Adsorption kinetics, equilibrium, and thermodynamic studies to understand adsorption behavior of evans blue dye by durian husk

• Main Authors: Basirun, Ain Aqilah, Othman, Ahmad Razi, Yasid, Nur Adeela, Halmi, Mohd Izuan Effendi, Gunasekaran, Baskaran, Shukor, Mohd Yunus Abd
• Format: Article
• Published: Springer 2023
• Online Access: http://psasir.upm.edu.my/id/eprint/106439/; https://link.springer.com/article/10.1007/s11814-023-1434-y?error=cookies_not_supported&code=b2fd4678-b846-4941-8c35-7eb3ce6c1f0c
• Institution: Universiti Putra Malaysia

Membrane isolation, ion exchange, precipitation, transformation, and biosorption are all viable methods for pollutant removal. Adsorption is a common commercial method to concentrate precious molecules or eliminate contaminants, and it is a cost-effective method of treating industrial wastewater. A novel method for increasing their removal effectiveness has been developed for this purpose, using a low-cost biosorbent made from durian husk and Evans blue (EB) dye as a subject. The EB dye adsorption percentage was determined to be 95.95% with 72.0 mg/g adsorption amount at optimal conditions of pH 2 and 40 °C. The second-order kinetic model fit the experimental data the best. Additionally, the results indicated that the Sips isotherm model fits the experimental data better and that the experiment involved single-layer adsorption on the adsorbent surface. A non-linear regression of the van’t Hoff plot gave negative values of Gibbs free energy (−39.38 to −41.48 kJ/mol) at all the temperatures studied (from 20 to 60 °C), indicating that the adsorption process is spontaneous and feasible. A negative value for the enthalpy (ΔHo=−23.37kJ/mol) indicated that the adsorption was exothermic, and the positive value of (ΔSo=54.55kJ/mol·K) concludes the nature of adsorption of Evans blue dye by Durian husk likely to follow a physisorption adsorption mechanism.