Optimization of Activated Carbon Preparation Process Using Eggplant Stems with Response Surface Methodology

This research investigates the key factors affecting the production of activated carbon from eggplant stems, aiming to optimize the process and enhance the value of agricultural by-products. Eggplant stems were utilized as the raw material, with potassium carbonate serving as the activating agent. The study examined variables including the amount of activator (A), carbonization temperature (B), and activation temperature (C). Through single-factor experiments, the preparation process was optimized using a combination of response surface methodology and the entropy weight method. A comprehensive evaluation score (Y) was derived from the activated carbon yield, iodine adsorption capacity, and methylene blue adsorption capacity. A quadratic regression model was established: This research investigates the key factors affecting the production of activated carbon from eggplant stems, aiming to optimize the process and enhance the value of agricultural by-products. Eggplant stems were utilized as the raw material, with potassium carbonate serving as the activating agent. The study examined variables including the amount of activator (A), carbonization temperature (B), and activation temperature (C). Through single-factor experiments, the preparation process was optimized using a combination of response surface methodology and the entropy weight method. A comprehensive evaluation score (Y) was derived from the activated carbon yield, iodine adsorption capacity, and methylene blue adsorption capacity. A quadratic regression model was developed ( R2 = 0.9602), indicating a high degree of accuracy. The factors were ranked in order of influence as follows: activator amount > activation temperature > carbonization temperature. The activator amount was identified as having the most significant effect on the score (P < 0.01), with a notable interaction between carbonization and activation temperatures (P < 0.05). The optimized preparation conditions included an activator dosage of 2.22 g, a carbonization temperature of 323°C, and an activation temperature of 714°C. Under these conditions, the results showed a yield of 29.25%, an iodine adsorption capacity of 886.78 mg/g, a methylene blue adsorption capacity of 140.90 mg/g, and a composite score of 0.677, with a relative error of just 0.296%. The established model effectively predicts and evaluates the preparation of activated carbon from eggplant stems, demonstrating a stable and reliable process. Additionally, the methylene blue adsorption performance of the activated carbon meets the first-grade standards for water purification.