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    华北潮褐土土壤中大肠杆菌的吸附动力学特征

    Adsorption kinetics of Escherichia coli in cinnamon soil of North China

    • 摘要: 以环境生物污染指示菌——大肠杆菌为研究对象,基于四种吸附动力学模型,研究了不同因素(生物炭、离子强度、土著微生物)下华北地区典型潮褐土对大肠杆菌的吸附动力学特征。结果表明:土壤对大肠杆菌的吸附动力学过程可以细化为快速(0~20 min)、慢速(20~60 min)和平衡吸附(80~120 min)3个阶段;准二级动力学方程能够较为准确地描述土壤对大肠杆菌的吸附动力学特征;土壤对大肠杆菌的吸附为非均相化学吸附,吸附速率的调控主要源于表面吸附和颗粒内扩散机制的协同作用;添加生物炭和提高离子强度会增加土壤对大肠杆菌的吸附量,而土著微生物的存在会降低土壤对大肠杆菌的吸附量。研究结果可为探索华北潮褐土土壤病原细菌控制途径提供理论基础。

       

      Abstract: As an indicator bacterium of environmental biological contamination, Escherichia coli (E. coli) was used as the research object, and the adsorption kinetics of Escherichia coli in typical agricultural soil of North China under different factors (biochar, ionic strength, indigenous microorganisms) were studied based on four adsorption kinetic models. The results showed that the process of adsorption kinetics of E. coli in soil can be refined to three following stages: fast adsorption (0~20 min), slow adsorption (20~60 min) and equilibrium adsorption (80~120 min). The quasi-secondary kinetic equation was suitable for describing the adsorption kinetics of E. coli. The adsorption of E. coli by soil was heterogeneous chemisorption, and the adsorption rate of E. coli was mainly fluctuated by the synergistic effect of surface adsorption and intragranular diffusion mechanism. The addition of biochar and the improvement of ionic strength increased the adsorption capacity of E. coli, while the presence of indigenous microorganisms decreased the adsorption capacity of E. coli in soil. These results can provide the theoretical basis of controlling pathway for pathogenic bacterial contamination in cinnamon soil of North China.

       

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