CuO(-CeO2)/Al2O3催化剂对萘催化氧化性能研究

采用浸渍法制备了CuO/Al2O3、CeO2/Al2O3和CuO-CeO2/Al2O3这3种催化剂,通过氮吸附、SEM、XRD等手段对催化剂的结构及组成进行了表征,利用固定床反应装置考察了活性组分、气体流量、催化反应温度对萘催化氧化性能的影响.结果表明,18%CeO2/Al2O3的萘催化活性较低,18%CuO/Al2O3和9%CuO-9%CeO2/Al2O3的活性较高,两者在300℃时对萘的去除率分别达到91%和89%;CuO-CeO2/Al2O3催化剂具有比CuO/Al2O3更好的低温活性;气流量的变化对两种催化剂性能的影响不大.     

Ce含量对Pd/Al_2O_3催化剂加氢脱硫性能的影响

采用浸渍法制备了Pd/Al2O3和Pd-CeO2/Al2O3催化剂,研究了不同Ce含量对Pd/Al2O催化剂加氢脱硫性能的影响,并运用XRD、TPR、TPD和噻吩吸附等手段表征了催化剂的吸附性能和酸性。结果表明,CeO2的加入导致Pd/Al2O3催化剂H2吸附性能的减弱和酸量的减少,但提高了噻吩的吸附性能。在噻吩加氢脱硫反应中,Ce含量为2%时Pd-CeO2/Al2O3催化剂的活性最高,随Ce含量的继续增加催化剂的活性下降,是由于催化剂对H2吸附和噻吩吸附综合影响的结果。     

CuO-Ru/Al2O3 催化臭氧化降解苯乙酮的研究

采用浸渍法制备了以活性Al2O3为载体的双组分催化剂CuO-Ru/Al2O3,利用该催化剂催化臭氧化降解了苯乙酮.结果表明,贵金属钌掺杂能显著提高CuO/Al2O3催化臭氧化苯乙酮的降解效率,如在相同条件下处理30 min后,单独臭氧氧化、CuO/Al2O3/O3和CuO-Ru/Al2O3/O3对苯乙酮水溶液的COD去除率分别为6.3%、20.0%和54.0%.pH对CuO-Ru/Al2O3催化臭氧化降解苯乙酮的效率并没有影响,但与单独臭氧化相比,该催化臭氧化体系更适合在中性或酸性条件下应用.CuO-Ru/Al2O3对水中臭氧有较好的催化分解活性,臭氧分解的速率常数达2.58×10-3s-1,高于二次水中臭氧的分解速率常数1.19×10-3s-1.叔丁醇的试验结果表明,CuO-Ru/Al2O3/O3降解苯乙酮反应遵循羟基自由基(.OH)反应机制.     

CuO-Ru/A_2lO_3催化臭氧化降解苯乙酮的研究

采用浸渍法制备了以活性Al2O3为载体的双组分催化剂CuO-Ru/Al2O3,利用该催化剂催化臭氧化降解了苯乙酮.结果表明,贵金属钌掺杂能显著提高CuO/Al2O3催化臭氧化苯乙酮的降解效率,如在相同条件下处理30 min后,单独臭氧氧化、CuO/Al2O3/O3和CuO-Ru/Al2O3/O3对苯乙酮水溶液的COD去除率分别为6.3%、20.0%和54.0%.pH对CuO-Ru/Al2O3催化臭氧化降解苯乙酮的效率并没有影响,但与单独臭氧化相比,该催化臭氧化体系更适合在中性或酸性条件下应用.CuO-Ru/Al2O3对水中臭氧有较好的催化分解活性,臭氧分解的速率常数达2.58×10-3s-1,高于二次水中臭氧的分解速率常数1.19×10-3s-1.叔丁醇的试验结果表明,CuO-Ru/Al2O3/O3降解苯乙酮反应遵循羟基自由基(.OH)反应机制.     

光助Fenton反应催化剂Fe/Al2O3的制备及其对六氯苯的催化活性研究

采用超声促进浸渍法制备了光助Fenton催化剂Fe/Al2O3,利用该催化剂对六氯苯（HCB）进行光助Fenton氧化降解,考察了浸渍液浓度、浸渍温度、灼烧温度和灼烧时间等制备条件对其催化降解六氯苯的活性的影响,确定了制备Fe/Al2O3的工艺条件,并对制得的催化剂进行表征。结果表明,超声促进浸渍法制备非均相光助Fenton反应催化剂Fe/Al2O3的最佳工艺条件为：浸渍液浓度25mmol/L,浸渍温度40℃,焙烧温度500℃,焙烧时间3h。在此条件下制备的催化剂对六氯苯的降解具有较高的催化活性。     

CuO/Al_2O_3和CeO_2/Al_2O_3催化氧化菲的实验研究

多环芳烃(PAHs)是一类持久性有机污染物,由于具有"三致"效应受到人们广泛关注,高效经济地捕集PAHs意义深远。选取一种典型的PAHs菲为研究对象,通过浸渍法制备Cu O/Al2O3和Ce O2/Al2O32种催化剂,采用固定床催化反应装置研究其对菲的催化能力,考察活性组分、负载率、气体流量、反应温度对菲去除率的影响。结果表明,随着负载率的升高,2种催化剂对菲的去除率均呈现增大的趋势,Cu O/Al2O3和Ce O2/Al2O3对菲催化效果最好的负载率分别为18%和25%;随着气体流量的增加,18%Cu O/Al2O3对菲的去除率逐渐下降,18%Ce O2/Al2O3没有明显变化;随着反应温度的升高,2种催化剂对菲的去除率均逐渐增加,18%Cu O/Al2O3和18%Ce O2/Al2O3对菲的去除率分别在300℃和325℃得到显著提升;通过对比不同负载率及工况下菲的去除率可以发现,Cu O/Al2O3对菲的催化能力要优于Ce O2/Al2O3。     

固体碱催化剂制备生物柴油的研究

以CH3COONa为活性组分,Al2O3载体,采用浸渍法制备Na2O/Al2O3负载型固体碱催化剂.用扫面电镜,表面积与孔径分析,红外三种表征方法对此催化剂表面结构及性能进行了分析,结果显示催化剂表面结构和性能良好;用Na2O/Al2O3作为催化剂进行生物柴油合成实验,催化剂表现出很好的催化活性.通过正交试验考察了醇油...     

催化湿式氧化工艺中负载型催化剂的研制

研究了过渡金属氧化物和稀土金属氧化物对乳化液废水催化湿式氧化工艺中的催化活性，得出：CuO的活性高于MnO2,Co3O4未表现出催化活性。CeO2、Nd2O3、Sm2O3均表现一定活性：制备了CuO／γAl2O3，Mn／γAl2O3负载型催化剂及其复合负载型催化剂，并对它们各自的催化活性和稳定性进行了研究。发现：Cu／γAl2O3负载型催化剂用于乳化液废水处理，200℃反应2h，CODCr去除率为88．4％，达到均相催化效果，比非催化提高13.0％，Mn／γAl2O3表现出负催化作用．复合负载型催化剂的活性低于Cu／γAl2O3。     

制备及反应条件对Pt/Al2O3蜂窝状催化剂性能的影响

采用多次涂层 浸渍法制备了蜂窝状Pt Al2 O3 催化剂 .并对焙烧温度和焙烧时间等不同制备条件和反应温度、O2 浓度和空速等不同反应条件下NOx 的选择性催化还原性能进行了研究 .实验表明 ,蜂窝状Pt Al2 O3 催化剂上NOx 转化率在反应温度为 30 0℃左右时出现最高值 .而随反应温度的升高 ,达到最高转化率所需的O2 浓度不断减小 ,分别为 8% ,6 %和 4 % .这可能是由于在高温下O2 会与NO发生竞争吸附 ,从而阻碍了NO催化还原反应的进行 ;同时随着空速的依次增加 ,催化剂的活性逐渐下降 ,催化剂活性曲线的峰值依次向高温方向移动 .实验还说明 ,在过高的焙烧温度和较长的焙烧时间的制备条件下 ,蜂窝状Pt Al2 O3 的催化性能明显下降 .这是因为高的焙烧温度和较长的焙烧时间能够导致蜂窝状Pt Al2 O3 催化剂的表面发生烧结现象 ,使得催化剂的比表面减小 ,从而导致活性降低 .     

Pd／Ce02-A1203对烟气中多环芳烃的催化氧化性能研究

采用浸渍法制备了不同负载量及不同钯铈比（Pd：Ce）的Pd/CeO2-Al2O3催化剂,并结合XRD、BET、SEM、O2-TPD和H2-TPR等方法对催化剂的性质进行了表征,研究了所制备的催化剂对燃煤烟气中多环芳烃（PAHs）的催化转化效率.XRD和SEM结果表明,Ce和Pd在Al2O3表面呈高度分散状态,有利于PAHs的催化氧化.BET测试表明,Ce的引入改变了催化剂表面孔径结构,提高其比表面积.O2-TPD和H2-TPR测试表明,适当钯铈比条件下制备的催化剂有较强的储氧能力和活性.催化氧化实验结果表明,所制备的Pd/CeO2-Al2O3催化剂对PAHs具有较高的转化效率,其平均转化率均在80%以上,且PAHs的毒性当量显著降低,钯铈比对PAHs的催化氧化性能影响较大,当催化剂的钯铈比为1：1时,PAHs的转化率最高,可达90%以上.     

Formic acid as an alternative reducing agent for the catalytic nitrate reduction in aqueous media

Formic acid was used for the nitrate reduction as a reductant in the presence of Pd:Cu/γ-alumina catalysts. The surface characteristics of the bimetallic catalyst synthesized by wet impregnation were investigated by SEM, TEM-EDS. The metals were not distributed homogeneously on the surface of catalyst, although the total contents of both metals in particles agreed well with the theoretical values. Formic acid decomposition on the catalyst surface, its influence on solution pH and nitrate removal efficacy was investigated. The best removal of nitrate (50 ppm) was obtained under the condition of 0.75 g/L catalyst with Pd:Cu ratio (4:1) and two fold excess of formic acid. Formic acid decay patterns resembled those of nitrate removal, showing a linear relationship between kf (formic acid decay) and k (nitrate removal). Negligible amount of ammonia was detected, and no nitrite was detected, possibly due to buffering effect of bicarbonate that is in situ produced by the decomposition of formic acid, and due to the sustained release of H2 gas.     

Pd-Cu/石墨烯协同零价铁(Fe0)的催化反硝化实验

为解决城市污水处理厂二级出水中硝态氮含量较高的问题,对Pd-Cu/石墨烯协同零价铁（Fe0）的新型催化反硝化法处理水体中NO₃--N进行了深入研究,重点对催化反硝化操作条件进行了优化。研究发现,新型催化反硝化法获得较好催化效果的最佳运行条件为:Fe0投加量为4 g/L,m（Pd）:m（Cu）为3:1,溶液pH为4.2,Pd-Cu/石墨烯投加量为4 g/L,反应时间为2 h,此时系统的NO₃--N去除率及N₂转化率分别为78%和74%。在催化反硝化反应中,Fe0主要以电子供体存在,其在一定的酸性条件下,可触发催化反应的发生。催化反应发生在催化剂的金属活性位（Pd和Cu）上。NO₃--N在催化剂作用下,通过脱氧反应被逐步去除并转化为N₂。此外,催化剂载体及催化反应中的传质效果也是影响催化效果的重要因素。     

In situ adsorption-catalysis system for the removal of o-xylene over an activated carbon supported Pd catalyst

An activated carbon (AC) supported Pd catalyst was used to develop a highly efficient in situ adsorption-catalysis system for the removal of low concentrations of o-xylene. In this study, three kinds of Pd/AC catalysts were prepared and tested to investigate the synergistic efficiency between adsorption and catalysis for o-xylene removal. The Pd/AC catalyst was first used as an adsorbent to concentrate dilute o-xylene at low temperature. After saturated adsorption, the adsorbed o-xylene was oxidized to CO2 and H2O by raising the temperature of the catalyst bed. The results showed that more than 99% of the adsorbed o-xylene was completely oxidized to CO2 over a 5% Pd/AC catalyst at 140℃. Brunauer-Emmett-Teller (BET) analysis, scanning electron microscopy (SEM), temperature-programmed desorption (TPD), and temperature-programmed oxidation (TPO) were applied to investigate the physical properties of o-xylene adsorption-desorption and the in situ adsorption-catalysis activity of the AC support and Pd/AC catalyst. A synergistic relationship between the AC support and the active Pd species for the removal of low concentrations of o-xylene was established.     

Pd-Cu@UiO-66催化还原水中硝酸盐

为解决地下水中硝酸盐含量过高的问题,首次制备了双金属Pd-Cu@UiO-66催化剂用于催化还原水中硝酸盐的研究,重点考察了不同调节剂制备的载体和工艺条件对脱硝性能的影响。结果表明:采用盐酸制备的UiO-66载体,Pd、Cu金属负载量分别为1%,氢气流量为70 mL/min时,硝酸盐脱除率为97.4%,N₂的选择性可达到95.2%。pKa值越低的调节剂所制备的载体粒径越小,越有利于活性金属的分散,且形成的金属粒径较小。活性金属的高度分散有利于活化氢的生成及Cu的电子迁移,能够提高脱硝反应中N₂的选择性。在反应过程中,双金属的协同效应是影响催化性能的关键因素。     

Pd/C气体扩散电极用于电化学降解4-氯酚的研究

采用氢气还原法制备Pd/C催化剂,利用XRD、TEM及XPS对该催化剂进行了表征,并利用此催化剂制备成新型的Pd/C气体扩散阴极;在隔膜电解体系中对4-氯酚进行降解,比较了不同通气方式下的去除效果.结果表明,所制备的催化剂中Pd以无定形态存在并高度分散在活性炭表面,形状比较规则,粒径在4.1 nm左右;制备的0.5%Pd/C催化剂表面的Pd摩尔分数达到1.29%;制备的Pd/C气体扩散阴极既对4-氯酚具有还原脱氯作用(通入H2时),又促进O2还原生成H2O2(通入O2时).采用先通氢气后通空气的方式对4-氯酚有很好的去除效果,反应60min后4-氯酚的转化率和脱氯率接近100%,120 min后阴极室COD去除率达到87.4%.因此,采用Pd/C气体扩散阴极可通过还原.氧化相结合的方法对氯酚类有机物进行降解.     

Conversion of the refractory ammonia and acetic acid in catalytic wet air oxidation of animal byproducts

Wet air oxidation (WAO) and catalytic wet air oxidation (CWAO) of slaughtered animal byproducts (ABPs) were investigated. Two step experiment was carried out consisting of a non-catalysedWAO run followed by a CWAO run at 170–275°C , 20 MPa, and reaction time 180 min. TheWAO (1st step) of sample (5 g/L total organic carbon (TOC)) yielded (82.0 4)% TOC removal and (78.4 13.2)% conversion of the initial organic-N into NH4 +-N. Four metal catalysts (Pd, Pt, Rh, Ru) supported over alumina have been tested in catalytic WAO (2nd step) at elevated pH to enhance ammonia conversion and organic matter removal, particularly acetic acid. It was found that the catalysts Ru, Pt, and Rh had significant e ects on the TOC removal (95.1%, 99.5% and 96.7%, respectively) and on the abatement of ammonia (93.4%, 96.7% and 96.3%, respectively) with high nitrogen selectivity. The catalyst Pd was found to have the less activity while Pt had the best performance. The X-Ray di raction analysis showed that the support of catalyst was not stable under the experimental conditions since it reacted with phosphate present in solution. Nitrite and nitrate ions were monitored during the oxidation reaction and it was concluded that CWAO of ammonia in real waste treatment framework was in good agreement with the results obtained from the literature for ideal solutions of ammonia.     

钯/泡沫镍对水体中4-氯酚的氢解脱氯研究

采用置换沉积法制备泡沫镍负载钯(Pd/Ni)催化剂,研究了其在H2作为供氢体时对水相中4-氯酚(4-CP)的催化氢解脱氯作用.考察了Pd负载量、H2流量和反应液pH值对4-CP转化率的影响.结果表明,在相对较低的Pd负载量和H2流量下即可实现4-CP的快速高效去除,且反应液pH值在3.04~10.97的范围对反应影响不显著.当Pd负载量为0.1%、H2流量为10mL/min、pH值为6.80时,反应1h,4-CP转化率达92.6%.Pd/Ni具有较高的稳定性,重复实验表明,该催化剂使用3次后,催化活性仅下降了2.0%.     

处理垃圾渗滤液的Fe/C空气阴极MFC性能研究

用浸渍法制得硝酸铁/活性炭粉催化剂,通过吸附法将催化剂吸附到碳毡上制作Fe/C催化剂碳毡空气阴极电极.通过改变初始活性炭粉投加量和硝酸铁浓度,考察了两者对以垃圾渗滤液为燃料的MFC产电性能影响;通过循环伏安测试,对不同硝酸铁浓度下自制阴极电极性能进行了评价;在最佳催化条件下考察了装置运行稳定性;并对不同进水COD浓度下同步产电和污水净化性能进行了研究.结果表明,随着活性炭粉投加量或硝酸铁浓度的增加,MFC产电性能均呈现先升高后降低的趋势;当活性炭粉投加量为1 g且硝酸铁浓度为0.25 mol.L-1时,电池性能最佳,功率密度为4 199.8 mW.m-3,表观内阻为465Ω;在硝酸铁和活性炭粉最佳比范围内,MFC的内阻和功率密度分别随着催化剂量的增加而减小和增加;循环伏安测试进一步表明,硝酸铁浓度为0.25 mol.L-1时放电容量最大,且性能稳定;在最佳催化条件下,随着进水COD浓度的增加,MFC产电性能增加,功率密度达5 478.92 mW.m-3,同时COD去除量也增加,最大为1 505.2 mg.L-1,垃圾渗滤液的COD去除率最大达89.1%.     

催化还原法深度处理污水中硝态氮的研究

为有效降低城市污水处理厂出水硝态氮的含量,减轻氮素污染,依次进行了基础性试验和验证性试验.基础性试验以Fe0为还原剂,以配置的KNO3溶液为试验用水对分别添加H+、Fe2+、Cu2+、Pd/Al2O3等后的脱氮效果进行了对比研究.试验结果表明,系统pH值为2.1,Fe2+、Cu2+投加量分别为1000mg/L时,系统均可获得较好的脱氮效果,分别为92%、41%、61%,产物均以氨氮为主;当投加10g/L催化剂Pd/Al2O3,调节系统pH值为3.02时,系统脱氮率可达48%,且其产物以氮气为主,副产物较少.在此基础上,验证性试验以北京市某污水处理厂出水为试验用水,对上述各方法的脱氮效果进行了试验验证,并对其可行性进行了分析.结果表明,在一定条件下,各方法均可达到理想的脱氮效果,其去除率分别可达到87%、36%、50%、46%.但综合脱氮效果、产物分析、出水水质等考虑,相比较而言,添加催化剂的化学催化还原法在去除污水中的硝态氮时具有更好的可行性.     

Reduction of nitrate from groundwater: powder catalysts and catalytic membrane

The reduction of nitrate contaminant in groundwater has gained renewed and intensive attention due to the environmental problems and health risks. Catalytic denetrification presents one of the most promising approaches for the removal of nitrate from water. Catalytic nitrate reduction from water by powder catalysts and catalytic membrane in a batch reactor was studied. And the effects of the initial concentration, the amounts of catalyst, and the flux H2 on the nitrate reduction were also discussed. The results demonstrated that nitrate reduction activity and the selectivity to nitrogen gas were mainly controlled by diffusion limitations and the mass transfer of the reactants. The selectivity can improved while retaining a high catalytic activity under controlled diffusion condition or the intensification of the mass transfer, and a good reaction condition. The total nitrogen removal efficiency reached above 80%. Moreover, catalytic membrane can create a high effective gas/liquid/solid interface, and show a good selectivity to nitrogen in comparative with the powder catalyst, the selectivity to nitrogen was improved from 73.4 % to 89.4%.