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| Synthesis of microbial immobilized biochar for the removal of ammonia nitrogen from aqueous solutions |
| Received:November 26, 2020 |
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| KeyWord:Paracoccus denitrificans;Pseudomonas;Raoultella;biochar;immobilized microorganisms;NH4+-N |
| Author Name | Affiliation | E-mail | | WU Meng-li | Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China | | | LI Jie | Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China | lijie@caas.cn | | ZHI Yan-cai | Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China
Institute of Environmental Processes and Pollution Control, School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China | | | LI Gang | Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China | | | LAI Xin | Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China | | | JU Xue-hai | Rural Energy&Environment Agency, Ministry of Agriculture and Rural Affairs, Beijing 100125, China | | | ZHANG Gui-long | Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China | zhangguilong@caas.cn |
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| Abstract: |
| To explore the effects of immobilized microbial biochar on the removal of ammonium nitrogen(NH4+-N) in water, a comparative experiment was conducted. Paracoccus denitrificans(T), Pseudomonas(J), and Raoultella(L) were immobilized on peanut shell biochar (BC) through adsorption and embedding methods. After adding the three microorganisms and their immobilized biochars into waste water containing ammonia nitrogen, the performance of these treatments on NH4+-N removal were assessed, as well as surface structure, functional groups, and pore structure parameters were evaluated. The results showed that both adsorption and embedding methods immobilized microorganisms on the surface of biochar as evident from the distribution of round, rod, and granular forms. The specific surface area and pore volume of immobilized Paracoccus denitrificans and Pseudomonas biochar reduced by 5.5%~17.2% and 5.4%~25.8% by the adsorption method, respectively. Regarding immobilized Raoultella biochar by adsorption, the specific surface area and micropore volume of biochar increased by 45% and 43% times, respectively, and the mesoporous and macroporous volumes also reduced. Although new functional groups, such as -CH2, C-H, and C=O bonds, were introduced via embedding, the specific surface area of embedded microorganisms on biochar reduced rapidly by 87.3%~96.3% in comparison with that of biochar and adsorbed microorganisms biochars. Moreover, the mesoporous pore volume decreased 84.1%~98.2% and the micropores were almost completely blocked by the embedded materials, such as polyvinyl alcohol hydrogel(PAH) and sodium alginate(SA). Therefore, the NH4+-N removal rate of immobilized microbial biochar prepared by the adsorption method was 1.16~3.44 times higher than that of the embedding method. Our results indicated that both adsorption and embedding methods fixed bacteria on the surface of biochar, and the effects of the embedding method on the pore structure and functional groups of biochar was significantly greater than that of the adsorption method. In comparison, adsorbed microorganisms biochars showed a higher efficiency in removing NH4+-N from the waste water than the embedded microorganisms biochars. |
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