Pengaruh Perlakuan Asam dan Proses Hidrotermal terhadap Hidrofobisitas Material Silika dari Lempung Alam

Hydrophobic silica material has been successfully synthesized and studied through two methods, the acid treatment method and the hydrothermal method. The acid treatment method is carried out by refluxing the natural clay in HCl solution with variations in concentrations of 2M, 4M and 6M for 6 hours at 90 oC. While the hydrothermal method is done by heating the silica material resulting from 4M acid treatment on clay with a solution of NaOH, ethanol, sodium silicate, and TPA Br in teflon-lined autoclave at a temperature of 170 oC for 24 hours with a variation of the time of aging before hydrothermal is 24, 72, and 168 hours. The calcination process at 600 oC is carried out later to remove the organic template on the material's framework. The materials obtained in each method were each characterized by functional groups, crystallinity, and moisture absorption. The acid and hydrothermal treatment process can improve the hydrophobicity of the material by decreasing moisture absorption. The highest decrease in moisture absorption in the acid treatment process is obtained material with 6M acid treatment which reduces the absorption of moisture from 0.13 g/g to 0.06 g/g of material. While the optimum results of the hydrothermal process are obtained by a material with a 24 hour long aging which reduces the absorption of moisture from 0.076 g/g to 0.03 g/g material.