【摘要】：海水淡化過(guò)程產(chǎn)生的濃鹽水中含有大量鈣鎂離子,直接排放不僅會(huì)對(duì)周邊環(huán)境造成污染,也是海洋資源的浪費(fèi)。由于鈣鎂離子物化性質(zhì)十分相似,目前的分離技術(shù)尚不能將二者有效分離。而被視為高效分離手段的乳化液膜技術(shù),由于選擇性高、傳質(zhì)速度快等優(yōu)點(diǎn),在金屬離子分離領(lǐng)域得到廣泛關(guān)注。本文提出以二(2-乙基己基)磷酸酯(D2EHPA)和二苯并-18-冠醚-6(DB18C6)作為流動(dòng)載體,利用二者對(duì)鈣鎂離子的選擇性,構(gòu)建一種雙載體乳化液體系,協(xié)同分離濃鹽水中的兩種離子,驗(yàn)證多因素下的雙載體乳化液對(duì)兩種離子的分離性能。通過(guò)對(duì)乳化液破乳率及對(duì)鈣鎂離子分離能力的初步考察,本論文選擇二氯甲烷為油相,草酸鈉溶液為內(nèi)水相。以乳化液的黏度變化和破乳率為衡量穩(wěn)定性的標(biāo)準(zhǔn),考察了油水比和表面活性劑含量、內(nèi)水相濃度和兩種載體對(duì)于乳化液穩(wěn)定性的影響。結(jié)果表明：隨著油水比降低,乳化液破乳率增加,同時(shí)間段內(nèi)黏度變化增大,油水比為1：1的乳化液30 min內(nèi)黏度降低23 mPa·s,破乳率僅有0.45%。表面活性劑含量越高,破乳率越小,乳化液穩(wěn)定性越好。乳化液穩(wěn)定性隨內(nèi)水相Na2C2O4濃度減小而升高,破乳率由2.5%(0.2M Na2C2O4)降為1.7%(0.18M Na2C2O4)。較二苯并-18-冠醚-6,二(2-乙基己基)磷酸酯為載體的乳化液破乳率稍升高0.8%,但對(duì)整個(gè)萃取過(guò)程無(wú)明顯影響。得到優(yōu)化的乳化液穩(wěn)定條件：油相為二氯甲烷、油水比為1:1、Span80含量為6%,內(nèi)水相Na2C2O4溶液為0.18mol/L、4%D2EHPA、0.015 mol/L DB18C6。分析D2EHPA和DB18C6分別為單載體以及共同作為雙載體時(shí),兩種乳化液體系對(duì)鈣鎂離子的萃取分離效果。D2EHPA為載體的乳化液對(duì)鈣離子的最高萃取率為92.12%,DB18C6為載體的乳化液萃取鈣離子效率為66.72%。雙載體乳液3 min后協(xié)同分離鈣離子的效率達(dá)到70%以上,30 min時(shí)達(dá)到99.38%,雙載體協(xié)萃因子達(dá)到11以上,而鎂離子僅有17.89%且協(xié)萃因子低于0.7,基本將鈣離子完全分離。該優(yōu)化結(jié)果下的操作條件：將外水相pH調(diào)至9.5,乳液組成為：90% CH2Cl2、6%Span80、4% D2EHPA、 0.017mol/L DB18C6、0.18 mol·L-1Na2C2O4、1：2油水比。
[Abstract]:The concentrated salt water produced by seawater desalination process contains a large amount of calcium and magnesium ions. Direct discharge will not only pollute the surrounding environment but also waste marine resources. Because the physicochemical properties of calcium and magnesium ions are very similar, the current separation technology can not separate them effectively. Because of its high selectivity and high mass transfer rate, the emulsion membrane technology, which is regarded as an efficient separation method, has attracted wide attention in the field of metal ion separation. In this paper, a two-carrier emulsion system was constructed using di (2-ethylhexyl) phosphate (D2EHPA) and dibenzo-18-crown-ether -6 (DB18C6) as mobile carriers. The separation performance of two kinds of ions was verified by double carrier emulsion under multiple factors. In this paper, dichloromethane was selected as oil phase and sodium oxalate solution as internal water phase through preliminary investigation of emulsion demulsification rate and separation ability of calcium and magnesium ions. The effects of oil / water ratio, surfactant content, internal water concentration and two kinds of carriers on the stability of emulsion were investigated according to the viscosity change and demulsification rate of emulsion. The results showed that the demulsification rate of the emulsion increased with the decrease of oil-water ratio, and the viscosity of the emulsion increased in the same time period. The viscosity of the emulsion with oil / water ratio of 1:1 in 30 min decreased by 23 MPA SPA, and the demulsification rate was only 0.45%. The higher the surfactant content, the smaller the demulsification rate and the better the stability of emulsion. The stability of the emulsion increased with the decrease of the concentration of Na _ 2C _ 2O _ 4, and the demulsification rate decreased from 2.5% (0.2M Na _ 2C _ 2O _ 4) to 1.7% (0.18m Na _ 2C _ 2O _ 4). Compared with dibenzo-18-crown ether -6, the emulsion demulsification rate of bis (2-ethylhexyl) phosphate was slightly higher than that of dibenzo-18-crown-ether -6, but the emulsion demulsification rate was slightly higher than that of dibenzo-18-crown ether -6, but had no obvious effect on the whole extraction process. The optimized conditions of emulsion stability are as follows: the oil phase is dichloromethane, the oil-water ratio is 1: 1, the Span80 content is 6 and the internal water phase Na2C2O4 solution is 0.18 mol / L EHPA-0.015 mol / L DB18C6. When D2EHPA and DB18C6 are single carrier and double carrier respectively, the extraction and separation effect of the two emulsions on calcium and magnesium ions. The highest extraction rate of calcium ion by emulsion of D2EHPA and DB18C6 is 92.12 and DB18C6 respectively. The extraction efficiency of calcium ion is 66.72 when the emulsion of D2EHPA and DB18C6 is the carrier. After 3 min, the synergistic separation efficiency of Ca ~ (2 +) and mg ~ (2 +) was 99.38 and 17.89%, respectively, and that of mg ~ (2 +) was only 17.89% and less than 0.7 after 30 min. The calcium ion was separated completely. The optimum operating conditions were as follows: the pH of the external water phase was adjusted to 9.5, the emulsion composition was: 1: 90% Ch _ 2Cl _ 2C _ 2 / 6Span804% D _ 2EHPA, 0.017 mol / L DB18C _ 6n 0.18 mol L ~ (-1) Na _ 2C _ 2O _ 4: 1: 2 oil-water ratio.
【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：TQ028.8;X703

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本文編號(hào)：2127087