Photocatalytic degradation pathway of methylene blue in water

The TiO(2)/UV photocatalytic degradation of methylene blue (MB) has been investigated in aqueous heterogeneous suspensions. In addition to a prompt removal of the color, TiO(2)/LTV-based photocatalysis was simultaneously able to oxidize the dye, with an almost complete mineralization of carbon and of nitrogen and sulfur heteroatoms into CO(2) NH(4)(+), NO(3)(-) and SO(4)(2-) respectively. A detailed degradation pathway has been determined by a careful identification of intermediate products, in particular aromatics, whose successive hydroxylations lead to the aromatic ring opening. These results suggest that TiO(2)/UV photocatalysis may be envisaged as a method for treatment of diluted waste waters in textile industries. (C) 2001 Elsevier Science B.V, All rights reserved.