MIL-101（Cr）在H2O2氧化环己烷反应中的催化性能

采用水热合成法制备了MIL-101(Cr)催化剂,考察了反应条件对其在H2O2氧化环己烷反应中催化性能的影响。利用XRD、FT-IR和UV-Vis等手段对MIL-101(Cr)反应前后结构的变化进行了表征。结果表明,MIL-101(Cr)在所选择的反应体系中存在Cr析出现象,其结构在以H2O2为氧化剂的反应体系中不稳定,经反应后形成了无定型物质,但催化活性不仅远高于新鲜MIL-101(Cr),而且还在重复利用中表现出良好的稳定性。     

Modification of Amberlite XAD-2 resin for U(VI) adsorption from Egyptian crude phosphoric acid

Adsorption of U(VI) from Egyptian crude phosphoric acid was studied using the modified Amberlite XAD-2 resin. Modification process was performed by soaking Amberlite XAD-2 resin in tri-butyl phosphate (TBP) and di-2-ethyl hexyl phosphoric acid (D₂EHPA) for increasing its adsorption capacity via equilibrium batch technique. For this purpose, different effective parameters such as: a dose of adsorbent, contact time, temperature, phosphoric acid concentration, and initial uranium (VI) concentration were investigated. The maximum sorption capacity by the modified resin achieved 67?mg?g^?1 of U (VI). Sorption of U (VI) follows both the Langmuir and Freundlich adsorption isotherms. Not less than 93% of the U (VI) uptaken by the modified Amberlite XAD-2 resin was desorbed using 1?mol?L^?1 NaCl?+?0.1?mol?L^?1 H₂SO₄.     

Deep Desulfurization of Model Gasoline by Adsorption on Mesoporous CeMCM-41

Abstract

Cerium atoms have been introduced into the framework of MCM-41 by a hydrothermal synthesis method with cetyltrimethylammonium bromide (CTMABr) as template, sodium silicate as silica source, and cerium chloride as cerium source. Desulfurization of various model fuels containing about 500 μg/g sulfur were studied over the synthesized CeMCM-41 with a liquid hourly space velocity of 7.5 hr^?1 at ambient conditions. The sulfur adsorption capacity was 10.0, 11.8, 14.0, and 15.4 mg(S)/g adsorbent for thiophene, dibenzothiophene (DBT), 4,6-dimethyldibenzothiophene (4,6-DMDBT), and tetrahydrothiophene (THT), respectively. The charges on S atom in thiophene, DBT, 4,6-DMDBT, and THT, calculated by using density functional theory (DFT), are ?0.159, ?0.211, ?0.214, and ?0.298, respectively, implying that the S-M bond between the adsorption sites and thiophene is much weaker than that between the adsorption sites and DBT, 4,6-DMDBT, or THT.     

Polyethylenimine-functionalized magnetic amorphous carbon fabricated from oil palm leaves as a novel adsorbent for Hg(II) from aqueous solutions

PEI (polyethylenimine) functionalized magnetic amorphous carbon thin film nano composite (Fe₃O₄-PEI-ACTF NC), was successfully synthesized and characterized by High Resolution Transmission Electron Microscope (HR-TEM), X-ray diffraction (XRD), Fourier-transform infrared spectrometer (FTIR), and Thermo gravimetric analysis (TGA). The synthesized nano composite Fe₃O₄-PEI-ACTF was developed as a highly efficient adsorbent for Hg(II) from aqueous samples. Effect of pH, contact time, adsorbent dose, initial concentration and temperature were investigated and optimized through batch adsorption technique. Besides, good magnetic performance of Fe₃O₄-PEI-ACTF NC makes it easily recovered from water with magnetic separation at low magnetic field. The adsorption kinetic data described well with the pseudo-second-order model and the equilibrium data fitted well to Langmuir isotherm model. The maximum adsorption capacity was 714?µg/g of Hg(II). Thermodynamic studies (ΔG°?<?0, ΔH°?>?0, ΔS°?>?0) implied an endothermic and spontaneous adsorption process in nature. Furthermore, the excellent reproducibility indicated that Fe₃O₄-PEI-ACTF NC has a promising application for removing heavy metals from aqueous environments due to high adsorption capacity and easily and quick separation.     

Preparation and Characterization of Novel Magnetic ZnFe2O4–Hydroxyapatite Core–Shell Nanocomposite and Its Use as Fixed Bed Column System for Removal of Oil Residue in Oily Wastewater Samples

Using magnetic nanoparticles to remove the dispersed oil from produced water is a promising way to overcome the difficulties faced by current treatment technologies. Therefore, in this study, novel ZnFe₂O₄-hydroxyapatite core-shell nanocomposites (ZFHA) was prepared by precipitation method and investigated as an adsorbent to remove residual oil from produced wastewater. The prepared ZFHA nanocomposites were studied by FTIR, X-ray diffraction, HRTEM, SAED, and EDX. The results revealed that hydroxyapatite was coated on the ZnFe₂O₄ surface and formed a core-shell structure. The effect of various parameters on oil adsorption process like bed height (59, 118 and 178 mm), flow rate (1, 3 and 5 mL min⁻¹), effect of temperature 25–77 °C, initial oil concentration (100, 500, 1000 and 10,000 ppm) and pH (2–10) were investigated. The experimental data showed that with increased column bed depth from 59 to 178 mm, breakpoint time (t_b) increased from 30 to 48 min. The highest equilibrium adsorption capacity of oil at optimum conditions (77 °C, 10,000 ppm, 3 mL/min and 178 mm) were estimated to be 3500 mg L⁻¹. The contact time decreased with the increase of bed height and flow rate. Adsorption kinetic was evaluated in a fixed bed column. Finally, the regeneration of the exhausted ZFHA adsorbent was assessed; which revealed satisfactory results for three times reusability after saturation. Therefore; ZFHA could be applied effectively for adsorption of residual oil from synthesis oily wastewater samples prepared from produced water of Egyptian fields of the petroleum industry.     

Ni-Zn复合氧化物用于反应吸附脱除噻吩

采用均匀共沉淀法制备了Ni-Zn复合氧化物吸附剂,并在固定床上考察了预还原、吸附条件、模拟油的不同组分对其吸附脱硫性能的影响。结果表明,还原态的Ni是吸附剂的主要活性成分,吸附反应最适宜的温度和压力分别为673 K、1.0 MPa,模拟油中的烯烃组分对吸附剂脱硫性能的影响比芳烃的影响大。吸附剂在温度673 K、压力1.0 MPa、液时空速60 h^-1、氢气与模拟油的体积比为200（氢气体积为标准状态下的体积）时对含硫质量浓度100 mg/L的模拟油A的硫容为360 mg/g。噻吩首先在Ni原子上进行氢解生成H₂S,然后H₂S快速与ZnO结合生成ZnS。此外该吸附剂对原料有很好的适应性,并具有很好的再生性能。     

金属有机骨架材料MIL-100(Fe)的一氧化碳吸附性能

采用水热法合成金属有机骨架材料MIL-100(Fe),并用XRD和氮气吸附方法考察了材料的晶体结构和比表面积,测试了材料在不同活化条件下的CO吸附容量。结果表明,活化后MIL-100(Fe)与不饱和气体分子CO作用力显著增强,250℃活化12h后,0.1MPa下样品的常温CO吸附量可达30.1cm3/g,而同条件下的N2吸附量只有3.9cm3/g,具有良好的CO/N2吸附分离性能。     

CO2 adsorption on systems involving ethylenediamine impregnated on nanoporous materials

Abstract

MCM-41 and MCM-48 materials were synthesized by the hydrothermal method, calcined and modified with ethylenediamine (EDA) by wet impregnation method. The X-ray diffraction patterns showed characteristic peaks of highly ordered MCM-41 and MCM-48 nanoporous materials, even after impregnation with amine. The MCM-41 and MCM-48 materials showed N₂ adsorption isotherms type IV and BET surfaces areas higher than 1000?m² g^?1. The carbon dioxide adsorption tests were carried out at room temperature in a magnetic suspension microbalance. The materials presented good performance for CO₂ capture, being favorable for applications where medium and high pressures are required.     

Magnetic hybridized Fe3O4/HKUST-1 composite modified with graphite oxide to remove thiophene from model fuels

Abstract

To improve the desulfurization adsorption performance of the magnetic hybrid material Fe₃O₄/HKUST-1, an innovative adsorbent Fe₃O₄/GO/HKUST-1 was synthesized. The desulfurization performance of Fe₃O₄/GO/HKUST-1 increased 24%, and the adsorption capacity increased to 38.21?mg/g because of a higher surface area and higher porosity than the parent materials. Moreover, the desulfurization capacity of Fe₃O₄/GO/HKUST-1 decreased 10% after five adsorption desorption cycles. Therefore, excellent adsorption properties and reusability make Fe₃O₄/GO/HKUST-1 attractive in the field of fuel desulfurization.     

Modification and characterization of NaY molecular sieve by Cr3+ and its adsorptive denitrogenation from model fuel

Abstract

The CrY, which was modified by Cr³+ from NaY, was confirmed by characterization with FT-IR, XRD, N₂ adsorption-desorption, and it was used to adsorb quinoline from model fuel. The suitable modification conditions were modified twice by 0.5?mol/L cobalt nitrate solution at 40?°C. The FT-IR spectra indicated the disappearance of 1147?cm^?1 peak and the blue shift of 1024?cm^?1, implying that Cr³+ had exchanged Na⁺ and successfully incorporated into the framework of NaY. The static denitrogenation experimental results indicated that the adsorption between quinoline and CrY was the coordination adsorption and π complex adsorption. The suitable conditions were 30?min at room temperature and the adsorption temperature had minor effect on denitrogenation. The kinetic model of CrY adsorbing quinoline belonged to Langmuir and Freundlich adsorption model.     

Evaluation and modeling of Fischer-Tropsch synthesis in presence of a Co/ZrO2 catalyst

Abstract

The present work focused on the application of response surface methodology (RSM), Box–Behnken design (BBD), for prediction of products distribution of Fischer-Tropsch synthesis (FTS) using a Co/ZrO₂ catalyst in a fixed bed reactor. The effect of four independent operating variables such as reaction temperature, pressure, space velocity and H₂/CO ratio on the responses (CH₄ and C₅⁺ selectivities) in FTS were investigated. The analysis of variance (ANOVA) results showed that the suggested quadratic models could well predict CH₄ and C₅⁺selectivities. The optimized operating condition was temperature 200.73?°C, pressure 20?bar, space velocity 1662.58?h^?1 and H₂/CO ratio 1.93.     

Adsorption of asphaltenes onto CaO,Co3O4, Fe3O4 and ZnO supported on 13X zeolite - An isothermal study

Abstract

Asphaltene has the highest molecular weight and the most polar organizers from petroleum. In this paper, the content of the asphaltenes from a crude oil was extracted and the amount of asphaltene in crude oil was measured to be 3.88%. Four metal oxides were added to 13X zeolite and 13X,10%CaO, 13X,10%Co₃O₄, 13X,10%Fe₃O₄ and 13X,10%ZnO were prepared. The adsorption behavior of the adsorbents was evaluated in asphaltenes adsorption. The capacity of the adsorbent for asphaltenes adsorption is as follows: 13X,10%CaO> 13X,10%Co₃O₄> 13X,10%Fe₃O₄> 13X,10%ZnO. The isotherm of adsorption of the asphaltenes over the adsorbent was studied and resulted that the experimental data could best fit with the Langmuir model, indicating that adsorption is as a monolayer.     

Molecular dynamics of methane adsorption in shale

In this paper, the supercritical gas molecule adsorption characteristics of methane in shale are quantitatively described by using the lattice theory. The results show that the methane adsorption capacity predicted by this theory is high, with the average absolute error 0.003 3 mmol·g^?1. There is a near-linear positive relationship between the adsorption potential between methane and the solid surface (?_s) and the experimental temperature. The value of the average potential between the adsorbate molecules (?_a) is distributed in ?0.841–1.791 kJ·mol^?1, and the absolute value of ?_a is significantly smaller than the absolute value of ?_s, indicats that the potential energy between the adsorbate molecules is significantly smaller than that between the adsorbate molecules and the pore surface of shale. When the temperature is relatively low (T = 308.55 K), the value of ?_s/?_a is 7.5 times; with the increases of the temperature, the magnification will gradually decrease and keep stabilize (3.37 times).     

Regeneration of AgXO@SBA-15 for reactive adsorptive desulfurization of fuel

Adsorbent regeneration is critical for a continuous adsorption–regeneration process and often underestimated. In this work,the regeneration of bifunctional AgXO@SBA-15 for [O]-induced reactive adsorptive desulfurization of liquid fuel is reported and further investigated. The spent AgXO@SBA-15 was regenerated in various types of solvents followed by calcination and tested in multiple desulfurization–regeneration cycles. The effects of regenerate solvents were also compared systematically. The original and regenerated AgXO@SBA-15 was characterized by X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray spectroscopy, N_2 adsorption, X-ray photoelectron spectroscopy and atomic absorption spectrometry. The recovery of desulfurization capacity using various solvents follows the order of acetonitrile [ acetone [ ethanol [ methanol [ water. Owing to the complete reduction of silver species to Ag~0 and severe agglomeration of Ag~0, the bifunctional AgXO@SBA-15 demonstrating [ 85%(2.60 mg-S/g) of sulfur removal dramatically reduced to \ 46%(1.56 mg-S/g) after only 1 st-cycle regeneration. It is suggested that polar organic species strongly adsorbed(or residual) on the spent AgXO@SBA-15, in that case, after solvent wash may contribute to the accelerated decomposition of Ag~+ to Ag~0 in the following calcination step. The desulfurization capacity decreased rather mildly in the later regeneration runs. Cautious choice of regeneration conditions and strategies to rational design stabilized adsorbents is required to avert the adsorbent deactivation.     

Cross-linked chitosan polymers as generic adsorbents for simultaneous adsorption of multiple mycotoxins

The primary objective of this study was to synthesize three types of cross-linked chitosan polymers and further investigate their adsorption capability for multiple mycotoxins, including aflatoxin B₁ (AFB₁), ochratoxin A (OTA), zearalenone (ZEN), fumonisin B₁ (FB₁), deoxynivalenol (DON) and T-2 toxin (T2). Among these synthetic adsorbents, cross-linked chitosan-glutaraldehyde complex presented the highest adsorption capability for AFB₁ (73%), OTA (97%), ZEN (94%) and FB₁ (99%), but no obvious adsorption for DON and T2 (<30%). The effect of various incubation conditions (contact time, dosage and pH) was also studied. Subsequently, the experimental data were fitted to Langmuir, Freundlich and Hill models. The best fitting model to describe AFB₁ and FB₁ adsorption was Langmuir model (R² ≥ 0.99), with the theoretical maximum adsorption amounts of 5.67 mg/g for AFB₁ and 15.7 mg/g for FB₁. The Hill model was the best model for OTA and ZEN adsorption (R² > 0.98), with the predicted maximum adsorption amounts were 24.8 mg/g for OTA and 9.18 mg/g for ZEN. In addition, the adsorption capability of adsorbent for the simultaneous presence of multiple mycotoxins was also evaluated in buffer system and simulated gastrointestinal condition. The results indicated that the coexisted multiple mycotoxins didn't affected the adsorption capability of adsorbent, whereas the adsorption amounts of toxins were decreased by some gastrointestinal components. The findings of this research suggest that chitosan–glutaraldehyde complex has the potential to be applied as multitoxin adsorbent material for reducing the combined adverse effect of multiple mycotoxins on humans and animals.     

甲苯和吡啶对Ag/TiO2-NaY吸附脱硫性能的影响

 以溶胶-凝胶法制备了TiO₂-NaY(TY)分子筛载体,采用浸渍法制备了Ag/TiO₂-NaY(AgTY)吸附剂,并用X射线衍射、傅里叶变换红外光谱和X射线光电子能谱技术对吸附剂进行了表征。在固定床吸附床上考察了含氮化合物和芳香族化合物对AgTY选择性吸附噻吩（TP）和苯并噻吩（BT）性能的影响,并研究了其吸附机理。结果表明,AgTY吸附剂中TiO₂主要以锐钛矿型存在,与NaY相比,TY分子筛的骨架结构并未发生明显的改变;在吸附温度50℃时,AgTY吸附剂对噻吩、苯并噻吩的穿透硫容分别为0.45%和0.63%;对噻吩模拟油,吡啶对吸附脱硫影响比甲苯的影响大,而对于苯并噻吩模拟油,甲苯的影响比吡啶的影响大。噻吩类硫化物与AgTY吸附剂之间主要以π络合及S—M配位作用机理吸附。     

Preparation of the Modified Y Zeolite for Removal of Organic Sulfur Compounds from FCC Gasoline

Abstract

Ce(IV)-loaded modified NaY (NH₄Y) zeolite was prepared for selective adsorptive desulfurization from fluid catalytic cracked (FCC) gasoline. Ce(β)Y was obtained from NH₄Y using a liquid-phase ion-exchange method. Ce(IV)Y was obtained from calcining Ce(β)Y at 550°C. The structures of the Ce(IV)Y and NaY samples, selective adsorption of organic sulfur compounds on Ce(IV)Y and NaY zeolite, sulfur content of FCC gasoline, and mechanism for adsorption of thiophene on Ce(IV)Y and NaY zeolite were investigated using X-ray diffraction (XRD), gas chromatography–sulfur chemiluminescence detection (GC-SCD), sulfur analysis, Fourier transform infrared (FTIR), frequency response (FR), and intelligent gravimetric analysis (IGA). The selective adsorption desulfurization from FCC gasoline containing organic sulfur compounds (S = 135 μg/g) was investigated with Ce(IV)Y adsorbent for removal.

The sulfur content was reduced to 20.14 μg/g. The thiophene adsorption mechanism showed that Ce(IV)Y can adsorb thiophene via π electronic interaction directly, and thiophene and Ce(IV) can form a stable sulfur–metal bond (S-M bond) that enhances the adsorption capacity of Ce(IV)Y for thiophene. This method for the modification of NaY zeolite provides a promising selective desulfurization process to prepare clean fuels.     

Demetallization and desulfurization of heavy oil residues by adsorbents

The purpose of the work is demetallization and desulfurization of heavy oil residues using adsorbents. Optimal parameters of the demetallization and desulfurization processes of heavy vacuum fraction of Pavlodar Petrochemical Plant LLP in the presence of a zeolite adsorbent containing vanadium oxide xerogel were established: temperature 340?°C, pressure 1?atm., bulk feed rate 1?h^?1. As a result of the process the extraction degree of vanadium, nickel and iron were 90, 70 and 60%, respectively, and the sulfur content decreased from 1.97 to 1.36%. Composition of the chemical adsorbent for demetallization and desulfurization of heavy vacuum fraction is established, too. Content of vanadium, iron and sulfur increase in composition of the adsorbent after treatment of heavy vacuum fraction, which confirms its high adsorption capacity regarding to metals and sulfur.     

吸附再生干法烟气脱硫吸附剂的制备

制备出吸附再生干法烟气脱硫吸附剂,研究了活性组分、载体制备方法及制备工艺条件对其吸附性能的影响,考察了其吸附效果与再生能力。结果表明,吸附剂载体以偏硅酸钠、硫酸铝为基本原料,采用凝胶法按偏硅酸钠、硫酸铝、导向剂、黏结剂顺序加料,在90℃晶化条件下制备;吸附剂以M2为活性组分,在浸渍温度为70℃,浸渍时间为4h,焙烧温度为350℃,焙烧时间为6h的条件下制备。按此条件所制备的吸附剂吸附效率达99％～100％,吸附容量达76～83g／kg,烟气经过吸附处理后硫体积分数降低到0．01％以下,达到GB13271—91的最高要求。经过5个循环稳定性实验,吸附剂的吸附率仍保持在99．0％以上,吸附容量在76g／kg以上。     

金属有机骨架材料MOFs用于C8芳烃吸附分离的探索研究

采用混合溶剂热法,以硝酸铝和对苯二甲酸为原料制备了金属有机骨架材料MIL-53;使用XRD、SEM手段对合成样品结构进行表征;通过吸附等温线测试、液相静态吸附平衡实验、脉冲实验评价最优制备方法下材料的吸附性能。结果表明：制备的MIL-53材料呈现均一的尺寸和分布,晶粒尺寸为50~80 nm;该材料在相同温度和压力下对不同组分的吸附量不同,在铝盐与对苯二甲酸摩尔比为1:1的条件下,以2-甲基甲酰胺为溶剂,制备的MIL-53材料的甲苯吸附量最大;合成的MIL-53材料优先吸附邻二甲苯。