Removal of thallium(I) from aqueous solution using modified sugar beet pulp

Sugar beet pulp, a waste-product of sugar-refining factories, is suggested as sorbent to remove thallium(I) from aqueous solutions in a batch process. The sorbent is enhanced in its removal efficiency by pretreatment with NaOH. The effects of pH, temperature, sorbent dosage, and initial concentration of Tl(I) are considered. The sorption process has been found to be rapid. Maximum removal efficiency of Tl(I) is observed at values of pH from 5 to 9 with a sorbent amount of 7 g L−1. Various isotherm models such as Langmuir, Freundlich, and Dubinin–Redushkevich isotherms are considered to describe the sorption process. The equilibrium data fit well to the Langmuir model with a maximum uptake capacity of 185 mg g−1. The thermodynamic parameters ΔG, ΔH, and ΔS indicate that the process is spontaneous and exothermic.