具有可见光增强芬顿活性的Ⅱ型2D/2D Cu2ZnSnS4/Bi2WO6异质结(英文)

高级氧化工艺(AOPs)是一种处理有机污染物的极具吸引力的技术.大量的前期研究工作集中在通过芬顿反应(Fenton)降解有机污染物.然而,芬顿反应需要在酸性条件下进行,必须在其过程中进行预处理.同时,反应后产生的含铁污泥需要进一步处理以满足排放要求,从而限制了芬顿反应的发展.作为另一种AOPs,光催化技术因反应条件温和、操作简单和选择性好等优点受到广泛关注.研究表明,各种铁基和铜半导体光催化材料形成光-芬顿(Photo-Fenton)系统,可有效解决芬顿反应中高价金属离子/低价金属离子的循环问题.为了充分利用芬顿氧化技术和光催化氧化技术在降解有机污染物方面的各自优势,构建具有宽太阳光谱响应的新型光芬顿催化剂具有重要意义.由于其独特的层状结构和优越的有机物光催化性能, Bi₂WO₆作为结构最为简单的钙钛矿型层状氧化物,其禁带宽度为2.6–2.8 eV,可响应可见光,已成研究最多的光催化材料之一.研究表明,将Bi₂WO₆与合适的助催化剂耦合以构建异质结是提高光生载流子分离效率、拓宽Bi₂     

过渡金属催化的三级胺氧化反应的研究进展

三级胺的氧化是自然界中最基本的反应之一.利用化学方法研究三级胺的氧化反应不仅可以提供合成含氮化合物的新方法和途径,也可以帮助我们了解生命体中三级胺氧化的反应过程和机理.近十年,过渡金属催化的三级胺氧化反应取得了一些重要的研究进展.主要总结了近年来以过渡金属为催化剂,在氧化剂的条件下,三级胺氧化反应研究领域中的重要研究结果,并展望了该研究领域未来研究的重点和挑战性问题.主要分为五个部分:(1)三级胺的氧化形成氧化胺;(2)三级胺的氧化Mannich反应;(3)三级胺的氧化去甲基化反应;(4)三级胺的氧化酰胺化反应;(5)三级胺取代基的氧化转化.     

褐煤选择性氧化制羧基化学品

褐煤选择性氧化制羧基化学品是其高效利用的一种重要途径.目前,褐煤氧化制化学品的方法主要包括硝酸氧化法、次氯酸钠氧化法、双氧水氧化法、钌离子氧化法、碱-氧气氧化法、催化氧气氧化法以及其他氧化法等.采用不同的氧化方法对褐煤进行氧化,可能得到组成与分布均存在较大差别的氧化产物.但所有的氧化产物均是一种羧基化学品的混合物,需要进行分离纯化.因此,研究者对不同类型羧酸混合物的分离也进行了大量研究.本文从反应和机理方面综述了褐煤氧化制备羧基化学品的不同方法及其特点,分析了不同氧化方法存在的问题,介绍了产物羧酸混合物分离的研究及其存在的问题,尝试提出了褐煤选择性氧化制羧基化学品研究的进一步发展方向.     

醚选择性氧化研究的新进展

本文综述了近年来醚选择性氧化研究的新进展. 主要介绍了铬(Ⅵ)类试剂, 过氧化物, 硝酸,氧和臭氧等各类氧化剂对选择性氧化以及醚的阳极电氧化研究状况 .     

具有可见光增强芬顿活性的Ⅱ型2D/2D Cu_2ZnSnS_4/Bi_2WO_6异质结（英文）

高级氧化工艺(AOPs)是一种处理有机污染物的极具吸引力的技术.大量的前期研究工作集中在通过芬顿反应(Fenton)降解有机污染物.然而,芬顿反应需要在酸性条件下进行,必须在其过程中进行预处理.同时,反应后产生的含铁污泥需要进一步处理以满足排放要求,从而限制了芬顿反应的发展.作为另一种AOPs,光催化技术因反应条件温和、操作简单和选择性好等优点受到广泛关注.研究表明,各种铁基和铜半导体光催化材料形成光-芬顿(Photo-Fenton)系统,可有效解决芬顿反应中高价金属离子/低价金属离子的循环问题.为了充分利用芬顿氧化技术和光催化氧化技术在降解有机污染物方面的各自优势,构建具有宽太阳光谱响应的新型光芬顿催化剂具有重要意义.由于其独特的层状结构和优越的有机物光催化性能, Bi_2WO_6作为结构最为简单的钙钛矿型层状氧化物,其禁带宽度为2.6–2.8 eV,可响应可见光,已成研究最多的光催化材料之一.研究表明,将Bi_2WO_6与合适的助催化剂耦合以构建异质结是提高光生载流子分离效率、拓宽Bi_2WO_6可见光响应范围的一种有效策略.在众多的窄带隙半导体助催化材料中,Cu_2ZnSnS_4作为一种p-型窄带隙半导体,可以响应可见光甚至近红外光.近年来,已经广泛报道了Cu2ZnSnS4可以作为与其他半导体光催化剂进行结合以提高光催化活性的有效助催化剂.在本文中,新型Cu_2ZnSnS_4/Bi_2WO_6(CZTS/BWO)异质结构通过简单的二次溶剂热法构建.异质结的成功形成得到了一系列表征方法的证实,比如XPS和HR-TEM.光催化活性结果表明,制备的CZTS/BWO异质结对有机污染物的降解具有优异的光催化性能,特别是当CZTS相对于异质结中BWO的质量分数为2%时.此外,加入过氧化氢(H_2O_2)可进一步提高染料和抗生素的降解效率.增强的光催化和光芬顿降解性能主要是由于BWO的引入,其提供了更多的活性位点,扩展了太阳光谱响应范围并加速了Cu(Ⅱ)/Cu(Ⅰ)的循环.催化剂的催化活性在经过四次循环实验后并没有显著降低.最终我们合理假设了光催化和光-芬顿催化机理.本项研究可为设计新型光-芬顿催化剂提供新的视角,即共同利用光催化活性和芬顿活性进行废水中残留有机物的净化.     

硼砂-对苯二甲酸电解液中AZ91D镁合金的阳极氧化处理

研究了硼砂-对苯二甲酸环保型电解液中AZ91D镁合金的阳极氧化.考察了对苯二甲酸对镁合金阳极氧化过程及其氧化膜性能的影响,并利用扫描电镜(SEM)、X射线衍射(XRD)、能量散射谱(EDS)、动电化极化和电化学交流阻抗谱(EIS)等进行了分析表征.结果表明,对苯二甲酸的浓度对阳极氧化成膜过程、氧化膜的表面形貌、厚度、相结构和耐腐蚀性能都有重要影响.在硼酸盐电解液中加入适量的对苯二甲酸后,氧化电流密度降低,过度放电现象受到了明显的抑制,所制得的阳极氧化膜的质量也有了显著改善.氧化膜表面变得光滑、致密,膜厚度略有降低.氧化膜与镁合金基底的结合更紧密,而且其耐腐蚀性能也得到了明显增强.该研究对于镁合金阳极氧化处理工艺的环保化及阳极氧化膜质量的提高都具有积极意义.     

蜈蚣毒素多肽RhTx的高效化学合成及复性折叠研究

二硫键的氧化折叠是合成二硫键构象锁定多肽的关键步骤.前人发展的二硫键氧化折叠策略主要有一次氧化折叠、多次氧化折叠和一锅法氧化折叠.目前对三种策略复性效率和收率等的比较性研究较少.分别采用三种氧化折叠策略制备目标蜈蚣毒素多肽RhTx.结果表明,两次氧化折叠策略的分离收率高于一次和一锅法氧化折叠策略,一锅法氧化折叠策略可能会导致较大比例的错误折叠.探索了数十毫克量级RhTx的高效制备方法,为进一步探索RhTx靶向TRPV1的结构机制等研究提供了工具分子.此外,对三种氧化折叠策略进行了系统比较,为二硫键构象锁定多肽的合成提供了参考.     

纳米Ni-Co-B非晶态合金抗氧化行为的原位XPS研究

采用原位XPS手段研究了纳米非晶态Ni-Co-B合金中B和Co的抗氧化行为、表面组成与氧化处理条件之间的关系以及各元素含量随深度的变化趋势.结果发现,氧优先氧化表面的元素B物种,在元素态B被完全耗尽后才开始氧化表面的元素态Co物种,在元素态B和Co均被完全氧化后,元素态Ni才开始被氧化.另外,研究还发现,在氧化过程中,B和Co的氧化物具有在表面富集的倾向.正是由于B和Co的优先被氧化才保护了催化加氢反应中的活性中心--元素态Ni.     

次氯酸钠引发的α-羟基酯的自由基氧化

次氯酸钠是一种绿色氧化试剂,可用于醇的氧化,但是对a-羟基酯的氧化较为困难.发展了一种以次氯酸钠为氧化剂,氢溴酸为添加剂的氧化方法,可以快速高效地完成a-羟基酯化合物的氧化.进一步研究发现自由基是反应的中间体,与传统的Stevens氧化拥有不同的机理.该方法也可以用于普通醇的氧化,并且对多羟基化合物的氧化具有很好的选择性.     

固定化血红蛋白氧载体的研究(Ⅱ)——氧化纤维素共价键联血红蛋白

以纤维素为载体,经高碘酸钠氧化后共价键联血红蛋白,制备氧载体.研究了氧化条件对血红蛋白固定量的影响.纤维素只有经过预氧化、碱处理和再氧化三步活化反应,才能使血红蛋白大量固定化,每克纤维素固定血红蛋白量达1.0g.氧载体稳定性好,血红蛋白不脱落.经铁氰化钾氧化,氧载体放氧效率为33.1%.     

Fenton及Photo-Fenton非均相体系降解有机污染物的研究进展

Fenton及photo-Fenton氧化法是一种有效的应用于环境污染物处理领域的高新氧化技术之一,对Fenton试剂的固定化可以减少铁离子的二次污染,提高催化能力和光利用率,及扩展pH等优势。本文综述了近年来Fenton及photo-Fenton非均相体系氧化降解有机污染物的研究状况。引用文献57篇。     

White Graphene undergoes Peroxidase Degradation

Hexagonal boron nitride (hBN) nanosheets are emerging as promising 2D materials for different types of applications. However, biodegradation of hBN materials is poorly explored owing to their high chemical inertness and strong oxidation resistance. The assessment of oxidation/biodegradation of hBN is important in developing biomedical tools. Herein, we report the first study on the biodegradability of hBN nanosheets comparing the enzymatic catalysis of two different peroxidases, horseradish peroxidase (HRP) and human myeloperoxidase (MPO), with the photo‐Fenton (P.F.) reaction. The results show that degradation of hBN nanosheets is different to that of graphene and graphene oxide, since partial oxidation was found using MPO after 35 h, while HRP failed to degrade hBN up to 60 days. Nearly complete oxidation/degradation was occurred by P.F. reaction in 100 h. These results are helpful in designing advanced conjugates for biomedical uses of hBN.     

非均相Fenton催化剂的组成结构设计与性能优化

非均相Fenton催化技术解决了均相Fenton反应存在的问题,具有pH适用范围广以及催化剂易于回收利用等优点,因而成为水处理领域的研究热点。本文首先介绍了非均相Fenton反应用于降解有机污染物的发展、反应机理以及机理的研究方法。总结了非均相Fenton催化剂的种类,主要包括铁氧化物、其它金属氧化物、金属有机框架材料。重点讨论了提高非均相Fenton催化剂活性及稳定性的方法,包括通过调控催化剂的形貌、尺寸、孔结构使催化剂具有更高的比表面积,将活性组分负载在具有高比表面积的载体上,通过与其它金属复合以及引入光、超声、微波等外场。最后,对非均相Fenton催化技术的发展进行了展望。     

Removal of atrazine from water using an iron photo catalyst supported on activated carbon

Atrazine is a systemic triazine herbicide, which has been classified as an endocrine disrupting pesticide of hormones and the reproductive systems of humans. Moreover, atrazine was recently considered as a potential carcinogen by several reports. The aim of this work was to synthesize and to evaluate an iron catalyst supported on activated carbon to remove atrazine from water. Five different treatment schemas were evaluated: (1) adsorption with the photocatalyst’s support alone, (2) adsorption with the supported photocatalyst alone, (3) adsorption coupled to heterogeneous Fenton reaction, (4) adsorption coupled to heterogeneous advanced oxidation with UV light and (5) adsorption coupled to heterogeneous photo assisted Fenton reaction. The photocatalyst synthesized, via the incipient wet impregnation method, showed 1176 ± 24 m²/g of Langmuir area and 1.6 % wt/wt of iron content. After 120 min of reaction time, total removal efficiencies in the treatment schemas using the photocatalyst ranged from 70 % (mainly adsorption with the photocatalyst alone) to 96 % (Adsorption and heterogeneous photo assisted Fenton reaction). The heterogeneous photo assisted Fenton reaction was the fastest and most efficient treatment schema, with results better than that reported for similar materials. The adsorption data was fitted to a kinetic model of pseudo-second order and the results of advanced oxidation process were fitted to a kinetic model of fractional order.     

Fenton-UASB-生物接触氧化处理Fischer-Tropsch合成废水的研究

用Fenton-UASB-生物接触氧化组合工艺对Fischer-Tropsch合成废水进行处理。实验结果表明,采用Fenton法对废水进行预处理,在pH值为3,H2O2的投加量为30 mL/L,Fe2+投加量为1.2 g/L,反应时间为120 min时,去除了63%的CODCr,有效地提高了废水的可生化性;Fenton预处理出水经UASB厌氧生物处理后,CODCr去除率达90%以上;最后经接触氧化后,出水CODCr达100 mg/L以下,达到了GB8978-1996《污水综合排放标准》中化工类废水的二级排放标准。     

Green Oxidative Degradation of Methyl Orange with Copper(II) Schiff Base Complexes as Photo‐Fenton‐Like Catalysts

Two copper(II) complexes, namely [Cu(HL)Cl] ( 1 ) and [Cu(HL)Br] ( 2 ), where HL is the multidentate Schiff base N‐[(2‐oxy‐acetate)benzyl]‐2‐aminothanol, were synthesized and fully characterized. The Cu^II ions in 1 and 2 are pentacoordinate and the coordination arrangement is best described as distorted square‐pyramidal. The degradation of methyl orange (MO) was investigated using 1 and 2 as homogeneous photo‐Fenton‐like catalysts. 1 and 2 exhibited similar catalytic activity at neutral pH. The results suggest that they have advantages on catalyzing efficient degradation of organic dye through photo‐Fenton‐like reaction.     

UV-Vis/H2O2/草酸铁络合物法在水处理中的应用

介绍了各光Fenton法的运行机理及存在的优缺点,综述了UV-Vis/H₂O₂/草酸铁络合物法在水处理中的应用状况,并对其今后的发展趋势进行了阐述.UV-Vis/H₂O₂/草酸铁络合物法是一种新的高级氧化技术,是对光Fenton法的发展,在处理高浓度难降解有机废水方面效果优于UV/Fe²⁺/H₂O₂法、UV/H₂O₂法、TiO₂法和WO₃法等,因其具有一定的利用太阳能的潜力,所以具有较好的应用前景.     

COD reduction of waste water streams of active pharmaceutical ingredient – Atenolol manufacturing unit by advanced oxidation-Fenton process

Active pharmaceutical intermediates (API) in waste waters have adverse effects on aquatic life and environment. The API have high COD value and low BOD₃ and hence difficult to treat biologically. In this study, advanced oxidation processes (AOPs) utilizing the H₂O₂/Fe⁺², Fenton reactions were investigated in lab-scale experiments for the degradation of Atenolol containing waste water streams. The experimental results showed that the Fenton process using H₂O₂/Fe⁺² was the most effective treatment process. With Fenton processes, COD reduction of wastewater can be achieved successfully. It is suggested that Fenton processes are viable techniques for the degradation of Atenolol from the waste water stream with relatively low toxic by-products in the effluent which can be easily biodegraded in the activated sludge process. Hence, the Fenton process with H₂O₂/Fe⁺² is considered a suitable pretreatment method to degrade the active pharmaceutical molecules and to improve the biodegradability of waste water.     

Photo fenton like process Fe3+/(NH4)2S2O8/UV for the degradation of Di azo dye congo red using low iron concentration

Degradation of Congo Red (CR) a di azo dye in aqueous solution is investigated by a Photo Fenton like process using Fe³⁺ ions as the catalyst and peroxy disulfate as the oxidant. The influence of various reaction parameters like, concentration of Fe³⁺ ions, concentration of the dye, concentration of ammonium persulfate, pH of the solution and the presence of hydroxyl radical scavenger are studied and optimal conditions are reported. The degradation rate decreased at higher dye concentration and at higher pH. The rate constant (k), catalytic efficiency (k_c) and process efficiency (Φ) are evaluated for different concentration of Fe³⁺ ions. The degradation of CR by the photo Fenton like process leads to the formation of 4-Amino, 3-azo naphthalene sulphonic acid, dihydroxy substituted naphthalene, dihydroxy substituted biphenyl, phenol, quinol etc., as intermediates, based on which probable degradation mechanism is proposed. These results show that a photo Fenton like process could be useful technology for the mineralization of di azo dyes under lower concentration of iron in acidic conditions. The present process is advantageous as it lowers the sludge production resulting from the iron comple      

Fe‐DPA as Catalyst for Oxidation of Organic Contaminants: Evidence of Homogeneous Fenton Process

Fenton‐type reactions using transition metal complexes in the decomposition of hydrogen peroxide to hydroxyl radical generation have received special attention due to their advantages over classical homogeneous processes involving soluble iron salts. Thus, the goal of this study was to investigate the use of an iron complex with the ligand pyridine‐2,6‐dicarboxylic acid (dipicolinic acid or DPA) as a homogeneous catalyst for the oxidation of the quinoline. The synthesized iron complex showed a molar ratio of 1:2 metal/ligand and was efficient in the quinoline oxidation at pH values near neutrality. The tests were monitored by mass spectrometry that allows identification of the different intermediates and showed complete oxidation of the quinolone compound. Moreover, in order to shed some light on the formation of hydroxyl radicals and the overall reaction mechanism, some theoretical calculations at the DFT level were performed. The results of this study demonstrated that the iron‐DPA complex is a good catalyst for the oxidation of quinoline by a Fenton‐like mechanism. All theoretical data show good agreement with experimental results.