Adsorption of Xylene From Air by Natural Iranian Zeolite

Aromatic organic solvents are extensively used in various industries. Xylene is a colorless, transparent liquid, with the characteristic odor of the aromatic hydrocarbons family, which is widely used in industries. Adsorption is a conventional method of purifying polluted air containing volatile organic compounds (VOCs). Zeolite has many unique properties such as high capacity, molecular sieve characteristics, nonflammability, thermal stability, and strong acid sites. Moreover, it is reconstructed at low temperatures. In this study, we investigated the effect of various parameters on the adsorption capacity of natural zeolite (clinoptilolite) for xylene adsorption. Physical and chemical properties of natural zeolites were tested by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) and elemental analyses of natural zeolites were characterized by X-ray diffraction. Xylene concentration was measured at various times through concentrations-measured valve before and after the adsorbent bed reactor by the direct reading of Phocheck (Ion Science Ltd, UK). Experimental results showed that clinoptilolite is a potential sorbent for xylene in the range of ppm, and the breakthrough time would be reduced by increasing the concentration. The optimal temperature of xylene adsorption on natural zeolite was 35℃ and by increasing the temperature, the absorption efficiency of clinoptilolite was declined. The results showed that the breakthrough time and the exhaustion point time at the optimal conditions are 65 and 95 minutes, respectively. Adsorption capacity of clinoptilolite was obtained as 1.69 mg xylene/g zeolite. Experimental results showed that clinoptilolite is a potential sorbent for xylene in the range of ppm and the breakthrough time was reduced by increasing the concentration. Adsorption rate were increased by increasing concentration of xylene. Presence of xylene molecules in high concentration enhances their transfer and contact with adsorbent; as a result, by increasing gas concentration, breakthrough time in zeolite will be shorter.