Equilibrium and kinetic studies for the adsorption of Mn(II) and Co(II) from aqueous media using agar-agar as sorbent

The intensification of industrial activity and environmental,accidents during recent years is greatly contributing to the increase of metal pollution in water resources, thereby causing threat to terrestrial as well as aquatic life. The toxicity of metal pollution is slow and long lasting, as these metal ions are non-biodegradable. The most appropriate solution for controlling the biogeochemistry of metal contaminants is sorption technique, to produce high-quality treated effluents from polluted wastewaters. Agar-agar, a readily available seaweed was used as sorbent for the removal of Mn(II) and Co(II) from aqueous media. Adsorption studies were performed by batch experiments as a function of process parameters: sorption time, pH, concentration of sorbate and sorbent. Freundlich model fitted best with the experimental equilibrium data among the two adsorption isotherm models tested. The kinetic data correlated well with the Lagergren pseudo second-order kinetic model for the sorption studies of both Mn(II) and Co(II) using agar-agar Adsorbed metal ions were quantitatively recovered from the spent adsorbent using 5.0 mol L-1 HCl. The efficiency of agar-agar for decontaminating Mn(II) and CO(II) from the electroplating effluent has also been evaluated. The results proved agar-agar to be a favorable adsorbent to remove and recover Mn(II) and Co(II)from waste for further use in diversified industrial applications.