Silica is a mineral that is abundant in the earth’s surface. Silica has also been used in human civilization, such as making glass, electronic devices, adsorbents, fertilizers and others. Utilization of natural silica requires technology that is reliable enough so that impurities in the natural silica do not interfere with its use. In this study, tests have been carried out on natural silica, such as chemical and physical activation, reactions with certain reagents and also modifications made to the natural silica. The desired result is that natural silica can be used as an adsorben, ion exchange and also a stationary phase in the chromatography column. From this research a natural silica modification has been obtained using dimethylamine (DMA) to convert natural silica into positive charge so that it can be used to increase the absorption of some anions.