Efficient use of algae biomass loaded with essential metal ions in the manufacture of feed additives

Abstract

In this study, the biosorption and desorption of Cu(II), Co(II), and Zn(II) ions on biomass of the green alga Cladophora sericea was examined to highlight the potential use of this biomass in the manufacture of feed additives. The selection of Cu(II), Co(II), and Zn(II) ions for the experimental studies was done considering their importance for living organisms. Biosorption of metal ions on algal biomass was performed in batch systems, at different initial metal ion concentration and contact time, at pH 5.5, 8 g L−1 biomass dosage and room temperature (21 ± 1 °C). The isotherm and kinetic parameters obtained by modelling the experimental data were used to evaluate the efficiency of biosorption processes. The high values of maximum biosorption capacities (21.18 mg Cu(II) g−1; 14.18 mg Co(II) g−1; and 33.78 mg Zn(II) g−1) and low contact time (around 15 min) indicate the possible use of this biomass as metal ion carrier in the manufacture of feed additives. Desorption of retained metal ions from loaded algae biomass was also examined, as a function of contact time. For similarity with gastric juice, 10 mL of HCl (1 mM) was used as desorption agent. The experimental data indicate that the metal ion desorption takes place gradually in time, but the desorption efficiency did not exceed 51% for all studied metal ions, after 24 h of contact time. The low efficiency of desorption processes is undesirable in the manufacturing of feed additives, and to minimize this disadvantage, the addition of activated carbon (AC) is proposed in this study. Simple mixing of loaded algae biomass with AC in a mass ratio of 1:1 determines the increase of desorption efficiency for all studied metal ions and opens new possibilities for the use of enriched algae biomass in the manufacture of feed additives.