Iranian Journal of

Background & objective: Synthetic dyes are extensively used in various industries such as textile, leather tanning, plastic, pulp and paper. Since dyes are toxic and even carcinogenic, discharging dye-containing wastewater into the environment poses serious environmental and health problems. Therefore, the purpose of this paper was to evaluate the removal of Reactive Red 120 from aqueous solutions using surface modified natural zeolite. Materials &Methods: The Semnan zeolite was sieved using standard sieves in size of 0.2 - 0.3 mm and then was modified by cationic surfactant. Batch adsorption studies carried out to study various parameters included contact time, initial concentration of Reactive Red 120, pH, and adsorbent dosage. The concentration of dye was measured using a UV-vis Spectrophotometer at the wavelength of 537 nm. Freundlich and Langmuir isotherms and Pseudo-first order and pseudo-second order kinetics were used to analyze the isotherm and kinetic data respectively. Results: The adsorption studies indicated that increasing of the contact time, initial concentration of Reactive Red 120, decreasing pH and adsorbent dosage leads to increasing dye adsorption. Equilibration of Reactive Red 120 adsorption was reached at lapse of 90 min. Moreover, it was found that Langmuir isotherm (R2=0.9814) and pseudo second-order kinetic (R2=0.9814) are well fitted with our data. Conclusion: The results of the study show that Iranian modified zeolite can be used effectively for removal of Reactive Red 120 in comparison with other parts of the world. Considering the cost, availability and ease of modification, it can be used to remove dye in industrial wastewater.