Fundamental studies on the intermediate layer of a bipolar membrane. Part VI. Effect of the coordinated complex between starburst dendrimer PAMAM and chromium (III) on water dissociation at the interface of a bipolar membrane

Starburst dendrimer polyamidoamine (PAMAM) is an ellipsoidal tree-like macromolecule with a well defined structure and many more amino groups than conventional macromolecules, which can be used to catalyze water dissociation in a bipolar membrane according previous work. The purpose of this research is to discover the effect of the coordinated complex between PAMAM G4 and Cr(III) on water dissociation in a bipolar membrane. The coordinated reaction between G4 and Cr(III) was investigated by UV-VIS absorption spectroscopy, and finally the molar ratio Cr(III)/G4 was chosen as 20. The I-V curves showed that the coordinated complex could be applied to accelerate water dissociation in a bipolar membrane, and the accelerative or catalytic effect was more prominent than separated G4 or Cr(III). Furthermore, the V-t curves showed that the coordinated complex in the intermediate layer was comparatively chemically stable, namely G4 had the function of fixing Cr(III) ions in the inter-mediate layer. Thus, it is expected that a bipolar membrane with high efficiency and comparative stability can be prepared by applying the coordinated complex between G4 and Cr(III) as the intermediate layer.