Equilibrium, Kinetics, and Thermodynamics of Dye Removal Using Alginate in Binary Systems

In this paper, dye adsorption properties of alginate in binary systems were investigated. Physical characteristics of alginate were studied using Fourier transform infrared and scanning electron microscopy. Three textile dyes, Basic Violet 16 (BV16), Basic Red 18 (BR18), and Basic Blue 41 (BB41) were used as model compounds in single and binary systems. The effects of alginate dosage, initial dye concentration, and pH on dye removal were elucidated at 25 °C. The dye adsorption isotherm, kinetics, and thermodynamics were studied. The presence of functional groups such as hydroxyl and carboxyl groups was detected. It was found that BV16, BR18, and BB41 followed the Langmuir and extended Langmuir isotherms in single and binary systems, respectively. The adsorption kinetics of dyes was found to conform to pseudosecond order kinetics in both single and binary systems. The thermodynamic data showed that dye adsorption onto alginate was spontaneous, endothermic, and a physisorption reaction. On the basis of the data of the present investigation, one could conclude that the alginate being a biocompatible, eco-friendly, and low-cost adsorbent might be a suitable alternative to remove dyes from colored aqueous solutions.