(11e) Removal of Estrone from Water with Adsorption on Zeolites Followed by Uv Photolysis | AIChE

(11e) Removal of Estrone from Water with Adsorption on Zeolites Followed by Uv Photolysis

Authors 

Wen, H. - Presenter, Worcester Polytechnic Institute
Bergendahl, J. - Presenter, Worcester Polytechnic Institute
Thompson, R. W. - Presenter, Worcester Polytechnic Institute


The presence of endocrine disrupting compounds (EDCs) in water is raising concern due to increasing evidence of their adverse estrogenic effects on aquatic organisms and humans. Current wastewater treatment processes typically remove less than 80% of entering estrone, an endocrine disrupting compound that is produced by humans as well as animals. However, because of its strong biological potency, small amounts are still able to exert adverse estrogenic effects on aquatic systems. Consequently, advanced treatment technologies are needed for reaching higher removal efficiency. This work investigated the combined technology of adsorption on hydrophobic molecular sieve zeolites and direct ultraviolet light photolysis for removing estrone (E1) from water. Adsorption on hydrophobic zeolites is a potentially new alternative for removing hydrophobic compounds such as estrogen from water. In this work, two types of zeolites, dealuminated Y (DAY) and silicalite-1, as well as a granular activated carbon, were evaluated for estrone adsorption capacity. The results demonstrated that DAY removed 99% of the estrone from water. The maximum adsorption capacity of estrone on DAY was estimated as 74 mg E1/g DAY. Silicalite-1 was the least effective adsorbant for estrone. Moreover, adsorption of E1 to DAY occured much faster than adsorption to activated carbon. Estrone reached adsorption equilibrium in 4 hours on DAY versus 8 days for GAC. Direct UV photolysis of E1 in solution was also evaluated as a method to remove estrone from water. Short-wave UV (254 nm) degraded E1 in solution much more effectively than long-wave UV-light (365 nm). No significant increase in degradation of E1 with UV photolysis was found with the addition of hydrogen peroxide. The regeneration of E1-contaminated DAY was investigated with a series of adsorption/direct UV (254 nm) irradiation cycles. No significant deterioration of adsorption capacity of DAY was observed over nine adsorption/regeneration cycles.