Removal Of Heavy Metals By Phanerochaete Chrysosporium From Waste Water

The increasing worldwide contamination of surface waters by heavy metals is one of the key environmental problems, because they are not biodegradable and can accumulate in living tissues. Cadmium, copper, zinc and their compounds are widely found in surface water. Their removal and recovery from wastewater is important for environmental protection and preservation of human health.Biosorption is a cost-efficient technique and no second pollution for treating large volumes of waste streams. Many fungal materials are used for heavy metal removal and recovery due to their good performance. In this research, living Phanerochaete chrysosporium mycelia were used for heavy metal adsorption. The biomass was successfully applied to the bioremediation of wastewater containing heavy metals of Cd(Ⅱ), Cu(Ⅱ) and Zn(Ⅱ). Some parameters such as pH, temperature, adsorption time and initial heavy metal concentrations were selected to study the effect on adsorption. FTIR spectroscopy was used to describe the surface functional groups and different kinetic models were compared in terms of their ability to describe Cd(Ⅱ), Cu(Ⅱ) and Zn(Ⅱ) binding by P. chrysosporium. Langmuir adsorption isotherm equation and Freundlich adsorption isotherm equation were used to simulate the adsorption.In this study P. chrysosporium was cultured expansilly with the Kirk liquid medium, the cultivating time was72hours, and control conditions to make it form mycelial pellet. The fungi were used to absorb heavy metals in wastewater.The use of live P. chrysosporium mycelia as biosorbent for Cd(Ⅱ), Cu(Ⅱ) and Zn(Ⅱ) biosorption from artificial wastewaters was studied. The uptake of heavy metal ions by the mycelia was dependent on environmental conditions. The optimum biosorption conditions of Cd(Ⅱ), Cu(Ⅱ) and Zn(Ⅱ) were pH5.5～6.5at37℃and6h. Under these conditions, The fungal biosorbent removed Cd(Ⅱ), Cu(Ⅱ) and Zn(Ⅱ) rapidly and efficiently with maximum metal removal capacities of66.23mg/g,74.78mg/g and54.12mg/g, respectively. The pseudo second-order kinetic model was superior to the pseudo first-order kinetic model, indicating that the adsorption might be a chemical process, which indicated that the change of surface sorption sites’ number is proportional to the square of remaining unoccupied surface sites’number. The maximum uptake of Cd(Ⅱ) simulated with Langmuir sorption isotherm model was68.03mg/g at pH6.5.Result of Fourier transform infrared (FTIR) spectrums indicated that hydroxyl and carboxyl groups were relevant to biosorption. Some crystalline particles were found outside the biomass of P. chrysosporium under scanning electron microscopy after Cd(Ⅱ) biosorption. Results of Energy dispersive X-ray analysis and FTIR revealed amino acids and proteins were involved in binding metal ions. The results demonstrated that P. chrysosporium was a good potential biosorbents for adsorbing heavy metals.