界面聚合-旋轉塗佈技術製備促進傳輸複合膜應用於二氧化碳捕獲程序

Facilitated transport composite membranes prepared by interfacial polymerization-spin coating technique for CO2 capture process

林勝平(Sheng-Ping Lin)

指導教授 ： 李魁然 ； 黃書賢

中原大學/工學院/化學工程研究所/碩士(2014年)

https://doi.org/10.6840/cycu201400717

摘要

摘要
本研究藉由界面聚合程序製備高效能二氧化碳促進傳輸薄膜。並使用界面活性劑改質基材膜之表面親水性，最後藉由塗佈Pebax以填補聚合層之缺陷並改善複合膜之親水性與二氧化碳親和性。
本實驗使用ethylenediamine (EDA)、triethylenetetramine (TETA)以及 pentaethylenehexamine (PEHA)作為水相單體，trimesoyl chloride (TMC)作為有機相單體，並使用非對稱結構polysulfone (PSf)作為基材，再由Ethylenediamine tetrakis (propoxylate-B-ethoxylate)改善基材膜之親水性，製備改質PSf基材膜(mPSf)，藉由界面聚合方式製備固定載體式的二氧化碳促進傳輸超薄複合薄膜。再以旋轉塗佈方式將Pebax1657®塗佈於界面聚合層之上以改善薄膜分離效能。並探討界面聚合條件(水相及有機相濃度、水相浸泡時間、有機相反應時間以及水相單體結構變化)以及進料氣體壓力變化對於分離效能影響，進而探討水氣引入薄膜結構內對於促進傳輸機制之影響以及混和氣體操作下分離效能之變化。
本研究使用衰減式全反射(ATR-FTIR)傅立葉紅外光譜儀、場發射掃描式電子顯微鏡(FESEM)、水接觸角量測儀、可變單一能量慢速正電子束分析儀 (VMSPB)以及氣體吸附測試來瞭解薄膜結構特性以及表面親疏水性。
經由氣體分離效能實驗結果顯示，界面聚合條件變化主要影響聚合層厚度以及胺官能基含量，而在浸泡0.1M 水相單體1分鐘並與0.001M 有機相單體反應1分鐘時有最佳的氣體分離效能。在最佳的界面聚合條件下所製備之Pebax/EDA-TMC/mPSf複合薄膜於進料壓力為1bar操作溫度為50℃的濕潤環境下，有最佳二氧化碳透過係數為52.98GPU，而二氧化碳/氮氣選擇性為157.7；相較之下，使用含有六胺的PEHA製備複合薄膜，Pebax/PEHA-TMC/mPSf，並於相同操作條件下則具有二氧化碳透過係數為134.2GPU，而二氧化碳/氮氣選擇性為113.5。當進料壓力下降至0.1bar，並於50℃的濕潤環境下進行氣體分離測試，Pebax/PEHA-TMC/mPSf複合薄膜之二氧化碳透過係數可提升為728.9GPU，而二氧化碳/氮氣選擇性則會上升為273.2，其原因在於高壓操作下造成載體飽和而降低了二氧化碳分離效能。在混和氣體操作環境下，會因為競爭吸附而使分離效能明顯下降。

關鍵字

界面聚合 ； 旋轉塗佈 ； 促進傳輸

並列摘要

Abstract
In this study, the CO2-selective PA TFC membranes with fixed-site carrier were prepared via the interfacial polymerization of water-soluble amine monomers including ethylenediamine (EDA), triethylenetetramine (TETA) and pentaethylenehexamine (PEHA) with acyl chloride monomer trimesoyl chloride (TMC) on the surface of asymmetric modified polysulfone (mPSf) membranes. The mPSf is prepared by immersed PSf support membrane into the ethylenediamine tetrakis (propoxylate-B-ethoxylate) surfactant solution to enhanced the hydrophilicity and filled the small pore on the surface to form a smooth surface. And then the Pebax1657® a block copolymer composed of flexible polyether and rigid polyamide, was coated on the PA TFC membranes via the spin-coating method to improve the separation performance. These TFC membranes were applied to CO2/N2 separation process. The effects of monomer structure, concentration of aqueous and organic solutions, feed pressure and water content on the gas transport properties including CO2 permeability, N2 permeability and CO2/N2 selectivity were investigated.
Attentuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, Field-Emission scanning electron microscope (FESEM) observation, Variable monoenergy slow positron beam (VMSPB), Microbalance and water contact angle measurement were used to characterize the chemical structure, morphology and hydrophilicity of the TFC membrane.
From the results, the better interfacial polymerization condition is 0.1M aqueous solution immersion and 0.001M organic solution contact. In this interfacial polymerization condition, the Pebax/EDA-TMC/mPSf membrane was prepared by EDA and TMC, its CO2 permeance and CO2/N2 selectivity is 52.98GPU and 157.7, respectively. Compared with EDA monomer, PEHA is more appropriate for the TFC membrane preparation. Because the facilitated transport mechanism is increase linear as the amine group content. Thus Pebax/PEHA-TMC/mPSf membrane CO2 permeance and CO2/N2 selectivity is 134.2GPU and 113.5, respectively. Under the low feed pressure (0.1bar) test, the facilitated transport mechanism efficiency can be increase, and then enhanced the CO2 permeance to 728.9 GPU and CO2/N2 selectivity to 273.2 for Pebax/PEHA-TMC/mPSf membrane. Because the competitive adsorption, the separation performance is decrease significantly for 15%CO2/85%N2 mixing gas test.

並列關鍵字

carbamate ion ； interfacial polymerization ； facilitated transport ； spin coating ； bicarbonate ion

參考文獻

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