Freshwater green macroalgae as a biosorbent of Cr(III) ions

The research was conducted to evaluate the possibility of using algae enriched with Cr(III) ions as a feed additive for horses. As a sorbent, macroalga Cladophora glomerata was chosen. The results of the kinetic and equilibrium experiments on biosorption of Cr(III) ions are presented. The pseudo-second order model was used for the description of kinetics. Equilibrium of biosorption process was described by Langmuir model. The effect of biosorbent dose: 0.1-1.0 g-L-1, initial metal ions concentration: 100-300 mg.L-1 and pH: 3-5 on the biosorption capacity in a batch system was evaluated. These factors played a significant role in affecting the biosorption capacity of biosorbent and the rate constant. Optimal pH for biosorption was 5, biosorbent dose 0.1 g.L-1, initial concentration of Cr(III) ions 300 mg-L-1. The maximum biosorption capacity determined from Langmuir equation was 107.5 mg.g(-1) (for C-s 1.0 g.L-1 pH 5). The experiments were also performed in a column system and they showed that almost 100% of Cr(III) ions were absorbed after 200 minutes. The FTIR and SEM-EDX technique confirmed binding of Cr(III) ions by the algal biomass. Due to very good biosorption properties, Cladophora glomerata can be considered as a carrier of microelement ions in animal feeding.