Preparation Of Modiifed White-rot Biomass Biosorbent And Sorption For Cr(Ⅵ) Contaminated Wastewater

Heavy metal pollution is one of the most harmful problems of water pollution.Because of the influence of human activities, such as mining, metal processing, metalsmelting, the burning of fossil fuels, heavy metal pollutants enter the water bodyaccompany wtih chemical production, solid waste, application of fertilizers,pesticides, and geological erosion, weathering and so on. In this paper, the applicationof many kinds of new and efficient modification technologies to heavy metal wasdiscussed in wastewater treatment. Low sorption capacity usually occurs whenapplied original materials (such as microorganism, inorganic or organic materials) onheavy metal sorption in wastewater. More interests are focused on the increase ofmaterials’ sorption capacity. This paper summarized the surface-modification of thematerials via physical or chemical modification to improve heavy metals adsorptioncapacity, such as incorporating polymer onto the surface of the bacteria, imprintingsurface molecular as adsorbent, immobilizing microbe biomass and acid modifyingmaterials, and so on. Comparing with conventional materials, the maximumadsorption capacity increased significantly when applying these new and efficientmodified materials. With the development of modified technologies, the applicationof modified materials will become the mainstream of heavy metal waste watertreatment in the future.P. chrysosporium mycelial pellet was cultured with the potato medium, thepreparation of modified biosorbent by polyethylenimine was described and thechanges of structure on biomass surface as well as the zeta potential before and aftermodification were observed. According to the SEM, the surface of modified biomaswas more close. Results of infrared spectroscopy showed that a large number of aminogroups and hydroxide radical groups were introduced by the modification ofpolyethylenimine. The point of zero potential for the modified biomass increasedfrom initial pH3to a much higher value of10.8, which showed that the PEI-modifiedbiomass can be expected to provide better adsorption performance for anionicadsorbates than the pristine biomass.The modified P. chrysosporium mycelial pellet was used to adsorb Cr(Ⅵ) fromthe wastewater. Some parameters such as pH, initial heavy metal concentrations andadsorption time were selected to study the effect on adsorption. Results showed thatthe optimal adsorption condition was pH3. When the adsorption time was3h, the sorption reached saturation. The optimal initial heavy mental concentration was250mg/L. Compared with the pristine biomass, the adsorption capacity increasedsignificantly while using modified biomass to adsorb Cr(Ⅵ) in wastewater. Under thecondition, the maximum adsorption capacity of polyethylenimine-modified white-rotbiomass reached344.8mg/g. Some Cr(Ⅵ) transformed to Cr(Ⅲ) in the solution.Compared with other adsorbents, the performance of the absorbent is enhancedsignificantly.