Study Of MIL-101 Prepared In Different Metal Bases And Its Carbon Dioxide Adsorption

Excessive high CO₂ content in air of open environment will cause global warming.Excessive concentration of CO₂ in air of closed environment will endanger human health.Studying the separation and capture technology of low concentration CO₂ in air of open environment and closed environment has certain health value and environmental significance.Metal-organic framework materials（MOFs）are a new type of nanoporous materials.Due to their structural and chemical properties,so they have good adsorption to gases and will become a new generation of new materials for CO₂ adsorption.Application of MIL-101material is very extensive in MOFs,which is mostly used for the adsorption and separation of high-concentration CO₂.However,it is very real about the study of the adsorption and separation of low-concentration CO₂.Therefore,we need studying the adsorption and separation of low-concentration CO₂ by MOFs,especially in air of open environment and closed environment.It has very important theoretical research significance and practical application value.In this paper,we mainly study the adsorption performance of MIL-101 adsorbent on low concentration of CO₂.We select the metal organic framework material with the best adsorption performance for CO₂ by changing different metal bases,to prepare MIL-101adsorbent with hydrothermal synthesis method.The metal groups selected in this paper are Cr-based,Fe-based and Al-based,respectively.We can find that the three different metal-based framework materials can adsorb CO₂ by comparing their structural characteristics,however the adsorption property characteristics are shown as follows:Cr-based>Al-based>Fe-based.As a result,select Cr-based metal organic framework material as the adsorbent for CO₂ is the best option and carry out follow-up research on it.We choose the metal organic framework material MIL-101（Cr）as the research object.The CO₂ adsorption experiment was carried out on a fixed bed to investigate the effects of inlet CO₂ concentration,gas flow,adsorption temperature,water vapor content and adsorption pressure on CO₂ adsorption capacity.Based on this experiment,we can obtain the optimal working condition parameters for the adsorption and separation of CO₂ in low concentration,to provide experimental data and technical reference for the CO₂ emission reduction work of air and closed environment.Based on the results,as the CO₂ concentration at the inlet increases from 400 ppm to 460 ppm,and the adsorption capacity of CO₂ decreases from 0.35mg/g to 0.28 mg/g;As the gas flux increases from 50 mL/min to 200 mL/min,and the adsorption capacity of CO₂ increases from 0.29 mg/g to 0.43 mg/g;As the adsorption temperature increases from 25℃to 60℃,and the adsorption capacity of CO₂ decreases from 0.31 mg/g to 0.19 mg/g;As the adsorption pressure increases from 0.1 MPa to 0.7 MPa,and the adsorption amount of CO₂ by the adsorbent also increases from 0.37 mg/g to 3.21mg/g.The proper amount of water vapor tends to favor the adsorption reaction,as the adsorption amount of the adsorbent to CO₂ increases firstly and then decreases when increasing the water vapor content.When the water vapor content is 8%,the adsorption capacity of the adsorbent to CO₂ is the largest and can up to 0.38 mg/g.In one word,the influence of each factor on CO₂ adsorption performance shows differently:adsorption pressure>adsorption temperature>inlet CO₂ concentration>gas flow>water vapor content.It turns out the adsorption pressure of 0.7 MPa,the adsorption temperature of 25℃,the inlet CO₂ concentration of 400 ppm,the gas flow of 200 mL/min,and the water vapor content of 8%are the optimal adsorption conditions for the adsorption of CO₂ by the metal organic framework material MIL-101（Cr）within the selected factors of the experiment.