Study On The Testing Of Specific Surface Area And Adsorption Isotherm Of Powders By Frontal Chromatogram

When powder's diameter become so small to some degree, its specific surface area shows more effect. During the process of petroleum, chemical engineering, metallurgy, atomic energy, medicine, chemical electrode, chromatogram and other fields of industry, agriculture and national defence, so many processes of them carry through on the specifically surface. So, it is very important to determine the powder'specific surface area.There are many ways to determine. Now days, the Nitrogen Surface Area which involves the flow chromatogram and dual flow chromatogram makes the most reliable and availability way. Using dates of adsorption isotherm during the range of pressure 0.05-0.35 can calculate the specific surface area by BET equation. The paper uses the type of ST-03 apparatus to do some basic research by flow chromatogram and dual flow chromatogram at first. Giving the error factor caused by electrical current, attenuation coefficient and gas pressure to the former and calculating the range of remedy coefficient of death room caused by temperature to the after are performed detailedly.The paper also uses the frontal chromatogram to determine which has the high efficiency opposite to other two ways. The author put forward that how to calculate the adsorption quantity and the actual adsorption model and want to get the ideally result through changing the working condition, but no success. The main reason is that the ideally suppose works so difficultly. Based upon this, a new way called step frontal chromatogram comes true. Its principle is that which divided the range of whole process into some little ones. So the exact result can be determined on the setting pressure points. The accuracy can be enhanced so much comparing the old way. Then, a brief model can be used to revise dates replacing a complex one. Manipulating conveniently, shorter working time and high accuracy are the excellence of this new way. According to this principle, the author designs and founds four ways to determine and gets different result. The author also analyses and compares these processes detailedly. At last, a new method for calculating the actual adsorption quantity is fond out.The author makes some mathematics models based on the principle and actual condition.