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1.
Meng Sun Gong Zhang Yang Liu Huijuan Liu Prof. Jiuhui Qu Prof. Jinghong Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(20):7611-7620
Development of novel nanocatalysts for the highly efficient in situ synthesis of H2O2 from H2 and O2 in the electro‐Fenton (EF) process has potential for the remediation of water pollution. In this work, AuPd/carbon nanotube (CNT) nanocatalysts were successfully synthesized by the facile aggregation of AuPd bimetals on CNTs. Characterization by X‐ray diffraction, transmission electron microscopy, and X‐ray photoelectron spectroscopy indicated that pure AuPd bimetallic heterogeneous nanospheres (≈20 nm) were well dispersed outside the CNTs, which resulted in better catalytic performance than Pd/CNTs alone: 0.36 M H2O2 was synthesized; 0.05 M Fe2+ optimally initiated the EF process due to the superior in situ Fe2+ regeneration; and the organic pollutant removal reached 100 % at 37 min, with a pseudo‐first‐order kinetic constant k1=0.051 min?1. Moreover, structural insights before/after catalysis revealed that Au strengthened the construction of the nanocrystals, avoided negative deactivation caused by AuPd agglomeration, and immobilized the active Pd(111). The catalytic stability of AuPd/CNTs over ten cycles implied long durability and promising applications of this material. 相似文献
2.
Ménana Haddou Florence Benoit‐Marquié Marie‐Thérèse Maurette Esther Oliveros 《Helvetica chimica acta》2010,93(6):1067-1080
The kinetics and mechanisms of the oxidative degradation of 2,4‐dihydroxybenzoic acid (2,4‐DHBA) by the Fenton and photo‐Fenton processes were investigated in detail by a combination of HPLC, IC, and TOC analyses. The formation of 2,3,4‐trihydroxybenzoic acid (2,3,4‐THBA) at an early oxidation stage shows that hydroxylation of the aromatic ring is the first step of the process. This intermediate was able to reduce FeIII and to contribute to the recycling of FeII. Complete mineralization could only be achieved under irradiation (photo‐Fenton). A detailed study of the dependence of the rate of mineralization on the concentration of H2O2 and dissolved O2 was carried out. It was found that, even at a low initial concentration of H2O2, mineralization by the photo‐Fenton process was complete in a relatively short time, provided that the O2 concentration was high enough, indicating that O2 may, at least in part, substitute H2O2. Channeling reaction pathways toward O2 rather than H2O2 consumption is of particular interest for the technical development of the photo‐Fenton process. 相似文献
3.
Polyoxometalate encapsulated in metal‐organic gel as an efficient catalyst for visible‐light‐driven dye degradation applications
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Contamination of industrial sewage by organic dye pollutants is one of the most common challenges to the daily life. Decontamination can be achieved by adsorption and photodegradation of the pollutants. Herein, an effective visible light‐driven photocatalyst of polyoxometalate encapsulated in metal–organic gel was presented. The resulting composite was named PMA@ MOG‐Cr [PMA= H3PMo12O40, MOG= metal‐organic gel]. Photodegradation of dye pollutants with PMA@ MOG‐Cr were tested. The introduction of Phosphomolybdic Acid significantly enhanced the light‐absorption properties of MOG‐Cr. The PMA@MOG‐Cr showed an excellent photodegradation efficiency of MB, RhB and MO as high as 99% and 97% in 60 min and 91% in 120 min of visible‐light irradiation with only 10 mg photocatalyst, which was the highest among the tested samples MOG‐Cr, PMA@ MOG‐Cr and Degussa P‐25. The mechanism of the photodegradation of dye pollutants with H2O2 over PMA@MOG‐Cr under the visible light was further illustrated. The introduction of PMA promotes effective separation of electron–hole pair by trapping and transferring photogenerated electron. Thus, the two components act in synergy to result in much improved adsorption of certain common organic dyes as well as enhanced oxidative degradation. This work provides a new approach to design MOG encapsulated Polyoxometalate for visible light‐induced photodegradation of organic contaminants for the environmental remediation. 相似文献
4.
在低温(200℃)下采用一步水热分解CoFe2O4纳米粒子表面的镉二硫代氨基甲酸酯配合物制备了磁性CoFe2O4/CdS纳米复合物,运用X射线衍射、红外光谱、扫描电镜、X射线能量散射谱、紫外-可见光谱、透射电镜(TEM)、N2吸附-脱附、X射线光电子能谱和振动样品磁强计对所制样品进行了表征.TEM结果表明,CoFe2O4/CdS纳米复合物由几乎均一的约20nm球形纳米粒子组成.光吸收谱显示该样品的带隙为2.24 eV,很适合用于声/光催化降解有机污染物.在紫外光照射下评价了CoFe2O4/CdS纳米复合物的声催化H2O2辅助降解甲基蓝、罗丹明B和甲基橙反应活性.结果表明,该纳米复合物对这3种染料均表现出很好的声催化活性(5-9 min内完全降解).另外,比较实验结果表明,CoFe2O4/CdS纳米复合物是一个比纯CdS更高效的声催化剂.因此,纳米复合是一种非常好的提高CdS声催化活性的手段.该CoFe2O4/CdS纳米复合物表现出的磁性使其很容易从反应混合物中分离出来而重复使用. 相似文献
5.
A new magnetic metal–organic framework nanocomposite (CoFe2O4/TMU‐17‐NH2) was prepared via an embedding approach by synthesis of the metal–organic framework crystals in the presence of magnetic cobalt ferrite nanoparticles. We demonstrated that the resulting magnetic nanocomposite can serve as a recyclable nanocatalyst for one‐pot synthesis of bis‐3,4‐dihydropyrimidin‐2(1H)‐one and 3,4‐dihydropyrimidin‐2(1H)‐one derivatives via three‐component reaction of 1,3‐diketone, urea or thiourea and aromatic aldehyde under solvent‐free conditions. CoFe2O4/TMU‐17‐NH2 was characterized using various techniques. The recovery of the nanocomposite was achieved by a simple magnetic decantation and it was reused at least seven times without significant degradation in catalytic activity. 相似文献
6.
Hydrophilic Fe3O4 nanoparticles were prepared with ferrocene as an iron source via the thermal decomposition method and their catalytic response towards methyl orange was investigated. The effects of the pH, temperature, H2O2 dosage, catalyst dosage and initial dye concentration on the degradation of methyl orange were researched in detail. Furthermore, the stability of the catalyst was evaluated by measuring the degradation rate in eight successive cycles. The study demonstrates that methyl orange can be completely degraded i.e., a 99% degratation rate was obtained within 3 min. This excellent catalytic activity is attributed to the small size and good dispersibility of the nanoparticles, which stimulate the rapid and massive generation of reactive oxygen species in the heterogeneous Fenton reaction. In addition, the magnetic separation of the catalyst offers great prospects for fast and economical decontamination of dye polluted water. 相似文献
7.
Cu nanoparticle‐connected ZIF‐8/reduced graphite oxide (RGO) composite was successfully prepared through a facile hydrothermal reaction using sulfate in this paper. The crossover mechanism of metal nanoparticles loading and RGO decoration to enhance the photocatalytic efficiency of pristine ZIF‐8 was studied. The results showed that the prepared Cu‐S@ZIF‐8/RGO has a strong ability to take advantage of sunlight, indicating an appreciable application prospect. RGO can act as a base to support the whole structure and serve as an electron sink to accept photoexcited electrons, realizing the formation of reactive oxygen species (ROS) and inhibition of electron–hole pair recombination. Cu nanoparticles act as connectors between ZIF‐8 and RGO to transfer electrons and realize the formation of partial ROS on its surface. The doped sulfate radical can promote to extend the utilization of the wavelength range by generating surface states. Cu‐S@ZIF‐8/RGO showed the best photocatalytic activity in simulated sunlight for eliminating rhodamine B and 4‐chlorophenol among all the prepared samples, the structure kept intact even in the presence of different kinds of anions. The crossover study of metal loading and RGO decoration can develop a new way for only UV‐responsive metal–organic frameworks to remove organic contaminants under sunlight irradiation. 相似文献
8.
Visible‐light‐driven photocatalytic degradation of fenpyroximate in rotating packed bed reactor using Fe3O4@PbS@Ni2P magnetic nanocomposite photocatalyst: Response surface modelling and optimization
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Soleiman Mosleh Mahmood Reza Rahimi Mehrorang Ghaedi Arash Asfaram Hamedreza Javadian Fardin Sadeghfar Ramin Jannesar 《应用有机金属化学》2018,32(10)
9.
In this work, we develop an inorganic cocatalyst of commercial MoO2 application in Fenton reaction, which can significantly enhance the Fe(III)/Fe(II) cycling efficiency to improve the oxidation activity for the remediation of Lissamine rhodamine B (L-RhB). 相似文献
10.
smet Kaya Fatma Moral Didem Erdener 《Journal of polymer science. Part A, Polymer chemistry》2004,42(11):2717-2724
The reaction conditions of the oxidative polycondensation of 2‐[(pyridine‐2‐yl‐methylene) amino] phenol (2‐PMAP) with air O2, H2O2, and NaOCl were studied in an aqueous alkaline medium between 60 and 90 °C. Oligo‐2‐[(pyridine‐2‐yl‐methylene) amino] phenol (O‐2‐PMAP) was characterized with 1H NMR, Fourier transform infrared, ultraviolet–visible, size exclusion chromatography (SEC), and elemental analysis techniques. Moreover, solubility testing of the oligomer was performed in polar and nonpolar organic solvents. With the NaOCl, H2O2, and air O2 oxidants, the conversions of 2‐PMAP into O‐2‐PMAP were 98, 87, and 62%, respectively, in an aqueous alkaline medium. According to SEC, the number‐average molecular weight, weight‐average molecular weight, and polydispersity index of O‐2‐PMAP were 2262 g mol?1, 2809 g mol?1, and 1.24 with NaOCl, 3045 g mol?1, 3861 g mol?1, and 1.27 with air O2, and 1427 g mol?1, 1648 g mol?1, and 1.16 with air H2O2, respectively. Also, thermogravimetric analysis showed that O‐2‐PMAP was stable against thermooxidative decomposition. The weight loss of O‐2‐PMAP was 96.68% at 900 °C. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2717–2724, 2004 相似文献
11.
Mingliang Ma Yuying Yang Dili Liao Ping Lyu Jinwei Zhang Jianli Liang Lizhi Zhang 《应用有机金属化学》2019,33(2)
A strategy has been developed for the synthesis, characterization and catalysis of magnetic Fe3O4/P(GMA‐EGDMA)‐NH2/HPG‐COOH‐Pd core‐shell structure supported catalyst. The P(GMA‐EGDMA) polymer layer was coated on the surface of hollow magnetic Fe3O4 microspheres through the effect of KH570. The core‐shell magnetic Fe3O4/P(GMA‐EGDMA) modified by ‐NH2 could be grafted with HPG. Then, the hyperbranched glycidyl (HPG) with terminal ‐OH were modified by ‐COOH and adsorbed Pd nanoparticles. The hyperbranched polymer layer not only protected the Fe3O4 magnetic core from acid–base substrate corrosion, but also provided a number of functional groups as binding sites for Pd nanoparticles. The prepared catalyst was characterized by UV–vis, TEM, SEM, FTIR, TGA, ICP‐OES, BET, XRD, DLS and VSM. The catalytic tests showed that the magnetic Fe3O4/P(GMA‐EGDMA)‐NH2/HPG‐COOH‐Pd catalyst had excellent catalytic performance and retained 86% catalytic efficiency after 8 consecutive cycles. 相似文献
12.
Linyan Yang Liangliang Xin Wen Gu Shengyun Liao Peiyao Du Jinlei Tian Yanping Zhang Rui Lv Xiaohua Wei Xin Liu Daizheng Liao 《中国化学》2014,32(3):227-232
A new coordination polymer, [Co2(L)2(4,4′‐bipy)]n·3nH2O ( 1 ) based on 5‐(3‐methyl‐5‐phenyl‐4H‐1,2,4‐triazol‐4‐yl)isophthalic acid (H2 L ) and 4,4′‐bipyridine (4,4′‐bipy) has been hydrothermally synthesized and characterized by single‐crystal X‐ray diffraction, XRPD, IR, and elemental analysis. Temperature‐dependent magnetic susceptibility and thermal degradation for 1 were also studied. The asymmetric unit of compound 1 consists of two crystallographically independent Co(II) ion, two L 2? ligand, one 4,4′‐bipy ligand, and three lattice water molecules. The 2D triangle networks were linked by the bridging 4,4′‐bipy ligand to give rise to a 2‐fold interpenetrated 3D architecture. The simplest cyclic motif of the 2D networks is a triangle ring consisting of three Co(II) cations and three L 2? ligands. So we can define Co(II) ions as 4‐connected nodes and the L 2? ligands as 3‐connected nodes. Thus, the 3D structure can be described as a 2‐fold parallel interpenetrated ins InS 3,4‐conn topology. 相似文献
13.
14.
Yue Liu Mingxin Lv Lu Li Hailong Yu Qiong Wu Jinhui Pang Yuxiang Liu Congxia Xie Shitao Yu Shiwei Liu 《应用有机金属化学》2019,33(4)
An amino‐functionalized silica‐coated Fe3O4 nanocomposite (Fe3O4@SiO2/APTS) was synthesized. The Fe3O4@SiO2 microspheres possessed a well‐defined core–shell structure, uniform sizes and high magnetization. An immobilized ruthenium nanoparticle catalyst (Fe3O4@SiO2/APTS/Ru) was obtained after coordination and reduction of Ru3+ on the Fe3O4@SiO2/APTS nanocomposite. The Ru nanoparticles were not only ultra‐small with nearly monodisperse sizes but also had strong affinity with the surface of Fe3O4@SiO2/APTS. The obtained catalyst exhibited excellent catalytic performance for the hydrogenation of a variety of aromatic nitro compounds, even at room temperature. Moreover, Fe3O4@SiO2/APTS/Ru was easily recovered using a magnetic field and directly reused for at least five cycles without significant loss of its activity. 相似文献
15.
Poly(D,L‐lactide‐co‐glycolide) 50:50 (PLGA)/graphene oxide (GO) nanocomposite films were prepared with various GO weight fractions. A significant enhancement of mechanical properties of the PLGA/GO nanocomposite films was obtained with GO weight fractions. The incorporation of only 5 wt% of GO resulted in an ~2.5‐fold and ~4.7‐fold increase in the tensile strength and Young's modulus of PLGA, respectively. The thermomechanical behaviors of composite films were investigated by dynamic mechanical analysis. Results indicated that the values of Tg and storage moduli of the PLGA/GO composites were higher than those of the pristine PLGA. The improvement in oxygen barrier properties of composites was presumably attributed to the filler effect of the randomly dispersed GO throughout the PLGA matrix. In this work, we also studied in vitro biodegradation behavior. PLGA/GO composite films were hydrolyzed at 37°C for periods up to 49 days. Because of the presence of GO nanosheets, degradation of composite films took place more slowly with increasing GO amounts. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
16.
The development of green and efficient catalysts for peroxymonosulfate (PMS) activation and organic pollutants degradation has received widespread attention. In this study, the hybrid CaCO3/OMS‐2 catalysts were prepared by a simple precipitation approach and characterized by X‐ray powder diffraction, N2 adsorption–desorption, scanning electron microscopy, transmission electron microscopy, X‐ray photoelectron spectroscopy and cyclic voltammetry. It was found that deposition of CaCO3 on OMS‐2 surface can weaken the Mn‐O bond by formation of Ca‐O‐Mn bond. The interactions between CaCO3 and OMS‐2 significantly enhanced Acid Orange 7 degradation in the presence of PMS with a pseudo‐first‐order kinetic constant of 0.21 min?1, which was much higher than those of OMS‐2 (0.026 min?1) and CaCO3 (0.021 min?1). The CaCO3/OMS catalysts were also much more efficient than other reported OMS‐2 hybrid catalysts, and could be performed over a wide solution pH and for other organic dyes degradation. Sulfate and hydroxyl radicals were formed from the oxidation of low valent manganese species by PMS as the active species in the system. This study can provide a simple method for the design of efficient manganese‐based hybrids for wastewater remediation via PMS activation. 相似文献
17.
In this work, new hydrogel films based on polyvinyl alcohol (PVA) and β‐cyclodextrin (β‐CD) were prepared with the aim of studying their ability as an antibacterial and drug carrier system. Gallic acid (GA) was used as an antibacterial drug which was encapsulated into the β‐CD cavity, and finally, β‐CD inclusion complex (GA/βCD‐IC) was prepared. On the other hand, silver nanoparticles (AgNPs) were synthesized on the graphene oxide (GO) surface (GO‐Ag), and the obtained GO‐Ag was used to enhance the antibacterial properties and mechanical strength of their films. FT‐IR and DSC analysis approved the formation of cross‐linking with glutaraldehyde between the PVA and β‐CD. Hydrogel films were characterized using XRD and SEM. The disc diffusion method showed the antibacterial activity for the films containing GO‐Ag and GA. Due to the good strength, elasticity, WVP, and swelling ability, PVA/GA/βCD‐IC/GO‐Ag can be proposed as a potential antibacterial drug delivery system. 相似文献
18.
Wannida Apisuk Alexandra G. Trambitas Boonyarach Kitiyanan Matthias Tamm Kotohiro Nomura 《Journal of polymer science. Part A, Polymer chemistry》2013,51(12):2575-2580
Ethylene copolymerizations with norbornene (NBE) using half‐titanocenes containing imidazolin‐2‐iminato ligands, Cp′TiCl2[1,3‐R2(CHN)2C?N] [Cp′ = Cp ( 1 ), tBuC5H4 ( 2 ); R = tBu ( a ), 2,6‐iPr2C6H3 ( b )], have been explored in the presence of methylaluminoxane (MAO) cocatalyst. Complex 1a exhibited remarkable catalytic activity with better NBE incorporation, affording high‐molecular‐weight copolymers with uniform molecular weight distributions, whereas the tert‐BuC5H4 analog ( 2a ) showed low activity, and the resultant polymer prepared by the Cp‐2,6‐diisopropylphenyl analog ( 1b ) possessed broad molecular weight distribution. The microstructure analysis of the poly(ethylene‐co‐NBE)s prepared by 1a suggests the formation of random copolymers including two and three NBE repeating units. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2575–2580 相似文献
19.
Oxidative carbonylation of β-aminoalcohols and 2-aminophenol in Pd(OAc)2/I2 catalytic system to produce the corresponding 2-oxazolidinones was conducted with high yields and selectivities in short reaction time. Mild reaction conditions, high catalytic turnover frequency value, improved yields and selectivities are the remarkable features exhibited by this process. 相似文献
20.
There is a relatively low efficiency of Fe(III)/Fe(II) conversion cycle and H2O2 decomposition (<30%) in conventional Fenton process, which further results in a low production efficiency of OH and seriously restricts the application of Fenton. Herein, we report that the commercial MoO2 can be used as the cocatalyst in Fenton process to dramatically accelerate the oxidation of Lissamine rhodamine B (L-RhB), where the efficiency of Fe(III)/Fe(II) cycling is greatly enhanced in the Fenton reaction meanwhile. And the L-RhB solution could be degraded nearly 100% in 1 min in the MoO2 cocatalytic Fenton system under the optimal reaction condition, which is apparently better than that of the conventional Fenton system (~50%). Different from the conventional Fenton reaction where the OH plays an important role in the oxidation process, it shows that 1O2 contributes most in the MoO2 cocatalytic Fenton reaction. However, it is found that the exposed Mo4+ active sites on the surface of MoO2 powders can greatly promote the rate-limiting step of Fe3+/Fe2+ cycle conversion, thus minimizing the dosage of H2O2 (0.400 mmol/L) and Fe2+ (0.105 mmol/L). Interestingly, the MoO2 cocatalytic Fenton system also exhibits a good ability for reducing Cr(VI) ions, where the reduction ability for Cr(VI) reaches almost 100% within 2 h. In short, this work shows a new discovery for MoO2 cocatalytic advanced oxidation processes (AOPs), which devotes a lot to the practical water remediation application. 相似文献