Preparation and performance of coal-based activated carbon based on an orthogonal experimental study

To improve the utilization value of coal resources and optimize the production process of coal-based activated carbon, an L9 (34) orthogonal experiment was designed to study the comprehensive effects of the carbonization temperature, heating rate, activation time and activator type on the specific surface area and iodine value of activated carbon prepared by physical activation, as well as the surface chemical and crystal properties. The results showed that large amounts of C–H and oxygen functional groups from the raw materials were lost in the process of preparing the activated carbon, and CaCO3 generated CaS through a two-step reaction. The raw materials were nonporous or macroporous materials, while the activated carbon developed a microporous structure. The same optimal working conditions were obtained when the iodine value and the specific surface area were used as the optimization target, as follows: 800 °C for carbonization, 10 °C/min for heating rate, 75 min for activation time, and steam + CO2 as the activator. Finally, activated carbon was prepared under the optimal experimental conditions. The results showed that this activated carbon had the highest specific surface area and iodine value. In addition, the iodine value had a good linear relationship with the specific surface area.