The Influence of Calcination on Property and Performance of Mesoporous Silica from Geothermal Sludge as a Drug Delivery System

Geothermal sludge has received interest due to its high amount of silica. Mesoporous silica is a potential reservoir for drug loading due to its unique characteristics, such as low toxicity, large surface area, and high pore volume. This study prepared mesoporous silica through the sol-gel method using cetyl trimethyl ammonium bromide (CTAB) surfactant. The acquired mesoporous silica was calcined at 400 °C for 5 hours and then analyzed. Through Fourier Transform Infrared (FTIR) spectroscopy, the ethyl group of CTAB was not detected in calcined silica. However, the BET surface area and pore volume of calcined mesoporous silica were slightly smaller than uncalcined silica. Curcumin was used as an active agent to be loaded into mesoporous silica. The largest curcumin loading in this study was achieved in calcined silica with a value of 833.40 ± 45.08 mg/g for a curcumin concentration of 8 mg/ml. Freundlich and pseudo-second-order models were the most suitable adsorption isotherms and kinetics for calcined mesoporous silica.