عنوان مقاله [English]
نویسندگان [English]چکیده [English]
The biosorption process of thorium in a batch system by modified brown algae Sargassum glaucescens is discussed in this paper. For this purpose, the results of biosorption on raw algae and modified by glutaraldehyde and diethylenetriamine (DETA) were compared. Also, other variables that are necessary for adsorption process design such as optimum pH, time effect, biosorption isotherm, adsorbent dosage, number of biosorbent recovery stages for reuse were investigated. It was deduced that 10% of glutaraldehyde solution is the best. The experimental results indicated that the maximum sorption was observed at pH 3.5. The uptake was rapid and the biosorption process reached equilibrium within 6h of contact time at the optimum pH. The kinetics data were fitted well to Lagergren’s pseudo-second-order rate equation. Modeling of equilibrium sorption data with the Langmuir and Freundlich models (two-parameter models), and Redlich-Peterson three-parameter model indicated that the Redlich-Peterson model gave a better fitting to the experimental observations. The maximum thorium sorption was 151.52 mg Th/g adsorbent obtained from the Langmuir isotherm. The algae recovery by using 1 M HCl solution for biosorbent reuse showed that the biosorbent capacity decreases from 89.15 mg Th/g adsorbent at the first stage of recovery to 70.02 mg Th/g adsorbent at its fifth stage.