高介孔体积油茶壳活性炭的制备工艺研究

Preparation of High Mesoporous Activated Carbon from Camellia oleifera Shell

以生物质油茶壳为原料,氯化锌为活化剂,探讨活化温度、氯化锌与油茶壳的浸渍比、油茶壳颗粒大小对制备的活性炭的比表面积、孔体积和介孔体积的影响规律,并对活性炭的组织结构、形貌、石墨化程度及表面化学成分进行了分析。结果表明,在考察的活化温度(T=500℃~800℃)范围内,活化温度对活性炭的比表面积和孔体积具有较大的影响,对孔径影响较小;在500℃时制备的活性炭具有较高的高比表面积和孔体积,活化温度越高,活性炭的比表面积和孔体积越小;氯化锌与油茶壳浸渍比为1时,制备的活性炭为微孔体系,当浸渍比为4时,活性炭具有较高的比表面积和最大的孔体积,其比表面积和孔体积分别为1890m^2·g^-1和2.42cm^3·g^-1,介孔体积占总体积的83.06%;在考察的油茶壳颗粒尺寸范围内,油茶壳原料颗粒的粒径对活性炭的组织结构影响较小。表面形貌和化学组成分析结果表明,活性炭表面由菜花状的小颗粒堆积而成,相互贯通的蠕虫状孔结构构成其孔隙结构,其表面含有一定数量的醚基、羰基、酚羟基及羧基等含氧官能团。

Activated carbon was prepared from Camellia oleifera shell by zinc chloride activation method.The influences of carbonization temperature,impregnation ratio and the particle size of C.olleifera shell on the specific surface area (SSA),pore volume (PV) and mesoporous volume (MV) of activated carbon were studied to provide a basis for preparing high mesoporous activated carbon.The pore textural properties,surface morphology,graphitization degree and surface chemical composition of activated carbon were analyzed.It was revealed that temperature had great influence on SSA and PV of activated carbon in the range of 500℃-800℃,but little influence on the pore size.Activated carbon prepared at 500℃ had the highest SSA and PV,the higher the temperature,the smaller the SSA and PV.When the ratio of ZnCl 2 to C.oleifera shell was 1∶1,the obtained activated carbon was a microporous system.While when the impregnation ratio was 4∶1,the activated carbon had a higher SSA (1890m^2·g^-1 ) and the largest PV (2.42cm^3·g^-1 ).The MV accounted for 83.06% of the total volume.The results of surface morphology and chemical composition analysis showed that the surface morphology of activated carbon was made up of cauliflower-like small particles and its interpenetrating worm-like pore structure formed the pore structure.The surface chemical composition contained the oxygen-containing functional groups such as ether,carbonyl,phenolic hydroxyl and carboxyl groups.