废CeO x -MnO x 基SCR脱硝催化剂还原酸浸综合回收铈锰

废选择性催化还原（SCR）脱硝催化剂中含有大量的有价金属,直接废弃易造成资源浪费及环境污染。以废CeO _x -MnO _x 基SCR脱硝催化剂为原料,采用热力学分析结合湿法冶金实验方法,研究了浸出条件对Ce、Mn元素浸出率的影响。结果表明,废催化剂直接酸浸Ce、Mn元素浸出率低,还原-酸浸Ce、Mn元素热力学条件上可行,抗坏血酸对Ce、Mn高价氧化物有明显的还原作用。当抗坏血酸质量分数为30%、硫酸浓度2mol/L、液固比6∶1、搅拌速度350r/min、80℃恒温反应5h时,Ce、Mn的浸出率分别达到92.09%、95.51%。加入抗坏血酸后,部分Ce⁴⁺和Mn⁴⁺还原为Ce³⁺和Mn²⁺,Ce⁴⁺/Ce的比值由75.82%降低到71.62%,Mn⁴⁺/Mn的比值由29.39%降低到27.17%,同时削弱了高价Ce辅助低价Mn向高价Mn转化的作用,使得Ce、Mn高效浸出,为CeO _x -MnO _x 基废催化剂中Ce、Mn资源化利用奠定了基础。     

Pd-based catalysts for catalytic wet oxidation of combined Kraft pulp mill effluents in a trickle bed reactor

Catalytic wet oxidation of combined pulp mill effluents was studied in a trickle bed reactor. Two types of supported Pd-based catalysts, eggshell and uniform catalysts, and a supported Pd–Pt uniform catalyst were employed. Supported Pd catalysts showed high activity for total organic carbon (TOC) and color removal at temperatures of 353–448 K and 1.84 MPa. Compared to uniform catalysts, the eggshell catalysts with a 0.2 wt.% Pd loading show promise for treatment of combined pulp mill effluents. High activity for TOC and color removal can be attributed to the high density of active Pd sites in the shell area and to the decrease of diffusion path for reactants and intermediates. No apparent deactivation of eggshell catalysts was observed after 40 h on stream. Potential application of the supported Pd catalysts for treatment of combined pulp mill effluents is discussed.     

MOx/Y催化剂常温催化臭氧氧化甲苯的性能

以Y分子筛为载体,采用等体积浸渍法制备了MO_x/Y催化剂,并用于常温催化臭氧氧化甲苯反应。采用XRD、BET、H_2-TPR、甲苯吸附对催化剂进行表征,以甲苯转化率维持95%以上的时间(t_(95))为指标对催化性能进行评价。结果表明:10%MnO_2/Y催化剂〔m(MnO_2)/m(Y)=0.1〕具有较大的比表面积(538.6m~2/g)和孔容积(0.440 cm~3/g),较好的催化臭氧氧化甲苯活性(t95=210 min);CuO的加入提高了催化活性,5%MnO_2-5%CuO/Y〔m(MnO_2)/m(Y)=0.05且m(CuO)/m(Y)=0.05〕催化剂上t95=240min,CO_x选择性为80.6%,CO_2与CO摩尔比为4.970。由表征结果可知,较大的比表面积和孔容积有利于甲苯吸附,CuO与Mn O_2之间的相互作用促进了氧化还原性能的提高,进而有利于催化活性的提高。GC-MS结果表明:反应副产物堵塞催化剂孔道,占据催化剂表面活性位,导致催化剂失活。5%MnO_2-5%CuO/Y催化剂失活-再生4次后t_(95)可达220 min。     

汽车尾气净化催化剂的研制及其性能的研究

研究了 Cu- Co- Ce- Mn- Pd- K- O/γ- Al2 O3 催化剂的活性、热稳定性等。结果表明 ,该催化剂具有低温活性高 ,热稳定性好等特点。对 CO、C6H14 氧化的 t50 % 和 t98% 分别为 1 40°C、2 60°C和 1 80°C、2 95°C。催化剂活性组分间及它们与载体间存在着协同效应。Ce O2 的引入使各活性组分以高度分散的非结晶形态存在 ,这些是催化剂低的起燃温度、高活性的主要原因。另外 ,Ce O2 和 K2 O的引入赋予催化剂 90 0°C高温不烧结的良好热稳定性     

Cu/CeO2催化剂催化二乙醇胺脱氢制亚氨基二乙酸

以硝酸铜和硝酸铈为原料,采用共沉淀法制备系列Cu/CeO_2催化剂。并用物理吸附(BET)、X射线衍射(XRD)、H2程序升温还原(H2-TPR)对催化剂的结构和还原性进行了表征,考察了其在二乙醇胺脱氢制亚氨基二乙酸反应中的催化性能。结果表明,经500℃焙烧、铜铈物质的量比为3∶1的Cu_3Ce_1催化剂还原温度最低,为230℃,且Cu_3Ce_1还原后表面有适量Cu活性中心,Cu_3Ce_1催化剂在二乙醇胺(DEA)脱氢制亚氨基二乙酸的反应中具有较好催化活性。该催化剂最适宜的反应条件为:m(DEA)∶m(Na OH)∶m(H2O)=1.15∶1.00∶2.42,催化剂用量6 g,反应温度180℃,反应压力1.1 MPa,反应时间4 h,搅拌转速600 r/min,Cu_3Ce_1催化剂上二乙醇胺的转化率为99.63%,亚氨基二乙酸选择性为95.73%,Cu_3Ce_1催化剂重复使用9次,无明显失活。     

Catalytic wet air oxidation of phenol and acrylic acid over Ru/C and Ru–CeO2/C catalysts

Ru/C catalysts promoted, or not, by cerium were prepared by impregnation of an active carbon (961 m² g⁻¹) with chlorine-free precursors of Ru and Ce. They were characterized by chemisorption of H₂ and of CO and by electron microscopy. TEM and H₂ chemisorption gives coherent results while CO chemisorption overestimates Ru dispersion. In Ru–Ce/C, Ce is in close contact with Ru and decreases Ru accessibility.

Catalytic wet air oxidation (CWAO) of phenol and of acrylic acid (160°C and 20 bar of O₂) was investigated over these catalysts and their performance (activity, selectivity to intermediate compounds) compared with that of a reference Ru/CeO₂ catalyst. Carbon-supported catalysts were very active for the CWAO of phenol but not for acrylic acid. Although high conversions were obtained, phenol was not totally mineralized after 3 h. It was shown that acrylic acid was more strongly adsorbed than phenol. Moreover, the number of contact points between Ru particles and CeO₂ crystallites constitutes a key parameter in these reactions. A high surface area of ceria is required to insure O₂ activation when the organic molecule is strongly adsorbed.     

非均相催化一步合成碳酸二苯酯ⅨCe的添加方法对Pd-Sn催化剂性能的影响

通过XRD、TPR对不同的Ce添加方法所得催化剂进行了表征,结果表明用溶胶-凝胶法所得催化剂中Ce、Sn主要以Ce_XSn_1-xO₂物相存在.用混烧法所得催化剂中,Ce和Sn分别以CeO₂、SnO₂物相形式存在,而用沉淀法所得的催化剂中,Ce则以CeO₂晶相的形式存在,Sn与载体其他元素形成了共融体.对3种催化剂的形貌和比表面积进行了表征,结果表明溶胶-凝胶法所得催化剂的表面呈蜂窝状、比表面积较大.用碳酸二苯酯（DPC）的合成实验对催化剂的活性及催化剂的寿命进行评价,结果表明无论是催化剂的活性还是催化剂的寿命,溶胶-凝胶法所得催化剂较好.此外还对DPC合成工艺条件进行优化.     

Uncatalyzed and catalyzed NO and N2O reaction using various catalysts and binary barium mixtures supported on activated carbon

The kinetics of the reaction of NO and N₂O with activated carbon, without catalyst, and impregnated with precursor salts of Mg, Mn, Ba, Pb, Cu, Ni, Fe and Co and their binary mixtures was investigated. The conversion of NO and N₂O was studied (300°C–900°C) using a TGA apparatus and a fixed-bed reactor. The reactor effluents were analyzed using a GC/MS on line. The best synergetic effects were observed for samples doped with Ba + Pb, Ba + Fe, Ba + Cu, Ba + Mn, and Cu + Mn. Adsorption of NO and N₂O (20°C–100°C) increased considerably in the presence of catalysts, but binary mixtures had no synergistic effects. In situ XRD was an useful tool for interpreting catalyst behavior and identifying phases during reaction conditions.     

Kinetics of wet oxidation of black liquor over a Pt–Pd–Ce/alumina catalyst

The catalytic oxidation of industrial wastewater from paper and pulp mills has been investigated in a slurry reactor at a temperature range 433–463 K and at pressures from 1.5 to 2.2 MPa. Adding Ce on alumina support promotes the catalytic activity for oxidation of black liquor. Pt–Pd–Ce/alumina catalyst shows a promising activity for wet catalytic oxidation of black liquor. The oxidation reaction over a Pt–Pd–Ce catalyst is characterized by an initial fast reaction step followed by a slow reaction step. The rate of total organic carbon (TOC) reduction was described by first-order kinetics with respect to TOC concentration in black liquor for both initial and later reaction steps. The activation energies were determined to be 54.53 and 50.13 kJ/mol for the initial and later oxidation steps, respectively. Comparison of the data with the generalized kinetic model was also presented.     

生物柴油副产物粗甘油催化氧化脱水制备丙烯酸

用生物柴油副产物粗甘油催化氧化脱水制丙烯酸,该过程耦合了甘油脱水制丙烯醛和丙烯醛选择性氧化制备丙烯酸两步反应。结果表明,在甘油脱水反应中,使用Cs3PW12O40, P-ZSM-5和Co0.5H2PO4/SiO2等固体酸催化剂,可得到较高的丙烯醛收率(最高86.9%)。利用上述催化剂和MoVW基氧化催化剂,在脱水/氧化双催化剂床层构型反应器中,以甘油为原料合成丙烯酸的收率达50%~80%,直接加入粗甘油可获得相似的丙烯酸收率。     

壳-核式RuO2-TiO2/CeO2-TiO2复合催化剂的制备及催化湿式氧化性能研究

以CeO2-TiO2为载体,通过化学沉积、纳米活性层包覆、纳米烧结的方法在其表面包覆了RuO2/TiO2纳米层,制备得壳-核式RuO2-TiO2/CeO2-TiO2复合催化剂。通过XRD、XPS、UV-Vis、BET、SEM、TEM等手段对催化剂进行了表征。结果表明:纳米层中的RuO2包覆在TiO2表面,也形成了一种壳-核式结构,TiO2粒子的粒径约15nm,其表面的RuO2厚度约4nm,包覆纳米层后催化剂的比表面积明显增大。以丁二酸为模拟废水,对催化剂的催化湿式氧化活性进行了测试,研究了反应温度、pH等因素对催化湿式氧化活性的影响。与浸渍法制备的催化剂相比,新催化剂催化湿式氧化丁二酸的活性显著提高。乙酸和丙烯酸是丁二酸降解的主要中间产物。     

负载型CeO_2/OMS-2催化剂对VOCs的催化氧化性能

采用回流法合成了OMS-2,同时以OMS-2为载体,采用浸渍法负载CeO_2制备了Ce/OMS-2催化剂,运用X射线衍射、拉曼光谱、BET、H_2-TPR和NH_3-TPD等方法对催化剂进行表征,并考察CeO_2/OMS-2催化剂催化氧化二氯甲烷和乙酸乙酯的性能。结果表明,CeO_2的加入并未改变OMS-2较好的八面体分子筛结构,CeO_2的晶粒很小且以高分散的形式存在;负载CeO_2的OMS-2催化剂比表面积都有增大趋势;随着CeO_2负载量的增加,低温和高温的还原峰都先向低温方向偏移再向高温方向偏移;随着CeO_2负载量的增加,高温处强酸性峰先向低温方向偏移再向高温方向偏移。反应活性结果表明,CeO_2/OMS-2催化剂活性比载体OMS-2的活性好,随着铈负载量的增加,催化活性先升高再降低,其中,CeO_2负载质量分数为1.0%(1.0Ce/OMS-2)时催化剂效果最好,这可能是由于铈的加入活化了OMS-2中的氧,影响了整体催化剂的酸性,进而影响反应性能。     

Co/Mn/Zr复合催化剂催化甲苯液相氧化

以乙酰丙酮锆或乙酸锆与乙酸钴和乙酸锰制备乙酸钴/乙酸锰/乙酰丙酮锆或乙酸锆(Co/Mn/Zr)三元复合催化剂。比较乙酸钴(Co)、乙酸钴/乙酸锰(Co/Mn)和Co/Mn/Zr催化剂体系对甲苯液相氧化反应的催化性能。结果表明:在催化剂中添加Zr可以降低反应温度,提高甲苯转化率和苯甲酸选择性。与乙酸锆相比,采用乙酰丙酮锆制得的Co/Mn/Zr具有较好的催化活性。在Co,Mn和Zr物质的量之比为5 5 1,Co与甲苯的物质的量之比为1 10 000,溶剂乙酸与甲苯质量比为1 2.3,反应温度160℃和反应压力1.4 MPa的条件下反应3 h后,苯甲酸选择性和甲苯转化率分别为80.2%和15.4%。     

Catalytic wet air oxidation of Kraft bleach plant effluents in a trickle-bed reactor over a Ru/TiO2 catalyst

Catalytic wet air oxidation of two acidic and alkaline Kraft bleach plant effluents (total organic carbon (TOC) content 1138 and 1331 mg l⁻¹, respectively) was investigated in a trickle-bed reactor at T=463 K and oxygen partial pressure of 8 bar. The reactor packed with titania or titania-supported ruthenium catalyst was operated in a low-interaction (LIR) trickle-flow regime either in continuous-flow or batch-recycle mode. In the off-gas, no carbon monoxide was detected in any of the runs. When the catalytic bed was composed of TiO₂ particles, moderate abatement of organic compounds from the bleach plant effluents was observed (TOC conversions up to 46 and 26%, respectively). The removal of parent organic material was further enhanced by deposition of metallic ruthenium (3 wt.%) on the titanium oxide support. In that case, the once-through oxidation produced decolorized outlet streams with TOC conversions as high as 89 and 88%, respectively. These values further increased to 98 and 95%, respectively, by running the trickle-bed reactor in the batch-recycle mode of operation; the residual carbon content in treated effluents was found in the form of acetic acid. No leaching of Ru or Ti was detected by ICP-AES analysis to the detection limits of 0.2 and 0.1 mg l⁻¹, respectively.     

催化湿式氧化纳米Ce/Mn催化剂的研制

为处理吡虫啉农药废水，通过共沉淀法制备了一系列Ce/Mn催化剂。当n(Ce)∶n(Mn)=2∶1和焙烧温度500 ℃时，所得催化剂颗粒直径为3.60 nm,催化剂的比表面积为127 m²·g^－1。在反应温度190 ℃、总压8.0 MPa、氧分压1.6 MPa、pH为8.42和加入2.0 g·L^－1催化剂的条件下，COD的最高去除率达93%。     

CeO_2-活性炭催化臭氧化降解水中草酸的研究

利用CeO_2的储氧和释氧能力,以高活性的活性炭作为催化剂载体,采用等体积浸渍法制备CeO_2-活性炭催化剂。分别用氮气低温吸附/脱附、XRD、XPS对CeO_2-活性炭催化剂进行表征。以CeO_2-活性炭作为催化剂,草酸作为模型化合物,催化臭氧化降解草酸的去除率达到77%。Ce组分的加入能显著提高草酸的去除率。Ce不仅能够提高反应体系中羟基自由基的浓度,还有利于O3分子直接氧化草酸。CeO_2-活性炭催化剂经过3次重复使用后,草酸去除率保持在70%以上,具有较好的稳定性。     

Effect of Mn/Al ratio in Co–Mn–Al mixed oxide catalysts prepared from hydrotalcite-like precursors on catalytic decomposition of N2O

The Co–Mn–Al mixed oxide catalysts were prepared by thermal decomposition of hydrotalcite-like precursors with Co/(Mn + Al) molar ratio of 2 and Mn/Al molar ratio varying from 0 to 2. The obtained catalysts were characterized by powder XRD, XPS, BET surface area and TPR measurements and tested in N₂O decomposition. The most active Co4MnAl catalyst exhibited both the optimum Mn/Al molar ratio and the optimum amount of components reducible in the temperature region in which the catalytic reaction proceeds (350–450 °C).     

Mn、Ce负载顺序对催化剂Mn-Ce/TiO2低温脱硝活性的影响

采用溶胶凝胶法制备了一系列Mn-Ce/TiO₂催化剂样品, 并用比表面积及孔径分析仪(BET)、X射线衍射仪(XRD)和扫描电子显微镜(SEM)等对催化剂进行了表征, 考察了活性组分Mn、Ce负载顺序对催化剂结构的影响, 并在固定床连续流动反应器上对其催化活性进行了评价。结果表明, 催化剂晶相均为锐钛矿型结构, Mn、Ce活性组分在载体表面高度分散或形成了无定形结构;Mn、Ce同时负载时催化剂表面活性组分分布均匀, 比表面积最大, 为97.6m²/g, 且催化剂孔径分布以中孔为主;Mn、Ce同时负载时催化剂活性最好, 反应温度为200℃时, NO转化率达到90%以上。     

催化湿式空气氧化处理磷霉素钠、黄连素制药废水试验研究

研究了用催化湿式空气氧化技术处理高含量、难降解的磷霉素钠和黄连素制药混合废水,考察了非贵金属Mn及稀土元素Ce协同Cu催化反应时CWAO处理效率。结果表明,以黄连素废水中的Cu2+作催化剂,反应温度为250℃、初始氧分压为1.3 MPa、反应停留时间0.5 h的条件下,COD平均去除率可达50%,此时废水中有机磷转化为PO43-;Mn、Ce的加入可使COD的去除率提高12%～18%,其中Mn与Cu协同作用效率最高,在初始氧分压为1.3 MPa下,COD去除率可提高至72%,99%以上的有机磷转化为PO43-,出水BOD5/COD提高至0.85,达到了CWAO预处理即提高2种制药废水可生化性的目的。     

锰铈相互作用对催化碳烟燃烧性能的影响

采用等体积浸渍法制备HZSM-5分子筛负载Mn（9Mn/Z）,Ce（9Ce/Z）和同时负载Mn、Ce（4.5Mn4.5Ce/Z）催化剂,并考察了它们的催化碳烟颗粒燃烧的性能。结果表明,同时负载Mn、Ce的催化剂（4.5Mn4.5Ce/Z）具有更好的催化碳烟燃烧的活性,碳烟转化率为50%时所对应的温度（T₅₀）为400℃,低于9Mn/Z（T₅₀=414℃）和9Ce/Z（T₅₀=447℃）催化剂。相比于纯碳烟的燃烧,T₅₀降低了128℃。通过氢气程序升温还原（H₂-TPR）测试,相比较催化剂9Mn/Z和9Ce/Z,催化剂4.5Mn4.5Ce/Z中混合氧化物的氢气的还原温度向低温方向产生了偏移,具有更好的氧化还原性,说明MnO_x和CeO₂产生了一定的相互作用;X射线光电子能谱（XPS）测试表明,样品4.5Mn4.5Ce/Z具有更多的表面化学吸附氧物种,这些氧物种有助于碳烟氧化燃烧,因而表现出较高的催化碳烟燃烧活性。