There are two types of air pollutants: particulate matter and gaseous matter, among which gaseous pollutants account for the main part, accounting for more than 75% of the pollutants discharged into the atmosphere worldwide every year. Gaseous pollutants are divided into inorganic pollutants and organic pollutants.In terms of species, organic pollutants account for the vast majority.Of the 25 gases listed by the U.S. Environmental Protection Agency (EPA) as toxic emissions, 18 are organic.These 18 kinds of organic matter account for 74.2% of toxic gas emissions.It is estimated that more than 30 million tons of organic matter are released into the atmosphere worldwide every year, posing a serious threat to human health and plant and animal growth.Organic pollutants are mostly produced in industrial processes.
silicon carbide manufacturerIn painting, printing, shoe making, plastic, rubber, bonding and other industrial processes, there are a large number of organic waste gas emissions.These waste gas, often contain benzene, toluene, xylene, ethyl acetate, methanol and other organic matter, itself toxic, long-term damage can lead to human death.The emission of this kind of waste gas, countries have clear provisions, strict control of its emission concentrationThe treatment of organic waste gas has been studied for a long time, and some effective control technologies have been developed.The widely used and studied control techniques include adsorption method, thermal destruction method, condensation method, absorption method, etc.
Among them, the adsorption method is widely used.Compared with other methods, the adsorption method has the advantages of high removal efficiency, thorough purification, low energy consumption, mature technology, recovery and solution, easy popularization and practical, and has good environmental and economic benefits.Activated carbon is the most commonly used adsorbent because of its huge specific surface area, large adsorption capacity, easy regeneration, abundant sources and low price.Although the application of charcoal as an adsorbent, human beings have had a long time, but the study of adsorption theory, but only in the end of the last century began to make progress.
aluminium oxide abrasiveIn 1916, Langmuir studied the adsorption of monolayer molecules and proposed the Langmuir adsorption isotherm equation.Freundlich and Zsigmondy proposed the capillary condensation theory for gas adsorption and obtained the semi-empirical Freundlich adsorption isotherm equation.Temkin also suggested a semi-empirical isothermal equation.
Based on Gibbs equation, Toth used dimensionless function V to derive another adsorption isotherm equation for heterogeneous surfaces.Fowler and Guggenhein derived a formula of the same form from the concept of statistical mechanics.Goldmann and Polanyi proposed the adsorption space theory, which believed that the continuous decrease in the molecular density of multiple layers on the surface of the adsorbent was caused by the weakening of the adsorption molecular force
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