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VSA typically draws the gas through the separation process with a vacuum. For oxygen and nitrogen VSA systems, the vacuum is typically generated by a blower. Hybrid vacuum pressure swing adsorption (VPSA) systems also exist. VPSA systems apply pressurized gas to the separation process and also apply a vacuum to the purge gas.
Dissolved gases also occur as a result of human contamination from fuel and chlorinated spill sites. As such, headspace gas chromatography offers a method for determining if there is natural biodegradation processes occurring in contaminated aquifers. [5] For example, fuel hydrocarbons will break down into methane. Chlorinated solvents such as ...
Gas chromatography (GC) is a common type of chromatography used in analytical chemistry for separating and analyzing compounds that can be vaporized without decomposition. Typical uses of GC include testing the purity of a particular substance, or separating the different components of a mixture. [ 1 ]
Gas separation can refer to any of a number of techniques used to separate gases, either to give multiple products or to purify a single product. Swing adsorption techniques [ edit ]
The mass spectrometry process normally requires a very pure sample while gas chromatography using a traditional detector (e.g. Flame ionization detector) cannot differentiate between multiple molecules that happen to take the same amount of time to travel through the column (i.e. have the same retention time), which results in two or more ...
Analytical thermal desorption, known within the analytical chemistry community simply as "thermal desorption" (TD), is a technique that concentrates volatile organic compounds (VOCs) in gas streams prior to injection into a gas chromatograph (GC). It can be used to lower the detection limits of GC methods, and can improve chromatographic ...
Brunauer, Emmett and Teller's model of multilayer adsorption is a random distribution of molecules on the material surface. Adsorption is the adhesion [1] of atoms, ions or molecules from a gas, liquid or dissolved solid to a surface. [2] This process creates a film of the adsorbate on the surface of the adsorbent.
The adsorption sites (heavy dots) are equivalent and can have unit occupancy. Also, the adsorbates are immobile on the surface. The Langmuir adsorption model explains adsorption by assuming an adsorbate behaves as an ideal gas at isothermal conditions. According to the model, adsorption and desorption are reversible processes.