真空浸渍制备膨胀石墨基C/C复合材料及其甲醛吸附性能

Preparation of expanded graphite-based C/C composites by vacuum impregnation and its adsorption properties on formaldehyde

以蔗糖为炭源,磷酸为活化剂,采用真空浸渍法经炭化、活化制得膨胀石墨基C/C复合材料。采用SEM、氮气吸脱附法、TG和TEM等测试手段,研究了磷酸/蔗糖质量比(Xp)、蔗糖浓度对复合材料孔结构和比表面积的影响,利用FTIR和Boehm滴定法对复合材料表面的化学官能团进行表征,并考察了C/C复合材料对甲醛的吸附能力。结果表明:膨胀石墨基C/C复合材料含有大量的微孔、一定量的介孔和大孔,表面含有丰富的含氧官能团,有利于对甲醛极性分子的吸附。在Xp=1.0、蔗糖溶液浓度为30%(质量分数)时所制得的膨胀石墨基C/C复合材料比表面积最高,达到2112m2/g,孔容为1.08mL/g,其对甲醛的吸附量为854mg/g,较同工艺制备的活性炭提高了26.9%。

The expanded graphite-based C/C composites were prepared by vacuum impregnation while expanded graphite （EG）, sucrose and phosphoric acid solution were selected as starting materials. The effect of phosphoric acid/sucrose mass ratio （Xp）, sucrose concentration on pore structure and specific surface area surface area of the composites was investigated by SEM, nitrogen adsorption/desorption techniques, TG and TEM. The surface chemical functional groups of composite material were characterized by FTIR and Boehm titration method. And the formaldehyde adsorption ability was investigated. The results indicate that there are a lot of micropores, a certain amount of meso- and macropores. The abandant oxygen- containing functional groups on the surface of the composites are benefit to the adsorption of formaldehyde. Under the condition of Xp = 1.0, 30% sucrose concentration（mass fraction）, the C/C composite is obtained with the highest surface area of 2112 m^2/g and total pore volume of 1.08 mL/g. The formaldehyde removal capabilities of expanded graphite-based C/C composites are 26.9 % higher than that of activated carbons which were prepared under the same condition.