GENTIAN VIOLET ADSORPTION ONTO BIOSORBENT CUPCAR: STATISTICAL PHYSICS MODELING AND CONSEQUENT INTERPRETATIONS

A cost-effective and environmental -friendly modified blend of wild carob and Cupressus sempervirens with H3PO4 (Cupcar-H3PO4) was developed for the extraction from aqueous solutions of cationic dye, crystal violet (CV). The capacity of adsorption was estimated to be 117.26mg/g at 25 degrees C with a pH of 6.22. Isotherm data were fitted using four advanced models to gain insights into the mechanism of CV retention on Cupcar-H3PO4. The multilayer with saturation model emerged as the most suitable advanced statistical physics model, suggesting that CV was adsorbed at Cupcar-H3PO4 biosorbent receptor site with the formation of ArC layers. According to the values of the captured crystal violet (CV) per site (n) , it was concluded that a multi -molecular (n > 1) process is occurred. This model revealed the potential for a varying quantity of CV molecules to be adsorbed at a specific site, emphasizing their adsorption with two distinct energies. Through thermodynamic examination, it is showed that the process of CV dye adsorption was endothermic and linked to physical forces. This analysis affirmed the possibility and natural occurrence of CV pollutant dye adsorption on the surface of this adsorbent. Finally, a pore size distribution (PSD) of Cupcar-H3PO4 is investigated.