Preparation and characterization of nano-sized silica xerogel particles using sodium silicate solution extracted from waste container glasses

Abstract

In this work, nano-sized silica xerogel particles were synthesized using sodium silicate solution prepared from waste container glasses (of mix colors) as precursor. The as-received waste container glasses of different mix colors (green, white and amber) from municipal dumpsite were initially washed, crushed and wet milled for 24 h then sieved through 63 μm mesh. The sieved glass slurries were then oven dried at 110 °C for 72 h to obtain powdered glass (GP). Appropriate amount of GP was reacted with 320 ml of 3 M NaOH solutions respectively in a 500 ml Erlenmeyer flask placed on a hot plate connected with a reflux condenser and continuously stirred at 40 rpm with the aid of magnetic stirrer for a period of 3 h under reaction temperature of 200 °C. The resultant solution was filtered to obtain sodium silicate solutions (SSS). 3 M HCl was prepared and was gently added into the SSS whilst continuously stirred to obtain a white gelly-like mixture (at pH ˂10). The gelly mixture was left for 18 h (ageing), then filtered and dried in an electric oven at 80 °C for 12 h to obtain highly pure silica gel particles and then characterized. The results showed that the synthesized nano-sized silica particles range between 0.031 (31 nm) μm to 0.051 (51 nm) μm.