TREATMENT OF OYSTER SHELLS AND PREPARING THEM AS AN ADSORBENT SURFACE TO TOLUIDINE BLUE DYE

The presence of dyes in drainage water is one of the important problems that many seek to solve. This study included the preparation of the adsorbent surface using the oyster shells as a basis for the preparation of chitosan, which is a series of carbohydrates and saccharides, by treating them with some simple chemical reactions that grab the acetyl group (de-acetylation), which is a part of the structure of chitin. Then the basic formula of Chitosan is ready to carry positive charges, which act as magnet to attract molecules of any substance beside it. A series of assays were undertaken to assess the efficiency of the adsorption process, such as the weight of oyster shells, equilibrium time, effect of pH, initial concentration of toluidine blue dye, and particle size of the adsorbent. These experiments have shown that the equilibrium time was 120 min, the optimum weight of oyster shells was 0.1 g in 100 mL of dye solution, and the particle size was 150 μm. They also showed there is an effect of the pH on the adsorption of the dye. The adsorption isotherm was well fitted to both the Freundlich and Langmuir models.