Dye Adsorption Kinetics and Isotherm Study Using Surfactant-Modified Biomass: Influence of pH Substantiated with Quantum Chemical Validation

Abstract

The current study offers a comprehensive understanding on the adsorption study employing the cost-effective biomass as an effective substitute against high-cost treatment options. The present work put forth the adsorption of hazardous cationic dye: Crystal Violet (CV) from aqueous solution using Rice Husk (RH) and surfactant Modified Rice Husk (MRH). Effect of the adsorbents: RH and MRH onto CV removal is determined considering various experimental parameters viz., mass, volume, dye concentration, contact-time, equilibrium temperature, and pH where maximum CV adsorption was achieved at pH = 8. Results obtained are attributed to the favorable ion-pair formation between CV and anionic surfactant: Sodium Dodecyl Sulfate (SDS) which is validated further using quantum chemical calculations. To counterpart the sorption process onto the adsorbent, the adsorption study was validated employing several kinetic models and isotherms. The thermodynamic conduct concluded the CV adsorption to be spontaneous (negative ?G) and endothermic (positive ?H) in characteristic at ambient temperature i.e., adsorption increases with temperature.