2.1.4. Determination of Reaction Temperature

Fixing the CS concentration of 0.1 mg/mL, the molar mass ratio of Na2SeO3 to Vc of 1:8, reaction time of 3 h, the reaction temperature varied from 25 to 85 ◦C. The particle size of the obtained SeCS is shown in Figure 1D. It could be seen that although the particle size of the obtained SeCS slightly decreased at 55 ◦C, there was no significant difference between 25 ◦C and 55 ◦C. When the reaction temperature was further separately increased to 70 ◦C and 85 ◦C, the particle size of the obtained SeCS both significantly increased. The reason might be that heating easily led to the violent movement of nanoparticles, thus increasing the chance and intensity of collisions and intensifying aggregation [22]. Therefore, in terms of saving energy, the optimal reaction temperature was selected as 25 ◦C.

In summary, these above results demonstrated that we optimized conditions for preparing SeCS as a CS concentration of 0.1 mg/mL, the molar mass ratio of Na2SeO3 to Vc of 1:8, reaction time of 3 h and reaction temperature of 25 ◦C, so SeCS used in subsequent experiments were obtained in optimal reaction conditions. Under the optimal reaction conditions, the SeCS was successfully prepared and inductively coupled plasma mass spectrometry (ICP-MS) was used to measure the Se content of the SeCS obtained. It was found that the Se content in SeCS was 33.18%, which is higher than that reported in previous studies [18,23].
