Optimization and Preparation of Sludge-based Activated Carbon by Two-step Pyrolysis and Performance Characteration

Sludge-based activated carbon was produced with sewage sludge from municipal wastewater treatment facility combined with corn straw as raw material by a two-step pyrolysis method through chemical activating ZnCl₂. First sludge was carbonized at 400 ℃ for 60 min, then it was mixed with activator solution at a solid to solution ratio of 1∶ 2. BET value and yield were observed according to the variation of temperature and the content of corn straw.Results showed that when activated carbon was produced under the condition of 25% corn straw content and 500 ℃ pyrolysis temperature, the BET surface area achieved 756 m²/g. The yield presented a trend of slow dropping with increasing temperature. When activated carbon was prepared under the temperature of 450 ℃ and corn straw content of 25%, yield attained the maximum value 43.1%.