Synthesis, Characterization, and Visible Light Degradation of Rhodamine B Dye by Carbon-Covered Alumina Supported Pd-TiO₂/Polysulfone Membranes

Abstract

Palladium doped titania nanoparticles supported on carbon-covered alumina (CCA/Pd-TiO2) impregnated polysulfone (PS) membranes were prepared by the phase inversion technique. The nano-sized CCA/Pd-TiO2 nanoparticles were uniformly dispersed in 18 wt% PS casting solution to synthesize CCA/Pd-TiO2 polysulfone membranes (PS/CCA/Pd-TiO2). The amount of the CCA/Pd-TiO2 was varied between 0.25% and 0.5% to form two types of membranes. These were casted on a non-woven fabric. The nanoparticles were added in order to enhance the photodegradation potential of the PS membranes under visible light. Raman, XRD, SEM, TGA, TGA-FTIR was used to characterize the membranes. The mechanical strength of the membranes was determined with an Instron tensile tester. The SEM results suggested that these membranes had a high degree of porosity and the nanoparticles were distributed on and within the PS membrane. The Raman analysis revealed the presence of the nanoparticles within the membrane matrix while the XRD results exposed the probability of interactions between the polymer and the nanoparticles. The two membranes were then tested for their capability to photodegrade Rhodamine B under visible light illumination. The 0.5% PS/CCA/Pd-TiO2 membrane photodegraded 80.4% of the dye while the 0.25% PS/CCA/Pd-TiO2 membrane degraded 70.8% of Rhodamine B over a 270 min period. The photodegradation followed a pseudo first-order reaction rate and the apparent rates were 0.00597 and 0.00448 min−1 for 0.5% PS/CCA/Pd-TiO2 membrane and 0.25% PS/CCA/Pd-TiO2, respectively.