以不同表面活性剂为模板合成Al2O3介孔纤维

分别以聚醚PPG(R–[O(C3H6O)m–O]–)和聚乙二醇PEG(2000)为模板,以Al(NO3)3·9H2O和CO(NH2)2为原料,在水热条件下合成η-Al2O3(PPG)和η-Al2O3(PEG)介孔纤维,并对材料进行表征,比较了醚类及醇类表面活性剂模板对产物性质的影响。通过静态吸附平衡试验考察了上述两种η-Al2O3介孔纤维对亚甲基蓝的吸附特性。结果表明：采用两种表面活性剂为模板均可合成η-Al2O3介孔纤维;表面活性剂种类对介孔结构、比表面积和孔体积有较大影响;η-Al2O3(PEG)表面介孔结构更加规则,平均孔径更小,比表面积和孔体积是η-Al2O3(PPG)的1.5倍;η-Al2O3介孔纤维对染料的吸附等温线符合Freundlich经验公式,不遵循Langmuir单分子层吸附方程,吸附为多分子层吸附(BET吸附等温方程)。η-Al2O3(PEG)对亚甲基蓝的吸附能力大于η-Al2O3(PPG)的,吸附行为遵循准一级、修正准一级和准二级动力学方程。     

高温下钙基吸附剂吸附CO_2的研究

CaO基吸附剂是一种理想的CO2高温吸附剂。利用热重分析仪研究了由不同前体制备的CaO高温下对CO2的吸附性能。利用吸附仪测定了各吸附剂的比表面积等参数。实验发现CaO的最佳吸附温度范围为700—750℃;由CaC2O4.H2O制得的CaC2O4-CaO具有良好的吸附性能,在实验条件下,其吸附量为理论吸附量的89.1%;在较宽的CO2体积分数范围内,CaC2O4-CaO始终保持很高的吸附性能;吸收速率的大小受吸附剂比表面积、孔体积、孔结构等参数的共同影响。高温下,CaO基吸附剂吸附CO2的微观机理有待进一步研究。     

一步水热法合成铜改性的介孔γ-Al_2O_3及其吸附脱硫性能研究

采用一步水热合成法,以Al(NO3)3为铝源,P123为模板剂,Na OH、Na2CO3和K2CO3分别为沉淀剂,Cu(NO3)2为铜源,制备出负载铜的金属有序介孔γ-Al2O3,并运用N2吸附-脱附和XRD等技术对其结构进行表征,同时探讨了铜改性的介孔γ-Al2O3对模型燃油中的噻吩的吸附性能。结果表明,这3种沉淀剂都能制备出比表面积大(226 m2/g),孔径分布中心为3.3 nm,孔体积为0.27~0.35 cm3/g的负载铜的介孔γ-Al2O3,且样品都保持了较好的介孔结构。样品对模型燃油中噻吩的吸附脱硫性能表明,用Na OH作为沉淀剂且负载铜的介孔γ-Al2O3样品对噻吩的吸附性能较好,原因在于此样品具有较大的比表面积且铜在此样品中的分散性较好。     

利用W/O微乳液制备具有规则介孔结构和类虫蚀表面的纳米氧化铝粉体

利用W/O微乳液制备了粒径在60～120 nm之间的介孔超细γ-Al2O3粉体,经过600℃焙烧后,其颗粒表面出现尺寸为2～5 nm的类虫蚀孔道结构,比表面也从仅经过干燥Al2O3粉体的248.3m2/g增加到336.0 m2/g.通过N2等温吸附-脱咐技术发现,在经过焙烧Al2O3粉体的孔径分布图中,在3.2 nm处存在一个尖锐的孔径分布,证实了表面类虫蚀孔结构的存在.颗粒表面类虫蚀孔结构的产生原因是在高温焙烧的作用下,吸附的有机物,如环己烷、表面活性剂以及助表面活性剂等的分解产生造孔作用而形成的.     

磁性介孔γ-Fe_2O_3制备及其处理含Cr(Ⅵ)废水的应用

以价格低廉的葡萄糖为模板剂,合成了磁性介孔γ-Fe2O3,其比表面积为99.97 m2/g,平均孔容为0.25cm3/g,孔径为33 nm。采用批量平衡试验,研究了300 K下介孔γ-Fe2O3对Cr(Ⅵ)的吸附特性和介孔γ-Fe2O3的再生及Cr(Ⅵ)的回收。试验结果表明:pH为3.5时,介孔γ-Fe2O3对Cr(Ⅵ)的饱和吸附量达到44.56 mg/g。Freundlich方程比Langmuir方程更好地描述了介孔γ-Fe2O3吸附Cr(Ⅵ)的行为,表明此吸附是多分子层物理吸附。300 K下,用0.01 mol/L的NaOH处理吸附有Cr(Ⅵ)的介孔γ-Fe2O3,可以实现介孔γ-Fe2O3的很好再生。再生的γ-Fe2O3经过5次循环使用,仍具有很好的吸附能力。     

不同活化剂对煤质活性炭孔隙结构影响

选取新疆呼图壁煤和山西大同煤为原料制备活性炭,研究不同活化剂对煤质活性炭孔隙结构的影响。根据煤样热重分析结果分别制备优质的炭化料,分别选取H_2O(g)活化与CO_2活化制得活性炭。活性炭的吸附性能以碘吸附值及亚甲蓝吸附值表征,活性炭的孔隙结构以N_2吸附-脱附等温线解析得到。试验结果表明:新疆呼图壁煤与山西大同煤采用H_2O(g)活化与CO_2活化制备的活性炭,其吸附性能及孔隙结构均较为优良,且受活化剂影响显著。相比H_2O(g)活化,CO_2活化促使活化反应缓慢有效地进行,有利于制得吸附性能、孔容积、比表面积与微孔结构均较为优良的活性炭。H_2O(g)活化有利于制得中孔结构发达、微孔孔径更为细小的活性炭。研究结果同时验证了通过选取不同的活化剂,可进行煤质活性炭孔隙结构的调变。     

一步水热法合成铜改性的介孔γ-Al_2O_3及其吸附脱硫性能研究

采用一步水热合成法,以Al(NO3)3为铝源,P123为模板剂,Na OH、Na2CO3和K2CO3分别为沉淀剂,Cu(NO3)2为铜源,制备出负载铜的金属有序介孔γ-Al2O3,并运用N2吸附-脱附和XRD等技术对其结构进行表征,同时探讨了铜改性的介孔γ-Al2O3对模型燃油中的噻吩的吸附性能。结果表明,这3种沉淀剂都能制备出比表面积大(>226 m2/g),孔径分布中心为3.3 nm,孔体积为0.27⁰.35 cm3/g的负载铜的介孔γ-Al2O3,且样品都保持了较好的介孔结构。样品对模型燃油中噻吩的吸附脱硫性能表明,用Na OH作为沉淀剂且负载铜的介孔γ-Al2O3样品对噻吩的吸附性能较好,原因在于此样品具有较大的比表面积且铜在此样品中的分散性较好。     

Ru/Al2O3催化剂表面分形分析

利用静态氮吸附仪在-196.15 ℃液氮气氛中,测定Ru/Al2O3催化剂的比表面积以及孔结构参数,研究了催化剂的孔容-孔径分布和吸附-脱附等温线。基于FHH多层吸附模型,利用全吸附数据计算出Ru/Al2O3催化剂的表面分形维数。结果表明,3种Ru/Al2O3催化剂的表面分形维数均约2.4,分形维数与比表面积和总孔体积无直接关联。     

芳胺废渣衍生多孔碳高效吸附去除对硝基苯酚

以工业生产过程中产生的芳胺废渣为碳前驱体，以乙酸镁作为氧化镁模板剂前驱体，采用一步法制备了N、O原位共掺杂的分级多孔碳(RPCs)。通过SEM和N2物理吸脱附对材料的形貌和孔结构进行表征,通过XPS对掺杂的N、O物种进行分析。按照质量比=1.00制备的RPC-1.00具有1427 m2/g的比表面积以及1.4713 cm3/g的孔容积。在出色的比表面积，丰富的孔结构和N、O掺杂物种的共同作用下，RPC-1.00针对对硝基苯酚的静态吸附量能够达到562.66 mg/g，固定床动态吸附量能够达到345.01 mg/g。理论计算发现，N、O原子的掺入能够增加吸附体系的色散力和静电吸引，能够有效提高吸附能。吡啶-N4和羧基结构也能产生很强的氢键作用力，提升了吸附能力。     

Co-Mo脱氧催化剂的制备及结构表征

采用醇凝胶-流动氮气干燥法制备了Al2O3载体,并与商业Al2O3和13X分子筛载体对比,通过N2低温吸附和XRD方法对催化剂的表面结构进行表征.结果表明,该方法制备的Al2O3载体的比表面积与商业Al2O3载体相当,而孔结构却大幅度改善,孔体积增大近一倍,具有最可几孔径分布在4.6 nm和18.6 nm的中孔结构,与商业13X分子筛的孔结构相近.当活性组分Mo负载质量分数小于5%时,催化剂的孔结构仍保持Al2O3载体的中孔结构,而Mo负载质量分数大于5%时,过量的Mo与载体Al2O3发生作用形成Al2(MoO4)3,在衍射图谱上出现了尖锐的衍射峰,该晶体的形成直接改变了催化剂的织构.     

色谱法测沸石分子筛上的吸附和传递系数

本文用脉冲色谱法研究了氧和氮在沸石分子筛上的吸附和扩散性能,用矩量分析法计算了氧和氮的吸附平衡常数和扩散系数。实验结果表明,沸石分子筛吸附剂优先吸附氮。     

硫脲改性磁性壳聚糖微球对Hg~(2+)的吸附特性

利用悬浮分散以及化学交联技术制备磁性壳聚糖微球,并经硫脲改性(SMCS),用于吸附水溶液中Hg2+。用光学显微图、红外、热重分析等对微球进行了表征;考察了pH值、Hg2+初始浓度、吸附时间以及振荡速率对Hg2+吸附的影响。结果表明,SMCS为球形,粒径50—80μm。SMCS对Hg2+有良好的吸附性能,饱和吸附容量(1.2—6.5 mmol/g)随pH值升高而增加,pH值为5.0时饱和吸附容量约为2.9 mmol/g。等温吸附线可用Freundlich等式拟合。吸附动力学结果表明,振荡速率为150—200 r/min时,为内扩散控制;50—150 r/min时,由外扩散和内扩散同时控制;振荡速率<<50 r/min时,为外扩散控制。吸附动力学可用拟二级模型拟合,初始吸附速率为0.22—1.77 mmol/(g.h),随振荡速率加快而增加。     

Adsorption separation of N2, O2, CO2 and CH4 gases by β-zeolite

In the present study, adsorption equilibrium and kinetic separation potential of β-zeolite is investigated for N₂, O₂, CO₂ and CH₄ gases by using concentration pulse chromatography. Adsorption equilibrium and kinetic parameters have been studied. Henry’s Law constants, heat of adsorption values, micro-pore diffusion coefficients and adsorption activation energies are determined experimentally. The three different mass transfer mechanisms, that have to take place for adsorption to occur, are discussed. From the equilibrium and kinetic data, the equilibrium and kinetic selectivities are determined for the separation of the gases studied.With β-zeolite, carbon dioxide has the highest adsorption Henry’s Law constant at all the temperatures studied, followed by methane, nitrogen and oxygen. Carbon dioxide separation from oxygen, nitrogen and methane has good equilibrium separation factors. This factor is not very high for methane/nitrogen and methane/oxygen systems and is the lowest for nitrogen/oxygen system. Micro-pore diffusion is the dominant mass transfer mechanism for all the systems studied, except CH₄, with β-zeolite. The kinetic separation factors are very small at high temperatures for all the systems studied. Nitrogen/carbon dioxide and oxygen/carbon dioxide can be separated in kinetic processes with reasonable separation factors at low temperatures. Both equilibrium and kinetic separation factors decrease as column temperature increases. Considering all the observations from this study, it was concluded that β-zeolite is a good candidate for applications in flue gas separations, as well as natural gas and landfill gas purifications.     

Evaluation of Phosphate Removal Efficiency from Aqueous Solution by Polypyrrole/BOF Slag Nanocomposite

The polypyrrole/basic oxygen furnace slag nanocomposite (PPy–BOFS) was synthesized and characterized by FTIR, SEM, ICP-AES, and X-ray diffraction studies and was employed as an adsorbent for the removal of phosphate ions from aqueous solution by the batch sorption method. The maximal amount of adsorption was found to be 9.13 mg/g (45°C). The Langmuir and Freundlich isotherms were used to describe the adsorption equilibrium. The kinetics of the adsorption process was investigated using the Lagergren rate equation and the Weber Morris intraparticle diffusion model. The FTIR and XRD pattern of the adsorbent before and after the adsorption was recorded to get better insight into the mechanism of the adsorption process. The results of equilibrium and spectral investigations revealed that the removal of phosphate by the nanocomposite involves various mechanisms followed by the nanocomposite and the constituents present in it.     

膨润土-活性炭复合吸附剂对锰离子的吸附

以膨润土和活性炭为原料制备了复合吸附剂并将之应用于含锰离子废水的吸附。考察了不同条件下该吸附剂对水体中Mn（Ⅱ）的去除效果,并研究了吸附动力学特征和等温吸附过程。结果表明膨润土和活性炭复合吸附剂对Mn（Ⅱ）具有优良的吸附能力,在25 ℃下,当投加量为4 g/L、Mn（Ⅱ）初始质量浓度为50 mg/L、溶液pH为6时,吸附180 min,吸附率为93.2%。准一级、准二级动力学和内扩散模型用来拟合吸附过程,结果表明准二级动力学符合该吸附过程,吸附速率常数为0.003 6 g/（mg·min）,内扩散过程不是吸附的限速步骤,还存在吸附机制的制约。用Langmuir和Freundlich模型描述吸附等温过程,结果得出该吸附过程服从Langmuir吸附,饱和吸附容量为27.781 mg/g。     

Adsorption behavior of Congo red from aqueous solution on La2O3-doped TiO2 nanotubes

Composite adsorbent, TiO₂ nanotubes doped by La₂O₃, were prepared and characterized by IR, XRD, SEM, and XPS, their adsorption properties were investigated in the aqueous solution employing Congo red as the target pollutant. The adsorption experiments exhibited that adsorption equilibrium of Congo red over the adsorbent was rapidly achieved within 10 min, and the adsorption kinetics was in accord with the pseudo-second-order kinetics model. Moreover, intraparticle diffusion was not the determining step in the entire adsorption process, and the adsorption belonged to a chemical adsorption. Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isothermal equations were utilized to fit the equilibrium adsorption data, in which the Temkin equation was verified to fit the adsorption behaviors most satisfactorily with the correlation coefficient of 0.998. The adsorption mechanism was also studied.     

Air separation by pressure swing adsorption

The original pressure swing air separation process, developed almost simultaneously by Exxon and Air Liquide, uses a nitrogen selective zeolite adsorbent to produce a high purity oxygen product. The same basic process is still widely used in small scale units although, for larger scale units, many modifications to the cycle have been introduced in order to reduce power consumption. Although nitrogen can in principle be recovered from the blowdown stream of such systems, if high purity nitrogen is the required product, it is more economic to use an oxygen selective adsorbent. Most adsorbents show either no selectivity or preferential adsorption of nitrogen. However, in small pore carbon molecular sieves or 4A zeolite there is a substantial difference in diffusion rates so that an efficient kinetic separation is possible. Somewhat different cycles are generally used in such processes. Progress in modelling the dynamic behaviour of both types of PSA system is reviewed and comparisons between experimental performance and the model predictions are shown. A simple linear driving force model provides a good overall prediction of the effects of process variables but the computationally more cumbersome diffusion model gives better quantitative agreement with experiment. Comparisons are drawn between the performance achieved (in nitrogen production) with two different kinetically selective adsorbents; RS-10 (a modified 4A zeolite) and Bergbau Forschung carbon molecular sieve.     

Modelling of a pressure swing adsorption process for oxygen enrichment with carbon molecular sieve

Adsorptive separation of oxygen from nitrogen and argon is carried out during the desorption steps of a pressure swing adsorption (PSA) process which uses carbon molecular sieves developed by Bergbau-Forschung GmbH. The adsorption isotherms of the three main components of air are very similar. On account of the pore size distribution of CMSN2, the diffusion coefficient of oxygen is more than eight times those of nitrogen and argon so that air separation occurs by adsorption kinetics. Experimental results for the individual steps and cyclic operation of the PSA process are presented and compared with the predictions of an isothermal plug-flow model. Adsorption rate is represented by a linear driving force equation. If the diffusion coefficients are adapted separately to every step, a good agreement is observed between the model calculations and experimental results.     

Production of argon free oxygen by adsorptive air separation on Ag‐ETS‐10

The purification of different components of air, such as oxygen, nitrogen, and argon, is an important industrial process. Pressure swing adsorption (PSA) is surpassing the traditional cryogenic distillation for many air separation applications, because of its lower energy consumption. Unfortunately, the oxygen product purity in an industrial PSA process is typically limited to 95% due to the presence of argon which always shows the same adsorption equilibrium properties as oxygen on most molecular sieves. Recent work investigating the adsorption of nitrogen, oxygen and argon on the surface of silver‐exchanged Engelhard Titanosilicate‐10 (ETS‐10), indicates that this molecular sieve is promising as an adsorbent capable of producing high‐purity oxygen. High‐purity oxygen (99.7+%) was generated using a bed of Ag‐ETS‐10 granules to separate air (78% N₂, 21% O₂, 1% Ar) at 25°C and 100 kPa, with an O₂ recovery rate greater than 30%. © 2012 American Institute of Chemical Engineers AIChE J, 59: 982–987, 2013     

含氟水在活性氧化铝吸附剂上动态曲线的模拟计算

建立了合适的吸附动态模型，用于描述含氟水在活性氧化铝吸附剂动态吸附特性，利用静态平衡实验数据及孔扩散系数能够对动态透过曲线进行很好的模拟计算，不仅可减少实验的工作量，而且对本体系吸附过程的工业放大设计具有指导意义，也为其它吸附过程数学模型的开发提供借鉴作用。