Mechanism of Adsorption of Congo Red on the Surface of Filter Paper in NaCl and 2-propanol Solutions

Adsorption of CR on the surface of filter paper was studied in the presence of 0.1 M NaCl and aqueous ethanol solutions. Here, effects of ionic strength, different percentages of ethanol on the equilibrium binding constants (K) and adsorption capacities ( ) of CR on the surface of filter paper were analyzed by the ARIAN model at 308, 318 and 328 K. Results of the analysis showed that this was a two-region process and maximum adsorption capacity of filter paper for CR decreased with increase in the concentration of ethanol and increased in the presence of 0.05, 0.25 and 0.5 M NaCl solution. The maximum adsorption capacity of the process in 0.5 M NaCl solution was 121.4 mg g-1 at 328 K.