| Summary: | 碩士 === 國立臺灣大學 === 化學工程學研究所 === 101 === According to this study, by using Polyvinyl alcohol(PVA) as selected layer to cast on Polysulfone(PSf) substrate in terms of preparing composite membrane, and to modify the membrane by using additive agents to develop high performance on gas separation. By using facilitated transport mechanism to improve carbon dioxide flux, and using carrier combining with carbon dioxide to improve facilitated transport in progress. It was mentioned in record that water plays an important role in carbon dioxide separation process. Regarding to the amino group, water molecular reacts with amino group and carbon dioxide to produce complex so that the amino group consumption is decreased and increase the amount of carbon dioxide to carrier and increase flux. Therefore, we are studying how the water in the environment will affect the separation process.
The results of experiment show that the membrane, under the condition of same composition, and environment without water, permeation and selectivity of carbon dioxide is less than the environment with water. So we can learn that water is an important factor on carbon dioxide separation process. When operating in the environment of water, carbon dioxide flux will increase from 21 GPU to 40 GPU when adding the molecular Polyethylene glycol which includes ether group. In addition, by adding the molecular which includes amino group will increase carbon dioxide performance obviously, especially in the condition of additive Branched Polyethylenimine(BPEI), It became more hydrophilic and the contact angle decreased from 39 degree to 25 degree. We can also learn that membrane’s water content is 104%, so the consumption of amino group is decreased and the carry of carbon dioxide is increased. Along with the increase of the concentration of amino group, the selectivity has obvious improvement that when the carbon dioxide flux is 31.7 GPU, the selectivity can get up to 546. The main reason is nitrogen has low solubility with water cause barrier to permeation, so nitrogen flux decrease serious follow the water content increase in the membrane, due to this reason, it can get high selectivity.
|
|---|
