Study On The Adsorption Of Heavy Metal Ions By Compound Microbial Flocculation

In company with the fast development of the metal plating, mining, dying, petrochemical and battery industries, a great deal of waste water containing the excessive dangerous heavy metal ions, such as cadmium,arsenic,lead and chromium ions, were discharged into the environment and would engender the great harm to the environmental ecology and the human health. Heavy metal ions were bioaccumulative pollutants. Cadmium,arsenic and lead had been regarded as endocrine-disrupting chemicals. The pollution of heavy metal ions in the water had been one of the most serious environmental problem in the world.The major methods to treat heavy metal wastewater, such as precipitation, ion exchange, electrochemistry and membrane technologies were restricted by technology and economy . In this paper, microbial adsorption method was used to remove the heavy metal ions from the solution. It had the advantages of wide raw material, low cost, few secondary pollution. It had good effect of adsorption when the concentration of the heavy metal waste water was below 100ppm.The biomass materials used in the study were compound microbial flocculation which is product of microbic metabolism by mixing and fermenting bacterial strains. The components were compound such as protein, amylase and grease etc. The absorbent in this study was compound microbial flocculation from three bacterial strains which had high effect of flocculation. The objects of adsorption were cadmium(â…¡),arsenic(â…¢),lead(â…¡)and chromium(â…¥)ions which had serious harm.First, the influence of shaker speed, temperature, time of culture of bacterial strains, pH value, absorbent dosage, concomitant ions were investigated. The experimental results indicated that lower shaker speed was good for the adsorption of Cd(â…¡)and Cr(â…¥) while higher shaker speed was benefit for the adsorption of As(â…¡)and Pb(â…¡).The effect of temperature on the adsorption wasn't obvious. It could reached good...