Adsorption study of Ni(II) and Zn(II) by activated bone char residue.

A large part of the chemical industry sectors, particularly industrial surface treatments, contributes to the contamination of water bodies with heavy metals. The environmental laws have been stringent regarding discharge of effluents containing these compounds. This study evaluated the removal of metals Ni(II) and Zn(II) by adsorption on activated bone char residue. To evaluate the adsorption capacity, experiments were performed using kinetics in a monocomponent system and adsorption isotherms in monocomponent and bicomponent systems. The models used to fit the isotherms were the Langmuir and Freundlich.

Zinc(II) desorption by Sargassum filipendula biomass in batch and in fixed-bed column for multiple sorption-regeneration cycles.

The reusability of the alga Sargassum filipendula was studied in batch reactor and in fixed-bed column in order to investigate Zn(II)-laden biomass regeneration. Four types of desorbing solutions at two different concentrations were tested and the results obtained to the desorption efficiencies were higher than 90% for three of the agents. Ten consecutive sorption-regeneration cycles at a flow rate of 8 mL/min were carried in fixed bed column with the feed concentration of 50 mg/L and using two eluent solutions: H(2)SO(4) (0.1 M) and MgSO(4) (3.5% at pH 3), which showed the best ability to elution tests in batch system. The column was used for a period of 30 days. The adsorption capacity decreased the passing of cycles, but the total amount of zinc removed after 10 cycles was approximately 8 times greater than if the biomass had been used for only one time, for both agents tested. Therefore, the regeneration in the Sargassum filipendula column through the two desorbing agents tested showing high efficient use of biomass and facilitating the process of treatment of wastewater containing metals that has successive exchanges of biomass.