Studies on the adsorption of dyes into clinoptilolite

Abstract Adsorption techniques are widely used to remove certain classes of pollutants from waters, especially those that are not easily biodegradable. Dyes represent one of the problematic groups. Natural zeolite was used as a low-cost adsorbent to evaluate its ability to remove color from effluents. In this paper, the adsorption of dyes into clinoptilolite was studied by a series of experiments. The influence of sorbent concentration, adsorption time, initial dye concentration, and pH has been analyzed in detail with Amido Black 10B and Safranine T respectively. The results indicate that clinoptilolite has a limited adsorption capacity for Amido Black 10B and has a good adsorption capacity for Safranine T. The adsorption isotherm has also been determined using the adsorption data. It was found that the adsorption isotherms for Safranine T dye-natural zeolite system and Amido Black 10B dye-natural zeolite system at 80 mg/L of solid concentration, pH 7.0 and 2 °C both fitted to the Langmuir isotherm. For the Safranine T dyenatural zeolite system, the fitted parameters q m and b L are 0.05513 mg/g and 1.9623 L/mg respectively, and for the Amido Black 10B dye-natural zeolite system, the fitted parameters q m and b L are 0.0112 mg/g and 0.5962 L/mg respectively.