K_(2)CO_(3)-水蒸气催化活化制备兰炭基活性炭的实验研究

Experiment study on the preparation of Blue coke-based activated carbon by catalytic activation of K_(2)CO_(3)-steam

选取粒度小于6mm的低价值兰炭末,以K_(2)CO_(3)为催化剂,采用溶液浸渍-水蒸气高温活化技术制备兰炭基活性炭,通过计算收率,碘吸附和亚甲基蓝吸附实验,低温N_(2)等温吸附/脱附实验以及扫描电子显微镜(SEM)表征活性炭孔结构特征,重点考察了催化剂溶液浓度、催化活化温度对孔隙结构的影响。研究表明,相比于常规水蒸气高温活化,K_(2)CO_(3)催化作用能缩短活化时间,活化30min已经十分充分。随着活化温度的上升和催化剂浓度的增加,亚甲基蓝吸附值先增大后减小,碘吸附值持续降低。当催化剂浓度为0.6mol·L^(-1),亚甲基蓝吸附值最高,为234.12mg·g^(-1)。催化活化过程的最佳温度是500℃,此时兰炭基活性炭比表面积和孔容积分别为579.32m^(2)·g^(-1)和0.309cm3·g^(-1),材料中孔和微孔均较为发达。用扫描电镜观察了催化活化制备的兰炭基活性炭的表面形貌,其已经没有规整且丰富孔隙形态,表面不再平整,整体杂乱无序,刻蚀痕迹明显。

Blue coke-based activated carbon(BAC)was prepared by the impregnation-steam catalytic activation method using blue coke powder as the raw material and K_(2)CO_(3)as the catalyst.The effects of different catalyst concentrations and temperatures on the sample yield,pore structure were investigated by Iodine adsorption and Methylene Blue adsorption experiments,N_(2)isothermal adsorption/desorption experiment,Scanning Electron Microscope.The results showed that steam catalytic activation could shorten reaction time,the reaction had been completed in 30 minutes.when the K_(2)CO_(3)concentration was 0.6mol·L^(-1),the prepared BAC had a highest methylene blue adsorption value(234.12mg·g^(-1)),the optimal activation temperature was 500℃,specific surface area and pore volume of BAC were 579.32m^(2)·g^(-1)and 0.309cm3·g^(-1)respectively,and the material belongs to microporous and mesopore activated carbon.The surface morphology of BAC prepared by catalytic activation was observed using SEM,there was no longer regularly and rich pore morphology,the surface was uneven,and the etching marks obviously.