Investigation of Thorium Biosorption from Aqueous Solutions by Chemically Modified Brown Algae Cystoseira Indica using Xanthation Method

In this work, the ability of the modified Cystoseira indica algae by the Xanthation method has been investigated for the biosorption of Th (IV) ions from aqueous solution in the batch mode. The effects of the three process independent variables including pH(2–6), biomass dosage (0.5 g L-1 – 2.5 g L-1) and initial metal concentration(50 mg L-1 – 250 mg L-1) were investigated using the response surface methodology (RSM) based on the central composite design (CCD). The accuracy of the model was confirmed by ANOVA such as low p-value, high F-value and Regression. The results of the optimization showed that the biosorption capacity of Th(IV) under the optimal conditions (pH=3.31, initial concentration 250 mg L-1, and biosorbent concentration 0.5 g L-1) will be 230.628 mg g-1. The results of the modeling showed that the experimental data of biosorption rate of thorium were better fitted by the pseudo second-order kinetic model, and also the Langmuir isotherm describes the experimental data of biosorption quite well. The maximum biosorption capacity of thorium was estimated to be 329.90 mg g-1 by the Langmuir isotherm. In addition, the specifications surface of algae and mechanism of biosorption were investigated using the Fourier transform infrared (FTIR) analysis.