Isotherm and kinetic studies of cadmium biosorption and its adsorption behaviour in multi-metals solution using dead and immobilized archaeal cells.

It is crucial to identify more biological adsorbents that can efficiently uptake metals from wastewater. Dry haloalkaliphilic archaea Natronolimnobius innermongolicuswas evaluated for Cd ions biosorption. The optimal operating conditions (pH, biomass dose, initial metal concentration, contact time, and isotherms models) were tested. Biosorption process is influenced by the metal's solution pH with maximum removal of 83.36% being achieved at pH 8. Cadmium ions uptake reaches equilibrium in about 5 min of biosorption process. The Langmuir model was determined to better fit the Cd(II) biosorption by dry archaea. The maximal uptake capacity (q) of Cd(II) was 128.21 mg/g. The effect of multi-component system on biosorption behaviour of Pb, Ni, Cu, Fe, and Cd ions by immobilized dried archaeal cells, dried archaeal cells, and dried bryozoa was studied using Plackett-Burman experimental design. The investigated biosorbents were effective at removing metals from contaminated systems, particularly for Fe, Pb, and Cd ions. Moreover, the interaction behaviour of these metals was antagonistic, synergistic, or non-interactive in multi-metals system. SEM, EDX, and FTIR spectra revealed changes in surface morphology of the biomass through the biosorption process. Finally, continuous adsorption experiment was done to examine the ability of immobilized biomass to adsorb metals from wastewater.