Synthesis of silica gel from glass waste for adsorption of Mg2+, Cu2+, and Ag+ metal ions

Abstract

Glass waste is broken glass which is generally no longer used but on the other hand the content of silica in glass is quite high at around 72.4% so that the glass has the potential to be extracted silica for further use for making silica gel. In this study, silica extraction was carried out by reacting glass and 1.5 M sodium hydroxide solution and then heating it in a furnace at 400°C. Silica gel synthesis was carried out by the sol-gel method with citric acid catalyst at pH 5. From the FTIR results, there were two main functional groups of silica gel, which were silanol and siloxane groups at wave number of 920 and 1100 cm-1 respectively. Silica gel obtained has acidity, water content, and water capacity 1,625; 60; and 112 mmol/g adsorbent. While the ability of silica gel adsorption on metal ions Mg2+, Ag+ and Cu2+ was 17.68; 12.75; and 9.48 mmol/g adsorbent respectively.