INFLUENCE OF UREA ADDITION ON PREPARATION AND ACIDIC PROPERTIES OF AMORPHOUS LANTHANUM PYROPHOSPHATE

Abstract

The addition of urea was studied as one of the preparation methods for porous phosphate particles. Urea was added to the preparation of lanthanum pyrophosphate from lanthanum nitrate and sodium pyrophosphate solutions. The precipitations prepared in various concentration of urea and their thermal products were estimated about the chemical composition, powder and acidic properties. The addition of urea on preparation of lanthanum pyrophosphate produced the increase of about 10-20 nm-radius pores. The large amount of urea covered the pore of lanthanum pyrophosphate. The amount of included urea in lanthanum phosphate was estimated from NH₃-TPD curves. The addition of urea did not improve the adsorption ratio of trimethylamine because of the balance between the remained urea and improvement of specific surface area.