金属钝化剂的研究进展

塑料和聚合物材料曝露在空气中被氧化降解使之失去使用价值,该问题可通过添加稳定剂解决。但当材料与金属接触时,某些金属离子或金属可加速氧化反应,这会大大降低制品的使用寿命。这时应加入金属钝化剂,以降低聚合物的降解。本文综述了该类产品的合成与应用,还介绍了一些工业化的品种。     

催化臭氧氧化工艺中催化剂应用的研究进展

催化臭氧氧化法作为一种高级氧化技术，在难生物降解有机废水的深度处理领域具有良好的应用前景。催化剂可以促进臭氧分解并生成活性自由基，增强有机污染物的降解速率和矿化程度，是影响催化臭氧氧化法效能的关键因素。文章阐述了均相和非均相催化臭氧法的反应机理，在此基础上梳理了近年来催化臭氧氧化工艺中常用催化剂的分类和研究进展，包括金属离子、金属氧化物、碳基材料、矿物质材料等，并对其在工业废水深度处理上的应用进行总结，探讨了该技术目前存在的问题，并展望了未来研究方向及应用前景，包括新型高效催化剂的制备、复杂难降解废水臭氧化预处理、二级生化处理出水的深度处理等。     

金属有机骨架及其衍生材料活化过硫酸盐在水处理中的应用进展

金属有机骨架材料(MOFs)具有以金属离子为中心的结构特征,因此利用MOFs及其衍生材料可构建非均相过硫酸盐催化氧化体系,该体系能耗低且高效,在水处理中具有良好的应用前景。本文综述了MOFs及其衍生材料活化过硫酸盐处理水中难降解有机污染物(包括有机染料、环境内分泌干扰物和抗生素)的研究现状,探讨了不同组成及结构的MOFs及MOFs衍生材料对催化降解水中有机污染物性能的影响,指出MOFs及其衍生材料的结构设计、合成策略、不饱和的金属活性位点以及反应体系中的活性物质等是体系催化降解能力的重要影响因素。最后总结了目前基于MOFs材料活化过硫酸盐作为一种新型的高级氧化技术在水处理应用研究中存在的问题,并提出新型高效联合活化体系的构建及活化作用机制深入的探索和完善是今后研究的重点。     

金属有机骨架及其衍生材料活化过硫酸盐在水处理中的

金属有机骨架材料（MOFs）具有以金属离子为中心的结构特征,因此利用MOFs及其衍生材料可构建非均相过硫酸盐催化氧化体系,该体系能耗低且高效,在水处理中具有良好的应用前景。本文综述了MOFs及其衍生材料活化过硫酸盐处理水中难降解有机污染物（包括有机染料、环境内分泌干扰物和抗生素）的研究现状,探讨了不同组成及结构的MOFs及MOFs衍生材料对催化降解水中有机污染物性能的影响,指出MOFs及其衍生材料的结构设计、合成策略、不饱和的金属活性位点以及反应体系中的活性物质等是体系催化降解能力的重要影响因素。最后总结了目前基于MOFs材料活化过硫酸盐作为一种新型的高级氧化技术在水处理应用研究中存在的问题,并提出新型高效联合活化体系的构建及活化作用机制深入的探索和完善是今后研究的重点。     

纳米二氧化钛复合材料降解水中污染物的研究

对金属离子掺杂纳米二氧化钛复合光催化材料降低水中污染物的研究进展进行了论述；金属离子掺杂纳米二氧化钛复合光催化材料相较于纳米二氧化钛，其禁带宽度变窄，提高了在可见光区的吸收性能，提高了光催化活性，提高了污染物降解率。     

铁络合物催化类Fenton氧化研究进展

综述了铁络合物催化类Fenton氧化的研究进展.铁络合物与铁相比具有更高的催化活性,可提高水中有机物的去除效果.均相类Fenton存在后续金属离子的去除问题,因此铁络合物作为催化剂的多相催化类Fenton氧化具有更好的应用前景.重点介绍了高分子负载铁络合物催化类Fenton氧化降解水中有机物的研究现状及铁络合物催化类F...     

TiO_2-过渡金属光催化降解有机废水

纳米TiO2掺杂过渡金属离子,能有效提高其光催化活性和反应效率,在处理有机废水等方面具有广阔的应用前景。综述了纳米TiO2的光催化氧化降解机理,纳米TiO2掺杂过渡金属离子的制备方法,掺杂不同金属离子对TiO2光催化性能的影响以及在多种有机废水降解方面的应用等。     

不同金属离子掺杂的含氧酸铋盐的制备及其光催化性能的研究

采用水热法制备了一系列金属离子掺杂的钨酸铋、钼酸铋、磷钼酸铋等含氧酸铋盐光催化材料,评价其在可见光下降解有机染料的光催化性能。详细考察了掺杂金属离子种类、掺杂量及有机染料种类对其光催化性能的影响。结果表明,0.5%Fe/Bi_2WO_6对罗丹明B的降解率最好,可达到98.3%。     

印度发明一种环保的塑料降解方法

<正>印度研究人员最新发明了一种环保的塑料降解方法,只需要将塑料放在含有葡萄糖和金属离子的70℃溶液中,连续搅拌数天,就可将塑料降解成分子。印度理工学院马德拉斯分校研究人员领衔的团队发现,新方法可用于降解聚四氟乙烯等塑料材料。相关研     

印度发明一种环保的塑料降解方法

<正>印度研究人员最新发明了一种环保的塑料降解方法,只需要将塑料放在含有葡萄糖和金属离子的70℃溶液中,连续搅拌数天,就可将塑料降解成分子。印度理工学院马德拉斯分校研究人员领衔的团队发现,新方法可用于降解聚四氟乙烯等塑料材料。相关研究论文已发表在美国化学学会期刊《可持续化学与工程》上。     

负载复合后过渡金属烯烃聚合催化剂研究进展

综述了负载和复合型后过渡金属烯烃聚合催化剂的研究进展。把后过渡金属催化剂负载化,可以适合现有工业生产的工艺要求,改善聚合物产品的形态结构、抑制粘釜现象等。用后过渡金属催化剂与其他过渡金属催化剂(如Ziegler-Natta催化剂、茂金属催化剂等)进行复合的目的主要是制备具有某些特定性能聚烯烃产物及使单一乙烯单体聚合制备支化聚乙烯。后过渡金属催化剂进行负载和复合后在改善聚烯烃产物性能、降低生产成本等方面有突出的优势．具有十分广阔的工业应用前景。     

Quantitation of Metals During the Extraction of Virgin Olive Oil from Olives Using ICP-MS after Microwave-assisted Acid Digestion

Trace metals such as Cu and Fe have negative effects on the oxidative stability of olive oils, and consequently, their concentrations are used as quality criterion. Also, maximum levels are established for heavy metals (As and Pb) in olive oils due to their high toxicity. Olive fruits can be contaminated with these metals from soil and air and from the use of pesticides or fertilizers, with the potential contamination of virgin olive oil (VOO) during its extraction from the fruits. This work presents two goals: (a) to optimize an analytical method for the determination of metals in raw olive fruits using an Abencor system; (b) to carry out a preliminary study of the fate of the metals during VOO extraction. The selected metals were quantified in raw olive fruits, and in the olive pomace and VOO obtained after their processing. The metal determination was performed by inductively coupled plasma-mass spectrometry after microwave-assisted acid digestion with HNO₃/H₂O₂. The results showed that most of the metals (at least 90 %) present in the olive fruits were retained by the olive pomace, so obtaining high-quality VOO from the point of view of its metal content.     

Zeolite-supported transition metal catalysts by design

Zeolite supported metal Catalysts are prepared by ion exchange or incipient wetness impregnation, or by deposition of metal complexes, followed by calcination and reduction. Hydrogen reduction of encaged transition metal ions yields metal dusters or isolated atoms and protons of high Brønsted acidity. The elementary steps in the genesis of mono- and bimetallic metal dusters have been unravelled by a combination of dynamic and spectroscopic methods. Small metal clusters can be anchored to zeolite cage walls by transition metal ions or protons; however, adsorption of a CO which can displace the protons from the metal, initiates migration of the primary carbonyl dusters leading to their coalescence. At low temperature, this process is limited by the geometry of the metal core vis-à-vis the cage window. Protons of high Brensted acidity can reoxidize metals at elevated temperature, even selectively “leach” the less noble metal atoms out of bimetal clusters. Large metal particles, present in zeolite voids or at the external surface, can be transformed into small particles, exposing virtually all their metal atoms, by either of two novel in situ techniques which are based on oxidative dispersion with oxygen or chlorine gas.     

Electronic Structure and Catalytic Properties of Transition Metal Nanoparticles: The Effect of Size Reduction

Size reduction of metal particles results in the formation of nanoparticles having short-range order and metastable state. Modeling of the nanoparticles can be obtained by various approaches. The major arrangement is the use of a model support on which metal nanoparticles can be created in a controlled way. Another approach is the use of amorphous alloy as precursor in which the ensemble of active sites (normally small metal nuclei embedded into amorphous matrix) is created. The modeling will be illustrated through the paper using SiO₂/Si(100) on which several transition metals will be deposited by pulsed laser deposition. Ultraviolet photoelectron spectroscopic technique as well as transmission electron microscopic technique will be utilized in characterization of the samples. CO chemisorption and CO oxidation as test reaction will be applied to show the connection between catalytic behavior and electronic properties or morphology of nanoparticles.     

State-of-the-art technology: Recent investigations on laser-mediated synthesis of nanocomposites for environmental remediation

In both developing and industrialized/developed countries, various hazardous/toxic environmental pollutants are entering water bodies from organic and inorganic compounds (heavy metals and specifically dyes). The global population is growing whereas the accessibility of clean, potable and safe drinking water is decreasing, leading to world deterioration in human health and limitation of agricultural and/or economic development. Treatment of water/wastewater (mainly industrial water) via catalytic reduction/degradation of environmental pollutants is extremely critical and is a major concern/issue for public health. Light and/or laser ablation induced photocatalytic processes have attracted much attention during recent years for water treatment due to their good (photo)catalytic efficiencies in the reduction/degradation of organic/inorganic pollutants. Pulsed laser ablation (PLA) is a rather novel catalyst fabrication approach for the generation of nanostructures with special morphologies (nanoparticles (NPs), nanocrystals, nanocomposites, nanowires, etc.) and different compositions (metals, alloys, oxides, core-shell, etc.). Laser ablation in liquid (LAL) is generally considered a quickly growing approach for the synthesis and modification of nanomaterials for practical applications in diverse fields. LAL-synthesized nanomaterials have been identified as attractive nanocatalysts or valuable photocatalysts in (photo)catalytic reduction/degradation reactions. In this review, the laser ablation/irradiation strategies based on LAL are systematically described and the applications of LAL synthesized metal/metal oxide nanocatalysts with highly controlled nanostructures in the degradation/reduction of organic/inorganic water pollutants are highlighted along with their degradation/reduction mechanisms.     

Metals and lipid oxidation. Contemporary issues

Lipid oxidation is now recognized to be a critically important reaction in physiological and toxicological processes as well as in food products. This provides compelling reasons to understand what causes lipid oxidation in order to be able to prevent or control the reactions. Redox-active metals are major factors catalyzing lipid oxidation in biological systems. Classical mechanisms of direct electron transfer to double bonds by higher valence metals and of reduction of hydroperoxides by lower valence metals do not always account for patterns of metal catalysis of lipid oxidation in multiphasic or compartmentalized biological systems. To explain why oxidation kinetics, mechanisms, and products in molecular environments which are both chemically and physically complex often do not follow classical patterns predicted by model system studies, increased consideration must be given to five contemporary issues regarding metal catalysis of lipid oxidation: hypervalent non-heme iron or iron-oxygen complexes, heme catalysis mechanism(s), compartmentalization of reactions and lipid phase reactions of metals, effects of metals on product mixes, and factors affecting the mode of metal catalytic action. Based on a paper presented at the Symposium on Metals and Lipid Oxidation, held at the AOCS Annual Meeting in Baltimore, MD, April, 1990.     

官能化聚烯烃的进展和应用

官能化聚烯烃是由聚烯烃改性后得到的产物,一般通过交联改性、共聚改性、固相力化学改性和接枝改性等方法制备,可应用于黏附、能源和封装等多重领域。基于聚烯烃高通量低成本的优势,聚烯烃接枝改性利用自由基反应直接向聚烯烃链上引入极性单体,较为经济便捷。聚烯烃接枝改性按反应条件的不同,又可分为溶液接枝、熔融接枝、辐射接枝、固相接枝和悬浮接枝。在接枝改性过程中,接枝率和接枝效率受多种因素影响,如聚烯烃型号、接枝单体、引发剂、共单体和反应条件等。本文综述了聚烯烃接枝改性不同接枝方法的研究进展,分析了各种接枝方法的优势和短板,并将接枝改性过程中的影响因素进行了总结。文章依据聚烯烃的可控自由基接枝改性和金属催化改性以及官能化聚烯烃的应用,展望了聚烯烃可控改性和官能化聚烯烃规模化生产。     

热化学还原法制备金属钛的技术研究进展

金属钛及其合金性能优异,是重要的功能与结构材料。元素钛虽储量丰富,但极易与其它金属及氧氮氢碳等间隙元素反应,特别是与氧化学结合力强,使金属钛的提取非常困难。目前金属钛的主流生产方法是Kroll法,虽经多年优化且已高度成熟,但生产成本及能耗较高。为降低金属钛的生产成本,提出了诸多热化学与电化学新方法。本工作综述了近十余种不同热化学还原法,包括以TiCl4为前驱体的Kroll法、Hunter法、ADMA法、TiRO法、气相还原法、CSIR-Ti法、ITP-Armstrong法及ARC法和以TiO2为前驱体的预成型还原法(PRP)、熔盐辅助的液钙还原法、导电体介入还原法(EMR)、镁热还原?金属钙脱氧两步法及氢气协同镁热还原(HAMR)法,还有以钛酸盐为原料的氟钛酸盐热还原法。常用的还原剂主要是活泼金属单质及其合金,包括钙、镁、铝、钠。论述了这些方法的技术特点及研究现状。这些工艺大都处于实验室或中试研究阶段,其工业化潜力也不尽相同,最终在产品质量和经济成本上能否比Kroll法更具优越性尚需验证。     

Large-scale preparation of nano-sized carbides and metal whiskers via mechanochemical decomposition of MAX phases

Nano-sized transition metal carbide powder is usually synthesized by chemical methods such as chemical vapor deposition, while its large-scale synthesis is a long-standing challenge due to high energy consumption and low yield; metal nanowires (NWs) (mainly noble metals) are usually prepared by wet chemistry, and more compositions and greener preparation routes for metal NWs are urgent to meet the needs of the high technology industry. Herein, MAX phases are mechanochemically decomposed, resulting in the fine corresponding binary M-X carbides and the A-site metal whiskers. This implies a feasible top-down route for efficiently preparing fine carbides and high-quality metal whiskers on large scale. Several example MAX phases (both 312 and 211) are selected to demonstrate the feasibility of this method. The carbides and metal whiskers are characterized by X-ray diffractometer, scanning electron microscope, transmission electron microscopy, and energy-dispersive X-ray spectroscopy to identify their morphology, composition, and phase. The compositional diversity of MAX phases bodes that this would be a promising alternative avenue to preparing various nano-sized carbides and single-crystal metal whiskers.     

赤泥吸附重金属离子性能及其机理研究进展

赤泥（RM）是铝土矿提取氧化铝时排放的工业废渣,对其进行改性后可作为一种低成本吸附剂有效吸附废水中的重金属离子。本文从赤泥的性质和组成进行讨论,分析赤泥吸附重金属离子的优势,总结酸改性、焙烧改性和复合改性对赤泥结构及重金属吸附性能的影响。在此基础上,阐述了赤泥吸附重金属离子的机理,列举了吸附热力学及吸附动力学模型。指出赤泥作为一种大宗工业废弃物,用作吸附剂吸附废水中的重金属离子,具有成本低、来源广泛等优点,同时可达到以废治废的目的,具有良好的应用前景。