Degradation of the drugs Gemfibrozil and Tamoxifen in pressurized and de-pressurized membrane photoreactors using suspended polycrystalline TiO2 as catalyst

The performance of two configurations of catalytic membrane photoreactors (pressurized and depressurized) in batch and continuous systems for the degradation of two pharmaceuticals (Gemfibrozil and Tamoxifen), using suspended TiO2 as catalyst, was investigated. The effects of parameters such as pH of the aqueous TiO2 suspensions, pump flow rate and membrane clean-up, on the efficiency of the membrane photoreactor, were studied. In the batch pressurized photoreactor, catalyst and drugs rejections presented interesting values but a small or no-rejection to degradation products of both the drugs was evidenced. A good operating stability (steady-state maintained for more than 1.5 h) was observed in the continuous systems, reaching a steady state in ca. 120 min and a complete abatement of the Gemfibrozil together a constant retentate mineralization of 60%. A TOC rejection of about 62% in the pressurized photoreactor was obtained, while the no TOC rejection in the de-pressurized (submerged membrane) system, showed the necessity to identify a membrane selective to intermediate products. However, in both systems one common benefit was the retention of the suspended catalyst in the reaction ambient and the possibility to run continuous operations. The permeate flux (65.1 L h(-1) m(-2)) was higher in the submerged membrane photoreactor showing it interesting for application purposes. (C) 2008 Elsevier B.V. All rights reserved.