Preparation of modified semi-coke from semi-coke: Process optimization

The work attempts to optimize the process of preparation of modified semi-coke from semi-coke using phosphoric acid (H₃PO₄) as the activating agent using the response surface methodology (RSM). The influences of three major dependent variables, the impregnation ratio, activation time, and activation temperature were assessed on the independent variables yield and the iodine number. The empirical relationship between the dependent and the independent variables were established using the quadratic response surface models, which were utilized to optimize the process parameters. The significance of each of the parameters and interaction among the parameters on the independent variable was assessed based on analysis of variance (ANOVA). The process variables were varied within the range of impregnation ratio (IR) from 1.5 to 4, activation time from 30 to 90 min and activation temperature from 550°C to 650°C. The optimized process conditions were estimated to be an IR of 2.29, activation time of 32 min, and an activation temperature of 605°C respectively using the process optimization tool. The BET surface area of modified semi-coke of the optimized sample was estimated to be 915m ²/g, with the pore volume of 0.71cm³/g, with an average pore diameter of 3.09 nm, with micropore volume fraction being 52.36%. The scanning electron microscope (SEM) images were utilized to visualize the surface pore structure.