本文選題：表面活性劑 + 親水性抑制��； 參考：《太原理工大學(xué)》2017年博士論文

【摘要】：褐煤是重要化石能源之一,隨著經(jīng)濟發(fā)展對能源需求的日益增長,褐煤在我國煤炭消耗中的比例逐年提高。褐煤的低煤化程度賦予它氧含量高、吸水能力強的特點,在開發(fā)利用過程中造成大量的能源浪費,如運輸成本高、燃燒熱值低等。然而傳統(tǒng)低階煤干燥提質(zhì)技術(shù)對于解決干燥后煤樣水分復(fù)吸的問題還不夠完善,不能滿足現(xiàn)階段對低階煤高效開發(fā)利用的要求。表面活性劑作為調(diào)節(jié)界面性質(zhì)的化工產(chǎn)品之一,其雙親分子結(jié)構(gòu)決定了它能夠在褐煤表面形成定向的緊密吸附層,疏水基團遠離吸附方向,降低褐煤表面親水性,抑制干燥后煤樣水分復(fù)吸。本文以芒來褐煤為實驗煤樣,研究了褐煤潤濕性及水分復(fù)吸性,考察了表面活性劑親水基團類型和疏水基團結(jié)構(gòu)(碳鏈長度、芳香結(jié)構(gòu)、環(huán)結(jié)構(gòu)、雙子結(jié)構(gòu)等)以及非離子表面活性劑HLB值對褐煤表面親水性抑制效率的影響,利用微量熱、微電泳、表面張力、紅外光譜、紫外可見光分光光度計、X射線光電子能譜儀(XPS)和液氮吸附等儀器表征方法和量子模擬計算方法分析了陽離子表面活性劑十六烷基三甲基溴化銨(CTAB)、陰離子表面活性劑十二烷基硫酸鈉(SDS)和非離子表面活性劑十二烷基聚氧乙烯醚(C12(EO)15)在褐煤表面的吸附特征和吸附機理,此外還考察了褐煤中有機質(zhì)、礦物質(zhì)和煤化程度對褐煤潤濕性以及褐煤親水性抑制效率的影響。得到主要結(jié)論如下:褐煤中有機質(zhì)的潤濕熱遠高于礦物質(zhì)的潤濕熱,是褐煤潤濕放熱的主體。礦物質(zhì)中高嶺石的潤濕熱高于方解石和石英。芒來褐煤水分復(fù)吸符合二級動力學(xué)模型,褐煤中復(fù)吸水分含量與潤濕熱負相關(guān),水分含量越高,潤濕熱越小。芒來褐煤水分復(fù)吸過程中在表面形成的單層或團簇吸附水降低潤濕熱較為顯著,在孔隙吸水或毛細凝聚吸水對潤濕熱影響較小。含氧官能團含量是影響褐煤潤濕熱的重要因素,隨著煤化程度增加,煤中含氧量減少,潤濕熱降低。極性潤濕劑和非極性潤濕劑對褐煤潤濕放熱差異顯著,水和無水乙醇對褐煤的潤濕熱遠大于正構(gòu)烷烴對褐煤的潤濕熱。褐煤吸附表面活性劑能夠降低褐煤潤濕熱,抑制干燥褐煤水分復(fù)吸,二者具有一致性,其本質(zhì)是表面活性劑吸附降低了褐煤表面的親水性。表面活性劑對褐煤表面親水性的抑制依賴于表面活性劑能在褐煤表面形成有效的定向緊密排列吸附層。這與表面活性劑分子結(jié)構(gòu)密切相關(guān)。具體表現(xiàn)在:親水基團中陽離子和非離子表面活性劑對褐煤親水性抑制效果優(yōu)于陰離子;疏水基團中,隨著疏水基團鏈長的增加,褐煤表面親水性抑制效率增加;疏水基團中含有支鏈和苯環(huán)結(jié)構(gòu)的表面活性劑不利于褐煤表面親水性抑制效率的增加;雙子結(jié)構(gòu)的gemini型表面活性劑對褐煤表面親水性的抑制效率高于單鏈結(jié)構(gòu)和雙疏水基結(jié)構(gòu)的表面活性劑;吐溫系列表面活性劑對褐煤表面親水性抑制效果不明顯;烷基糖苷類含多羥基的表面活性劑增強了褐煤表面的親水性;隨著非離子表面活性劑c12(eo)n的hlb值減小,褐煤表面親水性抑制效果有增加趨勢,最小值出現(xiàn)在hlb值為13.6附近。表面活性劑對褐煤親水性抑制的關(guān)鍵是抑制褐煤中有機質(zhì)的親水性。褐煤中礦物質(zhì)親水性抑制效率與礦物類型和表面活性劑種類相關(guān),陽離子表面活性劑對高嶺石更有效,而陰離子表面活性劑對方解石效果更好,石英表面親水性隨表面活性劑吸附波動較大。陽離子表面活性劑ctab在褐煤表面的吸附為放熱過程,可以用freundlich模型描述,其吸附速率較符合二級動力學(xué)模型;溫度升高、堿性條件和低離子強度對ctab在褐煤表面吸附有促進作用。ctab在褐煤表面吸附與褐煤表面含氧量密切相關(guān),煤中氧含量增加,ctab在煤表面吸附量增加。酸洗脫灰處理后,芒來褐煤中含氧官能團含量減少,ctab吸附量和親水性抑制效率降低。在低濃度條件下,褐煤中含氧官能團優(yōu)于礦物質(zhì)對ctab進行吸附,礦物質(zhì)中高嶺石對ctab的吸附能力高于石英和方解石。含氧官能團中,ctab在羧基組分表面吸附量大于其它含氧官能團組分表面吸附量。量子模擬計算結(jié)果表明不同含氧官能團對ctab吸附能力遵循強弱順序為:酚羥基羧基醇羥基羰基醚基。ctab在褐煤表面的吸附不僅發(fā)生在褐煤表面,還能夠在褐煤大孔結(jié)構(gòu)內(nèi)表面發(fā)生吸附,二者共同影響了ctab對褐煤親水性抑制效率。溫度升高、酸性條件和低離子強度對陰離子表面活性劑sds在褐煤表面吸附有促進作用。褐煤中礦物質(zhì)對sds吸附的影響強度高于褐煤中有機質(zhì),其中方解石對sds的吸附能力遠高于石英和高嶺土。不同煤化程度煤樣中的礦物質(zhì)含量對sds吸附的影響很大。由于靜電斥力存在,sds在褐煤含氧官能團表面吸附量少,其中羧基組分表現(xiàn)出優(yōu)于其它含氧官能團組分的吸附能力。芒來褐煤吸附sds后比表面積、平均孔徑、孔容均變小,表明了sds能夠在褐煤大孔結(jié)構(gòu)中發(fā)生吸附。非離子表面活性劑十二烷基聚氧乙烯醚(C_(12)(EO)_(15))在褐煤表面的吸附符合langmuir吸附模型,二級動力學(xué)方程可以描述C_(12)(EO)_(15)在褐煤表面的吸附動力學(xué)行為;溫度升高、堿性條件和高離子強度對C12(EO)15在褐煤表面吸附有促進作用。褐煤脫灰后,C12(EO)15的吸附量降低,但降低幅度不大。隨著煤化程度的增加,煤中氧含量降低,C12(EO)15在煤表面的吸附量呈減少趨勢。C12(EO)15在褐煤表面吸附覆蓋了表面含氧官能團,其中含羧基組分對C12(EO)15的吸附能力高于其它含氧官能團。C12(EO)15在褐煤表面的吸附覆蓋了褐煤中的微孔結(jié)構(gòu),還能在褐煤的大孔結(jié)構(gòu)內(nèi)表面發(fā)生吸附。本研究對應(yīng)用表面活性劑降低褐煤表面親水性,抑制干燥提質(zhì)煤樣水分復(fù)吸具有一定借鑒作用,為進一步研究表面活性劑在褐煤表面吸附機理和親水性抑制調(diào)控機制提供一些基礎(chǔ)數(shù)據(jù)。
[Abstract]:Lignite is one of the important fossil energy. With the increasing demand for energy in economic development, the proportion of lignite in coal consumption in China is increasing year by year. The low coalification degree of lignite is endowed with high oxygen content and strong water absorption ability, which causes a lot of energy waste in the process of exploitation and utilization, such as high transportation cost and low burning calorific value. The traditional low order coal drying technology is not perfect to solve the problem of moisture absorption of the coal samples after drying. It can not meet the requirements for the high efficiency development and utilization of low order coal at the present stage. As one of the chemical products that regulate the interfacial properties, the amphiphilic molecular structure of the surfactant determines its ability to form the direction of the lignite surface. The adsorption layer, the hydrophobic group is far away from the adsorption direction, reduces the hydrophilicity of lignite surface and inhibits the moisture absorption of coal samples after drying. In this paper, the wettability and water absorption properties of lignite are studied. The type of hydrophilic group and the solidarity structure of the surface active agents (carbon chain length, aromatic structure, ring structure, double structure, etc.) are investigated. The effect of the HLB value of non ionic surfactants on the hydrophilic inhibition efficiency of the lignite surface was investigated by means of microcalorimetry, microelectrophoresis, surface tension, infrared spectroscopy, UV VIS spectrophotometer, X ray photoelectron spectroscopy (XPS) and liquid nitrogen adsorption, and the analysis of the cationic surfactant sixteen. The adsorption characteristics and adsorption mechanism of alkyl three methyl ammonium bromide (CTAB), anionic surfactant twelve alkyl sulfate (SDS) and non ionic surfactant twelve alkyl polyoxyethylene ether (C12 (EO) 15) on the lignite surface, and the wettability of lignite and the hydrophilicity of lignite in lignite were also investigated. The main conclusions are as follows: the wetting heat of organic matter in lignite is far higher than the wet heat of minerals. It is the main body of wetting and exothermic heat of lignite. The moist heat of kaolinite in mineral is higher than calcite and quartz. The moisture absorption of lignite is in accordance with the two stage kinetic model, and the moisture content in lignite is negatively related to the wetting heat. The higher the content, the smaller the moisture and damp heat. The wetting heat of the monolayer or cluster adsorption water formed on the surface of the awn lignite is more significant in the process of water absorption. The effect of water absorption or capillary condensation on moisture and humid heat is less. The content of oxygen containing functional group is an important factor affecting the wet heat of lignite, and the oxygen content in coal decreases with the increase of coal chemical degree. The wetting and releasing heat of brown coal is significantly different from polar wetting agent and non polar wetting agent. The wetting heat of water and anhydrous ethanol on lignite is much greater than that of n-alkanes on lignite. The lignite adsorbing surfactants can reduce the moisture heat of lignite and inhibit the recovery of dry lignite water, and the two are consistent, and the essence is surface. The surfactant adsorption reduces the hydrophilicity of the lignite surface. The inhibition of the surface hydrophilicity of the surface active agent on the surface of the lignite depends on the ability of the surface active agent to form an effective directional close arrangement adsorption layer on the surface of the lignite. This is closely related to the molecular structure of the surfactant. The hydrophilic inhibition effect of lignite is better than that of anions; in the hydrophobic group, the hydrophilic inhibition efficiency of lignite surface increases with the increase of the chain length of the hydrophobic group, and the surface active agent containing the branched chain and the benzene ring structure in the hydrophobic group is not conducive to the increase of the hydrophilic inhibition efficiency of the lignite surface; the gemini type surfactant of the Gemini structure is on the lignite surface. The hydrophilic inhibition efficiency is higher than the surface active agent of single chain structure and double hydrophobic group; Twain series surfactants have no obvious inhibition effect on the surface hydrophilicity of lignite; alkyl glycosides have polyhydroxy surfactant enhanced the hydrophilic property of lignite surface; with the decrease of HLB value of non ionic surfactant C12 (EO) n, lignite meter The inhibition effect of surface hydrophilicity is increasing, the minimum value occurs near the HLB value of 13.6. The key to the hydrophilic inhibition of lignite is to inhibit the hydrophilicity of organic matter in lignite. The hydrophilic inhibition efficiency of lignite is related to the type of mineral and the species of surfactant, and the cationic surfactant is more effective for kaolinite. The effect of the anion surface active agent on the stone solution is better, the surface hydrophilicity of the quartz is more volatile with the surfactant. The adsorption of Cationic Surfactant CTAB on the lignite surface is the exothermic process, which can be described by the Freundlich model, and the adsorption rate is in accordance with the two stage kinetic model; the temperature increases, the alkaline condition and the low ionic strength are higher. The adsorption of CTAB on the lignite surface promotes the adsorption of.Ctab on the lignite surface closely related to the oxygen content of the lignite surface, the oxygen content in coal increases, and the adsorption of CTAB on the coal surface increases. After the acid washing, the content of oxygen containing functional groups in the lignite is reduced, the adsorption capacity of CTAB and the inhibition efficiency of hydrophilicity are reduced. Under the low concentration, the lignite is reduced. Oxygen functional groups are superior to minerals for CTAB adsorption. The adsorption capacity of kaolinite to CTAB in minerals is higher than that of quartz and calcite. In oxygen functional groups, the adsorption capacity of CTAB on the surface of carboxyl groups is greater than that of other oxygen functional group components. The results of quantum simulation show that different oxygen functional groups follow the adsorption capacity of CTAB. The order of strength and weakness is that the adsorption of phenol hydroxyl carboxyl alcohol hydroxyl ether group.Ctab on lignite surface not only occurs on the lignite surface, but also can be adsorbed on the surface of brown coal with large pore structure. The two factors affect the hydrophilic inhibition efficiency of CTAB to lignite. The temperature rises, the acid condition and low ionic strength are on the anionic surface active agent SDS in brown coal. The influence of surface adsorption on the adsorption of SDS in lignite is higher than that of organic matter in lignite. The adsorption capacity of calcite to SDS is much higher than that of quartz and kaolin. The mineral content in coal samples with different degree of coalification has a great influence on the adsorption of SDS. Because of the existence of electrostatic repulsion, SDS is adsorbed on the surface of oxygen functional group of lignite. The carboxyl group showed a better adsorption capacity than other oxygen functional group components. The specific surface area, the average pore size and the pore volume were smaller after the adsorption of SDS, which showed that SDS could be adsorbed in the macroporous structure of lignite. The adsorption character of non ionic surfactant twelve alkyl polyoxyethylene ether (C_ (12) (15)) on the lignite surface Combined with the Langmuir adsorption model, the two stage kinetic equation can describe the adsorption kinetics of C_ (12) (EO) (15) on the lignite surface; the temperature increases, the alkaline condition and the high ionic strength can promote the adsorption of C12 (EO) 15 on the lignite surface. After the lignite deashing, the adsorption capacity of C12 (EO) 15 decreases, but the decrease is not significant. With the increase of coalification degree, The oxygen content in coal is reduced, the adsorption of C12 (EO) 15 on the surface of coal shows a decreasing trend of.C12 (EO) 15 on the surface of lignite covering the surface oxygen functional group, and the adsorption capacity of the carboxyl group on C12 (EO) 15 is higher than that of other oxygen functional groups.C12 (EO) 15 on the lignite surface and covers the microporous structure in lignite, and it can also be in the large pore of lignite. This study has a certain reference effect on reducing the surface hydrophilicity of lignite surface and restraining the moisture absorption of the dry coal sample, and provides some basic data for the further study of surface active agents on the mechanism of lignite surface adsorption and the mechanism of hydrophilic inhibition.
【學(xué)位授予單位】：太原理工大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：TD849.2

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1 劉曉陽;表面活性劑吸附對褐煤潤濕性影響及其調(diào)控機制研究[D];太原理工大學(xué);2017年

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