Organic Amine Phase Change Capture CO₂ Mechanism And Regeneration And Its Catalytic Behavior On Gel

Global warming caused by the greenhouse effect is a serious challenge in today's society,and the main cause of the greenhouse effect is the massive emission of anthropogenic carbon dioxide(CO2).With the development of the economy,the CO2 emissions from industrial combustion of coal,oil,natural gas,etc.far exceeds the purification capacity of the Earth itself.At the same time,how to separate,capture,sequester and utilize CO2 as a potential carbon source has become a hot topic for global scholars.Most of the chemical absorbents reported so far are composed of primary and secondary amines with high absorption rate and tertiary amines with large absorption.H2O,ethanol and ionic liquids are used as assistants and corrosion inhibitors.There are still problems of complicated separation process,high ionic liquid cost,complicated regeneration process,sensible heat of solvent,high energy consumption,and difficulty in utilization.In order to overcome these shortcomings,this paper provides a phase change absorbent N,N-diethylethylenediamine(DEEDA),which does not contain water,ethanol and other adjuvants,and changes from a liquid state after absorbing CO2.The regeneration temperature is low.Compared with other phase change absorbents,the process of separating rich and poor phase of CO2 is reduced,and the latent heat of solvent is reduced,thus energy consumption is effectively reduced.The solid product DEEDA-Car contains zwitterion and can also be introduced into the PNIPAm gel system as an accelerator of ammonium persulfate(APS)to prepare a PNIPAm zwitterionic gel.A new idea of introducing zwitterion is introduced to overcome conventional PNIPAm hydrogel applications typically only utilize the limitations of their temperature re sponse properties.DEEDA is selected with both primary amine(NH2-)and tertiary amine(-N-)as the CO2 absorber,the phase transition changes from liquid phase to solid phase,The reaction mechanism,micro-morphology,crystallinity,thermal properties and regeneration properties of DEEDA were studied by testing and analyzing the reaction process and product samples.The results show that the CO2 absorption load of DEEDA reaches 0.466 mol CO2/mol amine at 25 0C,and the reaction mechanism is confirmed to follow the zwitterionic mechanism.The product is carbamate ion and protonated amine(DEEDA-Car).Furthermore,DEEDACar was observed to be fibrous or rod-shaped.XRD analysis showed certain crystallinity but solid amorphous,the thermal decomposition temperature was 50.62 ?.The percentage of CO2 absorbed and released after four absorption-regeneration tests was 72%and 92%in the first cycle,respectively.The regeneration performance is good.The DEEDA-Car was introduced into the PNIPAm gel system to prepare a zwitterionic gel.It was proved to be a promoter of peroxide initiator by the polymerization rate and viscosity average molecular weight The mechanism of the initiation was described.The super-hydrophilic functional groups-NCOO-and-NH3+exist in DEEDA-Car,and the electrostatic attraction between the two causes a corresponding change in the pore structure and VPTT inside the hydrogeL As the mass ratio of DEEDA-Car/N)PAm increases,the swelling rate of zwitterionic hydrogel is higher than that of traditional hydrogeL The pore size of hydrogel shown in SEM shows decreases with the increase of DEEDA-Car/NIPAm mass ratio.Rheological VPTT measurements showed that with the addition of DEEDA-Car,the higher the VPTT,making it adjustable.