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

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.