Photoactive polymer membranes for degradation of pharmaceuticals from water

Abstract Two different photosensitizer molecules were immobilized on a commercial polyethersulfone membrane by electron beam-mediated grafting. The resulting membrane surface generates singlet oxygen upon activation with light according to the photosensitizer‘s excitation wavelength. Thus, the immobilization procedure results in highly active membrane surfaces. The degradation of different pharmaceuticals (propranolol and ranitidine) by the photoactive membranes was investigated. The activity (singlet oxygen generation rate) and degradation efficiency regarding the two pharmaceuticals was studied next to membrane characteristics (scanning electron microscopy, permeance, contact angle, X-ray photoelectron spectroscopy). The immobilization led to increased surface hydrophilicity and permeance while preserving pore size and morphology. Both photosensitizer membrane systems showed high singlet oxygen generation activity. It was found that propranolol and ranitidine were efficiently converted by singlet oxygen to transformation products, but they were not completely mineralized as monitored by total organic carbon analysis and chromatography.