SO42-/TiO2-ZrO2固体酸催化乌桕籽油制备生物柴油的研究

乌桕籽油是一种可再生的木本植物油料,可与甲醇发生酯交换反应制得生物柴油.试验表明,固体酸催化剂SO42-/TiO2-ZrO2对乌桕籽油酯交换反应表现出了较高的催化活性,当反应温度为150 ℃、醇油物质的量比为12:1、催化剂用量为乌桕籽油质量的5%、反应时间为6 h时,乌桕籽油的酯化率达到95%以上,催化剂重复和再生使用效果良好.同时,对该催化剂的SEM,TEM,XRD,BET结构表征表明,该催化剂表面呈多孔状,颗粒大小分布在10～100 nm,比表面积为114 m2/g,是一种纳米固体催化剂.     

稀土固体超强酸SO42-/SnO2-CeO2催化合成生物柴油

以工业棕榈酸和甲醇为原料,采用溶胶-凝胶法制备稀土固体超强酸催化剂SO42-/SnO2-CeO2,催化合成生物柴油。考察了稀土氧化铈添加量、焙烧温度、焙烧时间、硫酸浓度、醇酸质量比、催化剂用量和反应时间对酯化反应的影响。结果表明,当氧化铈添加量为5%时,在2.0 mol/L硫酸浸渍后,于550℃下焙烧3 h制备的催化剂性能最好。正交试验结果表明,合成生物柴油的优化条件为醇酸质量比为15∶25,催化剂用量为棕榈酸质量的4%,反应时间为4 h,在此条件下,酯化率为95.4%。经GC-MS分析,酯产物主要为直链十六烷酸甲酯和10-十八碳烯酸甲酯。     

催化合成生物柴油的双金属络合物固体催化剂

制备了基于亚铁氰化锌的双金属氰化物络合物(DMC),可一步同时催化酯交换和酯化反应制备生物柴油,该催化剂体系具有不受水毒性影响的特点。用3wt%的DMC催化剂在433K,醇油摩尔比为16∶1以及水和脂肪酸含量各10wt%的条件下分别同时催化甘油三酯、脂肪酸和甲醇的酯交换、酯化反应,生物柴油产率可达98%以上。对催化剂进行X射线衍射、热重红外联用分析、元素分析、比表面积和孔体积测定、扫描电镜等手段表征,结果表明:该催化剂为晶态与非晶态组分混合结构,其表面晶态决定其在高水含量、高酸值的环境下仍具有较好的催化活性,验证得出活性位点可能为锌离子。     

固体碱催化猪油制备生物柴油

运用实验研究和理论分析相结合的方法,阐述猪油和甲醇在CaO催化剂作用下进行酯交换反应制取生物柴油的基本原理和操作方法,分光光度法测定甘油含量,计算生物柴油转化率,得出以CaO催化猪油制取生物柴油的适宜反应条件。结果表明:CaO做催化剂时,催化剂用量为2.0%,醇油物质的量比为6∶1,反应时间为150min,温度为60℃进行磁力搅拌,反应产率最高可达93.68%。     

多相催化剂用于制备生物柴油的研究进展

生物柴油是绿色可再生能源,属环境友好型燃料,是常规的化学柴油的优良替代品。综述了酯交换方法生产生物柴油过程中的多相催化剂的研究进展,主要包括固体酸催化剂、固体碱催化剂、固定化酶的研究状况,并对催化油脂酯交换反应的多相催化剂的今后研究方向提出几点建议。     

钙镁负载型固体碱制备生物柴油的研究

研究了CaO-MgO/SiO2负载型固体碱催化剂的制备条件,并对其进行XRD、FT-IR、BET和CO2-TPD表征分 析,仪器分析表明CaO成功引入到载体,MgO起助催化作用增强了碱性并研究该固体碱催化剂酯交换反应催化毛豆油制备生物柴油的条件.考查反应时间、反应温度、醇油比、催化剂用量和原料中水分含量的影响.研究表明,在反应时间6h,反应温度65℃,醇油比18:1,催化剂用量3%,原料油水份含量低于1%时,生物柴油收率可达95.4%,甘油收率达96%以上.     

植物油制备生物柴油的研究

以植物油为原料，在催化剂（KOH）的作用下，通过甲醇酯交换反应生成脂肪酸甲酯即生物柴油的试验研究，考察了醇油比、催化剂用量、反应温度、反应时间等反应条件的变化对植物油转化率和产品纯度的影响。     

固体超强酸催化微晶纤维素水解制备乙酰丙酸

乙酰丙酸是一种重要的平台化合物,其应用十分广泛。研究发现,多种固体酸可以催化微晶纤维素合成乙酰丙酸,其中固体超强酸SO42-/Ti O2催化效果最佳,通过BET比表面积,XRD,NH3-TPD和元素分析等手段对催化剂性质进行了表征。该研究以SO42-/Ti O2为催化剂,考察了反应时间、反应温度、催化剂用量对乙酰丙酸收率的影响,并使用GC对反应产物进行了分析。在反应温度为210℃,反应时间为1h,SO42-/Ti O2催化剂的用量为纤维素质量的2.5%时,乙酰丙酸的收率为68.5%。     

离子液体催化制备生物柴油的研究进展

生物柴油作为一种可再生的绿色能源,一出现就被赋予了替代化石燃料的使命。研发符合环境要求、活性高的催化剂及制备工艺是推动生物柴油走向产业化的重要一步。离子液体因其蒸汽压低、化学稳定性好、循环使用性好、结构可设计等优点,在近几年生物柴油的制备研究中常被作为催化剂使用。对生物柴油离子液体催化剂的研究,从单核功能化离子液体催化剂的研究开始,到双核离子液体,直至近两年出现的离子液体聚合物催的研究。随着研究的深入,离子液体催化剂的结构与其催化活性之间逐渐出现了一定的关联性,这种关联性将为进一步深入研究催化机理奠定基础。     

新型纸浆污泥生物炭基催化剂的制备及其催化合成生物柴油研究

以纸浆污泥生物炭为载体制备固体碱催化剂，并将其应用于生物柴油的制备。催化剂的物理化学性质通过热重分析（TG）、扫描电子显微镜及X射线能谱分析（SEM-EDS）、傅里叶变换红外光谱（FTIR）、X射线衍射（XRD）、N2吸附/脱附和CO2-TPD进行表征。结果表明：由于30K/PPSB-600催化剂的总碱度最高，具有非常好的的催化性能（生物柴油最大产率为98.5%）。此外，对催化剂的稳定性和利用周期性进行多次实验。通过8次回收实验后，新催化剂仍具有较高的催化性能（生物柴油产率为80%），其中少量失去催化活性的原因是K+的流失。     

整体型V2O5-WO3-MoO3/TiO2催化剂的制备

采用静态氮物理吸附法、X射线衍射及扫描电镜对自行研制的V2O5-WO3-MoO3/TiO2催化剂进行了物化性能表征测定,并在固定床连续积分反应器上进行了活性评价,研究了V2O5、WO3、MoO3等成分的含量对催化剂活性的影响,以及催化剂制备过程中浸泡时间、浸泡液浓度、温度等因素对催化剂负载量的影响.结果表明：催化剂活性成分及助剂比例均存在着最佳值,试验制备的催化剂V2O5/TiO2最佳比例为3%左右,WO3/TiO2比为15%,MoO3/TiO2比为30%;浸泡时间、浸泡液浓度对催化剂负载量的影响基本上呈指数衰减,在足够长的时间内,浸泡液温度只影响催化剂的负载速度,而对于负载量的影响可以忽略.     

Preparation and application of Ce/ZrO2−TiO2/SO42− as solid catalyst for the esterification of fatty acids

To develop heterogeneous and reusable catalyst for the esterification of fatty acids, in presence of triglycerides, sulfate species has been incorporated over Ce/ZrO₂–TiO₂ support. The catalyst activity was found to be a function of its Bronsted acidic sites which in turn depends on the cerium concentration in catalyst. The esterification of oleic acid with methanol or ethanol in presence of prepared catalyst has followed the first order kinetics and Koros–Nowak test has demonstrated that reaction rates are independent from diffusion limitations. An increase in acid or alcohol alkyl chain length (steric factor) was found to show negative effect on the esterification activity of catalyst. Although, the catalyst was able to catalyze the esterification even in presence of up to 12 wt% moisture (with respect to fatty acids), however, a decrease in turn over frequency (TOF) was observed. The catalyst has shown excellent stability as negligible sulfate leaching was observed and recovered catalyst was reused in five successive runs without significant loss in activity.Even in presence of triglyceride (vegetable oil) the catalyst was able to convert >98% free fatty acids into respective esters. The esterified oils were fruitfully employed, without any pre-neutralization and water washing, in homogeneous alkali catalyzed transesterification to achieve >98% fatty acid methyl ester (FAME) yield.     

气相沉积制备V2O5-WO3/TiO2催化剂及其脱硝性能的研究

以堇青石蜂窝陶瓷为基体,应用化学气相沉积技术(CVD)负载TiO2载体,浸渍V、WW化合物溶液,制备出V2O5-WO3/TiO2脱硝催化剂.利用扫描电子显微镜(SEM)、X射线能谱仪(EDS)、X射线衍射仪(XRD)和X射线荧光光谱仪(XRF)等表征催化剂微观结构和成分,并利用自行研制的活性评价装置分析了催化剂的脱硝效率.结果表明:制备的催化剂比表面积为78.8m2/g,平均孔径为6.8 nm;锐钛型TiO2载体在堇青石基体上沉积均匀、排列紧密,V2O5在TiO2载体上无定形态单层分散,微量V2O5在微区长大成针状,宽度均小于100 nm;在350℃、空速为1 000 h-1、nNH3/nNO摩尔比=1时,催化剂NO的脱除效率ηNO可达到98.3%.     

Preparation and hydrogen penetration performance of TiO2/TiCx composite coatings

Titanium carbide is a good candidate for tritium permeation barrier in a fusion reactor. However, its oxidation susceptibility and the mismatch between the ceramic coating and substrate are still a challenge. In this study, a promising candidate as a hydrogen permeation barrier, comprising a titanium-based ceramic TiO₂/TiC_x composite coating, was proposed. The preparation process of this TiO₂/TiC_x composite coating involves two steps of carbon ion implantation and oxidation under ultra-low oxygen partial pressure. According to the results, the optimal oxidation temperature for TiO₂ coating is 550 °C, with the increase of the oxidation temperature, the particles on the surface of the oxide layer become coarse and loosely arranged, and the protective performance of the oxide layer is greatly reduced. The hydrogen barrier permeation behavior of the composite coating in a fusion reactor was simulated via hydrogen plasma discharge environment, the results show that the hydrogen barrier permeation performance of the composite is significantly better than that of a single TiO₂ coating. In addition, the coatings treated with hydrogen plasma showed a certain self-repairing performance through the diffusion growth of the TiC_x layer. These findings illustrate a novel method for preparing composite coatings to restrain hydrogen permeation, providing insight into the development of hydrogen permeation barrier materials.     

Preparation and Characterization of CaO/CaSO4/Coal Fly Ash Sorbent for Sulfur Dioxide (SO2) Removal: Part I

A 2 level full factorial design of experiment was used to evaluate the significance of four sorbent preparation variables towards the structural properties of sorbent prepared from coal fly ash, calcium oxide (CaO) and calcium sulfate (CaSO₄) for flue gas desulfurization. The structural properties studied were BET specific surface area and average pore size of the sorbent while the experimental sorbent preparation variables studied were hydration period (x ₁), ratio of CaO to fly ash (x ₂), amount of CaSO₄ (x ₃), and drying temperature (x ₄). The surface area and average pore diameter of the sorbent obtained in this work range from 12.9 to 92.7 m²/g and 48.4 to 159.5 nm, respectively. The results revealed that there were significant influence of all the variables studied on the average pore diameter of the sorbent while only variables x ₁, x ₂, and x ₃ had significant influence on the surface area of the sorbent. X-ray diffraction (XRD) analysis revealed that the main phases detected in the sorbent was calcium alumino silicate hydrate compound. Scanning electron microscope (SEM) analysis showed that the sorbent consists of irregular shape particles that have a high structural porosity.     

V2O5-WO3/TiO2催化剂的制备及其动力学分析

采用浸渍法制备了V2O5-WO3/TiO2催化剂,考察了各运行工况对催化剂脱硝活性的影响,在实验的基础上,建立了经验性催化反应动力学方程。结果表明：当催化剂粒径小于40目、空速小于30000h-1时,可以消除SCR脱硝反应的内外扩散的影响。V2O5-WO3/TiO2催化剂的催化还原反应是一级催化反应,反应活化能为能为24232 J/mol,在消除内外扩散影响和NH3/NO比大于1的情况下,NO的反应级数为1.0493,O2的反应级数为1.1366,从而可以得到V2O5-WO3/TiO2催化剂催化反应速率方程式。     

Photocatalytic hydrogen production by reforming of methanol using Au/TiO2, Ag/TiO2 and Au-Ag/TiO2 catalysts

Abstract

We have investigated polyvinylalcohol stabilized Au and Ag based nanoparticles supported on titania prepared via sol immobilisation for the anaerobic, ambient temperature reforming of methanol with water for the photocatalytic production of hydrogen. The catalytic activity of the Au/TiO₂ catalysts was strongly affected by the metal loading and calcination temperature. Here, we report the preparation and use of supported Au–Ag nanoparticles, based on either the co-reduction or the consecutive reduction of the two metals. Au–Ag supported catalysts were more active than monometallic Au and Ag catalysts and the preparation methodology had a pronounced effect in terms of catalytic activity of the Au–Ag catalysts. In fact, using a consecutive reduction where Au was firstly reduced followed by reduction of Ag gave materials which exhibited the highest catalytic performance.     

TiO_2/C复合毫米球的制备及可见光催化活性研究

应用溶剂热条件下离子交换方法制备了C掺杂TiO2毫米球光催化剂。并通过元素分析、X射线衍射(XRD)、紫外-可见(UV-Vis)漫反射对其进行了表征。结果表明,TiO2为锐钛矿相,UV-Vis漫反射分析显示,与商业用P25相比,TiO2吸收边带红移,可见光吸收增强,同时证明C以掺杂的方式对TiO2进行了改性。以可见光催化降解甲基橙(MO)考察了材料的光催化活性,与P25相对比,C掺杂TiO2的光催化活性明显提高,并且催化剂可以通过自身重力沉降到反应容器底部,实现自分离。