Study on Preparation of Carbonaceous Adsorbent from the Sewage Sludge of an Urban Wastewater Processing Plant

Based on the characteristic of organic substance contained in the urban sewage sludge, the technological conditions of preparation for carbonaceous adsorbent from sewage sludge are studied.The factors influencing the performance and the production of the absorbent, such as activation temperature, activation time and so on, are discussed.The removal effect of sludge activated carbon is preliminarily discussed with scanning electron microscope analysis.The result indicates that optimal conditions for preparing sewage sludge-based activated carbon is the concentration of ZnCl₂ 3M, activation temperature of 550℃, 1h of activating time and 2:1 of the impregnation ratio of ZnCl₂/sawdust.Under the conditions, the iodine value of the sludge activated carbon is over 410mg/g, the BTE surface area is 227.3m²/g and the yield rate of product is 38.32%.This sludge activated carbon is used to treat wastewater with heavy metal when the adsorption equilibrium time is 60min, the adsorptive capacity of Cu²⁺ is 18mg/g.The effect of adsorption is better than power actived carbon.