Biosorption Of Crystal Violet Dye Using Papaya Seed and Optimization by Central Composite Design

Abstract

- The objective of this work is to study the biosorption of Crystal violet dye using Papaya seed powder as biosorbent from synthetic aqueous dye solution. Batch studies were conducted to study the  effect of parameters like contact time (5 to 90 min), temperature (283 to 323 K), pH (3 to 10), initial concentration of dye (20 to 120 mg/L)solution, dosage (0.5 to 2.5 g/L) and  size (72 to 120 µm) of the biosorbent. Experimental data was fitted in to the kinetic models and isotherms like Langmuir, Freundlich isotherms, Temkin isotherm and Harkin –Jura isotherms. It is observed that Freundlich isotherm fitted well. The thermodynamic parameters like enthalpy change (?H), entropy change (?S) and Gibbs free energy change (?G) were evaluated for the data. The positive value of change in enthalpy (?H) depicts the endothermic nature. The positive value of change in entropy shows spontaneity of process. The negative ?G signifys feasibility of biosorption.  And the results optimized by using Central Composite Design. The results indicated that Papaya seed powder can be an alternative biosorbent for treating Crystal violet waste water