Optimization of Preparation Conditions of Sewage sludge based Activated Carbon

Abstract

The volume of sludge is a growing problem worldwide due to the increase in the population and the growing in industry and agriculture. Therefore, sludge management and disposal are becoming problematic and required more intensive and creative efforts. The objective of this study was to produce activated carbon using sewage sludge as raw material. Preparation conditions of sewage sludge based activated carbon were optimized by applying Box-Behnken Design (BBD) in response surface methodology (RSM). Optimization process investigated the impact of interaction between chemical activation ratio, contact time and activation temperature on the surface area of activated carbon. A series of activated carbons were chemically activated using potassium hydroxide (KOH) and physically activated by pyrolysis process in tube furnace. The response of optimization process was the surface area of activated carbon which was depicted by the second-order polynomial regression model created by ANOVA. Optimum activated carbon characterizations were conducted by surface area (BET), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and Thermogravimetric analysis TGA. The maximum surface area of 377.7 m2/g was achieved at chemical activation ratio of 1, activation contact time of 3 hours and activation temperature of 500 ℃. According statistical analysis, the most significant parameter was the contact time, followed by chemical activation ratio and activation temperature.

Keywords

• Activated carbon
• Box-Behnken design
• Response surface methodology
• Sewage sludge