Industrial & Engineering Chemistry Research, Vol.50, No.11, 6638-6645, 2011
Comparative Study of Sonocatalytic Enhancement for Removal of Bisphenol A and 17 alpha-Ethinyl Estradiol
A series of experiments were conducted to compare the effectiveness of various catalysts in the production of H2O2 and in the degradation of endocrine disrupting compounds (EDCs), including bisphenol A (BPA) and 17 alpha-ethinyl estradiol (EE2), in water by sonocatalysis using ultrasonication at 28 kHz with a contact time of 60 min. The catalysts included a stainless steel wire mesh (SSWM), glass beads (GB), TiO2 powder, a Ti-wire mesh (Ti-WM), and an oxidized Ti-wire mesh (TiO2-WM). The most effective catalyst combination for the production of 215.7 mu M of H2O2, was the use of SSWM with TiO2 as the cocatalyst. A significantly lower sonochemical reactivity was observed when there was no added catalyst (18.5 mu M), SSWM (61.3 mu M), and TiO2 alone (134.1 mu M). For the given contact time and frequency, sonochemical reactivity was determined from the rate constants for H2O2 production. EDC sonodegradation occurred in the following order: SSWM + TiO2 (powder) > GB > TiO2 (powder) > SSWM GB > TiO2-WM > Ti-WM > SSWM > no catalyst, although the catalyst type, surface area, and amount were varied. Our findings suggest that TiO2-WM can be continuously reused for the catalysis of H2O2 production and the degradation of EDC.