Study on activated carbon made from sewage sludge by microwave
微波法制备污泥活性炭研究

Sludge-based activated carbon was made from surplus sewage sludge in an urban wastewater treatment plant by microwave heating. Phosphoric acid (H3PO4) was used as a sludge activating agent during the pyrolytic process. Microwave power, irradiation time and the concentration of H3PO4 had remarkable influences on the adsorption performance of the sludge-based activated carbon. The activated carbon prepared under the optimal conditions of microwave power 480W, irradiation time 315s and 40% concentration of H3PO4 had a surface area of 168m2/g and an iodine adsorption value of 301mg/g. In addition, the heave metals in the source sludge had been solidified in the course of microwave heating.Compared with the traditional commercial carbon, the sludge-based activated carbon was mainly mesoporous in nature. Finally, the sludge-based activated carbon as an adsorbent was employed for disposing COD in effluent of the urban sewage treatment plant. The aqueous adsorption test indicated that the sludge-based activated carbon had a notable adsorption capacity for COD and the removal efficiency of COD was more than 87%. The equilibrium data fitted well in the Languir model of adsorption.