There are many factors that should be considered in the application of activated carbon in the liquid phase, mainly including the amount of activated carbon added, temperature, time, pH, and operation mode.
1. The amount of activated carbon added
The amount of addition is an important factor affecting the liquid adsorption performance of activated carbon. Increasing the amount of activated carbon added will help increase the adsorption activity and adsorption effect, but will also increase the adsorption resistance during the adsorption process.Therefore, it is necessary to determine reasonable amount of addition, maximize the adsorption performance of activated carbon, and achieve the desired adsorption effect.
2. Time
The time required for decolorization or refining is affected by many factors, such as the particle size of charcoal, the amount of charcoal, the temperature and viscosity of the liquid, and generally it takes 10 to 60 minutes. The finer the carbon or the more the amount of carbon used, the shorter the time. When the viscosity of the liquid is large or the amount of carbon used is small, the time is longer. For a given pigment and a given type of activated carbon, under the same conditions, the adsorption of the pigment per unit mass of the activated carbon does not change much with the extension of time.
3. Temperature
Many studies have shown that the adsorption process of activated carbon in the liquid phase is exothermic, and lowering the temperature is beneficial to the improvement of adsorption performance. However, in the liquid phase, increasing the temperature can help promote the activity and diffusion of the liquid phase molecules, and enhance their adsorption in the pore structure of the activated carbon. In the actual application process, the determination of temperature not only needs to consider above factors, but also needs to take into account the characteristics of the liquid itself. For example, a liquid with a large viscosity needs to increase its fluidity by increasing the temperature. For some substances with a high melting point, it is also necessary to ensure the temperature is higher than the melting point. However, substances with poor heat sensitivity need to consider the effect of temperature on their active ingredients.In short, the effect of temperature on the application of activated carbon need to be considered both the adsorption performance and the application conditions. It is impossible to increase the adsorption amount by temperature change, and it is difficult to specify a uniform operating temperature, which depends on the situation.
4. PH value
The pH value has a significant effect on the liquid phase adsorption of activated carbon, especially for pigment adsorption. Since many natural pigments are acidic pigments and a small amount is alkaline pigments, the adsorption properties of activated carbon on pigments can be increased by selecting an appropriate pH value. The adsorption of some substances by activated carbon varies with the pH, including aqueous and non-aqueous solutions.
