耐性真菌HA吸附铅、锌的影响因素及吸附机理研

Influence factors and absorption mechanism of Pb(II) and Zn(II) by resistant fungus HA

摘要:

【目的】从铅锌矿区分离筛选出耐铅锌性菌株，并研究其吸附铅、锌的影响因素及吸附机理，为重金属污染微生物修复提供参考。【方法】以从铅锌矿区筛选出的耐铅锌真菌HA作为试验菌株，考察影响其对铅、锌去除能力的主要因素(初始浓度、pH、接种量)，同时通过等温吸附模型、动力学分析及红外光谱分析探讨其相关的吸附机理。【结果】经鉴定，从矿区筛选的对Pb2+、Zn2+有较强耐性的菌株HA为米曲霉(Aspergillus oryzae)；在初始铅、锌浓度的实验范围内(100-800 mg/L)，HA对铅、锌离子的去除率随着其初始浓度增加而减小，25 h后HA的生长进入平稳期，且对铅、锌离子的去除率趋于稳定。当铅、锌初始浓度为100 mg/L、pH为5.0时，HA对铅、锌离子的去除率均达到最高，分别为97.8%、54.1%；当HA接种量为1 mL时，其对铅、锌去除率的增长率达到最大。HA对铅、锌的吸附过程满足Langmuir吸附模型，其吸附以单层吸附为主。在动态吸附过程中，HA对Pb2+、Zn2+离子吸附性能与准二级动力学吸附方程的拟合程度更高，且对Pb2+的吸附效果明显高于Zn2+。红外光谱分析表明，HA细胞中羟基、烷基、酰胺基、羰基、磷酸基等参与了Pb2+、Zn2+的吸附过程。【结论】HA是一株对铅、锌有较强吸附能力的真菌，其吸附铅、锌影响因素及吸附机理研究结果将为重金属污染微生物修复提供指导。

Abstract:

[Objective] The purpose of this paper is to isolate and screen lead-zinc resistant strains from lead-zinc tailings areas. Its influence factors and mechanism of Pb(II) and Zn(II) adsorption also were studied. This work is expected to provide a reference for bioremediation of heavy metal pollution. [Methods] The fungus HA which was isolated and screened from lead-zinc tailings areas was used. The main influence factors (i.e., initial concentration of Pb(II) and Zn(II), pH, inoculation amounts) on the removal of Pb(II) and Zn(II) were investigated. And the related adsorption mechanism was also discussed by isothermal adsorption model, adsorption kinetics analysis and IR analysis. [Results] The resistant strain HA screened from tailings areas was identified as Aspergillus oryzae. In the experimental range of initial concentration of Pb(II) and Zn(II) (100–800 mg/L), the removal of Pb(II) and Zn(II) decreased with the increase of the initial concentration of Pb(II) and Zn(II). The growth of HA turned into stable period after 25 h, and the removal of Pb(II) and Zn(II) was relatively stable. The maximum biosorption was found at initial Pb(II) and Zn(II) of 100 mg/L and pH 5.0. Under such conditions, the adsorption rates of Pb(II) and Zn(II) was 97.8% and 54.1%, respectively. When the inoculation quantity of HA was 1 mL, the Pb(II) and Zn(II) adsorption rate of increment was the fastest. The adsorption process of Pb(II) and Zn(II) by HA was in accordance with Langmuir adsorption model, and its adsorption was given priority with monolayer adsorption. During the dynamic adsorption process of Pb(II) and Zn(II) by HA, a pseudo-second-order adsorption kinetics model was more suitable for describing the adsorption performance of HA, and the effect of HA on adsorption of Pb(II) was significantly higher than on Zn(II). IR analysis showed that the functional groups of HA such as hydroxyl, alkyl, amide, carbonyl and phosphate group were involved in the adsorption process of Pb(II) and Zn(II) by HA. [Conclusion] HA is a fungus having stronger adsorption ability for Pb(II) and Zn(II), and this research results of influence factors and mechanism of Pb(II) and Zn(II) adsorption would provide a guidance for bioremediation of heavy metal pollution.