Isotherm Adsorption of Solutes

Abstract

Adsorption is the accumulation of molecules on a solid surface due to unsaturated surface forces. In solutions, adsorption is influenced by factors such as the type of adsorbent and adsorbate, surface area, solute concentration, and temperature. The relationship between the amount adsorbed per unit area or mass of adsorbent and solute concentration at constant temperature is described by adsorption isotherms. An adsorbent is the material that captures substances, while an adsorbate is the substance retained. Adsorbents can be polar or nonpolar; polar adsorbents are further classified as acidic (e.g., silica, chlorosil) or basic (e.g., amines, magnesia). Basic adsorbents have a higher affinity for acidic compounds such as phenols and carboxylic acids. Adsorbents are porous, allowing gases or solutes to be bound on their surfaces. This distinguishes adsorption, which forms a surface layer, from absorption, where a fluid is taken up into another fluid. In this study, activated carbon was used as an adsorbent, and the obtained log C values were 0.28, 0.91, 1.26, 0.90, 2.15, and 3.39. The results indicate that increasing adsorption time decreases the required titrant volume. The calculated slope (0.9032) shows effective adsorption behavior.