Preparation Of Amino-modified SBA-15?p? Adsorbent And CO₂ Adsorption Properties

Greenhouse effect and environmental problems are caused by the massive emission of greenhouse gas CO₂.It is urgent to capture and reduce the emission of CO₂.Solid amine adsorbents have many excellence advantages,such as no corrosion to equipment,simple preparation,low regeneration energy consumption and well adsorption effect,so solid amine adsorbents have become the hot topic in the study of CO₂ capture.Using as-prepard SBA-15 powder?SBA-15?p??as the carrier in solid amine adsorbents can not only save time and energy of calcination,but also can make full use of the dispersion effect of the template agent P123,which is conducive to the adsorption property of adsorbents.In this paper,we used SBA-15?p?as the carrier to prepare a series of CO₂ adsorbent,and the adsorption process was optimized,then the CO₂ adsorption property and adsorption mechanism were researched.The main conclusions are as follows:1.Firstly,SBA-15?p?-xTEPA series CO₂ solid adsorbents were prepared by impregnation method.Characterization results showed that the TEPA-modified SBA-15?p?remained the ordered mesoporous channel structure.The synergistic effect of TEPA and P123 raised the initial decomposition temperature of adsorbents.Optimization experiment and orthogonal test showed that the adsorbent was suitable for a wide range of inlet flow and the saturated adsorption capacity of SBA-15?p?-60 TEPA in optimum adsorption conditions was 5.39 mmol/g,the adsorption capacity remained at 5.0 mmol/g after 9 times adsorption-desorption cycle.Adsorption kinetic study and deactivation simulation indicated that CO₂ adsorption on SBA-15?p?-60 TEPA is mainly chemical adsorption;The deactivation model can well simulate the dynamic adsorption breakthrough curves of CO₂ on SBA-15?p?-xTEPA and the correlation coefficient is more than 0.99.2.Secondly,SBA-15?p?-AP-x T solid adsorbent were prepared by grafting and impregnation method.P123 was extracted in the progress of grafting of APTES,the channel structure of SBA-15?p?was unchanged during the modify-cation process.The adsorbents are stable under 150 ?.The saturated adsorption capacity of SBA-15?p?-AP-70 T can reach to 5.687 mmol/g,and the breakthrough adsorption capacity is 81.4% of the saturated adsorption capacity,the adsorption capacity remained at 5.2 mmol/g after 15 times adsorption-desorption cycle.Simulation results showed that the adsorption kinetic and the CO₂ dynamic adsorption breakthrough curve conformed to Avrami model and deactivation model,respectively.3.Then,SBA-15?p?-xP-yT?P=PEI600,T=TEPA?series adsorbent were prepared by impregnation method.Physicochemical properties of SBA-15?p?were greately changed after modification,but its mesoporous channel structure is not affected.The thermal stability of this adsorbent was better than SBA-15?p?-xTEPA beacuse of the synergistic effect of PEI600,TEPA and P123.The saturated adsorption capacity and amine efficiency of SBA-15?p?-30P-40 T were 4.637 mmol/g and 0.359,respectively.CO₂ adsorption on SBA-15?p?-30P-40 T is the combination of physical adsorption and chemical adsorption,and the latter is the main.Deactivation model can well simulate the dynamic adsorption breakthrough curve of SBA-15?p?-30P-40 T.We concluded the formulas K0=1739.5-16.05 T and Kd=3.2273-0.0295 T by analyzing the deactivation simulation results of SBA-15?p?-30P-40 T in different temprature.4.Finally,CO₂ adsorption mechanism on the amino-modified SBA-15?p?solid adsorbent was studied by using in-situ infrared spectroscopy.Results showed that during the adsorption process,absorption peaks of NH2 and NH on adsorbent reduced gradually,absorption peaks of NCOOH,NHCOOH,NH3+,NH2+,NCOO-and NHCOO-appeared and enhanced.It is because of the primary and secondary amine of adsorbent generate zwitterionic intermediate RNCOOH and RNHCOOH with CO₂ at first,then the zwitterionic intermediate turn to proton products and carbamate under anhydrous condition...