capacity of thiolmodified biochar to MeHg reached 526~1 450 ng·g-1, which was significantly higher than that of raw biochar(331~533 ng·g-1). The adsorption rate constant(k2)of modified biochar(1.800~2.640)was significantly higher than that of raw biochar(0.014~0.156). All the results showed that compared with the raw biochar, the adsorption capacity of thiol-modified biochar was significantly improved, which effectively removed MeHg in water mainly through the functional groups(—SH and C—S)with MeHg formed —SHgCH3 and(CH3Hg)2S and other complexes. |
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