Synthesis of aluminophosphate by the ionothermal method using factorial design

This work addresses the ionothermal synthesis of aluminophosphates with magnesium incorporation in order to generate ion exchange sites. The deep eutectic mixture of urea and choline chloride acts as the solvent and template. A central composite design was used to systematically study the effects of some synthesis parameters on types of aluminophosphates and their ion exchange capacity. XRD analysis revealed that condensed AlPO-CJ2, AEL, AEN, and GIS topologies were formed. Mg incorporation was confirmed by thermogravimetric analysis and ion exchange experiments. The statistical analysis showed that the percentage of eutectic mixture in the gel was the main variable affecting the ion exchange capacity, followed by the crystallization time and the percentage of Mg in the gel. The percentage of choline chloride in the eutectic mixture did not have an influence on the ion exchange properties.

Figure optionsDownload as PowerPoint slideHighlights
► Aluminophosphates (Mg–AlPO’s) synthesis by the ionothermal method.
► The factorial experimental design can be used to determine the optimum synthesis condition.
► The statistical analysis showed the parameter of synthesis with the strongest effect on ion exchange capacity.