Mo-Na复合催化剂制备及其在医药废水处理中的应用

制备了Mo-Na复合催化剂用于催化湿式氧化处理医药废水。结果表明:Mo-Na复合催化剂具有较大的比表面积,热稳定性较好。随着催化剂用量的增加、反应温度的提高及反应时间的增加,催化湿式氧化对废水中污染物的去除效率均逐渐提高,且反应过程中催化湿式氧化体系的去除效率明显高于湿式氧化体系。反应温度190℃、催化剂为1.5 g/L、反应时间3 h时,催化湿式氧化体系对废水TOC与COD去除残余率分别为0.103 9、0.137 1。随着催化剂回用次数的增加,催化剂反应活性降低,催化湿式氧化对废水的去除效果逐渐下降。     

炭化活化条件对Cu/AC表面Cu价态及其催化降解苯酚的影响

采用前体浸渍法研制了生物质基载铜活性炭催化剂（Cu/AC）,利用N₂-吸附脱附、X射线光电子能谱等技术对Cu/AC性质进行了表征,在固定床反应器中研究了不同炭化活化条件所得Cu/AC催化湿式氧化降解苯酚性能。结果表明：Cu/AC表面Cu物种以Cu²⁺和（Cu⁺+Cu⁰）共存。随着制备Cu/AC炭化温度的升高,炭化过程中产生更多的挥发分,促进Cu²⁺还原为Cu⁺和Cu⁰,（Cu⁺+Cu⁰）含量增大,Cu/AC降解苯酚催化活性逐渐升高;随着炭化时间延长,（Cu⁺+Cu⁰）含量下降,Cu₂O、CuO较好地并入载体使晶格氧含量增加,催化活性先升高后下降;随着活化温度升高和活化时间延长,Cu/AC比表面积达到1096.1m²/g并有大量微孔生成,大量含氧官能团分解将炭化过程中还原生成的（Cu⁺+Cu⁰）氧化为Cu²⁺,晶格氧含量增加,催化活性随着活化温度的升高而升高,随着活化时间的延长先升高后下降。催化湿式氧化降解苯酚过程中,Cu/AC具有良好的稳定性和低的Cu离子浸出浓度。Cu/AC的最优制备条件为炭化温度800℃,炭化时间2h,活化温度880℃,活化时间为2h,所得Cu/AC在反应8.5h时实现98.5%的苯酚转化率和91.1%的COD转化率。     

DMDAAC改性污泥催化剂制备及在苯酚废水中的应用

苯酚废水处理技术中,低温催化湿式氧化技术(CWAO)因其对有机污染物去除浓度范围宽、反应温度低和去除率高等优点被广泛关注。用二甲基二烯丙基氯化铵(DMDAAC)掺杂污泥生物质炭制备出新型催化剂(DSMC),利用XRD、FTIR、SEM-EDX进行表征,采用响应面法分析法(BBD)对DSMC的制备时间、pH值、n(Fe³⁺)∶n(Fe²⁺)和n(DMDAAC)因素进行分析,并对DSMC投加量、CWAO温度、过硫酸钾(K₂S₂O₈)浓度以及pH值进行讨论和优化。结果表明,DSMC加入量1.0 g/L,pH=11.0,T=180℃,t=2 h,C_K2S2O8=4 000 mg/L时,COD去除率最佳。响应面优化制备参数为t=24 h, pH=11.98,n(Fe²⁺)∶n(Fe³⁺)=1.50,n(DMDAAC)=1.00 mol,该条件下DSMC的CO...     

Ru/TiO_2催化剂制备及其在有机酸废水湿式氧化中的应用

以纳米TiO_2为载体,通过优化制备方法,合成了高活性的Ru/TiO_2贵金属催化剂,采用X射线衍射(XRD)、N_2物理吸附、程序升温还原(H_2-TPR)和透射电镜(TEM)等手段对催化剂进行表征,并将制备的催化剂应用到湿式氧化处理3种有机酸模拟废水中。研究表明,氢气还原有助于Ru在TiO_2表面的分散,由此制备的催化剂氧化活性较高。在200℃,初始氧压3 MPa的条件下反应2 h,Ru/TiO_2在湿式氧化处理丙烯酸、丁二酸和乙酸有机酸模拟废水时,化学需氧量(COD)去除率分别达到95.3%,91.6%和70.1%。     

MnOx/GAC复合材料制备及其在苯酚废水处理中的应用

以商业颗粒活性炭(GAC)为载体,乙酸锰为锰源,采用等体积浸渍法制备系列MnO_x/GAC复合材料。通过X-射线粉末衍射、透射电镜、拉曼光谱等对改性前后活性炭材料进行微观分析,并探讨锰负载量、反应温度、反应时间等对MnO_x/GAC复合材料处理苯酚模拟废水性能的影响。结果表明,MnO_x/GAC复合材料的活性物种主要以Mn_3O_4、Mn_2O_3和MnO_2为主,呈现均匀分散纳米晶态。在20 mL 1 500 mg·L~(-1)苯酚废水中加入1 g Mn质量分数为8%的MnO_x/GAC复合材料,反应温度50℃,反应时间240 min条件下,苯酚转化率99.88%,COD降解率97.80%,吸附动力学遵循准二级动力学模型。     

催化湿式氧化法在苯酚废水预处理中的应用研究

与湿式空气氧化相比，催化湿式氧化可以在温和条件下达到较好的废水处理效果。考察了CuO/η－Al2O3和活性炭两种催化剂处理苯酚废水的催化效果，结果表明在温和条件下可以达到较高COD去除率：在140℃下，催化湿式氧化1h，CODcr去除率分别达到93．2％和88．4％。在160℃下，催化湿式氧化1h，CODcr去除率分别达到93．4％和90．1％。在140℃下，苯酚废水经过湿式空气氧化1h后，BOD5／CODcr仅仅达到0．08，不适合后续生物法处理；使用活性炭催化剂，BOD5／CODcr达到了0．18，而使用CuO／η－Al2O3催化剂，BOD5／CODcr达到了0．30，因此，用CuO／η－Al2O3催化剂处理苯酚废水可以在较低温度下达到预处理效果。     

Cu0.5-xFexZn0.5Al2O4尖晶石型复合氧化物催化剂在苯酚催化湿式氧化中的性能研究

采用溶胶-凝胶法制备了具有尖晶石结构的Cu0.5-xFexZn0.5Al2O4系列复合氧化物催化剂,考察了催化剂在苯酚催化湿式氧化反应中的活性和稳定性.结果表明,苯酚的CODCr去除率和抗积炭能力随Fe含量的增大而提高,在催化剂中引入Fe能在一定程度上抑制Cu的溶出,Culeached/Cutotal从9.19%(x=0)降低到了4.31%(x=0.25);Fe的溶出量随x值增大而减小.对反应后产物的色谱分析说明在含组分Fe量较高的催化剂上苯酚氧化中间产物的进一步转化速率较快.     

过氧化氢氧化苯酚铜锰复合氧化物催化剂的制备

采用固相法制备了新型催化剂铜锰复合氧化物催化剂。利用高效液相色谱法对苯酚过氧化氢氧化反应产物进行分析,以苯酚转化率和苯二酚收率为评价指标,对催化剂进行了评价。结果表明,催化剂性能随铜与锰物质的量比、焙烧温度、焙烧时间和研磨时间等因素的增大呈先升高再降低的趋势,并与络合剂的还原性有关。确定最佳工艺条件为:室温下,按锰与铜物质的量比1:2将Cu_2(OH)_2CO_3、MnCO_3和适量H_2C_2O_4·2H_2O混匀,置于研钵匀速研磨10 min,马弗炉400℃焙烧2 h。最佳条件下,苯酚转化率为63.7%,苯二酚收率为59.1%。     

CuO/γ-Al2O3/SiO2催化剂制备及其苯酚废水催化降解性能

以拟薄水铝石、SiO₂微球颗粒和纳米CuO为原料,经有机溶剂分散粘结、相转化和焙烧成型制备了CuO/γ-Al₂O₃/SiO₂负载型催化剂。采用SEM,XRD,BET和ICP对负载型催化剂进行表征和组成分析。在不同浓度、pH、温度和盐浓度下,测试了负载型催化剂对废水中难降解酚类物质的催化氧化效果。经60℃下2 h催化氧化处理后,100 mg/L COD的苯酚降解率可达81.79%,出水COD低至19.00 mg/L,因而可应用难降解废水处理。     

稳定高效Ru/TiO2-ZrO2催化剂处理苯酚磺酸废水

催化湿式氧化（CWAO）技术可高效处理有机废水,但现有催化剂的性能,尤其是其稳定性距工业应用还有很大差距。利用ZrO₂对TiO₂载体进行掺杂调变,研制出了具有良好稳定性的Ru/TiO₂-ZrO₂催化湿式氧化催化剂。结果表明, Ru/TiO₂催化剂在进行连续5次催化湿式氧化降解苯酚磺酸（phenolsulfonic acid,PSA）废水的反应后,总有机碳（total organic carbon,TOC）转化率由99.1%降低至65.3%;而Ru/TiO₂-ZrO₂催化剂在Ti/Zr质量比为9∶1~7∶3范围内,能表现出优良的反应性能,在连续5次反应后, TOC转化率稳定保持在90%以上。X射线仪衍射（XRD）、N₂吸脱附（BET）、X射线扫描微探针电子能谱仪（XPS）、氢气程序升温还原（H₂-TPR）和电感耦合等离子体发射光谱（ICP-OES）表征结果表明：ZrO₂能够进入TiO₂的晶格,TiO₂-ZrO₂固溶体的生成阻止了TiO₂由锐钛矿相向金红石相的转变。另外,ZrO₂的调变加强了Ru与载体的相互作用,有效抑制了活性金属Ru的流失。稳定的载体结构和良好的抗流失性能是Ru/TiO₂-ZrO₂催化剂具有优良反应性能的主要原因。     

Preparation and characterization of wet-proofed CuO/Al2O3 catalysts for the oxidation of phenol solutions

Two wet-proofed catalysts were prepared by subsequent coating steps with polytetrafluoroethylene fibers over a CuO/Al₂O₃ catalyst. They were tested for the oxidation of phenol solutions in a semi-batch reactor. Phenol conversion as well as Chemical Oxygen Demand (COD) was recorded. The hydrophobic coverage reduces the loss of active phase by leaching. Therefore, deactivation was attributed to the deposition of carbonaceous residues on the catalytic surface.     

陕北中低温煤焦油提酚工艺废水的处理

为了确定通过浸渍法制备的载铜活性炭的焙烧温度,并了解其催化氧化的处理效果,利用热重-红外光谱联机分析方法对载铜活性炭(Cu-AC)前驱物Cu(NO3)2/AC进行分析,确定Cu-AC的最佳焙烧温度为700℃。并以自制的Cu-AC为催化剂,H2O2为氧化剂,在m(H2O2)∶m(COD)=1.4,m(Cu-AC)∶m(H2O2)=1.5条件下,对中低温煤焦油提酚废水进行催化湿式过氧化法处理,COD去除率达到91.8%,取得了良好效果。     

Nature of carbonaceous deposits on the alumina supported transition metal oxide catalysts in the wet air oxidation of phenol

Al₂O₃ supported transition metal (Mn, Fe, Co, Ni, and Cu) oxide catalysts were prepared and tested for the wet oxidation of phenol. The supported copper oxide catalysts showed the highest catalytic activity due to their highest surface reducibility. There was carbonaceous deposits on the used catalysts for the wet oxidation of phenol and the supported manganese oxide catalysts showed the highest amount of carbonaceous deposits. These carbonaceous deposits must have their own micropores which resulted in the decrease of the pore volume and the increase of the surface area. The NMR and FTIR spectroscopy showed that the carbonaceous deposits were mostly of aromatic nature and contained some oxygen-bearing groups such as carboxylic acids and alcohols.     

Hydrogen peroxide promoted wet air oxidation of phenol: influence of operating conditions and homogeneous metal catalysts

The promoted wet air oxidation of phenol has been investigated through the addition of hydrogen peroxide as a source of free radicals. The reaction has been shown to proceed in two stages, an initial fast reaction associated with hydrogen peroxide consumption and a second slower step that occurs at a rate comparable with conventional wet air oxidation. An increase in temperature has a positive effect on both stages, while oxygen partial pressure only influences the second slower stage. The influence of pH on phenol oxidation is shown to be significant with the highest efficiency achieved at very alkaline conditions when phenol is completely dissociated. The catalytic activity of homogeneous metal salts was investigated in both the presence and absence of hydrogen peroxide. The combined addition of hydrogen peroxide and a bivalent metal (ie copper, cobalt or manganese) is shown to enhance the rate of phenol removal. However, in the absence of hydrogen peroxide only copper exhibited catalytic activity. Finally, a reaction mechanism involving different radical species has been proposed. From the experimental results the apparent activation energy (96.9 ± 3.5 kJ mol⁻¹) and pre‐exponential factor (1.6 ± 0.2 10¹⁰ s⁻¹) were calculated for hydrogen peroxide decomposition into hydroxyl radicals. © 1999 Society of Chemical Industry     

Influence of pH on the wet oxidation of phenol with copper catalyst

This work reports the influence of pH on the catalytic wet oxidation (CWO) of phenol performed with a commercial copper-based catalyst. The results obtained show that pH is a critical parameter able to modify the chemical stability of the catalyst, the significance of the oxidation reaction in the liquid phase, the reaction mechanism and, consequently, the oxidation route of phenol. Experiments have been carried out to study the mentioned aspects. Stirred basket and fixed bed reactors (FBRs) have been employed, at 140 °C and at 16 bar of oxygen pressure. Three initial pH values have been used: 6 (the pH of the phenol solution), 3.5 (adjusted by H₂SO₄) and 8 (by addition of Na₂CO₃). Furthermore, some phenol oxidation runs without solid catalyst but with different concentrations of copper in solution have been accomplish at pHo=3.5. At acid pH, important leaching of copper from the catalyst to the solution was achieved, finding this negligible at pH 8. It was found that the major contribution to the phenol conversion reached at acid pH by using the solid catalyst was due to the catalytic activity of the leached copper. Both oxidation mechanisms at acid and basic conditions have been elucidated to explain the differences in the type and distribution of the intermediates obtained. The catalytic phenol oxidation route found at pH=8 comprises intermediates less toxic than phenol while at acid pH the cyclic intermediates formed as first oxidation intermediates are far more toxic than phenol.     

Influence of preoxidizing treatments on the preparation of iron‐containing activated carbons for catalytic wet peroxide oxidation of phenol

BACKGROUND: Iron species were heterogeneously supported over activated carbons (AC) after different oxidizing pre‐treatments. The influence of the oxidizing method on the iron yield and the physicochemical properties of the iron‐containing activated carbons (Fe/AC) were studied. Thereafter, the activity and stability of Fe/AC catalysts for the wet peroxide oxidation of phenol as model pollutant was evaluated. RESULTS: The pre‐oxidizing treatment with HNO₃ was the most appropriate for iron incorporation, providing a Fe/AC catalyst with the highest TOC removal and oxidant efficiency. A high stability of the catalysts was observed with low values of iron leaching (below 1.5% of their initial iron contents). The best Fe/AC catalyst was studied at different reaction temperatures and initial phenol concentrations. CONCLUSION: The promising results for the Fe/AC catalyst using HNO₃ pre‐oxidizing treatment lay in the remarkable adsorption capacity of the carbon matrix and the potential activity of the iron species as Fenton‐like catalyst for the generation of oxidizing hydroxyl radicals. Copyright © 2012 Society of Chemical Industry     

Carbon supported platinum catalysts for catalytic wet air oxidation of refractory carboxylic acids

Carbon supported platinum (1% wt) catalysts were prepared by the incipient wetness impregnation method and by organometallic chemical vapor deposition. Catalyst characterization was carried out by means of adsorption and thermogravimetric techniques, and by electron microscopy. The catalyst with higher metal dispersion was produced by incipient wetness impregnation. The catalysts were tested in the catalytic wet air oxidation (200°C and 6.9 bar of oxygen partial pressure) of aqueous solutions containing low molecular weight (C₂ to C₄) carboxylic acids. Significant conversions (greater than 60% over 2 h) and 100% selectivity towards water and non-carboxylic acid products were observed for both systems. The initial reaction rate was used to compare the performance of the two catalytic materials and direct correspondence to the metal dispersion was found. No metal leaching was observed during reaction and no significant deactivation occurred in three successive catalytic oxidation runs. A kinetic model based on the Langmuir–Hinshelwood formulation was applied and the results were analyzed in terms of a heterogeneously catalyzed free radical mechanism.