负载型纳米零价铁及含铁双金属颗粒降解氯代有机物的研究进展

零价铁及含铁双金属颗粒因对氯代有机物降解效率高,而受到国内外的广泛关注.目前该领域的研究热点是纳米铁的改性研究.主要对零价铁及含铁双金属颗粒的负载改性、降解氯代有机物过程中主要的影响因素作了介绍.对颗粒负载改性技术存在的问题作了简要的探讨,并且展望了该技术的应用前景和发展趋势.     

纳米零价铁的强化改性及其对水污染治理最新研究进展

近年来,纳米零价铁的强化改性技术及其在水处理领域的应用成为研究热点。特别是针对卤代污染物、硝酸盐、重金属及废水中染料去除方面。介绍了纳米零价铁强化改性、负载功能化、工程实际应用及其对水污染治理研究进展,并对纳米零价铁改性的未来发展趋势进行展望。     

纳米零价铁的制备及应用研究进展

主要综述了新型水处理材料纳米零价铁及其特点、常用制备方法(高能球磨法、液相还原法),以及该材料的改性和在污废水处理中的应用等;最后对纳米零价铁的发展趋势进行了展望,对纳米零价铁深入研究的领域和亟待解决的问题进行了分析。     

纳米铁强化复合新技术对含氯有机污染物的脱氯降解

针对纳米铁存在的各种制约因素从而使其处理含氯有机污染物效率降低的问题,介绍了纳米铁强化复合新技术,包括纳米铁与化学技术的复合、纳米铁与生物技术的复合及纳米铁与高级氧化技术的复合技术对含氯有机污染物脱氯降解的进展。分析认为复合技术对含氯有机污染物具有较高的脱氯效率,指出对现有成熟技术进一步工程应用、开发高效低成本的NZVI复合新技术、加强NZVI/生物复合技术的开发与应用等是该技术今后的发展方向。     

纳米铁强化复合新技术对含氯有机污染物的脱氯降解

针对纳米铁存在的各种制约因素从而使其处理含氯有机污染物效率降低的问题,介绍了纳米铁强化复合新技术,包括纳米铁与化学技术的复合、纳米铁与生物技术的复合及纳米铁与高级氧化技术的复合技术对含氯有机污染物脱氯降解的进展。分析认为复合技术对含氯有机污染物具有较高的脱氯效率,指出对现有成熟技术进一步工程应用、开发高效低成本的NZVI复合新技术、加强NZVI/生物复合技术的开发与应用等是该技术今后的发展方向。     

纳米改性工业防腐蚀涂料的研制与应用

介绍了纳米改性工业防腐蚀涂料的制备工艺,包括纳米浓缩浆、纳米改性环氧封闭漆、纳米改性环氧云铁中间漆以及纳米改性含氟聚氨酯面漆等系列产品的制备与表征。测试结果表明,纳米材料在纳米浆及涂料中获得了良好分散,纳米改性复合涂层(即喷铝涂层+纳米改性环氧封闭漆+纳米改性云铁中间漆+纳米改性含氟聚氨酯面漆)的物理机械性能以及耐久性均得到显著提高,产品在实际工程应用中也取得了可喜成果。该纳米改性工业防腐蚀涂料具有良好的应用前景。     

纳米零价铁的改性及其在废水处理中的应用综述

纳米零价铁比表面积大、反应活性高,近年来在水处理中展现出了许多优势,但其易于团聚和氧化的特点使其在实际应用中受到了一定的限制,因此需要采用适当的方法对纳米零价铁进行改性。作者综述了纳米零价铁在废水处理中的应用及研究进展,包括常用制备方法和对重金属、有机卤代物及硝酸盐等污染物的去除效能;还介绍了纳米零价铁在实际应用中存在的问题及其改性方法,并对该技术的应用前景进行了展望,提出改性方法在工程中的应用是未来的研究方向。     

纳米氧化锌的制备及表面改性技术进展

介绍纳米氧化锌的制备方法以及表面改性技术进展。沉淀法是纳米氧化锌工业化生产方法,产品粒子小,粒径分布窄,分散性好。纳米氧化锌表面改性方法主要有表面包覆改性法、表面化学改性法、机械化学改性法和外膜层改性法等。     

零价铁硫化改性技术及其在水处理中的应用进展

总结了有关硫化零价铁(特别是硫化纳米零价铁)去除水体污染物的最新研究和进展,对硫化零价铁技术发展历程及其制备方法进行了介绍。深入分析了硫化试剂类型、硫化改性方法和S/Fe摩尔比对硫化零价铁处理水体污染物的影响,并且详细归纳、阐述了硫化显著提高零价铁反应活性的机制。最后提出了将来需要关注的问题以及研究方向。     

纳米零价铁的优化技术及应用研究进展

纳米零价铁具有比表面积大、反应活性高等优点,被广泛应用于地下水和土壤环境修复中。但纳米零价铁容易团聚且极易被氧化的特点使其在环境中的应用受到了一定的限制,因此纳米零价铁的优化改性是此领域的研究热点。本文主要综述了纳米零价铁优化技术,包括物理辅助、纳米双金属、分散改性、固体负载等。此外,对纳米零价铁在环境中的应用进展作了总结。     

Effect of addition of Al2O3 and Fe2O3 nanoparticles on the microstructural and physico-chemical evolution of dense magnesia composite

Up to 5 wt% of nano-alumina or nano-iron oxide was added to magnesia refractory matrix. The crystalline phases and microstructure characteristics of specimens sintered at 1600 °C for 4 h in an electric furnace were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The physical properties are reported in terms of density and porosity. The mechanical behavior was studied by a cold crushing strength (CCS) test. In addition, the chemical behavior with regard to slag attack was studied by the SEM technique. As a result, it was found that the presence of nano-iron oxide in the magnesia matrix induced magnesioferrite spinel formation, which improved the sintering process. Nano-iron oxide also influenced the bonding structure through a direct bonding enhancement. On the other hand, the presence of nano-alumina in the magnesia matrix induced magnesium-aluminate spinel formation, resulting in lower properties in comparison with those obtained by nano-iron oxide addition.     

Preparation of nano-sized iron oxide red using δ-FeOOH as seed and iron as raw material in liquid phase at low temperature

Uniform pseudocube nano-iron oxide red (hematite)particles was prepared in the liquid phase by using δ-FeOOH as seed and iron as raw material at low temperature. The effects of such factors as initial pH of reaction, concentration of catalyst, reaction time on the preparation of these hematite particles were investigated. The product was characterized by XRD, IR, FESEM. The results showed that pure pseudocube hematite particles could be prepared under the experimental conditions of solution initial pH 7, β=0.09（β=［Fe²⁺］/［δ-FeOOH］）, air oxidation temperature and time of 100℃ and 48 h respectively. The product crystallized integrally with particle diameter 90—100 nm, and its color was brightly red. This is a new method to prepare high-purity nano-iron oxide red with the characteristics of simple operation, non-pollution and low cost.     

以δ-FeOOH为晶种由铁低温液相制备纳米氧化铁红

引言纳米氧化铁红,具有良好的耐候性、耐光性、催化活性和化学稳定性,在光气敏材料、精细陶瓷、涂料、催化剂和生物医学工程等方面有广泛的应用价值和开发前景[1-3]。目前制备纳米氧化铁有很多种方法,从初始原     

Influence of ferrocene addition on the morphology and structure of carbon from petroleum residue

Nano-sized iron particle/carbon composites have been synthesized from a petroleum residue by heating at 420 °C with ferrocene under pressure. The morphologies and structural features of the composites were investigated using TEM, HREM and XRD measurements. The effect of ferrocene addition on the development of turbostratic carbon from the petroleum residue was discussed. It was found that, by increasing the amount of ferrocene added from 3% to 20%, the size of the nano-iron particles tended to increase from 20–80 nm to 30–180 nm. The iron particles pyrolyzed from ferrocene mainly exist in the forms Fe–O and Fe_1−xS when the ferrocene content was low (3% and 6%), and α-Fe when ferrocene contents were high (10% and 20%). Upon further heat treatment in the range 500 to 900 °C, the iron particles tended to aggregate and Fe–O and Fe_1−xS were transformed into α-Fe and austenite. In comparison with the carbon formed without ferrocene addition, the resulting carbon exhibited a turbostratic structure as shown by HREM, in which the d₀₀₂ spacing decreased with the increase of ferrocene loading and increasing temperature, suggesting the carbonization was promoted by the catalysis of the nano-iron particles.     

不同pH环境下CMS改性纳米铁在异质多孔介质中的迁移

纳米铁在污染土壤和地下水的修复中受到广泛关注。为进一步探究其在多孔介质的迁移行为，本研究采用羧甲基淀粉钠（CMS）对纳米零价铁（nZVI）进行包覆，进行了改性纳米零价铁的沉降试验，测量zeta电位与粒径分布探究其分散性；进行了不同pH条件下改性纳米零价铁在酸洗砂与水洗砂的柱实验，分析了化学异质性与pH对纳米铁在多孔介质迁移的影响。结果表明，CMS包覆纳米铁不仅使纳米颗粒本身稳定，而且还减少其在多孔介质表面沉积，大大提高了迁移性。pH=6～8时，nZVI的zeta电位由18.3mV减小到2.9mV，有效粒径由685nm增大到880nm，稳定性变差；而CMS-nZVI的zeta电位值由-19.7mV增大到-53.5mV，颗粒间静电排斥力增强稳定性变好。经能量色散X射线光谱（EDS）分析，水洗砂表面存在碳、铝、铁等氧化物杂质，这些杂质带有正电荷，会增强与带负电的CMS-nZVI的吸附作用，不利于其迁移；而经过酸洗后的石英砂，其表面杂质大大减少，在pH=8时，CMS-nZVI在酸洗砂最大迁移率为77.0%要好于水洗砂的63.0%。此外较高pH环境有助于增加石英砂介质的表面负电荷，减少颗粒与介质的吸附，促进纳米颗粒的迁移。     

Nearly monodispersed carbon coated iron nanoparticles for the catalytic growth of nanotubes/nanofibres

We present the single step preparation of nano-iron cores embedded in carbon layers and their preliminary application to the growth of carbon nanotubes. CO₂ laser pyrolysis of volatile iron and carbon precursors in a gas flow reactor was used in order to obtain the Fe–C nanocomposites. The structure and composition of the obtained nanopowders were analysed by transmission electron microscopy, high-resolution transmission electron microscopy, electron energy loss spectroscopy and Raman spectroscopy. The results indicate that the synthesized carbon embedded iron nanoparticles (∼3–7 nm mean diameter) present sharp particle distributions. The degree of agglomeration and the number of surrounding carbon layers depend on the relative concentration of reactive donors. Silicon substrates seeded with a dilution of Fe–C nanocomposites were further used to catalyze nanotubes/nanofibres growth by the laser-induced CVD method. A deeper insight in the inception and growth mechanism of these structures is needed in order to achieve different levels of encapsulation and subsequent nanotube growth.     

Plasma torch production of macroscopic carbon nanotube structures

Analysis of the many studies of carbon nanotube formation in high-temperature ovens clearly indicates the key requirements of nanotube formation are an ‘atomic’ carbon source and a source of nanometal particles. We adapted this formulation to the high temperature (>3000 K) environment found in a low-power (<1000 W) atmospheric pressure, microwave plasma torch, by simultaneously feeding carbon monoxide (carbon source), and (presumably) iron carbonyl (source of metal catalyst particles) through an argon stabilized plasma flame. This technique led to the relatively rapid (25 mg/h) formation of carbon nanotubes of a unique form: macro-sized ‘woven’ threads. Scanning electron microscopy and high-resolution transmission electron microscopy studies revealed that the woven threads consist entirely of carbon nanotubes (primarily carbon single-wall nanotube) and associated nano-iron particles. The structures appear ‘fractal’ in that each woven thread appears to be constructed of smaller threads that in turn are formed of yet smaller woven threads. Simple mechanical tests show the threads can be bent without breaking, and the thread will spring to its original shape when the force holding it is released. Threads of the size produced can be woven together to form actual cloth or ropes and thus this result represents a step toward the ultimate application of carbon nanotubes for super strong/light structures.     

磷铁渣制备电池级纳米磷酸铁

以磷铁废渣为原料提供磷源和铁源,用硝酸和硫酸混合溶液浸出磷铁渣中的铁和磷元素,并通过沉淀法制备电池级纳米磷酸铁。探究了硝酸浓度、反应时间、反应温度对磷铁渣溶解率的影响,并研究了反应过程中铁磷比、温度和pH对制备的磷酸铁性能影响。利用X衍射分析仪、扫描电子显微镜、热重分析仪、红外光谱仪和电感耦合等离子体发射光谱仪等分析手段对磷酸铁的形貌、晶体结构与化学成分进行了表征。实验结果表明,磷铁渣浸出最佳的实验条件为：硝酸浓度1.5mol/L,反应时间4h,反应温度90℃,此条件下磷铁的溶解率为95.11%;磷酸铁制备过程中的最佳实验条件为：铁磷比1∶1,反应温度60℃,反应pH=1.0,所制备的FePO₄结晶度高,颗粒形貌规整,分散均匀,一次颗粒粒径为100～200nm,铁磷摩尔比为0.97,杂质元素含量符合电池级磷酸铁的要求。     

Preparation and formation mechanism of nano-iron oxide black pigment from blast furnace flue dust

A mixed solution of ferrous and ferric sulfate leached from blast furnace (BF) flue dust was used to prepare nanometer-sized iron oxide black pigment (Fe₃O₄, magnetite) by the co-precipitation method. The pH value played a very important role in affecting the color and particle size of Fe₃O₄ and the evolution of green rust in to Fe₃O₄ or FeOOH. The experimental conditions including the solution pH, the way of adding precipitant, volume of air and reaction time for the formation of nano-iron oxide black pigment were investigated carefully in order to determine the optimal ones. The color, morphology and particle size of as-prepared Fe₃O₄ pigment were characterized by means of a color measurement instrument, X-ray diffraction (XRD) and transmission electron microscopy (TEM) respectively. The results showed that the obtained pigment had low average spectral reflectance (<4%), good oil absorption (～23%), high black intensity and narrow size distribution of 60–70 nm. Furthermore, the formation mechanism of Fe₃O₄ from the mixed solution of ferrous and ferric sulfate was discussed.     

Fe3O4 NPs类芬顿预处理对活性污泥法处理阿莫西林废水的影响

以阿莫西林为研究对象,探讨了其经不同程度磁性纳米铁（Fe₃O₄ NPs）多相类芬顿预处理后对活性污泥理化特性及其微生物群落结构的影响。结果表明,随着预处理程度（未经预处理、经40% H₂O₂预处理和经60% H₂O₂预处理）的升高,活性污泥对废水COD平均去除率由81.5%升高到89.1%,氨氮平均去除率由86.2%升高到95.6%,同时活性污泥中蛋白酶的含量由0.13 mg·g^-1升高到0.19 mg·g^-1。且随着阿莫西林预处理程度的升高,活性污泥溶性微生物产物（SMP）的三维荧光光谱（EEM）中可见光区类腐殖酸与类富里酸的吸收峰强度逐渐减小,表明活性污泥活性良好。对于微生物群落分布而言,在未经预处理、经40% H₂O₂、经60% H₂O₂预处理的条件下,变形菌门所占比例分别为73..81%、84.08%和77.08%,同时厚壁菌门所占比例为0.6%、0.82%与0.78%。变形菌门为优势菌种,诸多固氮细菌与聚磷菌属于变形菌门;而厚壁菌门可利用水解酶来分解蛋白质与糖类,两者所占比例的升高,为废水中污染物的高效去除提供了保障。