Photocatalytic efficiency of TiO2/poly[acrylamide-co-(acrylic acid)] composite for textile dye degradation

A novel photocatalytically degradable TiO2/poly[acrylamide-co-(acrylic acid)) composite hydrogel (TiO2/poly[AAm-co-AAc]) was synthesized by polymerization in an aqueous solution with N,N'-methyl-enebisacrylamide as the crosslinker and ammonium persulphate and TEMED as the initiator pair. The combined and separate effects of photodegradation and adsorption processes for dye removal were evaluated using methylene blue (MB) as the model dye for a photodegradation target, and compared with those of the neat poly[AAm-co-AAc], and a commercially available TiO2 photocatalyst (Degussa P-25). Without photodegradation (i.e. in the dark), the TiO2/poly[AAm-co-AAc] composite adsorbed up to 85% of the MB from a 5 mg L-1 MB solution in 15 min compared to only 10% for the pristine TiO2. The reproducibility in photodegradation of the reused poly[AAm-co-AAc] composite was also investigated, where poly[AAm-co-AAc] was found to be photocatalytically degraded under UV irradiation. Therefore, the TiO2/poly[AAm-co-AAc] composite hydrogel is a good dye adsorber with self-photodegradability and it also can easily be separated from the reaction by simple filtration. With these properties, the TiO2/poly[AAm-co-AAc] hydrogel can be called a green polymer for use in the photodegradation adsorption process for the abatement of various pollutants. (C) 2010 Elsevier Ltd. All rights reserved.