(585bt) Highly Efficient Photocatalytic Degradation of Organic Pollutants By TiO 2 -PDMS Composite Sponge

In this study, a composite of a polydimethylsiloxane (PDMS) sponge with TiO₂ has been successfully prepared using the very simple sugar-template method. PDMS sponge is a suitable substrate for selective absorption of organic pollutants from water and can be elastically deformed into any shape, and can repeatedly be compressed in air or liquids without collapsing enabling excellent recyclability. Additionally, TiO₂-PDMS composite sponge shows nice photocatalytic activity thus promoting potential in environmental applications. The photocatalytic degradation of Rhodamine B (RhB) dye under the solar light in the presence of composite sponge was examined to assess their efficiency towards degradation and removal of organic pollutants. The proposed composite is shown to first remove a significant amount of the organic dyes (Rh B) from solution by absorption (70% removal) even when incubated in the dark. Upon exposure to solar light, most of the remaining dyes in solution was photo-catalytically degraded on the surface of sponge (resulting in total 90% removal). More interestingly, these composite sponges can be recycled by exposing them to the solar light in the presence of clean water promoting the degradation of the dye absorbed in the sponge. The degraded products can be mostly removed by washing and squeezing the composite sponge. TiO₂-PDMS composite sponge exhibited enhanced performance towards degradation and removal of organic pollutants, e.g., RhB, in comparison with TiO₂ nanocatalyst(<100nm) alone. The enhanced performance is attributed to the combined effect of strong absorption of organic molecules and the photocatalytic degradation. Application of TiO₂ sponge for photodegradation also eliminates the need for separating catalyst from solution. The excellent performance and the recyclability of the PDMS sponge@TiO₂ suggest its promising applications in water treatment and environmental remediation.