改性竹炭对正己烷生物降解过程的强化机理

Mechanism of Biodegradation of N-Hexane by Bamboo Charcoal

摘要: 正己烷作为重要的工业原料被广泛应用，但其会对人体健康和大气环境造成严重危害。微生物技术凭借反应条件温和、环境友好、运行费用低和操作简单等优点越来越受到关注，但正己烷的超强疏水性导致了生物法难以高效去除正己烷。本文研究了一种双金属改性竹炭(Fe-Pd/BC)，并将其应用于正己烷的生物降解。实验结果表明，在Fe-Pd/BC投加浓度为0.05 g∙L⁻¹、NH₄⁺浓度3 g∙L⁻¹、pH 7.7、温度35℃条件下，300 mg∙L⁻¹的正己烷去除率在35 h可达94.63%。此外，在Fe-Pd/BC存在的情况下，与对照组相比，细胞疏水性从22.61%提高至45.78%，胞外蛋白质含量从38.14 μg∙mL⁻¹提高至46.27 μg∙mL⁻¹，细胞表面zeta电位从−14.7 mV降低至−18.4 mV。进一步的实验表明，Fe-Pd/BC可以通过参与细菌生长、提高zeta电位绝对值、暴露大量蛋白质疏水基团、增加CSH来提高正己烷的生物降解效率。本研究的结论证实通过添加Fe-Pd/BC来提高微生物降解效果是一种很有前景的正己烷废气治理技术。

Abstract: N-hexane is widely used as an important industrial raw material, but it will cause serious harm to human health and atmospheric environment. Microbial technology has attracted more and more attention because of its mild reaction conditions, friendly environment, low operation cost and simple operation. However, the super hydrophobicity of n-hexane makes it difficult for biological method to remove n-hexane efficiently. A bimetallic modified bamboo charcoal (Fe-Pd/BC) was studied and applied to the biodegradation of n-hexane. The experimental results show that under the conditions of Fe-Pd/BC concentration of 0.05 g∙L⁻¹, NH₄⁺ concentration of 3 g∙L⁻¹, pH 7.7 and temperature of 35˚C, the removal rate of n-hexane of 300 mg∙L⁻¹ could reach 94.63% in 35 h. In addition, in the presence of Fe-Pd/BC, compared with the control group, the cell hydrophobicity increased from 22.61% to 45.78%, and the content of extracellular protein increased from 38.14 μg∙L⁻¹ increased to 46.27 μg∙L⁻¹. The cell surface potential decreased from −14.7 mV to −18.4 mV. Further experiments show that Fe-Pd/BC could improve the biodegradation efficiency of n-hexane by participating in bacterial growth, increasing the absolute value of zeta potential, exposing a large number of protein hydrophobic groups and increasing CSH. The conclusion of this study confirmed that adding Fe-Pd/BC to improve the microbial degradation effect is a promising n-hexane waste gas treatment technology.