Alginate and alginate-zeolite beads for removal of cadmium present in water

The use of ALG beads and ALG-ZEO beads for the removal of Cd2+ was evaluated in a batch system, was determined the effect of pH, kinetics and adsorption isotherm. The characterization was carried out by FTIR, SEM and EDS. The EDS analysis showed that the main elements are C, O and Ca, these are associated with the chemical composition of alginate while the ALG-ZEO bead showed characteristic crystals of the zeolite. Cd2+ adsorption was carried out at pH 6 using ALG beads and ALG-ZEO beads as adsorbent. The suggested mechanism to explain the removal of the Cd2+ ion was is through a chemisorption process. Finally the adsorption process was adjusted to kinetic and isotherm models.

The role of Arthrobacter viscosus in the removal of Pb(II) from aqueous solutions

The aim of this paper was to establish the optimum parameters for the biosorption of Pb(II) by dead and living Arthrobacter viscosus biomass from aqueous solution. It was found that at an initial pH of 4 and 26 °C, the dead biomass was able to remove 97% of 100 mg/L Pb(II), while the living biomass removed 96% of 100 mg/L Pb(II) at an initial pH of 6 and 28 ± 2 °C. The results were modeled using various kinetic and isotherm models so as to find out the mechanism of Pb(II) removal by A. viscosus. The modeling results indicated that Pb(II) biosorption by A. viscosus was based on a chemical reaction and that sorption occurred at the functional groups on the surface of the biomass. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy coupled with energy dispersive X-ray microanalysis (SEM-EDX) analyses confirmed these findings. The suitability of living biomass as biosorbent in the form of a biofilm immobilized on star-shaped polyethylene supports was also demonstrated. The results suggest that the use of dead and living A. viscosus for the removal of Pb(II) from aqueous solutions is an effective alternative, considering that up to now it has only been used in the form of biofilms supported on different zeolites.