多孔结构无机材料比表面积和孔径分布对调湿性的影响

测试海泡石、沸石、硅藻土和坡缕石粘土的孔径和比表面积,研究其孔径和比表面积与吸放湿能力的对应关系.利用氮气等温吸附对孔隙结构进行测试、分析,通过BET法计算得出其比表面积分别为81.56、2.46、1.68和187.70 m2/g,平均孔径分别为8.53、18.20、31.57和11.79 nm.在温度25℃相对湿度分别为75%和35%的条件下进行吸放湿试验,4种样品的最大吸湿量分别为5.6%、2.2%、1.8%和6.0%,放湿量分别为4.4%、1.8%、1.6%、5.0%.数据对比发现,比表面积大且孔径分布符合在相应温湿度下以Kelvin公式计算出的孔径分布特点的矿物材料,如海泡石,吸放湿能力强.

The effect of the specific surface area and pore radius distribution of inorganic materials on the capacity of absorbing and desorbing moisture in the air

With the aid of the N_2 isothermal adsorption technology, the authors calculated the specific surface area and the pore radius distribution of sepiolite, zeolite, diatomite and attapulgite by using the BET method, and the results snowed that the specific surface areas were 81.56, 2.46, 1.68 and 187.70 m~2/g, whereas the pore radius distribution values were 8.53, 18.20, 31.57 and 11.79 run, respectively. Their maximal absorbing moisture values were 5.6%, 2.2%, 1.8% and6.0%, respectively, at 25 ℃ and 75% relative humidity. After the saturation of the absorbing moisture, the samples of these four kinds of minerals were put in the environment of 25C and 35% RH to make moisture discharge. The capacities of desorbing moisture were 4.4%, 1.8%, 1.6% and 5.0% , respectively. A comparison of the specific surface area and pore radius distribution of the four inorganic porous minerals with their capacities of absorbing and desorbing moisture in the air demonstrates that the sample whose specific surface area is relatively large and whose pore radius distribution is consistent with the computation result of Kelvin formula, such as sepiolite, has comparatively strong absorbing and desorbing moisture capacity in the air.