2.2. Preparation of surface treated silica with silane 69 (TSi)

First, 5%wt silane coupling agent (Si-69) was mixed with 800 ml ethanol, followed by stirring using a hot-plate magnetic stirrer for 1 h at 30 °C. After that, 100 g silica was put gradually into the mixture and continually stirred for 1 h. Then, it was dried in an oven at 100 °C for 12 h. It was called treated silica (TSi).