Enhanced adsorption of congo red using cationic surfactant functionalized zeolite particles

In the present work, natural and modified clinoptilolite by cationic surfactant used for congo red removal. Adsorption kinetic models showed that pseudo-second-order by R-2 > 0.99 for both adsorbents were well adapted. Congo red maximum adsorption capacities can attain 16.92 and 200 mg/g for natural and cationic surfactant modified clinoptilolite of the Langmuir isotherm, respectively. The enthalpy change (Delta H degrees) in the adsorption process are - 39.94 and -14.39 kJ/mol , showing the adsorption is an exothermic reaction. Delta S degrees < 0 shows that system confusion degree decreases and the order degree increases. The values of Delta G degrees for adsorption of CR onto NC and SMC ranges from 6242 to 9329 kJ/mol and - 3553 to - 2821 kJ/mol, respectively. The obtained results proved that cationic surfactant modified clinoptilolite powder can be applied effectively for removal of CR as natural adsorbent.