Removal of nickel and total chromium using Escherichia coli biofilm supported on clinoptilolite

Biofilm is communities of microorganisms attached to the surface and is able to concentrate metal species within their cell structure. Therefore, the aim of this study was to produce Escherichia coli biofilm on zeolite (clinoptilolite) and evaluate its ability for nickel (Ni) and chromium (Cr) adsorption from aqueous solutions. A laboratory-scale batch model was used for biodsorption assay. The effect of initial metal concentrations and pH on the removal efficiency was studied. Two isotherm equations were used for analyzing the experimental data. The results showed that Ni uptake by biofilm were higher than Cr. The biosorption process was best described by the Langmuir model. Fourier transform infrared confirmed that there are some functional groups on the biomass surface that may interact with the metal ions. It is concluded that the biofilm is very promising for the removal of metal ions from aqueous solution and hence may be encourage the utilization of biofilm in environmental applications.