HONOR PROGRAM Acid-base properties of natural adsorbents of synthetic dyesRada-Mayya Kostadinova1. INTRODUCTIONDyes are synthetic, water-soluble, dispersible organic compounds that cause discoloration of natural bodies of water when released into the environment. They are widely used in industries such as dyes, textiles, rubber, leather, paper, plastics, cosmetics, etc., to color their products and are invariably left in industrial waste. Synthetic dyes, suspended solids and dissolved organic materials are the main hazardous materials present in textile effluents. These materials can affect the physical and chemical properties of fresh water. In addition to the undesirable colors of textile effluents, certain dyes can degrade to produce carcinogenic and toxic products1. Additionally, colored effluent reduces light penetration and potentially prevents photosynthesis. Dyes, even in very low concentrations, affect aquatic life and the food chain2. Therefore, the removal of dyes from process effluents or waste becomes important for the environment. Due to the high degree of organic matter present in these molecules and the stability of modern dyes, conventional physicochemical and biological treatment methods are ineffective for their removal. Adsorption has been shown to be one of the most promising and widely used methods for removing inorganic and organic pollutants from contaminated water. Activated carbon is the adsorbent most used for this purpose because it has a high capacity for adsorption of organic matter and it has proven effective in the treatment of textile waste3. However, given the high cost and associated regeneration issues, there is a constant search for alternative low-cost adsorbents. Such alternatives...... middle of article ......lug, M., Laeanjeira, M., Favere, V. Adsorption of anionic dyes on biopolymer chitin. (1997) J. Braz. Chemical. Soc., 9: 435-44012. Liu Yi., Zheng Y., Wang, A. Enhanced adsorption of methylene blue from aqueous solution by chitosan-g-poly(acrylic acid)/vermiculite hidrogel composites. (2009) J.Environment. Sci., 22: 486-49313. Carpenter J., Sharma S., Sharma AK, Verma, S. Adsorption of dye using solid waste from leather industry as adsorbent. (2013) Int. J.Eng. Sci. Invent., 2: number 114. Karuppsdsmy., A Muthirulan, P., Sunduram MM Kinetics and dynamics of adsorption of brilliant green dye on various low cost adsorbents: a comparative study. (2012) J.Chem. And Pharm. Res., 12: 5101-511015. Mohd Nazdri Idris., Ahmad ZA, Ahmad MA Adsorption equilibrium of malachite green dye on rubber tegument-based activated carbon. (2011) Int. J. Basic and Appl Sci., 11:3