本文關(guān)鍵詞：金屬有機(jī)骨架結(jié)構(gòu)材料合成及其吸附正構(gòu)烷烴性能研究　出處：《華東理工大學(xué)》2017年碩士論文　論文類(lèi)型：學(xué)位論文

  更多相關(guān)文章： 石腦油 ZIF-8 正構(gòu)烷烴 吸附平衡 吸附動(dòng)力學(xué)

【摘要】：沸石咪唑酯骨架(ZIF)材料由于具有比表面積和孔體積大、結(jié)構(gòu)可調(diào)控性好、結(jié)構(gòu)穩(wěn)定性好等特點(diǎn),被廣泛應(yīng)用于吸附分離過(guò)程研究,具有潛在良好的應(yīng)用前景。本文通過(guò)溶劑熱法合成ZIF-8材料,優(yōu)化合成工藝條件,并對(duì)其吸附性能進(jìn)行研究,以期為該MOF材料應(yīng)用于石腦油中正構(gòu)烷烴吸附分離工藝提高分離效率和分子管理功能提供理論依據(jù)。論文首先以溶劑熱法合成ZIF-8,優(yōu)化了合成工藝條件,并對(duì)合成ZIF-8進(jìn)行分析表征。結(jié)果表明,在原料配比 n(C4H6N2):n(Zn(N03)2 6H20):n(HCOONa):n(MeOH)= 2:1:2.63:29.14、晶化溫度90℃、晶化時(shí)間15 h、攪拌速度800 r/min的優(yōu)化工藝條件下,ZIF-8收率為75.7%,合成ZIF-8晶體為十二面體方鈉石結(jié)構(gòu),平均粒徑1.58 μm,298 K下對(duì)正己烷的靜態(tài)飽和吸附容量為225.1 mg/g,較5A分子篩高出85%以上,吸附容量和吸附速率優(yōu)于巴斯夫產(chǎn)商業(yè)ZIF-8產(chǎn)品。隨后論文研究了石腦油中所含主要正構(gòu)烷烴在合成ZIF-8上的吸附平衡行為和動(dòng)力學(xué)特性。結(jié)果表明,Langmuir-Freundlich吸附模型能夠較好地描述正構(gòu)烷烴在合成ZIF-8樣品上的吸附平衡行為,在283～313 K的吸附溫度條件下,正己烷、正庚烷和正辛烷在ZIF-8上的吸附焓變分別為-27.90 kJ/mol、-28.00 kJ/mol和-28.70 kJ/mol,吉布斯自由能變分別為(-5.81～-3.46)kJ/mol、(-6.15～-3.82)kJ/mol 和(-6.46～-4.08)kJ/mol,熵變分別為-77.56(J/(mol.K))、-76.67(J/(moI K))和-78.03(J/(mol K))。各正構(gòu)烷烴在 ZIF-8 上吸附等溫線(xiàn)的分子模擬計(jì)算結(jié)果與實(shí)驗(yàn)測(cè)定值吻合較好。283～313 K下,正己烷、正庚烷和正辛烷在 ZIF-8 中的擴(kuò)散系數(shù)分別為(3.38～5.33)×10-12cm2/s、(2.02～3.30)×10-12cm2/s 和(1.21～2.09)×10-12cm2/s,擴(kuò)散活化能分別為 11.12 kJ/mol、12.11 kJ/mol 和 13.41 kJ/mol。以模型油為原料的動(dòng)態(tài)吸附實(shí)驗(yàn)結(jié)果表明,隨著正構(gòu)烷烴碳數(shù)的增加,正構(gòu)烷烴在ZIF-8床層上吸附的托馬斯速率常數(shù)增大、動(dòng)態(tài)吸附容量略有降低。在此基礎(chǔ)上,對(duì)ZIF-8成型工藝進(jìn)行研究并考察成型后ZIF-8對(duì)石腦油中正構(gòu)烷烴的吸附分離效果。結(jié)果表明,以田菁粉和酸性白土為成型助劑,成型后球形ZIF-8產(chǎn)品的機(jī)械強(qiáng)度為17N/cm,對(duì)正己烷、正庚烷和正辛烷的靜態(tài)飽和吸附量分別為209.7 mg/g、207.6 mg/g和204.3 mg/g。成型ZIF-8對(duì)石腦油中總正構(gòu)烷烴的靜態(tài)飽和吸附量隨吸/脫附循環(huán)次數(shù)增加無(wú)明顯變化,均維持在205 mg/g左右,表明ZIF-8具有良好的再生性能和循環(huán)使用效果。經(jīng)ZIF-8吸附分離吸余油的芳烴潛含量較原料石腦油提高了約11個(gè)百分點(diǎn),達(dá)到了與5A分子篩一致的吸附分離效果,且ZIF-8在吸附容量和吸附速率方面較5A分子篩有優(yōu)勢(shì)。
[Abstract]:Imidazole ester (ZIF) zeolite skeleton materials with specific surface area and pore volume, structure adjustment, structure stability, is widely used in adsorption separation process research, has a potential application prospect is good. This paper through the solvothermal synthesis of ZIF-8 materials, the optimum technological conditions of the synthesis, and to study the adsorption performance, in order for the application of MOF material in naphtha of n-alkanes in adsorption separation process and provide a theoretical basis for improving the separation efficiency and molecular management functions. Firstly on the solvothermal synthesis of ZIF-8, the synthesis process conditions optimization, analysis and characterization of the synthesis of ZIF-8. The results showed that the ratio of raw materials n (C4H6N2) n (Zn (N03) 2 6H20): n (HCOONa): n (MeOH) = 2:1:2.63:29.14, the crystallization temperature of 90 DEG C, the crystallization time of 15 h, optimization of process conditions for the stirring speed of 800 r/min, the yield of ZIF-8 was 75.7%, ten for the synthesis of ZIF-8 crystal Two face sodalite structure, the average particle size of 1.58 m, 298 K static in n-hexane saturated adsorption capacity is 225.1 mg/g, a 5A molecular sieve is 85% higher than that of adsorption capacity and adsorption rate is better than the BASF commercial ZIF-8 products. The paper studies the main content of n-alkanes in the synthesis of ZIF-8 the adsorption behavior and dynamics of naphtha. The results showed that the Langmuir-Freundlich adsorption model can describe the adsorption equilibrium is the constitutive behavior in the synthesis of ZIF-8 sample alkane and adsorption temperature at 283 ~ 313 K, n-hexane, n-heptane and n-octane enthalpy of adsorption on the ZIF-8 variable -27.90 kJ/mol respectively. -28.00, kJ/mol and -28.70 kJ/mol, the Gibbs free energy respectively (-5.81 ~ -3.46) kJ/mol (-6.15 ~ -3.82) and kJ/mol (-6.46 - -4.08) kJ/mol, respectively -77.56 (J/ entropy (mol.K), -76.67 (J/) (moI K) and -78.03 (J/ (MO) L K)). The molecular structure is on the ZIF-8 adsorption isotherms of alkanes in the simulated values are in good agreement with the.283 ~ 313 K results with experiment, n-hexane, n-heptane and n-octane diffusion coefficient in ZIF-8 respectively (3.38 ~ 5.33) * 10-12cm2/s (2.02 ~ 3.30) and 10-12cm2/s (x 1.21 ~ 2.09) * 10-12cm2/s, diffusion activation energies were 11.12 kJ/mol, 12.11 kJ/mol and 13.41 kJ/mol. in model oil as raw material and dynamic adsorption experiment results show that with the increase of n-alkanes, increase the Thomas rate constant of n-alkanes in ZIF-8 adsorption bed, dynamic adsorption capacity decreased slightly on the basis. On the study of ZIF-8 on the adsorption of naphtha and n-alkanes in separation of forming effect on ZIF-8 process. The results show that with Sesbania powder and acidic clay as a molding aid after molding, the mechanical strength of spherical ZIF-8 products for 17N/ Cm, of n-hexane, n-heptane and n-octane static saturated adsorption capacity were 209.7 mg/g, 207.6 mg/g and 204.3 mg/g. ZIF-8 for forming naphtha total n-alkanes the static saturated adsorption capacity with the adsorption / desorption cycles showed no obvious change was maintained at about 205 mg/g, show that ZIF-8 has the regeneration performance and the cycle of good use effect. The separation of aromatics content of raffinate oil was about 11 percentage points higher than the feedstock of ZIF-8 adsorption, and 5A zeolite reached consistent adsorption separation effect, and ZIF-8 in the adsorption capacity and adsorption rate compared with the 5A molecular sieve has advantages.

【學(xué)位授予單位】：華東理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類(lèi)號(hào)】：O647.3;TE626.9

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