Removal of Methylene Blue Using Cellulose Nanocrystal Synthesized from Cotton by Ultrasonic Technique

This investigation was concern to study the removal of methylene blue pollutants from aqueous solution using cellulose nanocrystal synthesized from cotton. The equilibrium adsorption data were analyzed using adsorption models of Langmuir, Freundlich and Temkin. The thermodynamic parameters were calculated using adsorption process on an cellulose nanocrystal for the methylene blue solution at three different temperatures. It was found that a cellulose at nano level has a very significant adsorption for methylene blue compared to that of bulk cellulose. The results showed that the model isotherms are fitting very well with the experimental data. The specific adsorption percentage of methylene blue was highly affected by addition of nano cellulose and decreasing with temperature compared to that of control sample. It has been found that the adsorption percentage was increased by increasing the methylene blue concentrations, and these values indicated that the methylene blue adsorption onto nano cellulose was spontaneous and exothermic in nature.

All values of Gibbs functions were negative with values of -15 and -17 kJmol-1 for 60% acid sonicaed for 120 min and 30% acid for the same time of sonification respectively, while values of enthalpy and entropy were about -5 kJmol-1 and 54 JK-1mol-1 for cellulose nanocrystal respectively. These results indicated that the adsorption process was feasible, spontaneous and exothermic.