THE EFFECT OF HEXAMETHYLENETETRAMINE AND TETRABUTYL AMMONIUM BROMIDE TEMPLATE ON THE LANTHANUM PHOSPHATE SYNTHESIS

Abstract

LaPO4 synthesis through the sol-gel method and synthesis of LaPO4 with the addition of templates through the hydrothermal method have been successfully carried out. The templates used are hexamethylenetetramine (HMT) and tetrabutylammonium bromide (TBABr). The concentration of precursor, pH, and aging time in the sol-gel method can affect the structure and morphology of LaPO4. In this study, the ratio of La3+: PO43-, pH, and aging were varied to obtain the optimal condition in used sol-gel method. The optimization results show that LaPO4 is formed at pH 9, the ratio of moles La3+:PO4 3-is 1:1, and the aging time is 72 h. The obtained solids were characterized by X-ray diffraction, FTIR, SEM-EDX, and adsorption-desorption N2. The XRD results showed that LaPO4 without templates (LaP) and LaPO4 with TBABr templates (LaPT) had a hexagonal crystal structure, meanwhile, LaPO4 with HMT templates (LaPH) had a monoclinic crystalline structure. The surface area of LaP, LaPH, and LaPT was 93.28; 69.37; and 107.00 m2/g, respectively, while the pore diameters were 7.04; 16.91; and 8.30 nm, respectively. SEM morphological observations of LaP, LaPH, and LaPT solids are in the form of aggregates that have not been evenly distributed and pore sizes that have not been uniform, and differences are seen between LaP, LaPH, and LaPT.