Easy-handling semi-floating TiO 2 -based aerogel for solar photocatalytic water depollution.

One of the capital issues of photocatalytic technology is how to use photocatalytic materials in real world conditions. Suspension photocatalysts are the most effective, while the handling and recovery of nanoparticles are very challenging and costly. Herein, we report the design of semi-floating aerogel TiO 2- based photocatalyst for the oxidation of dyes and photoreduction of Cr(VI). TiO 2 aerogel-based photocatalyst was fabricated through in situ polymerization using borax, poly(vinyl alcohol) and polyvinylidene in the presence of H 2 O 2  as a catalyst. Cubic TiO 2 aerogel of few centimetres was designed for the photocatalytic tests under solar light irradiation. TiO 2 aerogel showed a good photoactivity against the oxidation of three types of dyes and Cr(VI) photoreduction. In terms of dyes, the kinetics of methylene blue oxidation was the fastest as compared to rhodamine B and methyl red, while, a total reduction of Cr(VI) at 10 ppm was obtained within 30 min after the addition of tartaric acid as hole scavenger. TiO 2 aerogel can be easily recovered, washed and recycled. TiO 2 aerogel can move freely from the top to the deep solution. The semi-floating property could be an advantage to enhance the mass transfer along with bulk solution, as compared to totally floating-based photocatalysts.