【摘要】：論文基于吸附凈化氣相多環(huán)芳烴(PAHs)對高效吸附、低耗再生的實(shí)際需求與技術(shù)發(fā)展趨勢,采用介孔吸附劑,針對吸附熱力學(xué)與動(dòng)力學(xué)、脫附再生特性和微觀吸附機(jī)制三大關(guān)鍵問題,展開了系列的實(shí)驗(yàn)與分子模擬研究。搭建了氣相PAHs準(zhǔn)平衡吸附實(shí)驗(yàn),分別對三種PAHs(萘、菲、芘)在三種典型介孔吸附劑(硅基MCM-41、SBA-15和碳基CMK-3)上的吸附相平衡與吸附動(dòng)力學(xué)進(jìn)行了研究,獲取了吸附等溫線與不同濃度下的穿透曲線,確立了 Freundlich、Langmuir模型分別對大、小吸附質(zhì)的適用關(guān)系,以及準(zhǔn)確的恒定濃度波穿透曲線模型。研究結(jié)果表明,內(nèi)擴(kuò)散為PAHs吸附的主要控速步驟,介孔材料較傳統(tǒng)吸附劑具有更高的吸附速率,并存的微孔結(jié)構(gòu)有助于在低濃度下提高PAHs吸附量,且微-介交聯(lián)孔結(jié)構(gòu)利于吸附傳質(zhì),但無序微孔結(jié)構(gòu)會(huì)增加大分子(菲、芘)的內(nèi)擴(kuò)散阻力。提出了優(yōu)化后的脫附熱分析方法,基于程序升溫(TPD)實(shí)驗(yàn)確立了各吸附體系的脫附峰值溫度及脫附動(dòng)力學(xué)三因子,發(fā)現(xiàn)了隨機(jī)成核增長模型為PAHs脫附的主流機(jī)理函數(shù),菲/SBA-15與芘/CMK-3則分別由于二維擴(kuò)散與π-π作用而呈現(xiàn)特殊機(jī)理。MCM-41 一維介孔中的PAHs脫附行為基本一致,SBA-15微-介交聯(lián)孔可促進(jìn)脫附傳質(zhì),CMK-3富含微孔的碳棒陣列雖強(qiáng)化吸附但會(huì)抑制脫附擴(kuò)散。合理的微孔分布是優(yōu)選高效PAHs吸附劑的關(guān)鍵因素。基于多尺度分子模擬方案,構(gòu)筑了 MCM-41與SBA-15模型,采用蒙特卡洛法與分子動(dòng)力學(xué)法模擬了 PAHs的吸附效果及吸附狀態(tài),結(jié)合實(shí)驗(yàn)印證了微-介交聯(lián)孔是提高平衡吸附量、穩(wěn)定吸附熱及均衡吸附質(zhì)分布的關(guān)鍵因素;隨分子量增大,吸附質(zhì)相對介孔表面的平鋪性、有序度與穩(wěn)定性增大。采用第一性原理進(jìn)一步模擬研究了 PAHs在硅基表面上的吸附構(gòu)型、相互作用能及各作用力貢獻(xiàn)等微觀特性,揭示了對于以物理吸附為主的PAHs吸附,色散力占主導(dǎo)作用且對疏水表面上的吸附促進(jìn)尤為顯著,PAHs分子離域π電子起到靜電吸引作用,氫鍵則主要起到側(cè)向約束PAHs吸附質(zhì)的作用。論文研究成果可為介孔材料吸附凈化氣相PAHs提供理論和技術(shù)參考,具有重要的科學(xué)意義和應(yīng)用價(jià)值。
[Abstract]:Based on the actual demand and technical development trend of adsorption and purification of gas phase polycyclic aromatic hydrocarbons (PAHs) for high efficiency adsorption and low consumption regeneration, a series of experiments and molecular simulation studies were carried out by using mesoporous adsorbents to solve the three key problems of adsorption thermodynamics and kinetics, desorption regeneration characteristics and micro adsorption mechanism. The adsorption phase equilibrium and adsorption kinetics of three kinds of PAHs (Naphthalene, phenanthrene, pyrene) on three typical mesoporous adsorbents (silicon-based MCM-41,SBA-15 and carbon-based CMK-3) were studied by gas phase PAHs quasi-equilibrium adsorption experiments. the adsorption isotherms and penetration curves at different concentrations were obtained, and the applicable relationships of Freundlich,Langmuir models for large and small adsorbents were established. And an accurate constant concentration wave penetration curve model. The results show that internal diffusion is the main rate control step of PAHs adsorption. Mesoporous materials have higher adsorption rate than traditional adsorbents. The coexisting microporous structure is helpful to increase the adsorption capacity of PAHs at low concentration, and the micro-mesocrosslinked pore structure is conducive to adsorption and mass transfer, but the disordered microporous structure increases the internal diffusion resistance of macromolecules (phenanthrene, pyrene). The optimized desorption thermal analysis method was proposed. Based on the temperature programmed (TPD) experiment, three factors of desorption peak temperature and desorption kinetics of each adsorption system were established. It was found that the random nucleation growth model was the mainstream mechanism function of PAHs desorption, while phenanthrene / SBA-15 and pyrene / CMK-3 showed special mechanisms due to the interaction of two-dimensional diffusion and 蟺-蟺, respectively. the desorption behavior of PAHs in one-dimensional mesoporous SBA-15-41 was basically the same. SBA- 15 micro-dielectric crosslinked pores can promote desorption mass transfer. CMK-3 carbon rod arrays rich in micropores enhance adsorption but inhibit desorption diffusion. Reasonable micropore distribution is the key factor to optimize high efficiency PAHs adsorbents. Based on the multi-scale molecular simulation scheme, the MCM-41 and SBA-15 models are constructed. Monte Carlo method and molecular dynamics method are used to simulate the adsorption effect and adsorption state of PAHs. Combined with experiments, it is proved that micro-dielectric crosslinked pores are the key factors to improve the equilibrium adsorption capacity, stabilize the adsorption heat and the distribution of equilibrium adsorbents. With the increase of molecular weight, the flatness, order and stability of the adsorbents relative to the mesoporous surface increase. The adsorption configuration, interaction energy and contribution of various forces of PAHs on silicon surface were further simulated by first principle. It is revealed that dispersion force dominates the adsorption of PAHs based on physical adsorption and promotes the adsorption on hydrophobic surface. PAHs molecule delocalized 蟺 electrons play an electrostatic attraction, while hydrogen bonds mainly act as lateral binding PAHs adsorbents. The research results of this paper can provide theoretical and technical reference for adsorption and purification of gas phase PAHs of mesoporous materials, and have important scientific significance and application value.
【學(xué)位授予單位】：北京科技大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：TB383.4;O647.3

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 楊權(quán);劉應(yīng)書;李子宜;楊雄;王占營;姜理俊;;萘在介孔分子篩MCM-41與SBA-15上的吸附特性研究[J];燃料化學(xué)學(xué)報(bào);2015年12期

2 梅磊;賀璐;范垂鋼;郝麗芳;李松庚;宋文立;;活性炭對低濃度萘的吸附性能[J];過程工程學(xué)報(bào);2014年02期

3 周宏倉;薛鴻斌;張翠翠;蔡華俠;肖旭;謝文杰;;萘和苊在活性炭上的脫附動(dòng)力學(xué)研究[J];中國電機(jī)工程學(xué)報(bào);2010年32期

4 周宏倉;蔡華俠;薛鴻斌;宋園園;張翠翠;陸建剛;;萘在炭質(zhì)吸附劑上的靜態(tài)吸附機(jī)理[J];環(huán)境科學(xué)研究;2010年05期

5 黃海鳳;褚翔;盧晗鋒;張波;陳銀飛;;兩種介孔分子篩動(dòng)態(tài)吸附VOCs的研究[J];中國環(huán)境科學(xué);2010年04期

6 李經(jīng)民;莊智仁;;XAD-4微孔介質(zhì)半揮發(fā)性PAHs吸附機(jī)制特征的研究[J];過程工程學(xué)報(bào);2006年S2期

7 李晶;李忠;奚紅霞;夏啟斌;;苯在改性活性炭上的脫附活化能[J];過程工程學(xué)報(bào);2006年05期

8 趙文昌;程金平;謝海;馬英歌;王文華;;環(huán)境中多環(huán)芳烴(PAHs)的來源與監(jiān)測分析方法[J];環(huán)境科學(xué)與技術(shù);2006年03期

9 李湘;李忠;羅靈愛;;程序升溫脫附活化能估算新模型[J];化工學(xué)報(bào);2006年02期

10 馬正月,陳皓侃,李文,李保慶;煙氣中多環(huán)芳烴吸附脫除的研究[J];燃料化學(xué)學(xué)報(bào);2004年05期

相關(guān)博士學(xué)位論文 前1條

1 王克亮;有序介孔碳制備及萘吸附性能的實(shí)驗(yàn)和分子模擬研究[D];華南理工大學(xué);2012年

，

本文編號：2501245