基于靜電紡絲技術(shù)的活性碳納米纖維及其電容器脫鹽研究
發(fā)布時(shí)間：2018-10-10 19:18
【摘要】：淡水是一種寶貴的資源,是人類賴以生存和發(fā)展的最基本物質(zhì)之一。淡水資源緊缺將成為制約我國(guó)經(jīng)濟(jì)和社會(huì)可持續(xù)發(fā)展的重要因素。淡水資源的補(bǔ)給可通過(guò)海水、苦咸水淡化及污水的再生回用等途徑,因此,開(kāi)發(fā)高效脫鹽技術(shù)滿足缺水地區(qū)的淡水供給具有重要意義。傳統(tǒng)的脫鹽方法,如電滲析、反滲透存在能耗高、成本高、再生復(fù)雜等問(wèn)題,導(dǎo)致其推廣應(yīng)用受限。電容去離子技術(shù)是近年來(lái)發(fā)展起來(lái)的新型脫鹽技術(shù),該技術(shù)以純雙電層電容原理吸附離子,脫鹽過(guò)程再生可逆性好,操作壓力小,能耗低,水回收率高,而且整個(gè)過(guò)程無(wú)氧化還原反應(yīng)發(fā)生,無(wú)二次污染等,相比現(xiàn)有的反滲透(RO)和電滲析,具有良好的應(yīng)用前景。 本文以商業(yè)活性炭纖維氈(ACF)和基于靜電紡絲技術(shù)制備的活性碳納米纖維(A-ECNF)作為自支撐電極材料組裝電容器并進(jìn)行脫鹽研究。分別考察了目標(biāo)電壓、充電電流密度及溶液流速等對(duì)電容器脫鹽性能的影響,并采用循環(huán)伏安、電化學(xué)阻抗、掃描電子顯微鏡等多種技術(shù)表征了A-ECNF電極的特性。主要結(jié)果如下： 1、以商業(yè)ACF電極作為自支撐電極組裝電容器,研究了目標(biāo)電壓及充電電流密度對(duì)電容器脫鹽量、脫鹽速率、電流效率及電極表面pH值的影響。結(jié)果表明：在一定范圍內(nèi)隨著目標(biāo)電壓的升高,脫鹽量逐漸增加,電流效率呈先增大后減小的趨勢(shì)。目標(biāo)電壓過(guò)高,電極表面極化嚴(yán)重,導(dǎo)致電極表面微區(qū)pH值顯著變化。研究發(fā)現(xiàn),當(dāng)目標(biāo)電壓為1.2V,充電電流為38mA/g時(shí),該商業(yè)ACF電極的脫鹽量為4.92mg/g,電流效率為32.3%。電化學(xué)表征驗(yàn)證,由于離子在電極表面擴(kuò)散受阻,從而導(dǎo)致低的脫鹽容量。 2、以聚丙烯腈(PAN)和N,N-二甲基甲酰胺(DMF)混合液為紡絲前驅(qū)液,采用靜電紡絲技術(shù)制備碳納米纖維(ECNF),考察了PAN濃度、紡絲電壓及接收距離對(duì)ECNF形貌的影響。結(jié)果表明：PAN濃度為9%,紡絲電壓為15kV,接收距離為20cm時(shí),獲得的ECNF直徑在220nm左右。并采用ZnCl2試劑作為活化劑處理ECNF得到活性碳納米纖維(A-ECNF),以改善ECNF的性能,增大其比表面積。研究發(fā)現(xiàn)ECNF經(jīng)ZnCl2活化處理后,纖維的表面形貌無(wú)明顯變化,仍保持原有良好的柔韌性,可作為自支撐電極直接用于電容器組裝：接觸角測(cè)試表明,與活化前相比,活化后ECNF具有更好的水潤(rùn)濕性。并考察了活化劑量(ZnCl2/ECNF比例)對(duì)A-ECNF的影響,BET測(cè)試表明,隨著ZnCl2/ECNF比例的提高,纖維的比表面積逐漸增大,當(dāng)比例為2：1時(shí),活化得到的A-ECNF比表面積高達(dá)430m2/g,而未活化的ECNF比表面積為12.4m2/g;循環(huán)伏安及電化學(xué)阻抗測(cè)試表明,隨著ZnCl2/ECNF比例的提高,獲得的A-ECNF電極的電容電流逐漸增大,電阻逐漸減小,離子在電極表面的遷移速率明顯提高。 3、將ZnCl2活化后的A-ECNF作為自支撐電極組裝成電容器,進(jìn)行恒流充放電脫鹽研究,對(duì)比不同ZnCl2/ECNF比例時(shí)所得A-ECNF電極的脫鹽性能,發(fā)現(xiàn)ZnCl2活化可以明顯改善電極的脫鹽性能,且脫鹽速率隨著其比例的提高而增大。當(dāng)ZnCl2/ECNF比例為2：1時(shí),A-ECNF的脫鹽速率最快,脫鹽量最高。以ZnCl2/ECNF比例為2：1時(shí)制得的A-ECNF作為電極材料,研究了電極材料的充放電穩(wěn)定性及充電電流密度、溶液流速和目標(biāo)電壓對(duì)A-ECNF電極的脫鹽速率、脫鹽量和電流效率的影響。結(jié)果表明,在合適的參數(shù)下(充電電流密度為36mA/g,溶液流速為10ml/min;目標(biāo)電壓為1.2V), A-ECNF電極的脫鹽量高達(dá)10.2mg/g,電流效率高達(dá)57.1%,明顯優(yōu)于ECNF電極。此外,對(duì)比現(xiàn)有的不同電極材料的脫鹽性能,發(fā)現(xiàn)A-ECNF的脫鹽性能和目前較好的碳材料如碳化物衍生炭材料的脫鹽量相當(dāng)。循環(huán)穩(wěn)定性測(cè)試進(jìn)一步表明該ZnCl2活化的A-ECNF有望用于電化學(xué)脫鹽。
[Abstract]:Freshwater is a valuable resource, which is one of the most basic materials for human survival and development. The shortage of fresh water resources will be an important factor restricting the sustainable development of our country's economy and society. The replenishment of fresh water resources can be used in seawater, brackish water desalination and regeneration of sewage. Therefore, it is of great significance to develop efficient desalination technology to meet the freshwater supply in water shortage area. The traditional desalination method, such as electrodialysis and reverse osmosis, has the problems of high energy consumption, high cost, complex regeneration and the like, and the popularization and application of the desalination method are limited. The technology of capacitance deionization is a new kind of desalination technology developed in recent years. This technology can adsorb ions with pure double-layer capacitance principle, has good regeneration reversibility of desalting process, small operation pressure, low energy consumption, high water recovery rate, no redox reaction in the whole process, no secondary pollution and so on. Compared with the existing reverse osmosis (RO) and electrodialysis, the invention has good application prospect. Activated carbon nanofibers (A-ECF) prepared by commercial activated carbon fiber felt (ACF) and electrostatic spinning technology were used as self-supporting electrode materials to assemble capacitors and to conduct desalination. The effects of target voltage, charge current density and solution flow rate on the desalination performance of capacitor were investigated. A-ECF electrode was characterized by cyclic voltammetry, electrochemical impedance and scanning electron microscope. Properties. Main results 1. Using commercial ACF electrode as self-supporting electrode assembly capacitor, the desalting capacity, desalting rate, current efficiency and electrode surface p of capacitor were studied. The results show that, with the increase of the target voltage in a certain range, the desalting capacity increases gradually, and the current efficiency increases first. Reduced trend. The target voltage is too high, the electrode surface polarization is serious, resulting in the pH of the micro-zone on the surface of the electrode. The results show that when the target voltage is 1. 2V and the charging current is 38mA/ g, the desalting capacity of the commercial ACF electrode is 4.92mg/ g, and the current efficiency is 3.2. 3%. Electrochemical characterization verification, resulting in low diffusion of ions on the surface of the electrode The desalting capacity of PAN and N, N-MAA (DMF) was used as spinning precursor, and carbon nanofibers (ECF) were prepared by electrostatic spinning technology. The PAN concentration, spinning voltage and receiving distance were investigated. The results show that the diameter of CNF is 9%, the spinning voltage is 15kV, and the receiving distance is 20cm. An active carbon nanofiber (A-ECNF) was obtained by using ZnCl2 reagent as an activating agent to improve the performance of ECF. It was found that after the activation treatment of ZnCl2, the surface morphology of the fiber remained unchanged, the original good flexibility was still maintained, and the self-supporting electrode could be used as the self-supporting electrode directly for capacitor assembly: the contact angle test showed that after activation, the ECF was activated. The effect of activator amount (ZnCl2/ ECF ratio) on A-ECF was investigated. BET test shows that with the increase of ZnCl2/ ECF ratio, the specific surface area of the fiber gradually increases. When the ratio is 2: 1, the surface area of A-ECF obtained by activation is higher than 0.89m2/ g, and the non-activated ECF ratio surface area is 12. 4m2/ g, cyclic voltammetry and electrochemical impedance tests show that with the increase of ZnCl2/ ECF ratio, the capacitance current of A-ECF electrode increases gradually, the resistance decreases gradually, and the ions are on the surface of the electrode. and 3, assembling the A-ECF activated by ZnCl2 as a self-supporting electrode into a capacitor, carrying out constant-current charge-discharge desalination research, comparing the desalination performance of the A-ECF electrode obtained when the ratio of different ZnCl2/ ECNF is compared, and finding that the ZnCl2 activation can obviously improve the desalination performance of the electrode, When the ratio of ZnCl2/ ECF is 2: 1, the removal of A-ECNF A A-ECF prepared by the ratio of ZnCl2/ ECF to 2: 1 is used as the electrode material, and the charge and discharge stability of the electrode material and the desalting rate of the charging current density, the solution flow rate and the target voltage on the A-ECF electrode are studied. The results show that under proper parameters (charge current density is 36mA/ g, solution flow rate is 10ml/ min; target voltage is 1. 2V), the desalting capacity of A-ECNF electrode is up to 10.2mg/ g, and the current efficiency is 57. 1%. Compared with the existing desalination performance of different electrode materials, the desalting performance of A-ECF and the better carbon material such as carbide are found. The desalination amount of the derived carbon material is comparable. The cycle stability test further indicates that the ZnCl2 activated A-EC
【學(xué)位授予單位】：東華大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TQ342.742;TU991.26
本文編號(hào)：2262948
[Abstract]:Freshwater is a valuable resource, which is one of the most basic materials for human survival and development. The shortage of fresh water resources will be an important factor restricting the sustainable development of our country's economy and society. The replenishment of fresh water resources can be used in seawater, brackish water desalination and regeneration of sewage. Therefore, it is of great significance to develop efficient desalination technology to meet the freshwater supply in water shortage area. The traditional desalination method, such as electrodialysis and reverse osmosis, has the problems of high energy consumption, high cost, complex regeneration and the like, and the popularization and application of the desalination method are limited. The technology of capacitance deionization is a new kind of desalination technology developed in recent years. This technology can adsorb ions with pure double-layer capacitance principle, has good regeneration reversibility of desalting process, small operation pressure, low energy consumption, high water recovery rate, no redox reaction in the whole process, no secondary pollution and so on. Compared with the existing reverse osmosis (RO) and electrodialysis, the invention has good application prospect. Activated carbon nanofibers (A-ECF) prepared by commercial activated carbon fiber felt (ACF) and electrostatic spinning technology were used as self-supporting electrode materials to assemble capacitors and to conduct desalination. The effects of target voltage, charge current density and solution flow rate on the desalination performance of capacitor were investigated. A-ECF electrode was characterized by cyclic voltammetry, electrochemical impedance and scanning electron microscope. Properties. Main results 1. Using commercial ACF electrode as self-supporting electrode assembly capacitor, the desalting capacity, desalting rate, current efficiency and electrode surface p of capacitor were studied. The results show that, with the increase of the target voltage in a certain range, the desalting capacity increases gradually, and the current efficiency increases first. Reduced trend. The target voltage is too high, the electrode surface polarization is serious, resulting in the pH of the micro-zone on the surface of the electrode. The results show that when the target voltage is 1. 2V and the charging current is 38mA/ g, the desalting capacity of the commercial ACF electrode is 4.92mg/ g, and the current efficiency is 3.2. 3%. Electrochemical characterization verification, resulting in low diffusion of ions on the surface of the electrode The desalting capacity of PAN and N, N-MAA (DMF) was used as spinning precursor, and carbon nanofibers (ECF) were prepared by electrostatic spinning technology. The PAN concentration, spinning voltage and receiving distance were investigated. The results show that the diameter of CNF is 9%, the spinning voltage is 15kV, and the receiving distance is 20cm. An active carbon nanofiber (A-ECNF) was obtained by using ZnCl2 reagent as an activating agent to improve the performance of ECF. It was found that after the activation treatment of ZnCl2, the surface morphology of the fiber remained unchanged, the original good flexibility was still maintained, and the self-supporting electrode could be used as the self-supporting electrode directly for capacitor assembly: the contact angle test showed that after activation, the ECF was activated. The effect of activator amount (ZnCl2/ ECF ratio) on A-ECF was investigated. BET test shows that with the increase of ZnCl2/ ECF ratio, the specific surface area of the fiber gradually increases. When the ratio is 2: 1, the surface area of A-ECF obtained by activation is higher than 0.89m2/ g, and the non-activated ECF ratio surface area is 12. 4m2/ g, cyclic voltammetry and electrochemical impedance tests show that with the increase of ZnCl2/ ECF ratio, the capacitance current of A-ECF electrode increases gradually, the resistance decreases gradually, and the ions are on the surface of the electrode. and 3, assembling the A-ECF activated by ZnCl2 as a self-supporting electrode into a capacitor, carrying out constant-current charge-discharge desalination research, comparing the desalination performance of the A-ECF electrode obtained when the ratio of different ZnCl2/ ECNF is compared, and finding that the ZnCl2 activation can obviously improve the desalination performance of the electrode, When the ratio of ZnCl2/ ECF is 2: 1, the removal of A-ECNF A A-ECF prepared by the ratio of ZnCl2/ ECF to 2: 1 is used as the electrode material, and the charge and discharge stability of the electrode material and the desalting rate of the charging current density, the solution flow rate and the target voltage on the A-ECF electrode are studied. The results show that under proper parameters (charge current density is 36mA/ g, solution flow rate is 10ml/ min; target voltage is 1. 2V), the desalting capacity of A-ECNF electrode is up to 10.2mg/ g, and the current efficiency is 57. 1%. Compared with the existing desalination performance of different electrode materials, the desalting performance of A-ECF and the better carbon material such as carbide are found. The desalination amount of the derived carbon material is comparable. The cycle stability test further indicates that the ZnCl2 activated A-EC
【學(xué)位授予單位】：東華大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TQ342.742;TU991.26
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