Y型分子筛微波法改性及其选择性吸附脱硫性能

通过微波法进行液态离子交换对NaY分子筛进行改性，采用静态实验对不同吸附剂的脱硫性能进行了考察，筛选出Ce(Ⅳ)-Y吸附性能最好。采用固定床技术对Ce(Ⅳ)-Y的吸附脱硫能力进行了研究，同时运用程序升温脱附法（TPD）和频率响应方法（FR）对吸附脱硫机理进行了进一步探讨。采用微波法进行离子交换改性后的Ce(Ⅳ)-Y分子筛的离子交换度与传统水热法比较有明显提高，吸附容量较NaY有显著提高。     

Properties of zeolite Y in various forms and utilization as catalysts or supports for cerium oxide in ethanol oxidation

Zeolite Y in sodium form (NaY) was synthesized using silica source from rice husk, transformed to ammonium form (NH₄Y), and calcined to convert to proton form (HY). The direct conversion of NH₄Y to HY resulted in loss of the zeolite crystallinity and lower surface area. Thus, the NH₄Y was further used in the preparation of cerium (Ce) catalysts. The NH₄Y was also treated with a basic solution in an attempt to generate mesopores but only site defects were likely formed. The supported Ce catalysts with good Ce dispersion were prepared by wetness impregnation of Ce precursor solution on NaY, NH₄Y, and base-treated NH₄Y. Upon calcination, the generated catalysts were notated as Ce/NaY, Ce/HY, and Ce/YB. In catalytic testing on ethanol oxidation at varying temperature in a continuous laboratory-scale fixed-bed reactor, all the zeolites gave low ethanol conversion at 100–300 °C. The catalytic activity significantly improved with the presence of Ce. The Ce/YB showed the higher ethanol conversion and CO₂ yield than Ce/NaY and Ce/HY probably because of the presence of more local site defects on the zeolite.     

影响CeY分子筛吸附脱硫性能因素的研究

通过液相离子交换法对NaY分子筛进行改性制得CeY分子筛，采用静态法考察了改性CeY分子筛中铈离子的负载量、焙烧温度、铈的价态、吸附水和分子筛骨架的结构对CeY分子筛吸附脱硫性能的影响。采用XRD和ICP分别对不同CeY分子筛的骨架结构及阳离子负载量进行了分析。结果表明，二次交换后,离子交换度达到88.9%，分子筛已达到交换平衡；最佳焙烧温度为500 ℃，温度过高会破坏分子筛的骨架结构；Ce(Ⅳ)Y的脱硫性能明显好于Ce(Ⅲ)Y；分子筛上的吸附水对硫化物的吸附能力也有较大的影响。     

超声法制备Ce^4＋/13X分子筛的吸附脱硫性能

采用在离子交换过程中引入超声的方法制备了Ce4 /13X分子筛,考察了超声法对分子筛的制备及脱硫性能的影响,并考察了静态吸附条件对Ce4 /13X在低硫模型汽油(硫含量为23 mg/kg)中的脱硫性能影响。结果表明,超声法可显著缩短分子筛离子交换平衡的时间,提高离子交换度,且能有效地提高活性组分Ce在分子筛表面的含量,脱硫实验结果也显示吸附容量有明显的提高。常温常压,吸附时间为2.5 h,剂油质量比为0.0072的条件下,Ce4 /13X对噻吩的脱硫效果最好,吸附量为0.07653mmol/g,脱硫率可达到76.5%。Freundlich等温式能很好地关联噻吩在Ce4 /13X上的吸附平衡数据。450℃空气气氛中焙烧4 h的方法,可较好地再生Ce4 /13X。     

Preparation of metallic cobalt inside NaY zeolite with high catalytic activity in Fischer–Tropsch synthesis

Metallic cobalt clusters are synthesized inside the cages of NaY zeolite by a method including four steps, i.e.: (1) ion exchange, (2) precipitation of exchanged cobalt cations, (3) calcination and (4) reduction of the calcined oxide nano-particles inside the zeolite. As compared with that prepared by the ion exchange followed directly by calcination and reduction and that by the conventional impregnation method, the sample by this four-step method exhibits higher CO conversion and higher selectivity to n-C₁₀–C₂₀ paraffins in Fischer–Tropsch (FT) synthesis. The small metallic cobalt clusters inside the supercages of NaY zeolite probably account for the high catalytic performances.     

噻吩、苯和正辛烷在Y型分子筛上的选择性吸附

采用重量法测定了温度为373 K、335 K和302 K时,噻吩、苯和正辛烷在NaY分子筛及CeY分子筛上的吸附等温线。结果表明，各温度下,噻吩在NaY分子筛和CeY分子筛上的饱和吸附量基本相同，并且其吸附量相对于苯和正辛烷较大。苯和正辛烷在CeY分子筛上的饱和吸附量很小，且较NaY分子筛上的吸附量明显的下降。CeY分子筛对噻吩有更高的选择性。     

Synthesis and application of magnetic NaY zeolite composite immobilized with ionic liquid for adsorption desulfurization of fuel using response surface methodology

Magnetic NaY zeolite immobilized with 1-butyl-3-methylimidazolium tetrachloroferrate ([bmim]Cl/FeCl₃) ionic liquid as a reusable, efficient, and easily separable adsorbent was synthesized to remove dibenzothiophene from n-hexane. SEM–EDX, FT-IR were used for characterization of the synthesized magnetic sorbent. The prepared ionic liquid was characterized by with NMR, and mass spectrometry. The magnetic property of the sorbent was considered by VSM method. The obtained saturation magnetization of 19.5 emu g^?1 confirmed the facile separation of magnetic zeolite immobilized with [bmim]Cl/FeCl₃ after adsorption process. Central composite design was applied to predict the proposed process and to achieve the optimum conditions for three influential parameters of temperature, time, and sorbent mass. At the predicted conditions, temperature of 23.2 °C, time of 24.7 min, and sorbent mass of 0.836 g, the sulfur removal of 97.9 ± 0.5 % was experimentally obtained which was close to the model sulfur removal prediction of 98.4 %. This noticeable agreement proved the proper and acceptable estimation of the central composite design model for the proposed process. The experimental data were reasonably fitted to the Langmuir and Freundlich model which shows that the sorption takes place on a heterogeneous material. The sorption capacities of 2.957 (mg g^?1) were achieved from sorption isotherms.     

噻吩、苯和正辛烷在NaY和CeY分子筛上的热脱附

采用智能质量分析仪(IGA),利用程序升温脱附法(TPD)研究了噻吩、苯和正辛烷在NaY和CeY分子筛上的热脱附行为,测定了升温速率为15 K/min时3种吸附质在NaY和CeY上的热重(TG)和微分热重(DTG)曲线。结果表明,3种吸附质在NaY上脱附比较容易,苯和正辛烷在CeY上脱附也很容易,但噻吩在CeY上脱附比较困难,噻吩有一部分不能完全脱附。CeY对噻吩具有较好的吸附选择性,而NaY的吸附选择性不好。     

离子改性Y分子筛吸附分离1,1,1,2-四氟乙烷/1,1-二氟-2-氯乙烯

用CaCl₂、La（NO₃）₃和Ce（NO₃） ₃溶液对NaY分子筛进行离子改性制备出CaY、LaY和CeY分子筛。将其及NaY为吸附剂,利用动态吸附法评价其吸附分离1,1,1,2-四氟乙烷（HFC-134a）产品中微量1,1-二氟-2-氯乙烯（HCFC-1122）的性能。同时采用X射线衍射（XRD）、吡啶红外（FTIR）和氨-程序升温脱附（NH₃-TPD）等手段对新鲜及再生后的吸附剂进行结构和表面性质表征。结果表明：CaY、LaY与CeY分子筛上的Brønsted酸中心可与HCFC-1122形成p-吸附配合物,从而将吸附流出气中HCFC-1122的残余率降低至1.0%以下;Brønsted酸强度越高,p-吸附配合物越容易形成,最低吸附温度越低（CeY     

Al2O3-supported Mixed Ca and Zn Compounds Prepared from Waste Seashells for Synthesis of Palm Fatty Acid Methyl Esters

Waste mixed seashells of Perna viridis, Anadara granosa, Amusium pleuronectes, and Meretrix meretrix, as abundant, low-cost, and nontoxic calcium sources, were used as renewable raw materials in the preparation of a heterogeneous base catalyst for the transesterification of palm oil in refluxed methanol. The new mixed metal compound catalyst was prepared by mixing the calcined seashells with Zn(NO₃)₂ and Al₂O₃ in an acidic aqueous solution, followed by calcination at 500°C (ZSA-500). The ZSA-500 catalyst exhibited an enhanced surface area, dispersion, and total basicity compared to the parent calcined seashells. The fatty acid methyl ester (FAME) yield attained over ZSA-500 was 99 wt.% and dropped by 3% after five repetitive uses when the reaction was performed for 3 h at 60°C and ambient pressure with 10 wt.% catalyst and a methanol:oil molar ratio of 30:1. Structural and thermal analysis indicated that the active phases of ZSA-500 had a high stability against the glycerol adsorption as well as the phase transformation to calcium glyceroxides (Ca(C₃H₇O₃)₂).     

Photocatalytic degradation of omethoate using NaY zeolite-supported TiO2

The degradation of omethoate was conducted using H₂O₂ as oxidant, TiO₂ supported on NaY zeolite as photocatalyst and a 300W lamp as light source. The effect of the calcination temperature of the photocatalyst, the amount of TiO₂ loaded on NaY zeolite, the photocatalyst amount, the pH value and the radiation time on the degradation ratio of omethoate were investigated. The results show that TiO₂/NaY zeolite photocatalyst prepared by sol-gel method had good photocatalysis. The photocatalytic optimum oxidation conditions of omethoate are as follows: the calcination temperature of the photocatalyst is 550°C,the amount of TiO₂ loaded on NaY zeolite is 35.2 wt-%, the amount of photocatalyst is 5 g/L, pH = 8 and the radiation time is 180 min. Under these conditions, the removal ratio of omethoate is up to 93%.     

噻吩在CeY分子筛上的吸附行为

采用智能质量分析(IGA)和程序升温脱附和微分程序升温脱附（TPD/DTPD）法研究了噻吩在CeY上的热脱附行为和吸附热力学,并和NaY进行对比。发现噻吩在CeY分子筛上有很好的选择性吸附,噻吩和CeY分子筛之间的吸附主要是金属离子和硫原子的化学键力作用,而在NaY上的吸附作用属于分子间力作用。吸附热力学也证明了噻吩在CeY上既有物理吸附作用也有强的化学吸附作用。     

CO2 Capture Using CaO Modified with Ethanol/Water Solution during Cyclic Calcination/Carbonation

The calcium‐based sorbent cyclic calcination/carbonation reaction is an effective technique for capturing CO₂ from combustion processes. The CO₂ capture capacity for CaO modified with ethanol/water solution was investigated over long‐term calcination/carbonation cycles. In addition, the SEM micrographs and pore structure for the calcined sorbents were analyzed. The carbonation conversion for CaO modified with ethanol/water solution is greater than that for CaO hydrated with distilled water and is much higher than that for calcined limestone. Modified CaO achieves the highest conversion for carbonation at the range of 650–700 °C. Higher values of ethanol concentration in solution result in higher carbonation conversion for modified CaO, and lead to better anti‐sintering performance. After calcination, the specific surface area and pore volume for modified CaO are higher than those for hydrated CaO, and are much greater than those for calcined limestone. The ethanol molecule enhances H₂O molecule affinity and penetrability to CaO in the hydration reaction so that the pores in CaO modified are obviously expanded after calcination. CaO modified with ethanol/water solution can act as a new and promising type of calcium‐based regenerable CO₂ sorbent for industrial applications.     

频率响应法研究噻吩在分子筛上的吸附行为

运用频率响应方法（Frequency Response）研究了噻吩在NaY分子筛和CeY分子筛上的吸附行为,在（335～473） K和（13.3～133.3） Pa绘制频率响应谱图,并根据频率响应谱图计算每个吸附过程的动力学参数。研究结果表明,噻吩在NaY和CeY分子筛上的吸附均以吸附为速率控制步骤,噻吩在NaY分子筛上的吸附是由于π电子作用和孔填充机理;噻吩在CeY分子筛上的吸附过程是由于π络合和形成S—M键的机理。     

Sulphur dioxide removal using South African limestone/siliceous materials

This study presents an investigation into the desulfurization effect of sorbent derived from South African calcined limestone conditioned with fly ash. The main aim was to examine the effect of chemical composition and structural properties of the sorbent with regard to SO₂ removal in dry-type flue gas desulfurization (FGD) process. South African fly ash and CaO obtained from calcination of limestone in a laboratory kiln at a temperature of 900 °C were used to synthesize CaO/ash sorbent by atmospheric hydration process. The sorbent was prepared under different hydration conditions: CaO/fly ash weight ratio, hydration temperature (55-75 °C) and hydration period (4-10 h). Desulfurization experiments were done in the fixed bed reactor at 87 °C and relative humidity of 50%. The chemical composition of both the fly ash and calcined limestone had relatively high Fe₂O₃ and oxides of other transitional elements which provided catalytic ability during the sorbent sorption process. Generally the sorbents had higher SO₂ absorption capacity in terms of mol of SO₂ per mol of sorbent (0.1403-0.3336) compared to hydrated lime alone (maximum 0.1823). The sorbents were also found to consist of mesoporous structure with larger pore volume and BET specific surface area than both CaO and fly ash. X-ray diffraction (XRD) analysis showed the presence of complex compounds containing calcium silicate hydrate in the sorbents.     

Recovery of Zinc Ions From the Resulting Solution after Copper Cementation with Metallic Zinc

In this study, recovering of zinc ions in the residual solution occurring after copper cementation by zinc metal was investigated. The zinc ions in the solution were recovered by using sodium bicarbonate as precipitation agent. After the precipitated product was separated from the solution, it was dried at 80°C for 5 h in an oven and was subjected to the calcination process to obtain zinc oxide. The XRD and SEM analyses of the precipitated and calcined products were carried out. It was determined that the precipitated solid was Zn₅(CO₃)₂(OH)₆ (hydrozincite) and the calcined product was ZnO.     

Doping effects of cerium ion on structure and electrochemical properties of polyaniline

Polyaniline (PANI)/Ce³⁺ and PANI/Ce⁴⁺ composites were successfully prepared by in situ polymerization in an aqueous solution of poly(2‐acrylamido‐2‐methylpropane sulfonic acid) and characterized by Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, X‐ray photoelectron spectroscopy, SEM, TEM and electrochemical methods. The results showed that the PANI/Ce ion composites had a high degree of sphericity, high electrical conductivity and good electrochemical performance. The conductivity of PANI/Ce(NO₃)₃ reaches a maximum of 46.76 S cm^?1 at 20 wt% of Ce(NO₃)₃. It is increased by 377% by comparison with that of pure PANI. In particular, the polarization results showed that the corrosion current density (0.47 µA cm^?2) and the inhibition efficiency (97%) of PANI/Ce(NO₃)₃ were better than the results for PANI and PANI/Ce(SO₄)₂ composite. This suggested that the PANI/Ce(NO₃)₃ composite has promising applications in conductive materials, anticorrosion coatings and other related fields. © 2017 Society of Chemical Industry     

Effect of Calcination Temperature of Kaolin Microspheres on the In situ Synthesis of ZSM-5

ZSM-5 zeolite has been successfully synthesized in-situ on calcined kaolin microspheres by the hydrothermal method using n-butylamine as a template. The supported ZSM-5 was characterized by X-ray diffraction and scanning electron microscopy. The effect of calcination temperature of kaolin microspheres on the in-situ synthesis of ZSM-5 was investigated. The influence of the pretreatment temperature on the properties of kaolin microspheres including phase transformation, amounts of active SiO₂ and Al₂O₃, and pore structures, was studied using fourier transform infrared (FT-IR), nitrogen adsorption and chemical analysis. The results showed that when the calcination temperature increased from 300 to 900 °C, the amount of active SiO₂ in the kaolin microspheres increased slightly and the amount of active Al₂O₃ initially increased rapidly and then decreased steadily. The surface area and pore volume of the kaolin calcined at both low and high temperatures was less than those of kaolin calcined at a medium temperature. The property changes of kaolin caused the relative crystallinity of in situ synthesized ZSM-5 to vary.     

Synthesis of Porous Submicron Gd0.1Ce0.9O1.95 Particles by Carbon Nanoparticle-Addition Ultrasonic Spray Pyrolysis (CNA-USP) and Nanoparticle Preparation by Ball Milling

A new ultrasonic spray pyrolysis method, called carbon nanoparticle-addition ultrasonic spray pyrolysis (CNA-USP), is developed to synthesize nanoparticles of electrolyte material for solid oxide fuel cell applications. In CNA-USP, carbon nanoparticles are added in a precursor solution. First, Gd_0.1Ce_0.9O_1.95 (GDC) particles were synthesized from an aqueous solution of Ce(NO₃)₃ 6H₂O and Gd(NO₃)₃ 6H₂O by using the CNA-USP method. The resulting synthesized GDC particles were agglomerated, porous, primary particles on the order of 10 nm in diameter. EDX images revealed uniform distributions of Ce, Gd, and O in these porous particles. Then, these agglomerated, porous submicron GDC particles were ground into primary nanoparticles by ball milling for 24 h. The average diameter of the ground GDC nanoparticles was about double of their average crystallite size.

Copyright 2014 American Association for Aerosol Research     

Changes in the chemical composition of V2O5-loaded CVC-TiO2 materials with calcination temperatures for NH3-SCR of NOx

In this study, the aim was to evaluate the effect of calcinations temperature on the catalytic activity and chemical composition of V₂O₅/TiO₂. We prepared V₂O₅-loaded CVC-TiO₂ catalysts by a combination of chemical vapor condensation (CVC) and impregnation method at different calcination temperatures. These catalysts were analyzed for their ability to catalyze NH₃-based selective catalytic reduction of NO_x. Compared with V₂O₅ loaded P25-TiO₂ (commercial). V₂O₅/CVC-TiO₂ catalysts calcined above 200 °C exhibited better performance towards NO_x conversion than that by a commercial catalyst prepared using P25-TiO₂ (calcined at 500 °C). In addition, the NO_x conversion rate obtained with the sample calcined at 500 °C gave the best result (90 %) at a reaction temperature of 200 °C. From the XPS results, we observed that the V^4+/5+ ratio was well balanced when the V₂O₅ loaded CVC-TiO₂ sample was calcined at 500 ºC.