Title : Sorption of Alizarin red from Aqueous Solution Using Chitosan?Charcoal Composite
It is estimated that over 10% of the dye used in textile processing does not bind to the fabric and is therefore released to the environment. Some of these compounds constitute serious threats because of their carcinogenic potential or cytotoxicity The study investigated the removal efficiency of Alizarin red from aqueous solution using chitosan− charcoal composite as adsorbent. Deproteination was carried out by placing 200g of powdered snail shell in 4% w/v NaOH for 2hours. The sample was then placed in 1% HCl for 24hours to remove CaCO3. Deacetylation was done by boiling in 50% NaOH for 2hours. 10% Oxalic acid was used to dissolve the chitosan before mixing with charcoal at 550C to form the composite. The composite was characterized by Fourier Transform Infra-Red and Scanning Electron Microscopy measurements. The efficiency of adsorption was evaluated by varying pH of the solution, contact time, initial concentration, and adsorbent dose. Maximum removal of Alizarin removal was achieved at pH 4 for composite while pH 2 and 5 were obtained for chitosan and charcoal respectively. The results showed that adsorption of Alizarin red followed the pseudo–second–order rate equation and fit the Langmuir and Freundlich isotherms. The data showed that composite was best suited for crystal violet removal. Thermodynamic parameters such as enthalpy change (ΔHº), free energy change (ΔGº), and entropy change (ΔSº) indicate that the adsorption process of Alizarin red was endothermic, spontaneous, and feasible.