Synthesis of calcium phosphate hydrogel from waste incineration fly ash and its application to fuel cell.

Waste incineration fly ash was successfully recycled to calcium phosphate hydrogel, a type of fast proton conductor. The crystallized hydrogel from incineration fly ash had a lower electric conductivity and a lower crystallinity than that from calcium carbonate reagent. However, the difference in electric conductivity between these crystallized hydrogels decreases with temperature. This was due to the presence of potassium in the incineration fly ash. The fuel cell with a membrane electrode assembly (MEA) using the calcium phosphate hydrogel membrane prepared from incineration fly ash was observed to generate electricity. The performance of this fuel cell was almost equal to that of a mixture of K(2)CO(3) and CaCO(3) reagents; further, the performance of the former was superior to the fuel cell with a perfluorosulfonic polymer membrane at temperatures greater than approximately 85 degrees C.