RESUMEN
A mixture of five commonly used pharmaceuticals and personal care products (PPCPs) was degraded using a new combined catalyst under visible light irradiation. Scanning electron microscopy and X-ray diffraction analysis revealed that the combined catalyst was composed of copper-plating iron doped Cu2O (FeCu/Cu2O). Compared with the Fe/C inner micro-circuit, the electric currents flowing between Cu and Fe increase the speed of anodic Fe dissolution. Moreover, due to the photochemical properties, Cu2O can accelerate the PPCPs degradation processes under the irradiation of visible light. In addition, shaking increased the dissolved oxygen concentration in the solution, which not only preconditioned the photo-catalysis reaction, but also set the stage for Fe reduction. According to the experimental results, we propose the possible reaction mechanism of the reaction.
Asunto(s)
Cobre/química , Galvanoplastia/métodos , Productos Domésticos/efectos de la radiación , Hierro/química , Luz , Preparaciones Farmacéuticas/efectos de la radiación , Carbono/aislamiento & purificación , Catálisis/efectos de la radiación , Cerio/química , Cobre/aislamiento & purificación , Fluorometría , Concentración de Iones de Hidrógeno/efectos de la radiación , Radical Hidroxilo/química , Hierro/aislamiento & purificación , Microscopía Electrónica de Rastreo , Compuestos Orgánicos/aislamiento & purificación , Soluciones , Espectrofotometría Ultravioleta , Factores de TiempoRESUMEN
The degradation characteristics of PPCPs commonly found in surface water under UV treatment were examined for 30 kinds of PPCPs using a UV/Lamp1 that emits light at a wavelength of 254 nm and a UV/Lamp2 that emits light at 254 nm and 185 nm in pure water. When a UV dose of some 230 mJ/cm(2) was introduced to the 30 PPCPs, photodegradation rates of about >3% (theophylline) to 100% (diclofenac) and about >15% (clarithromycin) to 100% (diclofenac) were observed for UV/Lamp1 and UV/Lamp2, respectively. This study also showed that UV/Lamp2, which photolyzes water molecules and generates OH radicals, is more effective for PPCP removal than UV/lamp1. It was postulated that the degradation rates of sulfamethoxazole, sulfamonomethoxine, sulfadimethoxine and sulfadimidine, all, including sulfamethoxazole, derived from sulfanilamide, under UV/Lamp1 resulted mainly from the bond-breaking reactions occurring between -SO(2)- and its side atoms, the C-S bond and the N-H bond. Some PPCPs with amide bonds, such as cyclophosphamide and DEET, were highly resistant to photodegradation by UV/Lamp1. AOPs (Advanced oxidation processes) such as the UV/H(2)O(2) or UV/O(3) processes should therefore be considered for their potential to remove these substances effectively.