Equilibrium and Kinetic Studies of Safranine Adsorptionon Alkali-Treated Mango Seed Integuments

In this study , Safranine absorption onto mango seed integuments (raw and NaOH treated) has been investigated. The effects of solution pH, initial dye concentration, contact time, point zero charge and surface chemistry of the adsorbent were studied batch-wise. Safranine adsorption onto the untreated sample is influenced by the pH of the aqueous solution whereas, adsorption with the NaOH- treated sample is independent of the pH of the solution. Boehm titration showed the acidic groups of the treated sample has a higher value (0.660 mmol/g) than the untreated sample (0.375 mmol/g). Freundlich isotherm model resulted in the best data fitting for the untreated sample. However, Langmuir model indicated the best fitting with the NaOH-treated sample. The adsorption kinetics was found to obey pseudo second order kinetic model for both samples. An approximate increase of 26 % was found in the amount of dye adsorption due to the treatment with NaOH.