Biosorption of Methylene Blue from Aqueous Solution by Juglans Regia Shell

Abstract

In this study, Juglans regia shells were used for removal of methylene blue from aqueous solutions. Batch biosorption studies were carried out under various conditions such as average biosorbent particle size (0.212-0.300mm; 0.600-0.850 mm; 0.850-1.700 mm), initial dye concentration (in the range 25-125 ppm), temperature (from 30 to 60 ^oC) and biosorbent dosage (in the range 0.1-0.5 g). The experimental results showed that the percentage of biosorption increased with a decrease of particle size. Experimental data were analyzed by model equations such as Langmuir, Freundlich and Temkin isotherms and it was found that the Langmuir isotherm model best fitted the obtained biosorption data. Thermodynamic parameters such as ∆G, ∆Hand ∆Swere also calculated as -0.69, 14.22 kJ/mol, and 46.85 kJ/mol K, respectively. The negative value of ∆Gconfirmes the feasibility of the process, the value of ∆Hwas positive, indicating that the sorption is endothermic and the positive value of ∆S shows the increasing randomness at the solid/liquid interface during sorption process. Overall, the present study underlies the alternative use of Juglans regia shell for removal of cationic dye, Methylene blue.