Study on Cu-Mn-Based Catalysts for Synthesis of Dimethyl Ether from Carbon Dioxide Hydrogenation

二氧化碳催化加氢直接合成二甲醚既可以利用二氧化碳制得有用的化学品，又可以解决二氧化碳的环境污染问题，对于保证经济的高速发展和实现长期可持续发展战略均具有重要意义。CO2加氢合成二甲醚的双功能催化剂由甲醇合成和甲醇脱水组分复合组成，只有当两种活性组分“协同催化”时，方能充分发挥催化剂的整体功能。本文以铜锰基甲醇合成催化剂和HZSM-5分子筛甲醇脱水催化剂所构成的双功能复合催化剂作为主要研究对象，利用XRD、BET、H2-TPR、SEM、H2-TPD、NH3-TPD、XPS和加压固定床活性评价等多种研究方法系统地考察了下列诸因素对复合催化剂结构和性能的影响：甲醇合成催化剂制备过程中的沉淀温度、PH...Direct synthesis of dimethyl ether (DME) from carbon dioxide by catalytic hydrogenation is of great economical and environmental importance, not only to synthesize the useful chemical products, which will utilize carbon dioxide more efficiently, but also to reduce the greenhouse effect resulting from carbon dioxide. The bifunctional catalysts used for this reaction were composed of the methanol sy...学位：工学硕士院系专业：化学化工学院化学工程与生物工程系_工业催化学号：X20043300

Effect of Ultrasonic Treatment on Cu-Mn-Si/HZSM-5 Catalysts for Dimethyl Ether Synthesis

采用共沉积法、超声共沉积法制备Cu-Mn-SI/HzSM-5复合催化剂,并用bET、SEM、H2-TPr和XPS等手段进行了表征,考察超声处理方法对催化剂催化加氢性能的影响。结果表明,超声处理使催化剂颗粒的分散更为均匀,催化剂的比表面积增大,颗粒度更加细小。H2-TPr和XPS分析表明,经过超声处理后促进了Cu+的生成,增强了铜锰复合氧化物相互作用,有利于催化剂表面活性中心物种Cu+和Mn3+形成。Cu+和Mn3+可能共同构成了Cu-Mn-SI/HzSM-5催化剂的活性中心。Cu-Mn-Si/HZSM-5 catalysts were prepared by co-precipitation method and co-precipitation method combining with supersonic vibration, and characterized by BET, SEM, H2-TPR and XPS to analyze the physical structure and catalytic performance of the catalysts.The results showed that ultrasonic treatment can make partical uniform and tiny, and increase the special surface area.H2-TPR and XPS results suggested that it can promote the creation of Cu+ on surface of catalyst and enhance the interaction of copper-manganese compound oxide, so that active specie Cu are difficult to be reduced by ultrasonic treatment.And ultrasonic treatment could make more Cu+ and Mn3+ formed, promote the interaction of Cu+ and Mn3+.Our study indicated that active centers in Cu-Mn-Si/HZSM-5 catalyst may be Cu+ and/or Mn3+ species

微生物吸附-化学还原法合成金钯纳米线机理研究

采用微生物吸附-化学还原法,以大肠杆菌(ECCs)为模板、十六烷基三甲基溴化铵(CTAB)为保护剂、抗坏血酸(AA)为还原剂制备金钯纳米线(Au-PdNWs),考察不同金钯摩尔比对合成金钯纳米材料的影响,并通过SEM、TEM、XRD等技术进行了表征,研究其形成机理。结果表明,吸附还原作用使ECCs在短时间内还原生成了少量Pd(0)和Au(0),大量的钯离子和金离子聚集在ECCs表面周围;还原剂AA的加入使ECCs表面成为优先成核位点,菌体表面基团与晶核相互作用阻止其迁移;在CTAB的作用下,菌体表面的纳米颗粒逐渐形成链状纳米中间结构,中间结构通过Ostwald熟化作用进一步形成Au-Pd纳米线。通过ECCs和CTAB协同作用,有利于一维纳米结构的生长。福建省教育厅中青年教科研项目(JAT171117);;莆田市工业科技类科研项目(2016G2020

Effect of Various Prepared Method on Catalytic Performance of Cu-Mn-Si/HZSM-5 Catalyst for CO_2 Hydrogenation

分别采用物理混和、共沉积法和超声共沉积法制备了Cu-Mn-Si/HZSM-5复合催化剂,并用XRD、BET、H2-TPR、H2-TPD和NH3-TPD等手段进行了表征,考察3种制备方法对催化剂催化加氢性能的影响。结果表明:超声共沉积法制备的Cu-Mn-Si/HZSM-5催化剂颗粒均匀、粒径小、催化性能最好。H2-TPR、H2-TPD和NH3-TPD分析表明,采用超声共沉积法制备催化剂,更能促进Cu(Ⅰ)、Cu(Ⅱ)之间的相互转换,增强了铜锰复合氧化物相互作用,有利于催化剂表面活性物种Cu+形成。同时,增强了对H2的吸附强度,使表面的酸度增强,促进了催化剂活性的提高。Cu-Mn-Si/HZSM-5 catalysts were prepared via the physical hybrid method,co-precipitation method and Ultrasonic co-precipitation method,and these catalysts were characterized by XRD,BET,H2-TPR,H2-TPDand NH3-TPD to analyse catalytic performance of the catalysts.The results showed that although sonication can not obviously change the physical structure of catalysts,it can make partical uniform and tiny,and.The results indicated that Cu-MnSi/HZSM-5 catalysts prepared by the Ultrasonic co-precipitation method had uniform grain,small grain size and the best catalytic capacity.H2-TPR,H2-TPD and NH3-TPD results suggested that it promote the creation of Cu+ on surface of catalyst and enhance the interaction of copper-manganese compound oxide so that active specie Cu are difficult to be reduced by ultrasonic co-precipitation method.At the same time,adsorption sites for H2 were increased,acidity of surface of catalyst was increased and acid sites were stronger,promoting enhancement of activity of catalyst

Effects of Calcination Temperature on Catalytic Performance of Cu-Mn-Si/HZSM-5 Catalysts

采用共沉淀法制备二氧化碳催化加氢合成二甲醚的催化剂Cu-Mn-SI/HzSM-5,考察了焙烧温度对其催化性能的关系。结果表明:焙烧温度过高、过低均不利于二氧化碳加氢。当焙烧温度为400℃时,在反应过程中有更多的Cu+存在,催化剂的活性最高。当焙烧温度超过400℃时,晶相CuO颗粒变大,催化剂的活性显著降低。在考察的范围内,最适宜的焙烧温度为400℃。The effects of calcination temperature on the catalytic performance of Cu-Mn-Si/HZSM-5 catalysts prepared by co-precipitation method for the synthesis of dimethyl ether by hydrogenation of carbon dioxide were investigated.The results shows that moderate temperature will be the most beneficial to catalytic hydrogenation.When calcination temperature is 400℃ , more Cu+ exists in the reaction process.When calcination temperature is higher than 400 ℃, the particles of CuO become bigger, resulting in the decrease of catalytic activity.The moderate temperature is 400℃ in the researched temperature range

Preparation of Au Nano-Wire with Waste Gold-Containing Catalyst by E.Coli Adsorption-Chemical Reduction Method

采用大肠杆菌吸附-化学还原法,以大肠杆菌(ECCS)为模板、十六烷基三甲基溴化铵为保护剂、抗坏血酸为还原剂,由废含金催化剂制备金纳米线(AunWS)。采用Xrd,SEM,TEM等技术对AunWS进行表征。研究了AunWS对罗丹明6g(r6g)和4-巯基苯甲酸(4-MbA)的拉曼散射信号的增强效果。实验结果表明:在制备过程中加入微生物ECCS,可使金回收率提高约20百分点;当溶液PH小于4时,反应2 H后,有大量呈线状的AunWS聚集沉降,金回收率可达99%1以上。表征结果显示,AunWS呈多晶结构,晶格间距为0.23 nM。表面增强拉曼散射分析表明,AunWS对r6g和4-MbA具有良好的拉曼光谱增强性能。The Au nano-wires(AuNWs) were prepared with waste gold-containing catalyst by E.Coli adsorptionchemical reduction method using E.Coli cells(ECCs)as bio-template,cetyltrimthyl ammonium bromide(CTAB)as protective agent and ascorbic acid(AA) as reducing agent,and characterized by XRD,SEM and TEM.The enhancement effects of AuNWs on Raman scattering signals of Rhodamine 6G(R6G) and 4-sulphur benzoic acid(4-MBA) were studied.The experimental results indicate that:The Au recover rate can be increased by about 20 percent with the addition of ECCs;When the solution pH is less than 4 and the reaction time is 2 h,plenty of linear AuNWs are gathered and settled,and the Au recover rate reaches 99%.The characterization results show that the AuNWs exhibits the polycrystalline structure with 0.23 nm of lattice spacing.The surface-enhanced Raman scattering(SERS) analysis results show that AuNWs have good enhancement effects on Raman spectra of R6 G and 4-MBA.福建省教育厅A类科研项目(JA14440); 莆田市工业科技类科研项目(2012JG01

Study on Catalytic activity of Cu-Mn/HZSM-5 Catalyst for Dimethyl Ether Synthesis

研究不同铜锰比、助剂Si、Zr、Zn对Cu-Mn/HZSM-5催化剂在二氧化碳加氢合成二甲醚的催化活性的影响。结果表明,n(Cu)/n(Mn)的最佳值为4/3;助剂Si的加入能显著提高Cu-Mn/HZSM-5催化剂的性能,在2.0MPa、250℃、空速2100h-1;V(H2)/V(CO2)=3.2下,当催化剂中w(SiO2)=3.5%时,二氧化碳的转化率和二甲醚的收率分别为23.86%和9.33%。XRD和H2-TPR表明,适量SiO2的加入,使CuO晶相峰明显减弱,促进表面Cu的分散;铜锰复合氧化物进一步向非晶态转化,阻止Cu的深度还原,从而提高了催化剂的活性。在考察的范围内,最适宜的反应温度为260℃左右。提高氢碳比,有利于提高催化剂的催化活性。The influences of Cu/ Mn ratio and Si,Zr,Zn promoters on the performance of the Cu-Mn/HZSM-5 catalysts for CO2 hydrogenation to dimethyl ether were studied.It was found that the optimal molar ratio of Cu to Mn was 4/3,the addition of SiO2 promoter could obviously improve the performance of the Cu-Mn/HZSM-5 catalyst,and the optimized adding amount was 3.5% of the catalyst mass(calculated as oxides),with which 23.86% of the conversion of CO2 and 13.74% of the yield of DME were reached under 2.0MPa,250℃,GHSV 2100h1,volume ratio of 3.2 of H2 to CO2.The XRD and H2-TPR results suggested that the suitable introduction of SiO2 can make peak intensity of crystal phase CuO weaking,and promotes disperse of Cu.The copper-manganese compound oxide more translats into amorphous phase from crystal phase,and it prevents deep deoxidize of Cu.All of those results improv the activity of catalyst.The optimum reaction temperature is 260℃ in selected range.Increasing H2/CO2 volume ratio is helpful to improve the catalytic activity

Study on desulfurated catalyst prepared by biological reduction for SO_2 adsorption

在室温条件,采用大肠杆菌(ESCHErICHIA COlI)与常规浸渍法制备的Cu O/γ-Al2O3相互作用制备了一种络合催化剂,并研究了催化剂在液相中的脱硫和再生性能。研究表明:该络合催化剂在Cu负载量为2%时,对SO2的饱和吸附量可达312.2 Mg/g·CAT,当SO2浓度为100Mg/l,催化剂浓度1g/l时,其脱硫率能达到92.8%;吸附后的催化剂可通过加热再生,4次再生后其脱硫率为80.5%,是一种性能良好的脱硫剂。fTIr和XPS分析表明,在有氧和水条件下,菌粉表面的把Cu2+还原成Cu+,然后Cu+与菌粉中的羧基相互作用形成的络合物是吸附SO2的活性中心。A complex catalyst was prepared by bioreduction method with Escherichia coli at low temperature and its desulfurization ability and regenerative property were studied.Stoichiometric amounts of Cu(NO3)2 aqueous solution was impregnated on γ-Al2O3 for the preparation of Cu2+/ γ-Al2O3.The loading weight of Cu2+ is 2%.Experiments also showed that the adsorbent had a good capacity of SO2(312.2 mg/g adsorbent), and the efficiency of desulfurization can reached 92.8% when concentration of SO2 and adsorbent were 100 mg/L and 1 g/L respectively.There results indicated that it can be easily regenerated and theregenerative adsorbent still has a good SO2 adsorption ability, higher than 80.5% of that in fresh adsorbent after four regenerations.FTIR and XPS analysis showed that biomass can reduce Cu2+ to Cu+ by aldose and keep the valence of copper exposed to O2 and H2 O atmosphere, then Cu+ and bacteria powder in the carboxyl group formed by the interaction of the complexes are the active center SO2 adsorption.福建省教育厅A类科研项目(JA14440); 莆田市工业科技类科研项目(2012JG01)资

市政工程施工管理中常见问题及对策

市政工程的资金来源大部分都是政府拨款，无论建筑工程施工中遇到任何的风险，最终都会有政府来担负，这样就造成了施工单位更加注重的是施工进度，而对施工质量较为忽视。一味的追赶工期，而没有严格遵照规范标准来落实工程施工工作，最终导致工程项目在设计上的性能存在诸多的问题，从而为建筑工程施工工作埋下诸多的隐患，这对于工程施工工作按部就班的进行会造成一定的阻碍。</jats:p