In this study, a novel bio-composite was synthesized from inexpensive raw material e.g., Salvadora persica, fatty acid and glycerin. Polyalkyd/Salvadora persica bio-composite was tested as new and effective sorbent for removing the hazardous cationic dye e.g. crystal violet from wastewater. The factors effecting on the crystal violet removal process were examined e.g., the Polyalkyd/Salvadora persica bio-composite dosage, crystal violet dye concentration, contact time, pH and wastewater temperature. The results were indicated that the Polyalkyd/Salvadora persica bio-composite was highly efficient for removing crystal violet dye from acidic and alkaline solution (pH 2-13) within 30 minutes at room temperature (25 ◦C). To examine the sorption mechanism for the removing process, the results and experimental data were analyzed using several diffusion and kinetic models e.g., Morris–Weber, Reichenberg, Bangham, Pseudo-first-order and Pseudo-second-order. From results obtained the pseudo-second-order equation best represented for the removal of crystal violet from wastewater. The thermodynamic parameters (ΔH, ΔG, and ΔS) were also calculated, the results showed that the removing process of crystal violet using Polyalkyd/Salvadora persica bio-composite was spontaneous and exothermic, suggesting a decrease in randomness during the removal process.