Desorption And Recovery Of Organic Molecules Under Microwave On Adsorber With High Applicability To Microwave

Microwave regeneration technology is recognized as a high-efficiency and energy-saving regeneration technology. However, the traditional activated carbon is flammable and unstable under the condition of microwave irradiation.Compared to activated carbon, zeolite and polymer resin have better thermal and structural stability, and have the similar surface area and enormous porous structures, which have shown great potential applications in adsorption of VOCs, may effectively compensate for the limitations of activated carbon in the microwave regeneration application.Three commercial zeolites NaY(Si/Al=3.8), USY-1(Si/A1=4.7)and USY-2(Si/A1=7.2) were used as adsorbers for cyclohexanone,butanone and acetone,their adsorption-desorption performance were investigated. The results show that the adsorption capacity of cyclohexanone in gas phase is 0.3798g/g on USY-2,0.2968g/g on USY-1,0.2813g/g on NaY.High desorption efficiency above 90% can be achieved under microwave irradiation for 10 minutes. No any polycondensation reactions of ketone moleculars happened under the process of microwave regeneration,while serious coking would be appeared under traditional heating regeneration.The Y-zeolite also has good adsorption performance even after several adsorptions/desorption cycles under microwave irradiation, Y-zeolite presents stable crystal structure which can be totally reused. The temperature of regeneration bed is 70 ℃, that is energy-saving and no need of colling before re-adsorption.The high-quality liquid products can be gained after desorption under microwave irradiation.Polydivinylbenzene(PDVB) resin was selected as another adsorber for organic pollutants that is adapted to microwave regeneration.Its adsorption and desorption performance were investigated using benzene,toluene and methylene chloride as typical nonpolar organic pollutants. The results show that the adsorption capacity of toluene in liquid phase on PDVB resin is 10.81 g/g. The desorption efficiency is above 50% under single microwave irradiation. Using microwave concomitant ultrasonic atomizated water, high desorption efficiency above 90% can be achieved under microwave irradiation for 10 minutes. The PDVB resin also has good adsorption performance even after several adsorptions/desorption cycles under microwave irradiation, PDVB resin presents stable crystal structure which can be totally reused. The temperature of regeneration bed is below 50℃, that is energy-saving and no need of colling before re-adsorption.The high-quality liquid products with low moisture content can be gained after desorption under microwave irradiation.The experimental results demonstrated that according to the difference of dielectric constant of adsorbate/adsorber system, by using proper introduction of ultrasonic atomized water as microwave asorbing medium, the adsorbates can be regenerated more easily by desorption of adsorbers and achieved the recycling of adsorber. The excellent research results involving the microwave regeneration of adsorber will make it attractive for fundamental research and industrial applications.