Removal of Crystal Violet Dye from Aqueous Solutions onto Date Palm Fiber by Adsorption Technique

The adsorption of crystal violet (CV) onto date palm fibers (DPFs) was examined in aqueous solution at 25°C. The experimental maximum adsorption capacity value was 0.66 × 10−6. Langmuir, Freundlich, Elovich and Temkin models were applied to describe the equilibrium isotherms. The influence of pH and temperature on dye removal was evaluated. The percentage removal of CV dye by adsorption onto DPF at different pH and temperatures showed that these factors play a role in the adsorption process. Thermodynamic analysis was performed, and the Gibbs free energy ΔGο, enthalpy change ΔHο, and entropy ΔSο were calculated. The negative values of ΔGο indicate spontaneous adsorption. The negative value of ΔHο indicates that the interaction between CV and DPF is exothermic, and the positive value of ΔSο indicates good affinity between DPF and CV. The kinetic data were fitted to a pseudo‐second‐order model.