Adsorption of metal ion, Co(II) on Eucheuma spinosum

Eucheuma spinosum is one of the seaweed species that found abundantly in Takalar Regency. We used the biomass of the seaweed as an adsorbent for the removal of metal Co(II) ions from an aqueous solution. The adsorption of Co(II) ion by E.spinosum biomass was carried out in various contact time, pH, and concentration. The concentration of metal ion Co(II) before and after adsorption was determined using the Atomic Absorption Spectrophotometer (AAS). The adsorption capacity of Co(II) ions by E. spinosum seaweed was determined using the Langmuir and Freundlich isotherms. The results showed that the optimum time was 20 min, and the optimum pH was 3. Adsorption of metal ion Co(II) using E. spinosum seaweed was in parallel to the Freundlich isothermal model with the adsorption capacity (Qo) of 3.46 mg g-1. The functional group involved in adsorption of Co(II) metal ions was C-OH groups.