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| The adsorption effects and mechanisms of biochar immobilized sulfate-reducing bacteria(SRB) on Cr (Ⅵ) |
| Received:October 05, 2020 |
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| KeyWord:biochar carrier;sulfate-reducing bacteria;Cr(Ⅵ) pollution;adsorption kinetics;optimized conditions |
| Author Name | Affiliation | | ZHU Xiao-li | School of City and Environment, Northwest University, Xi' an 710127, China | | LI Xue | School of City and Environment, Northwest University, Xi' an 710127, China | | KOU Zhi-jian | School of City and Environment, Northwest University, Xi' an 710127, China | | WANG Jun-qiang | School of City and Environment, Northwest University, Xi' an 710127, China
Xi' an Jinborui Ecological Technology Co., Ltd., Xi' an 710065, China | | SHANG Xiao-qing | School of City and Environment, Northwest University, Xi' an 710127, China
Xi' an Jinborui Ecological Technology Co., Ltd., Xi' an 710065, China | | CHEN Chao | Xi' an Jinborui Ecological Technology Co., Ltd., Xi' an 710065, China |
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| Abstract: |
| Biochars were produced from rice straw, wheat straw, and corn straw at 300, 500℃, and 700℃, respectively, and the adsorption effects of sulfate-reducing bacteria(SRB) immobilized by different biochars on Cr(Ⅵ) were compared. Subsequently, the SRB immobilized by XM700(produced from rice straw pyrolysis under 700℃) denoted as IBXM700 was chosen as experimental material based on its higher capability for Cr(Ⅵ) removal than that of other materials. The surface morphology and characteristics of IBXM700 were determined with Scanning Electron Microscope(SEM), Fourier Transform Infrared Spectrosopy(FTIR), and BET surface area(BET). Furthermore, the influence parameters related to the adsorption process, including pH, adsorption time, the amount of biochar added, and the initial concentration of Cr(Ⅵ), were investigated. In addition, the adsorption process was described using adsorption kinetics and an isothermal model. The results showed that the optimized conditions were as follows:a pH of 5.0, a biochar amount of 0.6 g·100 mL-1, an adsorption time of 24 h, and an initial Cr(Ⅵ) concentration of 100 mg·L-1. The adsorption process of Cr(Ⅵ) by IBXM700 was properly fitted by pseudo-first-order kinetics and the Langmuir model, which indicated that the adsorption of Cr(Ⅵ) by IBXM700 is based on monolayer adsorption with ion exchange, surface physical adsorption, and chemical adsorption. SRB could reduce SO42- to S2- and secrete reductase for the reduction of Cr(Ⅵ) to Cr(Ⅲ), thus removing Cr(Ⅵ). Therefore, reduction and adsorption might be the main removal mechanisms of Cr (Ⅵ) by IBXM700. |
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