Separation of m-cresol and p-cresol by NaZSM-5 with different Si/Al ratios

m-Cresol and p-cresol are widely used in medicine and pesticides as important chemical intermediates. They are generally produced as a mixture in industry and are difficult to separate due to the similarities in both chemical structures and physical properties. The adsorption behaviours of m-cresol and p-cresol on zeolites (NaZSM-5 and HZSM-5) with different Si/Al ratios have been compared by static experiments. Selectivity on NaZSM-5(Si/Al = 80) could be greater than 6.0. Adsorption kinetics and isotherms were investigated in detail. The kinetic data was correlated by PFO, PSO, and ID models, the NRMSE of which were 14.03%, 9.41%, and 21.11%, respectively. In the meanwhile, according to the NRMSE of Langmuir (6.01%), Freundlich (57.80%), D-R (1.1%), and Temkin (0.56%) isotherms, adsorption on NaZSM-5(Si/Al = 80) was mainly a monolayer and chemical adsorption process. It was endothermic for m-cresol and exothermic for p-cresol. The Gibbs free energy, entropy, and enthalpy were calculated accordingly. The adsorption of cresol isomers on NaZSM-5(Si/Al = 80) were both spontaneous, and it was exothermic (