Abstract: Using Keggin-type copper-substituted heteropolyanion PW11O39Cu(Ⅱ)(H2O)5-(PW11Cu) as a visible photocatalyst, and organic dye Rhodamine B(RhB) as a model pollutant, this work reports a study on the visible photocatalysis of PW11Cu towards RhB degradation in aqueous solution under visible light irradiation. A visible photocatalysis mechanism is proposed. At the same time, influences of the initial RhB concentration, the initial PW11Cu concentration and the solution pH on the degradation rate of RhB are also examined. Experimental results show that 100% of RhB degradation is reached at 80 min under visible light irradiation of a solution containing 15.6 μmol/L PW11Cu and 10 μmol/L RhB, and a total organic carbon removal is about 33%. The visible photocatalytic degradation of RhB follows the quasi-first order kinetic regime and the observed rate constant is estimated to be 3.1×10-2, 2.0×10-2 and 1.5×10-2 min-1 corresponding to the initial RhB concentration of 20, 30 and 40 μmol/L, respectively.

Key words: copper-substitutes heteropolyanion, homogeneous photocatalysis, Degradation of Rhodamine B, total organic carbon