Adsorption of Cu ( II ) and Ni ( II ) in Aqueous Solution using Biofilm Supported with Kaolinite Clay

Adsorption of each of the ions Cu (II) and Ni (II) on Escherichia coli ATCC25922 and Staphylococcus epidermidis RP62A supported by kaolinite clay in a batch system was investigated. Equilibrium adsorption capacity was determined to be a function of the solution pH, contact time, and initial metal concentrations. The results obtained from the adsorption experiments were used to understand the driving forces that govern the interaction between metal ions and the biosorbent. Minimum inhibitory concentration (MIC) values of E. coli ATCC 29522 for Cu (II) and Ni (II) are two times greater than S. epidermidis RP62A which means E. coli ATCC 29522 is very resistant to metals than that of S. epidermidis RP62A.The experimental data were analyzed by the Freundlich and Langmuir isotherms. The adsorption kinetics of metal ions best fits the pseudo-second order. The effect of pH on metal ion uptake was studied by performing equilibrium sorption experiments with varying the solution pH from 4 to 8. The result showed the optimum pH for the three metals is at pH 5 with initial concentration of 100 mg/L at contact time of 24 hours with constant temperature of 370C. Keywords— biosorbent, adsorption, Escherichia coli ATCC29522, Staphylococcus epidermidis RP62A