HEAVY METALS BIO-ADSORPTION BY HIBISCUS SABDARIFFA L. FROM CONTAMINATED WATER

Abstract

The metal biosorption is the removal of metal ions by inactive, nonliving biomass due to highly attractive forces present between them. Bio-adsorption capacity of Hibiscus sabdariffa L. commonly known as Roselle or red sorrel purchased from Fenooj region in Sistan province in the south-eastern region of Iran in a batch system of waste water by considering the effects of various parameters like initial concentration, pH, contact time, temperature, agitation speed and bio-adsorbent dose were studied. According to boost the capacity of bio-adsorption black tea residue was added to the red tea residue by different concentrations and percentages. Effect of various pH; temperature; dose of red tea residue in accompany by of black tea residue after infusion of 10 minutes in contaminated waste water solution in different contact time and initial concentration , particle size and agitation speed were studied. The samples were analyzed by standardized international protocols in Nutrition and Food Sciences Research Center in Pharmaceutical Sciences Branch, Islamic Azad University. The best results obtained by 0.5 % of red tea + 3 % black tea residues after 40 minutes. Further increase in contact time more than 40 minutes did not show significant increase in bio-adsorption (p > 0.05). The results of current study revealed, that using 0.5 % red tea residue in accompany by 3 % black tea residue can remove and decrease cadmium and nickel significantly and for cobalt decreasing the rate of adsorption is not as much as 2 other metals but remove cobalt after 40 minutes in remarkable contents.