Photocatalytic degradation of L- acid by TiO_2 supported on the activated carbon

TiO2 sol was prepared by sol-gel technique with tetrabutyl titanate as precursor. Supported TiO2 catalysts on activated carbon were prepared by soak and sintering method. The aggregation of nano-TiO2 particles can be effectively suppressed by added polyethylene glycol （PEG） as a surface modifier. The average particle diameter of TiO2, specific surface area and absorbability of catalyst can be modified. Based on characteristics of the TiO2 photocatalyst with XRD, specific surface area, adsorption valves of methylene blue and the amount of TiO2 supported on the activated carbon, the photocatalytic degradation of L-acid was studied. The effect of the factors, such as pH of the solution, the initial concentration of L-acid on the photocatalytic degradation of L-acid, were studied also. It was found that when the pH of the solution is 1.95, the amount of photocatalyst is 0.5 g, the concentration of the L-acid solution is 1.34×10^3 mol/L and the illumination time is 7 h, the photocatalytic degradation efficiency of L-acid can reach 89,88%, The catalyst was reused 6 times and its degradation efficiency hardly changed.

Inactivated properties of activated carbon-supported TiO_2 nanoparticles for bacteria and kinetic study

The activated carbon-supported TiO2 nanoparticles(TiO2/AC)were prepared by a properly controlled sol-gel method.The effects of activated carbons(AC)support on inactivated properties of TiO2 nanoparticles were evaluated by photocatalytic inactivation experiments of Escherichia coli.The key factors affecting the inactivation effciency were investigated,including electric power of lamp, temperature,and pH values.The results show that the TiO2/AC composites have high inactivation properties of E.coli in compari...

Highly reactive and reusable heterogeneous activated carbons-based palladium catalysts for Suzuki-Miyaura reaction

Suzuki-Miyaura reaction of aryl halides with phenylboronic acid using a heterogeneous palladium catalyst based on activated carbons(AC) was systematically investigated in this work. Two different reaction modes(batch procedure and continuous-flow procedure) were used to study the variations of reaction processing. The heterogeneous catalysts presented excellent reactivity and recyclability for iodobenzene and bromobenzene substrates in batch mode, which can be attributed to stabilization of Pd nanoparticles by the thiol and amino groups on the AC supports. However, significant dehalogenation in the reaction mixture and Pd leaching from the heterogeneous catalysts were observed in continuous-flow mode.This unique phenomenon in continuous-flow mode resulted in a dramatic decline in reaction selectivity and durability of heterogeneous catalysts comparing with that of batch mode. In addition, the heterogeneous Pd catalysts with thiol-and amino-modified AC supports exhibited different reactivity and durability in batch and continuous-flow mode owing to the difference of interaction between Pd species and AC supports.

Effect of Activated Carbon as a Support on Metal Dispersion and Activity ofRuthenium Catalyst for Ammonia Synthesis

Ten kinds of activated carbon from different raw materials were used as supports to prepare ruthenium catalysts. N_2 physisorption and CO chemisorption were carried out to investigate the pore size distribution and the ruthenium dispersion of the catalysts. It was found that the Ru dispersion of the catalyst was closely related to not only the texture of carbon support but also the purity of activated carbon. The activities of a series of the carbon-supported barium-promoted Ru catalysts for ammonia synthesis were measured at 425 ℃, 10 0 MPa and 10 000 h -1. The result shows that the same raw material activated carbon, with a high purity, high surface area, large pore volume and reasonable pore size distribution might disperse ruthenium and promoter sufficiently, which activated carbon as support, could be used to manufacture ruthenium catalyst with a high activity for ammonia synthesis. The different raw material activated carbon as the support would greatly influence the catalytic properties of the ruthenium catalyst for ammonia synthesis. For example, with coconut shell carbon(AC1) as the support, the ammonia concentration in the effluent was 13 17% over 4%Ru-BaO/AC1 catalyst, while with the desulfurized coal carbon(AC10) as the support, that in the effluent was only 1 37% over 4%Ru-BaO/AC10 catalyst.

THE HYDROXYLATON OF INACTIVE HYDROCARBONS WITH ACTIVE CARBON SUPPORTED METALLOPORPHYRINS

A supported Mn-porphyrin catalyst was prepared by adsorption of Mn-porphyrin on active carbon, and found to be efficient for the hydroxylation of hexane with hydrogen peroxide.

Strengthening decomposition of oxytetracycline in DBD plasma coupling with Fe-Mn oxide-loaded granular activated carbon

A catalytic approach using a synthesized iron and manganese oxide-supported granular activated carbon(Fe-Mn GAC) under a dielectric barrier discharge(DBD) plasma was investigated to enhance the degradation of oxytetracycline(OTC) in water. The prepared Fe-Mn GAC was characterized by x-ray diffraction and scanning electron microscopy, and the results showed that the bimetallic oxides had been successfully spread on the GAC surface. The experimental results showed that the DBD?+?Fe-Mn GAC exhibited better OTC removal efficiency than the sole DBD and DBD?+?virgin GAC systems. Increasing the fabricated catalyst and discharge voltage was favorable to the antibiotic elimination and energy yield in the hybrid process. The coupling process could be elucidated by the ozone decomposition after Fe-Mn GAC addition, and highly hydroxyl and superoxide radicals both play significant roles in the decontamination. The main intermediate products were identified by HPLC-MS to study the mechanism in the collaborative system.

STUDIES ON THE PREPARATION OF ZINC-CONTAINING ACTIVATED CARBON FIBERS AND THEIR ANTIBACTERIAL ACTIVITY

Several kinds of activated carbon fibers, using sisal fiber as precursors, were prepared with steam activation or with ZnCl2 activation. Zinc or its compounds were dispersed in them. The antibacterial activities of these activated carbon fibers were determined and compared. The research results showed that these sisal based activated carbon fibers supporting zinc have stronger antibacterial activity against Escherichia coli and S. aureus. The antibacterial activity is related to the precursors, the pyrolysis temperature, and the zinc content. In addition, small quantity of silver supported on zinc-containing ACFs will greatly enhance the antibacterial activity of ACFs.

Effects of the Different Supports on the Activity and Selectivity of Iron-Cobalt Bimetallic Catalyst for Fischer-Tropsch Synthesis

Silica, alumina, and activated carbon supported iron-cobalt catalysts were prepared by incipient wetness impregnation. These catalysts have been characterized by BET, X-ray diffraction （XRD）, and temperature-programmed reduction （TPR）. Activity and selectivity of iron-cobalt supported on different carriers for CO hydrogenation were studied under the conditions of 1.5 MPa, 493 K, 630 h^-1, and H2/CO ratio of 1.6. The results indicate that the activity, C4 olefin/（C4 olefin＋C4 paraffin） ratio, and C5 olefin/（C5 olefin＋C5 paraffin） decrease in the order of Fe-Co/SiO2, Fe-Co/AC1, Fe-Co/Al2O3 and Fe- Co/AC2. The activity of Fe-Co/SiO2 reached a maximum. The results of TPR show that the Fe-Co/SiO2 catalyst is to some extent different. XRD patterns show that the Fe-Co/SiO2 catalyst differs significantly from the others; it has two diffraction peaks. The active spinel phase is correlated with the supports.

Efficient activation of sulfite for reductive-oxidative degradation of chloramphenicol by carbon-supported cobalt ferrite catalysts

Activation of(bi)sulfite(S(IV))by metal oxides is strongly limited by low electrons utilization.In this study,two carbon-supported cobalt ferrites spinels(CoFe^(2)O_(4) QDs-GO and CoFe^(2)O_(4) MOFs-CNTs)have been successfully synthesized by one-step solvothermal method.It was found that both catalysts could efficiently activate S(IV),with rapid reductive dechlorination and then oxidative degradation of a recalcitrant antibiotic chloramphenicol(CAP).Characterizations revealed that CoFe^(2)O_(4) spinels were tightly coated on the carbon bases(GO and CNTs),with effectiveness of the internal transfer of electrons.O_(2)˙−was identified for the reductive dechlorination of CAP,with simultaneously detection of both•OH and SO_(4)^(˙−)responsible for further oxidative degradation.The sulfur oxygen radical conversion reactions and molecular oxygen activation would occur together upon the carbon-based spinels.Spatial-separated interfacial reductive-oxidation of CAP would occur with dechlorination of CAP by O_(2)^(˙−)on the carbon bases,and oxidative degradation of intermediates by SO_(4)^(˙−/•)OH upon the CoFe^(2)O_(4) catalysts.

碳负载Cs和Cu基催化剂用于1,1,2-三氯乙烷的气相脱氯化氢

采用浸渍法制备了Cs/AC和Cu/AC催化剂,并在1,1,2-三氯乙烷的气相脱氯化氢反应中进行了评价。在浸渍过程中,活性炭表面产生高度分散的Cs物种和少量结晶的Cu物种。Cs/AC催化剂具有优异的催化性能,在573 K、1000 h^(−1)的反应条件下,转化率稳定在86.7%。实验和理论计算表明,CsCl物种促进了1,1,2-三氯乙烷的吸附和活化,从而提高了原料转化率。这项工作为探索高效经济地合成偏二氯乙烯提供了一种很有前景的策略。

Dechlorination of 2,2＇,4,4＇,5,5＇-hexachlorobiphenyl by thermal reaction with activated carbon-supported copper or zinc

Activated carbon （AC）-supported copper or zinc made from ion exchange resin （IRCu-C and IRZn-C） have an increased metal load of 557.3 mg·g^-1 and 502.8 mg·g^-1 compared to those prepared by the traditional method involving impregnation with AC and copper （II） citrate or zinc citrate solution （LaCu-C and LaZn-C） of 12.9 mg·g^-1 and 46.0 mg·g^-1 respectively. When applied to decompose 2,2＇,4,4＇,5,5＇-hexachlorobiphenyl at 250 ℃, IRCu-C achieved higher activity of 99.0% decomposition efficiency than LaCu-C of 84.7%, IRZn-C of 90.5% and LaZn-C of 62.7%. When the reaction temperature rose to 350 ℃, all the four kinds of reactants can decompose PCB- 153 with efficiency above 90%. Further, X-ray photoelec- tron spectroscopy characterization of IRCu-C before and after the reaction indicated transformation of 19.1% of Cu atoms into Cu^2＋, illustrating that Cu is the active ingredient or electron donor promoting the decomposition of PCB- 153. The mechanism underlying this process differs from a traditional H donor. However, there is no significant change on the surface of IRZn-C before and after the reaction, suggesting that Zn acts as catalyst during the process of PCB-153 decomposition.

碳球负载纳米零价铁活化过硫酸盐降解水中恩诺沙星的性能研究

恩诺沙星(ENR)属于氟喹诺酮类抗生素,具有稳定性强、难分解、易富集等特性,常用于水产养殖、畜禽养殖等,其在环境中总体浓度较低,但长期低剂量暴露可能对人体健康和生态环境带来极大风险。采用碳球(CS)负载纳米零价铁(nZVI)活化过硫酸盐(PS)去除水体中的ENR。应用两步碳热还原法制备了碳球负载纳米零价铁(Fe@C),采用单因素实验研究了Fe@C投加量、PS浓度、ENR初始浓度和pH值对ENR降解的影响及降解动力学,通过自由基及降解产物分析推测了Fe@C活化PS降解ENR的反应机制与降解路径。结果表明,ENR的降解符合准一级动力学,在温度为25℃、Fe@C投加量为0.3 g∙L^(-1)、PS浓度为1 mmol∙L^(-1)、ENR初始质量浓度为10 mg∙L^(-1)、pH值为3的条件下,ENR降解率最高达98.6%。ENR降解率随着腐植酸(HA)、氨氮(NH3-N)、碳酸氢根离子(HCO3-)浓度的升高而降低。氯离子(Cl-)在低浓度时对ENR的降解有微弱的促进作用,高浓度时有抑制作用。自由基淬灭实验表明SO4-∙是ENR降解的主要自由基。根据ENR的降解产物,推测哌嗪环的裂解、喹诺酮环的分解及脱氟为ENR主要降解途径。碳球负载纳米零价铁活化PS高级氧化工艺可作为一种高效去除水中ENR的工艺。

CeO_(2)载体在CO_(2)加氢制甲醇中的应用和研究进展

随着经济的快速发展,CO_(2)排放导致的温室效应日益严峻,通过与绿氢反应将其转化为甲醇等有价值的化工产品是减少CO_(2)排放、缓解全球气候变暖的有效途径。近年来,CeO_(2)负载金属催化剂在CO_(2)加氢制甲醇反应中得到了广泛关注。本文主要综述了CeO_(2)表面氧空位和碱性位点、Ce3+/Ce4+可逆氧化还原能力、几何形貌等特性在CO_(2)/H_(2)吸附活化和甲醇形成过程中所起到的重要作用,比较了CeO_(2)与ZrO_(2)、ZnO以及复合金属氧化物等载体在反应中的差异,提出了CeO_(2)载体催化剂在确认活性关键中间体、兼顾CO_(2)转化率和甲醇选择性、提高催化活性与稳定性等方面的不足和挑战,以期为新型CO_(2)加氢制甲醇催化剂的设计提供有益参考。

AC@Fe_(3)O_(4)的制备及其对水中乳液的吸附性能研究

煤矿液压支架乳液在使用的过程汇入矿井水中,大幅度增加了处理难度。粉末活性炭(AC)具有比表面积大、吸附能力强等优点,可以应用于含乳液矿井水的处理中,但存在吸附后固液分离难以及AC再生回用难的问题。基于此,本研究以AC、FeCl_(3)·6H_(2)O、FeCl_(2)·4H_(2)O为原料,通过化学共沉淀法制备了活性炭负载Fe_(3)O_(4)复合材料(AC@Fe_(3)O_(4)),并应用于液压乳液废水的吸附处理。结果表明,磁性活性炭对乳液的吸附在90 min时达到吸附平衡,当乳液的初始体积分数为0.5%,温度为25℃,振荡速度为200 r/min时,对乳液的吸附量为1.07 mL/g。吸附动力学研究表明,磁性活性炭对乳液的吸附更符合伪二级动力学模型,表明其对乳液的吸附主要是化学吸附,Langmuir等温线模型对磁性活性炭吸附乳液的拟合度较高,通过拟合计算得到的理论饱和吸附量为1.51 mL/g,而实验中优化吸附量也达到1.07 mL/g。吸附平衡后分离出的AC@Fe_(3)O_(4)在甲醇中乳液的脱附率可以达到90%以上,吸附剂可以重复利用,经过5次循环仍能保持良好的吸脱附性能,并且在外加磁力的作用下可实现液固分离,回收利用简单方便。

High activity of a Pt decorated Ni/C nanocatalyst for hydrogen oxidation

The Pt decorated Ni/C nanocatalysts were prepared for hydrogen oxidation reaction（HOR） in fuel cell.By regulating the contents of Pt and Ni in the catalyst,both the composition and the structure affected the electrochemical catalytic characteristics of the Pt-Ni/C catalysts.When the Pt mass content was 3.1% percent and that of Ni was 13.9% percent,the Pt-Ni/C-3 catalyst exhibited a larger electrochemically active surface area and a higher exchange current density toward HOR than those of pure supported platinum sample.Our study demonstrates a feasible approach for designing the more efficient catalysts with lower content of noble metal for HOR in fuel cell.

Synthesis of Polyketone by Copolymerization of Styrene and CO Using Carbon Nanotube-Complex Pd^(2+) Catalyst

The dipping method was devised to deposit Pd onto carbon nanotube as supported catalyst(Pd/CNT) for the copolymerization of carbon monoxide(CO) and styrene(ST) towards the formation of polyketone(PK).The Pd/CNT was characterized by X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD) and high-resolution transmission electron microscopy(HRTEM).The construction and crystallization property of PK were evaluated by Fourier transform infrared spectroscopy(FTIR),13C-nuclear magnetic resonance(NMR) and XRD,respectively.The catalyst showed excellent activity and reusability in promoting the fabrication of PK.It can be recycled 14 times with the highest total catalytic activity of 4 239.64 gPK/(gPd·h) at Pd content of 8.63wt%.The results indicate that the prepared catalyst is effective to catalyze the copolymerization of CO and styrene.

Study on the Active Phases of Ni-W System Hydrotreating Catalysts

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碳载铁基双金属活化过硫酸盐降解有机污染物

过硫酸盐高级氧化技术因具有氧化性强、稳定性高、药剂易于运输等特点,被广泛应用于有机污染场地的修复中,在环境治理领域具有广阔的应用前景。通常过硫酸盐需要激活才能有效地去除有机物,碳载铁基双金属材料因碳材料的多孔结构和高比表面积可以提高金属的分散性,而且还可以吸附目标污染物,是一种能够高效活化过硫酸盐降解有机污染物的激活剂。该研究在关注碳载铁基双金属的制备方法的基础上,分析了碳载双金属活化过硫酸盐氧化体系的主要机制,探讨了影响碳载铁基双金属活化过硫酸盐体系降解效率的主要影响因素及碳载铁基双金属材料的稳定性,并进一步展望了碳载铁基双金属活化过硫酸盐体系降解有机污染物的研究方向和发展趋势。

铁酸钴复合碳纳米管活化过硫酸盐降解铬黑T的性能及机理

采用水热法制备了不同质量比铁酸钴/碳纳米管(CoFe_(2)O_(4)/CNT)复合材料,并将其用于活化过一硫酸盐(PMS)降解偶氮染料铬黑T(EBT)。使用扫描电镜、X射线衍射仪、X射线光电子能谱仪等方法进行了表征。结果表明,引入CNT改善了CoFe_(2)O_(4)团聚现象,同时CNT加速CoFe_(2)O_(4)表面电子转移过程进一步提高了CoFe_(2)O_(4)催化活性。质量比为4∶1的CoFe_(2)O_(4)/CNT表现出最高催化活性,CoFe_(2)O_(4)/CNT-4∶1+PMS降解EBT过程符合准一级动力学模型,其反应速率常数是CoFe_(2)O_(4)+PMS体系的2.02倍。单因素条件实验得出在CoFe_(2)O_(4)/CNT-4∶1投加量为0.20g/L、PMS投加量为0.20g/L、EBT质量浓度为100mg/L、pH为5.8、反应温度为25℃条件下,反应60min后EBT降解率可达到99.8%。CoFe_(2)O_(4)/CNT-4∶1循环使用三次后EBT降解率能达到67.8%。猝灭实验证明反应体系中存在着SO_(4)^(-)·、·OH、O_(2)^(-)·和^(1)O_(2)四种活性物质,其中^(1)O_(2)是主要活性物质。Fe^(2+)/Fe^(3+)、Co^(2+)/Co^(3+)价态循环和氧物种改变促进了活性物质生成。

乙炔氢氯化多元铜基催化剂的制备及应用

以CuCl_(2)为活性组分、非贵金属SnCl_(4)和BiCl_(3)为助剂,采用等体积浸渍法制备多元铜基催化剂。结果表明,在反应温度150℃、V(HCl)/V(C_(2)H_(2))=1.10、乙炔空速为315 h^(-1)的条件下,10%CuCl_(2)-5%SnCl_(4)-1%BiCl_(3)/AC三元催化剂的初始活性达到50%;乙炔氢氯化反应9.5 h后,催化活性依然超过相同条件下的汞催化剂。BET、H_(2)-TPR和XPS表征分析结果表明,乙炔氢氯化反应发生在催化剂微孔内;Sn助剂提高了催化剂的抗还原性,稳定了Cu活性组分的价态,从而改善了铜基催化剂的初始活性。