石墨烯電容去離子性能的原子及電子層次理論模擬
發(fā)布時(shí)間：2018-09-06 10:19
【摘要】：隨著社會(huì)重工業(yè)技術(shù)高速發(fā)展和人們需求的不斷提升,工業(yè)污水和生活污水對(duì)有限的可用的淡水資源造成嚴(yán)重污染,從大量的海水中獲取經(jīng)濟(jì)實(shí)惠的淡水資源成為了眾多學(xué)者關(guān)注的焦點(diǎn)。目前海水淡化技術(shù)中蒸餾、電滲析,反滲透和離子交換等方法存在各自的缺點(diǎn)。電容去離子技術(shù)實(shí)現(xiàn)低能耗無(wú)污染成為可能。石墨烯具有較高的比表面積和良好的電導(dǎo)率等優(yōu)點(diǎn),吸引眾多學(xué)者利用其進(jìn)行電容去離子技術(shù)研究,但是目前對(duì)其除鹽的理論研究較少。本文利用模擬計(jì)算的方法對(duì)其電容性能和脫鹽性能進(jìn)行研究。運(yùn)用分子動(dòng)力學(xué)模擬方法(LAMMPS)和密度泛函理論(CASTEP)計(jì)算了本征石墨烯的界面電容,通過(guò)對(duì)本征石墨烯電極施加電荷來(lái)模擬充電過(guò)程來(lái)研究與1-丁基-3-甲基咪唑六氟磷酸鹽([BMIM][PF6])離子液體形成的界面電容。結(jié)果表明,在?a=±0.6 V時(shí)本征石墨烯具有較大的界面電容,約為70 F/g,與實(shí)驗(yàn)值基本吻合。運(yùn)用分子動(dòng)力學(xué)模擬考察了不同操作條件對(duì)本征石墨烯電容去離子性能的影響。根據(jù)出水口處氯化鈉離子和水分子的數(shù)量比作為除鹽率指標(biāo),并通過(guò)對(duì)電極表面流體流速和離子吸附量等手段探討了操作條件變化對(duì)除鹽率的影響。結(jié)果表明,增加電極表面電荷密度、減小電極板間距和降低流體流速均提高電容去離子性能。運(yùn)用分子動(dòng)力學(xué)模擬和密度泛函理論計(jì)算了含缺陷石墨烯電極和氮摻雜石墨烯電極的界面電容,計(jì)算結(jié)果與本征石墨烯比較發(fā)現(xiàn),隨著含缺陷量增加界面電容逐漸降低,氮摻雜量增加界面電容逐漸升高,并且當(dāng)?shù)獡诫s率為4.1%時(shí),具有較大的界面電容,約為122 F/g,與實(shí)驗(yàn)值基本符合。以含缺陷石墨烯和氮摻雜石墨烯作為電極,運(yùn)用分子動(dòng)力學(xué)模擬對(duì)兩種電極除鹽性能進(jìn)行研究。結(jié)果表明,隨著含缺陷量的增多,除鹽率逐漸降低;氮摻雜量的增多,除鹽率逐漸升高。
[Abstract]:With the rapid development of social heavy industry technology and the increasing demand of people, industrial sewage and domestic sewage cause serious pollution to the limited available freshwater resources, It has become the focus of many scholars to obtain economical fresh water resources from a large amount of seawater. At present, the methods of distillation, electrodialysis, reverse osmosis and ion exchange have their own shortcomings in seawater desalination. It is possible to realize low energy consumption and no pollution by capacitive deionization technology. Graphene has many advantages, such as high specific surface area and good conductivity. In this paper, the capacitance and desalination performance are studied by means of simulation calculation. The interfacial capacitance of intrinsic graphene was calculated by molecular dynamics simulation method (LAMMPS) and density functional theory (CASTEP). The interface capacitance formed with 1 Ding Ji 3 methyl imidazolium hexafluorophosphate ([BMIM] [PF6]) ionic liquid was studied by charging the intrinsic graphene electrode to simulate the charging process. The results show that the intrinsic graphene has a large interfacial capacitance of about 70 F / g at a value of 鹵0.6 V, which is in good agreement with the experimental value. The effects of different operating conditions on the deionization properties of intrinsic graphene capacitors were investigated by molecular dynamics simulation. According to the quantity ratio of sodium chloride ion and water molecule at outlet as desalination rate, the influence of operation conditions on desalination rate was discussed by means of flow velocity and ion adsorption amount on electrode surface. The results show that increasing the surface charge density of the electrode, decreasing the electrode plate spacing and decreasing the flow rate can improve the performance of capacitance deionization. The interfacial capacitance of graphene electrode containing defects and that of nitrogen-doped graphene electrode is calculated by using molecular dynamics simulation and density functional theory. Compared with the intrinsic graphene electrode, it is found that the interface capacitance decreases with the increase of defect content. When the nitrogen doping ratio is 4.1, the interfacial capacitance is about 122F / g, which is in good agreement with the experimental value. The desalination properties of the two electrodes were studied by molecular dynamics simulation using graphene containing defects and nitrogen-doped graphene as electrodes. The results show that the desalination rate decreases with the increase of the defect content, and the desalination rate increases with the increase of nitrogen doping content.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：P747
本文編號(hào)：2226050
[Abstract]:With the rapid development of social heavy industry technology and the increasing demand of people, industrial sewage and domestic sewage cause serious pollution to the limited available freshwater resources, It has become the focus of many scholars to obtain economical fresh water resources from a large amount of seawater. At present, the methods of distillation, electrodialysis, reverse osmosis and ion exchange have their own shortcomings in seawater desalination. It is possible to realize low energy consumption and no pollution by capacitive deionization technology. Graphene has many advantages, such as high specific surface area and good conductivity. In this paper, the capacitance and desalination performance are studied by means of simulation calculation. The interfacial capacitance of intrinsic graphene was calculated by molecular dynamics simulation method (LAMMPS) and density functional theory (CASTEP). The interface capacitance formed with 1 Ding Ji 3 methyl imidazolium hexafluorophosphate ([BMIM] [PF6]) ionic liquid was studied by charging the intrinsic graphene electrode to simulate the charging process. The results show that the intrinsic graphene has a large interfacial capacitance of about 70 F / g at a value of 鹵0.6 V, which is in good agreement with the experimental value. The effects of different operating conditions on the deionization properties of intrinsic graphene capacitors were investigated by molecular dynamics simulation. According to the quantity ratio of sodium chloride ion and water molecule at outlet as desalination rate, the influence of operation conditions on desalination rate was discussed by means of flow velocity and ion adsorption amount on electrode surface. The results show that increasing the surface charge density of the electrode, decreasing the electrode plate spacing and decreasing the flow rate can improve the performance of capacitance deionization. The interfacial capacitance of graphene electrode containing defects and that of nitrogen-doped graphene electrode is calculated by using molecular dynamics simulation and density functional theory. Compared with the intrinsic graphene electrode, it is found that the interface capacitance decreases with the increase of defect content. When the nitrogen doping ratio is 4.1, the interfacial capacitance is about 122F / g, which is in good agreement with the experimental value. The desalination properties of the two electrodes were studied by molecular dynamics simulation using graphene containing defects and nitrogen-doped graphene as electrodes. The results show that the desalination rate decreases with the increase of the defect content, and the desalination rate increases with the increase of nitrogen doping content.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：P747
【參考文獻(xiàn)】
相關(guān)期刊論文 前4條
1 趙洪武;;淺析我國(guó)水資源現(xiàn)狀與問(wèn)題[J];才智;2012年16期
2 唐登勇,鄭正,蘇東輝,郭照冰;活性炭纖維在水處理中的應(yīng)用研究新進(jìn)展[J];工業(yè)用水與廢水;2003年04期
3 吳鋒;徐斌;;碳納米管在超級(jí)電容器中的應(yīng)用研究進(jìn)展[J];新型炭材料;2006年02期
4 舟成;;我國(guó)水資源現(xiàn)狀與問(wèn)題研究[J];資源節(jié)約與環(huán)保;2013年10期
，本文編號(hào)：2226050
本文鏈接：http://sikaile.net/kejilunwen/haiyang/2226050.html
最近更新
教材專著
