Preparation and analysis of activated carbon from sewage sludge and corn stalk

• Corn stalk was added to sludge to increase the BET surface area of activated carbon.
• The recycle of corn stalk and the disposal of sludge were realized.
• Compared with commercial AC, the produced mixed-AC is more economical.

In this study, activated carbon (AC) was prepared using corn stalk and sewage sludge by chemical activation method, which not only solved the sludge’s disposal problem, but recycled the agricultural waste (corn stalk). The effects of operating conditions (including activation reagent, activation temperature, concentration of activation reagent, pyrolysis time, impregnation ratio and corn stalk addition) on BET surface area and production yield of AC were investigated. The powder characters (like BET surface area, pore-size distribution and pore volume) were presented. Scanning electron microscope (SEM) and Thermo Gravimetric and Fourier Transform Infrared Spectroscopy (TG-FTIR) analysis were also used for the characterization of produced ACs. Results showed that the pure-AC with a higher BET surface area of 475.0 m2/g could be obtained when the concentration of activation reagent (ZnCl2) was 4 M, the activation temperature was 600 °C and the pyrolysis time was 60 min. If 25.0% corn stalk was added, the BET surface area reached to 769.0 m2/g. Through the comparison between the production and the commercials, it can be seen that the two have almost equal methylene blue dye removal efficiency and adsorption. Besides, the sludge based AC is more economic.

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