The pyrolytic synthesis of calcium phosphate compounds from carbonized fowl droppings

Abstract We succeeded in producing biomimetic calcium phosphate compounds, β-tricalcium phosphate (β-TCP: Ca 3 [PO 4 ] 2 ) or biphasic calcium phosphate of two-phase ceramics (BCP) with hydroxyapatite (HAp: Ca 10 [PO 4 ] 6 [OH] 2 ) and β-TCP, from carbonized fowl droppings via one-pot hydrothermal reactions. It occurred to us to use the residue, mineral traces and organic compounds in fowl droppings obtained by carbonization as control reagents for the synthesis reaction. Through this selective generation of the single-phase Mg-doped β-TCP, a stratified formation that resembled a natural nacreous layer was achieved. Further, we were able to produce only HAp/32.4% β-TCP possessing comparatively high mechanical strength in two-phase BCP ceramics by using incinerated fowl droppings prepared from carbonized fowl droppings sintered in air at 800 °C. In the adsorption of ammonia gas, biomimetic calcium phosphate compounds synthesized from fowl droppings have comparable loading capacities to activated carbon.