Preparation Of High Specific Area Actived Carbon From High Sulphur Occurring Coal

Preparation of high specific area activated carbon from high sulphur occurring coal is presented in this article. The coal sample was treated by chemical oxidation with KNO3 in advance, and then treated by chemical activation with KOH. Chemical oxidation and further activation were carried in a stainless steel tube under circumstance of nitrogen in a tubular furnace.During chemical oxidation of coal powder, effects of temperature, mass of oxidant, heating time on formation of satisfactory carbonized material are investigated at present. It has been shown that the most suitable conditions for carbonized material preparation are as follows: at temperature of 400 C, in a ratio of oxidant of 4.8% based mass of coal powder added, and in a 30min of heating time. On the other hand, an explanation for mechanism of formation of the carbonized material by oxidation with KNO3 is given in this paper. Initially, KNO3 was decomposed and gave out oxygen so that alky] side chain of coal molecule structure is oxygenated to form function groups with oxygen and pyrolysis takes place simultaneously, Thus some function groups of coal molecule structure are ruptured while coal molecule structure is destroyed to some extent. Ultimately, the capability of recombination of coal molecule structure is restrained and balminess degree in residual carbon is decreased with forming non-graphitic carbons which is highly proficient to activation of carbon in the following process.After chemical oxidation pretreatment, the resultant carbonized material was undertaken being activated with KOH under the nitrogen circumstance at around 800C. Then the activated material was washed by both acid solution and hot water early and late. Finally it was dried at 110C. During the process of activation, effect of operation conditions such as amount of KOH added, temperature and time treated on characteristics of adsorption and yield of activated carbon were studied in details. The suitable conditions were obtained as the amount of 71% of KOH (based on the mass of mixture) and 800 C of temperature and 1.5h of time as well.Analysis for porous structure for the resultant samples was made by ASAP instrument. It has been shown that a narrow distribution of porous structure and a high specific area could steadily be obtained for most resultant samples. The micro porous is up to 1.1ml g-1 contrast to total porous 1.21ml g-1 and specific area reaches to around 2579.76m2/g. As far as characteristics of adsorption of resultant activated carbon, capability of adsorption for phenol is as high as 281.06mg /g for the most.