Particle Characteristics of Diatomite Activated by Alkaline Solution

In this study, the activation of natural diatomite was done with alkaline solution. The diatomite powder was sieved and purified prior to activation at room temperature (Alk-DA RT) and 85 °C (Alk-DA 85 °C). The effect of activation time of Alk-DA 85 °C samples was observed for 1 h, 2 h and 5 h. At temperature interval from room temperature to 530 °C, the weight loss for all of Alk-DA are less than R-DA. The reduction of particle aggregation was found in Alk-DA at both RT and 85 °C as shown in SEM images, indicating the activation by NaOH that effectively breaks down the bulky structure. The formation of silanol group (Si-OH) were obtained on the surface of Alk-DA. However, BET result revealed there is no increment of surface area and porosity in case of RT. In addition, Alk-DA 85 °C samples at 1 h and 2 h provided the spongy surfaces with obvious improvement of surface area, and reduction in porosity and pore size. In contrast, Alk-DA 85 °C 5 h showed more cluster of particle aggregation. Moreover, it can be observed that Alk-DA 85 °C 1 h is the most interesting for further study since it potentially provides high gas adsorption but only requires a shorter activation time.