Preparation Of Activated Carbon Functional Ceramics

Activated carbon functional ceramics were prepared by using a certain way to fixactivated carbon onto the diatomite-porous ceramics. The activated carbon ceramics havemost merits of the porous ceramics as well as a high surface area and high-absorptioncharacteristics. In the meantime, the porosity and specific surface area of porous ceramicscan also be significantly improved by the adhesion of activated carbon on or into the wholesubstrate. So, the composite of activated carbon and porous ceramics widely extend theirindividual application range which can be considered as new promising compositematerials with multi-functional and widely used prospects.The activated carbon functional ceramics materials were prepared by usingdiatomite-porous ceramics as the carrier and phenolic resin or coal tar pitch as the carbonsource in this experiment, the formulas, manufacturing process and material propertieswere all discussed. During this process, the effects of diatomite material preheatment,binder additive and sintering system on the properties of porous ceramics were discussed.The adhesive ability, carbonization and activation technological conditions on theperformance of materials were synthesized discussed. The effects of activating agent(KOH, ZnCl2, and H3PO4) on the performance of activated carbon multi-functionalceramics are discussed emphatically. Iodine absorption measurement was used to test theperformance of activated carbon multi-functional ceramics. SEM, BET and other analyticalmethods were used to investigate the properties activated carbon multi-functionalceramics.The experiment results show that diatomite is an ideal raw material to prepare porousceramic matrix. The pore-forming agent could obviously enhance porosity of porousceramic and its optimum content is5%(wt%). The sintering system has a great effect onthe performance of porous ceramic matrix. The best sintering process is heating up at rateof200℃/h, sintering temperature of800℃, and holding for60min. Under these conditions,a porous ceramics with a porosity of55.99%, bulk density of1.03g/cm3and bendingstrength of11.29MPa.Phenolic resin is an ideal precursor to prepare activated carbon materials. Theexperiment shows that the technological conditions of impregnation, carbonization and activation are very important. Based on a comprehensive analysis, the suitabletechnological conditions of impregnation are double dipping for two hours each time underthe vacuum conditions. The curing temperature of150℃is determined to be the optimaland the best curing time is30min. The best carbonization process is heating up to800℃and holding for60min at a rate of200℃/h. Different activator has different influences onthe performance of activated carbon multi-functional ceramics. For KOH activator, thebest concentration is25%and the best activation temperature is700℃for90min. ForZnCl2,the best concentration is20%and the best activation temperature is800℃for90min. Again for H3PO4,the best concentration is40%, activation temperature is400℃,and activation time is150min. By comparing, ZnCl2activation is the most effective oneand the corresponding properties for ceramics are iodine absorption178.26mg/g, specificsurface area is84.81m2/g with a carbon content of15.14%.When coal tar pitch is used as precursor to prepare activated carbon materials, thesuitable dipping temperature is determined to150℃and time is30min. The optimumpre-oxidation process is heating up at rate of150℃/h to420℃and holding for60min. Theoptimum carbonization process is heating up at rate of200℃/hto700℃and holding for60min. An activated carbon ceramics with iodine absorption of43.81mg/g can be derivedfollow these techniques. The influences of three activators on the properties of ceramicswere also discussed. For KOH, the best concentration is20%, activation temperature is800℃, and activation time is60min. ZnCl2with a concentration of35%, at850℃for60mincan bring into the best effect. For H3PO4,the best concentration is determined to be20%and the best temperature is500℃for60min. In which, by comparing, H3PO4is consideredto be the best activating agent. It can increase the iodine adsorption from43.81mg/g to173.1mg/g and specific surface area is87.548m2/g with a carbon content of20.17%.