均相与非均相超声-芬顿催化降解水中罗丹明B

以染料罗丹明B(RhB)为目标污染物,以泡沫铁为非均相催化剂,比较均相与非均相超声芬顿体系对RhB的去除效果,并考察了RhB初始含量、溶液初始pH、H_2O_2投加量等因素的影响。通过对不同体系反应速率、Fe~(2+)含量变化以及H_2O_2产量的比较分析,探索比较了降解机制。结果表明,均相超声芬顿体系对RhB的去除率高于非均相超声芬顿体系,当初始RhB的质量浓度为5 mg/L,初始pH为3,H_2O_2投加量为0.5 mmol/L时,RhB去除率分别达到99.86%、94.43%;前40 s符合一级反应动力学方程,基于泡沫铁的非均相芬顿体系可在超声辐射下产生更多Fe~(2+)和H_2O_2,从而有利于对目标污染物的持续降解。     

石墨相氮化碳负载尖晶石型铁钴硫化物活化过氧乙酸降解自然水体中罗丹明B的研究

通过水热法合成了一种新型氮化碳负载尖晶石型铁钴硫化物(FeCo₂S₄-CN),并将其用于活化过氧乙酸(PAA)降解罗丹明B(RhB),考察了初始pH和常见水体组分对FeCo₂S₄-CN/PAA体系降解RhB的影响,在此基础上研究了该体系对两种自然水体中RhB的降解效能和机理,论证该技术实际应用的可行性。结果表明,近中性条件(pH=6.5)最有利于FeCo₂S₄-CN/PAA体系降解RhB。SO₄^2-、NO₃^-、Ca²⁺、Mg²⁺以及低浓度Cl^-与富里酸(FA)几乎不影响RhB的降解;而HCO₃^-、高浓度的Cl^-与FA能够竞争FeCo₂S₄-CN/PAA体系产生的活性自由基,从而抑制RhB的降解。自...     

Fe_3O_4@MOF纳米复合材料高效催化降解废水中罗丹明B

通过共沉淀法分步合成Fe_3O_4/Cu_3(BTC)_2金属有机骨架(MOF)纳米复合材料,并对材料进行了傅里叶红外光谱、X射线衍射、透射电镜和磁化强度表征。结果表明,复合纳米材料具有较好的晶形和磁性,易于分离。在初始溶液pH为5.6、反应温度为40℃、H_2O_2浓度为0.1 mol/L时,0.2 g/L Fe_3O_4/Cu_3(BTC)_2复合纳米材料对质量浓度10mg/L的RhB的脱色率大于98.8%。通过猝灭实验,提出·OH自由基是参与催化降解反应的主要活性中间体。基于经济、高效的催化降解能力和易于分离,Fe_3O_4/Cu_3(BTC)_2MOF材料可用于染料废水中RhB的催化降解去除。     

斜板液膜反应器光电催化降解罗丹明B

采用溶胶-凝胶法制备了TiO2/Ti电极,进行光电催化降解罗丹明B(RhB)试验。确定了最佳降解条件:外加偏压+0.8 V、废水流量7.7 L/h、初始pH=2.5和电解质质量浓度2.0 g/L。在最佳条件下,处理20 mg/L的RhB溶液1.5 h,脱色率和TOC去除率分别达到97.3%和76.2%。结果表明,由于同时强化了激发光源的利用率和溶液的传质效率,斜板液膜反应器可高效降解RhB。     

多聚磷酸络合纳米铜降解罗明丹B研究

为增强纳米零价铜(nZVC)/H_2O_2体系在中性条件下的氧化能力,以罗明丹B(RhB)模拟染料废水为对象,对nZVC/H_2O_2/多聚磷酸(PPA)体系氧化降解RhB效果进行了研究。结果表明,反应60 min时,nZVC/H_2O_2体系中RhB的降解率为13.49%,nZVC/H_2O_2/PPA体系中RhB的降解率为89.29%;通过投加叔丁醇发现,体系中反应物种主要为HO~·;pH的改变对nZVC/H_2O_2/PPA体系氧化能力影响不大;同时,提高H_2O_2、PPA、nZVC投加量均会对RhB的降解起促进作用;降解反应遵循二级反应动力学。PPA的加入可以有效提升nZVC/H_2O_2体系在中性条件下的氧化能力,有效降解水中目标污染物。     

壳聚糖包被纳米铁催化降解罗丹明B研究

针对纳米零价铁(NZVI)催化过硫酸盐(PS)的高级氧化技术中,NZVI易团聚、易被氧化和难以重复利用等问题,采用中和法制备了壳聚糖包被纳米零价铁(CS@NZVI),作为过硫酸盐的催化剂,对其进行了表征,并以罗丹明B(RhB)为目标污染物,研究催化过硫酸盐降解RhB的优化条件和降解反应动力学。结果表明,优化降解条件为:RhB、PS初始质量浓度分别为8 mg/L、3g/L,CS@NZVI投加量为0.7 g/L,初始pH=2.5,温度为55℃,在此条件下,1 h降解率为91%,反应速率常数为0.040 9 min-1。催化降解行为均符合1级动力学模型。PS-CS@NZVI体系使反应活化能从20.4 kJ/mol下降到10.9 kJ/mol,证明了材料对过硫酸根的催化作用。该催化剂可重复使用4次,反应速率常数均在0.0360 min-1以上。     

还原氧化石墨烯膜负载Co3O4活化过硫酸氢钾降解罗丹明B

以RGO(还原氧化石墨烯膜)为载体,采用水热法制备RGO/Co₃O₄高效复合催化剂。通过XRD(X射线衍射仪)、SEM(扫描电子显微镜)和XPS(X射线光电子能谱仪)等手段对复合催化剂的结构、形貌和化学组成等进行表征,并以RhB(罗丹明B)为降解物评价复合催化剂活化PMS(过硫酸氢钾)的反应活性。另外,考察了PMS质量浓度、RhB初始质量浓度、pH值及温度对催化剂活化PMS降解RhB的影响。结果表明：在PMS质量浓度为100 mg/L、RhB初始质量浓度为10 mg/L、pH值为7、温度为25℃时反应18 min对RhB降解率为98%。自由基捕获实验结合ESR(电子顺磁共振)结果表明体系中同时存在SO₄^-·和HO·2种活性自由基。循环实验结果显示催化剂经过5次循环使用后对RhB的降解率仍保持90%以上,显示优异的循环稳定性。     

磁性污泥生物炭活化过硫酸盐降解罗丹明B

采用微波热解法制备磁性污泥生物炭(MBC),并通过XRD、FT-IR和SEM对其晶体结构、表面官能团及形貌进行表征。以罗丹明B(RhB)为目标污染物,研究MBC活化过硫酸盐(PDS)的性能。结果表明MBC活化PDS能够有效去除水体中RhB,效果优于磁性Fe₃O₄,归功于MBC具有丰富的官能团和发达的孔隙结构。此外,探究催化剂投加量、PDS添加量、温度和pH值对MBC活化PDS降解RhB的影响。MBC活化PDS降解RhB主要通过非自由基过程,其中单线态氧(¹O₂)是主要的反应活性物种。     

Bi_(12)O_(17)Cl_2光催化降解RhB——响应曲面法优化反应条件

利用水热法制备出Bi_(12)O_(17)Cl_2,并对其进行了SEM和XRD表征,研究在不同条件下光催化降解RhB活性。通过单因素实验确定主要的影响因素和水平,利用响应曲面法对主要影响因素进行优化。通过分析实验结果,建立了Bi_(12)O_(17)Cl_2光催化降解罗丹明B(RhB)的二次多项式模型。预测光催化降解RhB的最佳反应参数是:催化剂投加量32.65 mg,RhB初始浓度5.53 mg/L,反应时间160.13 min,预测降解率可达100%。     

铜铝层状双金属氧化物活化过一硫酸盐降解罗丹明B

本研究采用沉淀-煅烧法制备了Cu:Al不同摩尔比的层状双金属氧化物(CuAl-LDO)，用于活化过一硫酸盐(PMS)降解罗丹明B(RhB)。研究了催化剂剂量、PMS剂量、pH、RhB质量浓度、温度和无机阴离子对RhB降解的影响。通过扫描电镜(SEM)、X射线衍射仪(XRD)、傅里叶红外光谱(FTIR)、X射线光电子能谱(XPS)等技术手段进一步表征了样品的性能。结果表明，在投加30 mg/L的CuAl 2:1-LDO和PMS、反应温度为25℃、pH=5.61、RhB质量浓度为100 mg/L的条件下，30 min内的RhB降解率为97.1%。同时，CuAl 2:1-LDO/PMS反应体系在pH值3.00-11.00的较宽范围内,对RhB的降解率具有90%以上，并在第四次循环实验中降解率仍达到71%。其次，电子自旋共振(EPR)、猝灭实验和Uv-vis光谱结果表明,在CuAl 2:1-LDO/PMS体系中产生了较多的硫酸根自由基(SO4-·)和羟基自由基(·OH)，其中·OH在RhB的降解过程中起主导作用，攻击芳香烃环使染料脱色。     

化学沉淀-水热法合成高矫顽力碳纳米管磁性复合材料

采用化学沉淀-水热法成功的合成了一种新颖的Ni0.75Zn0.25Fe2O4纳米晶包覆多壁碳纳米管(Ni0.75Zn0.25Fe2O4-CNTs)磁性复合材料.采用透射电镜、X射线衍射、红外光谱和振动样品磁强计等方法对制备的样品进行了表征.透射电镜结果表明Ni0.75Zn0.25Fe2O4纳米晶包覆在碳纳米管表面,纳米晶的大小为8～15 nm.X射线衍射结果表明:200℃是制备纳米Ni0.75Zn0.25Fe2O4包覆碳纳米管复合材料较好的反应条件,比合成单相Ni0.75Zn0.25Fe2O4纳米晶的温度要低.磁性复合材料中Ni0.75Zn0.25Fe2O4晶体的大小约为16.0nm.红外结果表明NiZn的特征峰在590cm-1和414cm-1处.磁滞回线结果表明室温下复合材料具有较高的矫顽力(Hc=27 244.3 kA/m).     

CNTs／TMO复合催化剂对含高氯酸钾烟火药剂分解反应速率的影响

采用化学沉淀法制备沉积于碳纳米管(CNTs)表面上的CuO、Fe2O3复合催化剂.用光电子能谱(XPS)对复合催化剂进行表征,研究了CuO/CNTs和Fe2O3/CNTs复合催化剂对含高氯酸钾烟火药剂分解反应的影响.结果表明,CuO和Fe2O3颗粒均匀地附着在碳纳米管表面上,Cuo/CNTs和Fe3O3/CNTs复合催化剂能够提高含高氯酸钾烟火药剂的反应速率,复合催化剂对高氯酸钾烟火药剂的催化性能明显优于Fe2O3和CuO混合物的催化性能.     

High Oxygen‐Reduction‐Activity and Methanol‐Tolerance Cathode Catalyst Cu/PtFe/CNTs for Direct Methanol Fuel Cells

A novel nanocomposite Cu/PtFe/carbon nanotubes (CNTs) was designed, prepared and examined as a cathode catalyst for direct methanol fuel cells (DMFCs). The effects of Fe and Cu on oxygen reduction reaction (ORR) activity and methanol tolerance were investigated by varying their amounts or their configurations in the nanocomposite. The experimental results show that PtFe alloy on CNTs could not enhance methanol tolerance, but could improve the ORR activity. Cu was deposited on PtFe/CNTs to obtain better methanol tolerance. The optimum molar ratio of Cu/Pt/Fe in Cu/PtFe/CNTs is 2.1:1:0.7. After 500 cycles in 1 M HClO₄ solution, the Cu/PtFe/CNTs catalyst is fairly stable with 92% of its original ORR activity and 89.6% of its original electrochemical active surface areas (EAS) maintained.     

Fe2O3/CNTs纳米粒子的制备及其对高氯酸铵燃速的催化作用

采用液相沉淀法制备沉积于碳纳米管（CNTs）表面的Fe2O3复合纳米催化剂,用透射电子显微镜（TEM）和光电子能谱（XPS）对制备的Fe2O3／CNTs复合纳米催化剂进行表征,研究了Fe2O3／CNTs复合纳米催化剂对高氯酸铵（AP）燃烧的催化性能。结果表明,纳米级Fe2O3颗粒均匀包覆在CNTs表面,Fe2O3／CNTs复合纳米催化剂能明显降低AP的分解温度,提高AP单元推进剂的燃速;Fe2O3／CNTs复合纳米催化剂对AP的催化活性明显优于纳米Fe2O3、纳米Fe2O3和CNTs的简单混合催化剂。     

Growth mechanism and field emission behavior of carbon nanotubes grown over 300 nm thick aluminium interlayer

The influence of thick aluminium (Al) ~ 300 nm interlayer on the growth and field emission (FE) properties of carbon nanotubes (CNTs) deposited on silicon coated with a 2 nm iron (Fe) catalyst was studied. The CNTs were grown over silicon substrate with and without Al-interlayer via CVD. It was observed that the presence of such high thickness of the interlayer on the substrate resulted in higher growth rate, narrower diameters and longer height of CNTs compared to CNTs grown on silicon (Si) substrate coated only with Fe. Al-interlayer hinders the diffusion of Fe into silicon, hence promotes the growth rate. Literature reports that a thick layer of Al causes Fe to diffuse into it, negatively affecting the growth. However, in our experiments, no evidence of depletion of Fe from the substrate was observed. Unique patterns of grown CNTs could be attributed to anisotropic Al-melting over the silicon substrate resulting in Al/Fe rich and deficient regions. The drastic improvement of current density from 0.41 mA/cm² to 20 mA/cm² at a field of 3.5 V/μm was found with Al-interlayer CNT grown samples. These mechanisms of improvements in field emission characteristics have been discussed in detail.     

Removal of hexavalent chromium ion from aqueous solution using nanoscale zero-valent iron particles immobilized on porous silica support prepared by polymer template method

Porous silica supported nanoscale zero-valent iron was prepared by a polymer template method in order to effectively remove a hexavalent chromium ion (Cr(VI)) in an aqueous solution. It did not show a deterioration of Cr(VI) removal efficiency, which could be caused by the surface oxidation and agglomeration of nanoscale zero-valent iron (NZVI) particles. Porous silica by the polymer template method showed quite unique structure, which we named as quasi-inverse opal silica (QIOS), and it showed high surface area (375.4m²/g) and fine pore size (76.5 nm). NZVI immobilized on the surface of QIOS (NZVI@QIOS) was added to an aqueous Cr(VI) solution at 0.025 g/L, and it showed over 96% Cr(VI) removal efficiency. Such a high removal efficiency of Cr(VI) was maintained over two weeks after preparation (92% after 16 days). Morphology of porous silica supported nanoscale zero-valent iron was analyzed by TEM and FE-SEM. Identification of the reaction compounds produced by the reaction of Cr(VI) and zero-valent iron (Fe(0)) was made by the application of XPS.     

Influence of ionic substitution in improving the biological property of carbon nanotubes reinforced hydroxyapatite composite coating on titanium for orthopedic applications

The present work is aimed for the development of carbon nanotubes (CNTs) reinforced single mineral (Sr, Mg, Zn) as well as multi minerals (Sr+Mg+Zn) substituted hydroxyapatite composite (M-HAP) coatings on titanium (Ti). The effect of different mineral ions substitution and CNTs reinforcement in HAP composite coating is discussed in detail. Fourier Transform Infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) equipped with energy dispersive X-ray analysis (EDX), and high resolution transmission electron microscopy (HRTEM) were used to characterize the structural and morphological behavior of the composite coatings. The corrosion resistance of the composite coatings in simulated body fluid (SBF) solution was evaluated by the potentiodynamic polarization and electrochemical impedance spectroscopic (EIS) studies. In addition, the biocompatibility of the composite coatings was evaluated by in vitro culture of human osteoblast MG63 cells on the composite coated Ti. All these results essentially suggest that CNTs/M-HAP composite coated Ti can be a potential candidate for orthopedic applications.     

Combination of photocatalytic and photoelectro-Fenton/citrate processes for dye degradation using immobilized N-doped TiO2 nanoparticles and a cathode with carbon nanotubes: Central composite design optimization

In this report, commercial TiO₂ nanoparticles were doped with nitrogen by a manual grinding method using urea. The prepared catalyst was characterized by X-ray diffraction (XRD), diffuse reflectance spectra (DRS), and transmission electron microscopy (TEM). N-doped TiO₂ was immobilized on ceramic plates by methyl tri-methoxy silane. Next, multi-walled carbon nanotubes (CNTs) were stabilized on carbon paper to fabricate the cathode. Scanning electron microscopy (SEM) was employed to confirm stabilization of the CNTs. The prepared cathode and immobilized catalyst were utilized for the degradation of C.I. Direct Red 23 (DR23) by the photoelectro-Fenton (PEF) process in the presence of citrate (Cit) combined with a photocatalytic process. The coupled PEF/Cit/N-TiO₂ process could be performed under visible light, not only due to the formation of iron–citrate complexes, but also because of the incorporation of nitrogen to the crystalline structure of TiO₂ and the generation of TiO₂ complexes with electrogenerated H₂O₂. Results demonstrated that the degradation efficiency of DR23 (20 mg/L) using the identical operational conditions, followed a decreasing order of: PEF/Cit/N-TiO₂ > PEF/Cit > PEF > EF > N-TiO₂. Eventually, a model was developed by the central composite design (CCD) method, describing the degradation efficiency as a function of the operational parameters.     

Growth and electrical characterization of high-aspect-ratio carbon nanotube arrays

The remarkable properties of carbon nanotubes (CNTs) make them attractive for microelectronic applications, especially for interconnects and nanoscale devices. In this paper, we describe a microelectronics compatible process for growing high-aspect-ratio CNT arrays with application to vertical electrical interconnects. A lift-off process was used to pattern catalyst (Al₂O₃/Fe) islands to diameters of 13 or 20 μm. After patterning, chemical vapor deposition (CVD) was involved to deposit highly aligned CNT arrays using ethylene as the carbon source, and argon and hydrogen as carrier gases. The as-grow CNTs were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results demonstrated that the CNTs have high purity, and form densely-aligned arrays with controllable array size and height. Two-probe electrical measurements of the CNT arrays indicate a resistivity of ∼0.01 Ω cm, suggesting possible use of these CNTs as interconnect materials.     

Fabrication of pH‐sensitive poly(2‐(diethylamino)ethyl methacrylate)/palygorskite composite microspheres via Pickering emulsion polymerization and their release behavior

The poly(2‐(diethylamino)ethyl methacrylate)/palygorskite (PDEAEMA/PAL) composite microspheres were prepared via Pickering emulsion polymerization using palygorskite (PAL) as an emulsifier. The morphology, chemical structure, and content of PDEAEMA/PAL composite microspheres were investigated by polarizing optical microscopy, scanning electron microscopy (SEM), Fourier‐transform infrared (FT‐IR) spectroscopy, and thermal gravimetric analysis (TGA). The pH‐responsive behavior of composite microspheres was studied by measuring their size at different pH values. Furthermore, their release behavior was investigated using rhodamine B (RhB) as a model molecule. It was proven that the release properties of RhB from PDEAEMA/PAL composite microspheres could be controlled by adjusting the pH values. The study of release kinetics found that Higuchi model was fit for RhB release from PDEAEMA/PAL composite microspheres at pH 5.0, 7.4, and 10.0. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42179.