عنوان مقاله [English]
نویسنده [English]چکیده [English]
The cadmium metal not only has detrimental effects on the nervous system, the kidneys, and the human fetus but is also lethal because of its carcinogenic effects. Biological absorption of cadmium has a number of advantages over conventional methods that include high removal efficiency for eliminating heavy metals from dilute solutions, availability and abundance of the required materials in nature, and reproducibility and reusability of the materials. In this study, the biosorption of cadmium (II) ions onto the dry biomass of two brown algae, Cystoseira indica and Fucus serratus, was investigated. Cystoseira indica was collected from the coastal areas of the Oman Sea and Fucus serratus was collected from the coastal area of the Atlantic Ocean. The algae were first dried, washed three times with tap water, and finally washed with distilled water without ions before they were isolated in pieces 0.5-1.5 mm in diameter. In all the experiments, distilled water was used to which known amounts of cadmium were added before the algae were introduced into the solution. The metal ion concentrations in the solution were measured using the atomic absorption spectrophotometer before and after the metal came into contact with the algae. The optimum pH for the adsorption of cadmium was found to be 3/0 ± 5/6 and 3/0 ± 5/5 for Cystoseira indica and Fucus serratus, respectively. The maximum metal uptakes by both algae were observed in acidic pH conditions. The time required for the biosorption of the metal to reach equilibrium was 360 minutes for Cystoseira indica and 300 minutes Fucus serratus. The adsorption capacities for Cystoseira indica and Fucus serratus using the Langmuir isotherm were determined as 44/58 and 54/95 mg /g, respectively. Moreover, the functional groups involved in cadmium uptake in both algae were identified. Finally, the results of this study showed that Fucus serratus algae had a higher capacity for adsorbing cadmium ions than did Cystoseira indica.