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| Characteristics of bovine bone biochar at different pyrolysis temperatures and its adsorption of Cd2+ |
| Received:January 19, 2023 |
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| KeyWord:bovine bone;biochar;adsorption kinetics;adsorption isotherm;Cd2+ |
| Author Name | Affiliation | E-mail | | HUANG Tao | School of Environmental Science and Engineering, Changzhou University, Changzhou 213164, China | | | HU Linchao | School of Environmental Science and Engineering, Changzhou University, Changzhou 213164, China | hulc@cczu.edu.cn | | WU Jianan | School of Environmental Science and Engineering, Changzhou University, Changzhou 213164, China | | | ZHANG Wenyi | School of Environmental Science and Engineering, Changzhou University, Changzhou 213164, China | | | MAO Linqiang | School of Environmental Science and Engineering, Changzhou University, Changzhou 213164, China | |
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| Abstract: |
| Here, the physicochemical properties of bovine bone biochar and its adsorption properties for Cd2+ at different pyrolysis temperatures were studied. Bovine bone biochar was prepared at 300, 350, 400, 500, 700, and 900 ℃ using waste bovine bone as the raw material and the method of slow pyrolysis with limited oxygen at a controlled temperature. The bovine bone biochar was characterized by thermogravimetric analysis（TG）, Fourier transform infrared spectroscopy（FTIR）, and scanning electron microscopy（SEM）, and its Cd2+ adsorption characteristics were analyzed using batch adsorption experiments. The results showed that the pH value and ash content of bovine bone biochar increased with increasing pyrolysis temperature, simultaneously the aromatics gradually strengthened, and the pore size and specific surface area increased, but the contents of volatile matter, organic carbon, and total nitrogen decreased. The pseudosecond order kinetics model could accurately fit the adsorption kinetics of Cd2+ for the five bovine bone biochar species（R2>0.999）, and the adsorption rate was dominated by intra-particle diffusion near the adsorption equilibrium. The Cd2+ isothermal adsorption process of bovine bone biochar was consistent with the Langmuir model. Bovine bone biochar prepared at 700 ℃ showed the best adsorption effect on Cd2+ and the maximum equilibrium adsorption capacity was 44.32 mg·g-1. With the increase in pyrolysis temperature, the complexation of functional groups in the Cd2+ adsorption mechanism of bovine bone biochar was weakened, whereas the surface adsorption, cation exchange, and π electron coordination effects increased. Our results suggest that energy consumption costs and tail gas collection should be fully considered in the process of preparing bovine bone biochar on a practical scale. |
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