However, the growth of Fe3O4 nucleu

However, the growth of Fe3O4 nucleus is easier to happen when the temperature is higher than 45 °C,resulting in larger size nanoparticles when the temperature is higher than 45 °C at the beginning synthesis of nanoparticles. On the other hand, a plausible explanation for this is that by increasing the reaction temperature there is more energy within the solution, this would increase mobility and cause a greater number of collisions between the particles [25]. Therefore, the initial temperature of 45 °C will be used for this experiment. 2.2.3. Effect of Stirring rate on Particle Size The TEM results in Figure 3 show that when the stirring rate was increased from 400 rpm to 800 rpm, the average sizes of the Fe3O4 nanoparticles were decreased from 9.41 nm to 7.83 nm. When the stirring rate is increased, the energy transferred to the suspension medium is also increased and the reaction solution can be dispersed into smaller droplets and the size is reduced [24]. Another explanation for this reduction was the anomalous diffusion of particles at higher degree of agitation reduced the growth kinetics of the particles, and resulted in the smaller sized particles [26].