Research on preparation of activated carbon adsorbent from sewage sludge and its application

The paper aims at introducing the authors' study on the different influential factors on the adsorbent capability of the activated products by taking the surplus sludge as raw material. It has also introduced different activating ways to prepare the activated carbon adsorbent and contrasting the effects of different activators. The results of our study reveal that the activated carbon adsorbent made by way of chemical activation proves better with the optimum activator being complex of ZnCl_2 and H_2SO_4. Moreover, the optimum preparation conditions are concentration of two activators 5 mol·L -1(the ratio of ZnCl_2 and H_2SO_4 is 2:1), at the activating temperature of 550 ℃, in the proportion of solid to liquid 1∶2.5, in a period of 2 h. The capacity of iodine adsorption was 488.02 mg·g -1, at the rate of 86.6%. The stage of weight loss of dry sludge occurred at 244.62 ℃(approximately 34.19%). The adsorbent gained can be used to treatment wastewater to effectively remove organic substances. It can also be found that the adsorbent amount may have strong effect on the adsorption of the organic substances in wastewater treatment. On the condition that the activated carbon adsorbent concentration is 0.5%, the removing rate of COD will be 68.18% with the equilibrium adsorption time being about 60 min, and the equilibrium adsorption capacity41.24 mg·g -1. If the chromaticity color of wastewater is improved, the treatment effect turns better than the commodity of pellet carbon, the removing rate of COD of commodity of pellet carbon is 48.72%, and the equilibrium adsorption time is approximately 90 min, the equilibrium adsorption capacity is 30.78 mg·g -1. Therefore,the performance of the adsorption of activated carbon adsorbent made from sewage sludge proves positive.