Comparative study of the photocatalytic decolorization of rhodamine B dye by AgI-Ag3PO4 prepared from co-precipitation and ion-exchange methods

Photocatalysts in AgI-Ag3PO4 system were prepared from co-precipitation and ion-exchange methods. With an increment of KI concentration, the products prepared from both methods changed from Ag3PO4 to a combination of 3 phases (Ag3PO4, Ag5I2PO4 and AgI), then a mixture of AgI and Q (where Q = Ag5I2PO4 (for co-precipitation method) or Ag3PO4 (for ion-exchange method)), and finally to AgI. The preparation method strongly effected on the formation of Ag5I2PO4 in the products. Using the co-precipitation method, Ag5I2PO4 was formed easier than that of ion-exchange method. Product containing high concentration of AgI induced degradation of rhodamine B (RhB) favoring through the N-deethylation process. The dominant mechanism of the RhB degradation for photocatalyst with high Ag3PO4 or Ag5I2PO4 content occurred by the cleavage of chromophore structure of the RhB. (C) 2017 Elsevier B. V. All rights reserved.