Synthesized Silica Mesoporous from Silica Geothermal Assisted with CTAB and Modified by APTMS

Abstract

Mesoporous silica is one of the modifications from silica particle; it can used as host of drug delivery. This study focused on the synthesis of mesoporous silica. The precursor of silica is sodium silicate, obtained from silica geothermal. Assisted with cetyltrimethylammonium bromide (CTAB) as a surfactant, to produce silica particle with mesoporous structure. Then modified with 3-Aminopropyltrimethoxysilane (APTMS) to modified the mesoporous silica with amine functional group, so it can be a matrix of slow-release urea fertilizer. The precursors used was sodium silicate from silica geothermal; the surfactant was CTAB at 0.03 molar ratio. Stöber method used in this research with the addition of ethanol, NH4OH, CTAB, and water with a mol ratio of 10: 22.8: 0.03: 5.2 to 1 mol sodium silicate, respectively. The mesoporous silica characterized by using BET and FTIR. It is then modified with (APTMS) to increase the absorbed urea as slow-release urea fertilizer. The mesoporous silica revealed a diameter of 15.310 Å and 19.025 Å at adsorption and desorption, respectively and having the adsorption-desorption curve type of IV which classified as the mesoporous particle. The results showed that the addition of CTAB strongly influenced porosity of silica particles. Several functional groups indicate ammonia from APTMS have modified the mesoporous silica, such as 2930 cm−1 ascribed to the stretching modes of CH2 groups and vibrational modes at 155 cm−1 represent NH2. It approved that mesoporous silica modified with APTMS adjusted with ammonia functional group, so it proved as a matrix of slow-release urea fertilizer.