Shahlaa E. Ebrahim

Competitive biosorption of Pb(II), Cr(III), and Cd(II) from synthetic wastewater onto heterogeneous anaerobic biomass in single, binary, and ternary batch systems

Biosorption of lead, chromium, and cadmium ions from aqueous solution by dead anaerobic biomass (DAB) was studied in single, binary, and ternary systems with initial concentration of 50mg/l. The metal-DAB affinity was the same for all systems. The main biosorption mechanisms were complexation and physical adsorption of metallic cations onto natural active functional groups on the cell wall matrix of the DAB. It was found that biosorption of the metallic cations onto DAB cell wall component was a surface process. The main functional groups involved in the metallic cation biosorption were apparently carboxyl, amino, hydroxyle, sulfhydryl, and sulfonate. These groups were part of the DAB cell wall structural polymers. Hydroxyle groups (‐OH) were responsible for 37, 52, and 31% of the removal of Pb(II), Cr(III), and Cd(II) by DAB through complexation mechanisms; whereas carboxylic groups (C=O) were responsible for 21, 14, and for 34%of the removal of Pb(II), Cr(III), and Cd(II), respectively. Biosorption data were fitted to four isotherm models. Langmuir model was best fitted to the experimental data than Freundlich, Sips, and Redlich‐Peterson models for single system. While for binary and ternary metal systems, extended Langmuir model were fitted experimental data better than interaction factor, a combination of Langmuir‐Freundlich and Redlich‐Peterson models. The maximum uptake capacities were 54.92, 34.78, and 29.99mg/g for Pb(II), Cr(III), and Cd(II), respectively. Optimum pH was found to be 4.

Performance of Biomass Adsorber Column for Competitive Removal Pb(II), Cr(III) and Cd(II) ions from Synthetic Wastewater

The adsorption of Pb(II), Cr(III) and Cd(II) onto dead anaerobic biomass (DAB) in single, binary and ternary system was studied using fixed bed adsorber. A general rate multi- component model (GRM) was utilized to predict the fixed bed breakthrough curves for triple-component system. This model considers both external and internal mass transfer resistances as well as axial dispersion with non-liner multi-component isotherm (Langmuir model). The effects of important parameters, such as flow rate, initial concentration and bed height on the behavior of breakthrough curves were studied. The equilibrium isotherm model parameters such as isotherm model constants, pore diffusion coefficients were obtained from the batch experiments. The results showed that the GRM was found suitable for describing the adsorption process of the dynamic behavior of the DAB adsorber column.