电生成Fenton试剂及其对染料降解脱色的研究

以可溶性铁为阳极，多孔石墨电有为阴极，Na2SO4为支持电解质，通过后，铁从阳极溶解生成二价亚铁离子Fe^2 ，氧在阴极上还原为过氧化氢H2O2，于电解现场发生Fenton反应，产生羟基自由基即Fenton试剂，在低电流密度（10mA/cm^2）下，可有效地抑制阴，阳两极两反应的发生，所产生的羟基自由基浓度足以有效地进行染料废水的降解与脱色，脱色率达100％，CCDCr去除率达80％。     

新型二氧化铅阳极电催化降解有机污染物的特性研究

通过XRD、SEM等表征,以酚类化合物为目标污染物,研究了经改性的新型含氟β-PbO2阳极电催化氧化污染物的特性.结果表明,该电极对酚类有机污染物的降解显示了良好的电催化活性、稳定性和抗腐蚀性,有较好的环保应用前景.进一步通过羟基自由基清除剂异丙醇加入前后降解效果的比较证实了本系统中有机污染物的降解主要基于羟基自由基的作用机理,是一种电化学高级氧化工艺.     

电化学技术在选磷回水利用中的应用

研究表明，浮选磷矿的废水经电化学处理后可循环利用，通过改进的方法测定废水中悬浮颗粒的ζ电位和废水的透光率，可确立电化学处理的适宜参数。     

掺硼金刚石电极电催化氧化酚类有机物的取代基效应

本文主要以当前水环境中存在酚类有机污染物为研究对象,探讨酚类有机污染物在掺硼金刚石(BDD)电极上的取代基效应,具体研究具有不同位置及种类官能团的取代酚类有机污染物在BDD电极上的电催化氧化过程,通过化学需氧量和浓度变化考察有机污染物在电催化降解过程中的降解趋势,深入分析电极种类、官能团位置与种类与电催化氧化活性之间的联系的同时,研究阳极材料电催化氧化有机污染物的机理及动力学。结果表明,有机物在电极表面的电催化过程以电产生羟基自由基为媒介,对苯二酚在不同电极上的电催化活性与电极析氧电位及表面产生羟基自由基量有着重要的联系,BDD电极拥有最强的电催化氧化活性;不同取代基团的对位取代酚在BDD电极上的电化学降解实验显示电催化反应速率受取代官能团自身的电子效应制约,有机物矿化过程中羟基自由基首先进攻苯环的对位发生取代反应,同时取代基脱离苯环过程成为整个取代酚类电化学降解过程的决速步骤,且有机物的电催化反应速率与取代基特征Hammett常数σ呈近似线性关系。     

碳酸氢盐活化的过氧化氢：一种有机废水处理的新技术

水污染问题已成为影响我国可持续发展的关键问题之一,为有效提高现有污水处理的效率及其回收利用,各种催化氧化技术受到了广泛的关注。目前发展的各类高级氧化技术在实际的应用过程中明显受到了氧化剂的利用率、催化剂的浸出、寿命及成本等问题的严重限制。因此基于新的理念、发展新的催化氧化技术仍然受到广泛的关注。
　　最近几年,利用碳酸氢盐活化过氧化氢,应用于有机废水的降解逐渐受到环境催化领域的关注。碳酸氢盐本身是一种低毒性、广泛存在于环境及生物体系的化学物质,通过它活化过氧化氢产生过碳酸氢盐氧化剂,该氧化剂能够直接氧化有机物。同时,在各种过渡金属催化剂的存在下,通过该过碳酸氢盐可以形成氧化能力更强的各种自由基(如羟基自由基等) 及高价态的过渡金属离子参与有机废水的降解。虽然传统认为碳酸盐及碳酸氢盐对高级氧化法降解有机废水不利,原因是认为它们能捕捉羟基自由基,形成氧化能力更低的碳酸根自由基。现有的研究已充分表明,较低浓度的碳酸氢盐能够加快有机废水的氧化降解,而且通常比单独使用过氧化氢效率更高,这些新的发现已明显突破了传统意义上对碳酸氢盐作用的理解。更为重要的是,在微量碳酸氢盐的存在下,其产生的微碱性环境极大地消除了负载型氧化物催化剂在废水降解过程中的金属离子流失、从而极大地延长了催化剂的寿命。该缺点是各种基于过渡金属氧化物催化剂的高级氧化技术难以广泛推广的关键性挑战,原因是随着氧化降解的进行,废水体系由于有机酸的生成而逐渐酸化,进而引发氧化物催化剂的酸溶而流失。在这点上,碳酸氢盐活化过氧化氢系统由于其天然的微碱性环境体现出了其明显的优势。
　　本文即是在本课题组工作基础上,对该领域内国内外研究进展加以总结,以期获得国内外同行的进一步关注。综述的主要内容包括：(1)碳酸氢氧活化过氧化氢的相关知识介绍,(2)均相碳酸氢氧活化过氧化氢降解有机废水的研究进展,(3)基于金属氧化物催化剂的碳酸氢氧活化过氧化氢降解有机废水的研究进展,和(4)碳酸氢盐在其他高级氧化技术中的应用。虽然基于碳酸氢氧活化过氧化氢降解有机废水的研究还处于早期探索阶段,还有很多基础科学问题如降解机理等值得进一步探索,期望通过该综述的介绍能够让同行对碳酸氢氧活化过氧化氢降解有机废水有一个比较全面的了解,进而推动该研究方向的发展,为有机废水的催化处理提供新的机会。     

微波-活性炭处理有机废水的研究进展

微波-活性炭技术具有选择性强、升温快、效率高、时间短、易于自动控制等特点,在有机废水处理领域应用广泛.其机理主要是"热点"理论和"羟基自由基"理论.本文主要综述了近十年来微波-活性炭处理含酚废水、焦化废水,制药废水、染料废水和其他有机废水的研究现状,并对微波-活性炭技术进行了展望.     

碳酸氢盐活化的过氧化氢:一种有机废水处理的新技术（英文）

水污染问题已成为影响我国可持续发展的关键问题之一,为有效提高现有污水处理的效率及其回收利用,各种催化氧化技术受到了广泛的关注.目前发展的各类高级氧化技术在实际的应用过程中明显受到了氧化剂的利用率、催化剂的浸出、寿命及成本等问题的严重限制.因此基于新的理念、发展新的催化氧化技术仍然受到广泛的关注.最近几年,利用碳酸氢盐活化过氧化氢,应用于有机废水的降解逐渐受到环境催化领域的关注.碳酸氢盐本身是一种低毒性、广泛存在于环境及生物体系的化学物质,通过它活化过氧化氢产生过碳酸氢盐氧化剂,该氧化剂能够直接氧化有机物.同时,在各种过渡金属催化剂的存在下,通过该过碳酸氢盐可以形成氧化能力更强的各种自由基(如羟基自由基等)及高价态的过渡金属离子参与有机废水的降解.虽然传统认为碳酸盐及碳酸氢盐对高级氧化法降解有机废水不利,原因是认为它们能捕捉羟基自由基,形成氧化能力更低的碳酸根自由基.现有的研究已充分表明,较低浓度的碳酸氢盐能够加快有机废水的氧化降解,而且通常比单独使用过氧化氢效率更高,这些新的发现已明显突破了传统意义上对碳酸氢盐作用的理解.更为重要的是,在微量碳酸氢盐的存在下,其产生的微碱性环境极大地消除了负载型氧化物催化剂在废水降解过程中的金属离子流失、从而极大地延长了催化剂的寿命.该缺点是各种基于过渡金属氧化物催化剂的高级氧化技术难以广泛推广的关键性挑战,原因是随着氧化降解的进行,废水体系由于有机酸的生成而逐渐酸化,进而引发氧化物催化剂的酸溶而流失.在这点上,碳酸氢盐活化过氧化氢系统由于其天然的微碱性环境体现出了其明显的优势.本文即是在本课题组工作基础上,对该领域内国内外研究进展加以总结,以期获得国内外同行的进一步关注.综述的主要内容包括:(1)碳酸氢氧活化过氧化氢的相关知识介绍,(2)均相碳酸氢氧活化过氧化氢降解有机废水的研究进展,(3)基于金属氧化物催化剂的碳酸氢氧活化过氧化氢降解有机废水的研究进展,和(4)碳酸氢盐在其他高级氧化技术中的应用.虽然基于碳酸氢氧活化过氧化氢降解有机废水的研究还处于早期探索阶段,还有很多基础科学问题如降解机理等值得进一步探索,期望通过该综述的介绍能够让同行对碳酸氢氧活化过氧化氢降解有机废水有一个比较全面的了解,进而推动该研究方向的发展,为有机废水的催化处理提供新的机会.     

掺硼金刚石膜电极表面产生羟基自由基的原位ESR研究

建立了原位电化学-电子顺磁共振(ESR)方法,系统研究了掺硼金刚石(BDD)膜电极表面在水溶液中的羟基自由基(·OH)产生规律.结果表明,在高于析氧电位时,·OH的生成速率随着阳极电位的升高、电流密度的增加而增大,增加速率逐渐减缓.与此同时,与氢终端的BDD膜电极相比,氧终端的BDD膜电极表面因具有较好的亲水性而具有更高的·OH产生能力.在电化学氧化处理有机废水的过程中,电极表面处于氧终端的状态,有利于·OH产生并保持较高的活性.溶液pH值也在一定程度上影响·OH生成反应,酸性溶液中,BDD膜电极表面的·OH产生能力强于在中性或碱性溶液中.进一步研究发现,BDD膜电极表面还可能生成O3-·0自由基.本研究为深入探索BDD膜电极表面·OH的产生机制提供了研究手段,为阐述BDD膜电极电极在污染物处理中高效性的本质提供了有效的证据.     

新型Ti/TiOxHy/Sb-SnO2电极上苯胺电化学氧化反应

苯胺是一种重要的化工原料,广泛应用于印染、制药、造纸、橡胶等领域.随着化工行业的迅速发展,苯胺的需求量越来越大.然而,苯胺毒性高,大量使用势必造成水体中苯胺浓度的升高,给人类健康及生态环境造成危害.因此,急需一种高效、洁净、经济的方法处理含苯胺废水.电化学氧化法比较新颖,相比传统废水处理方法,它具有高效、简单、清洁等优点,因此被应用于很多废水处理当中,但过多的能耗限制了其进一步广泛应用.阳极作为电化学氧化技术的核心部件,直接影响到电化学氧化反应性能.因此开发出一种高效、经济的阳极材料很有必要.此外,对苯胺降解条件的优化也同样重要.关于苯胺电化学氧化,已有的研究包括Pt电极、PbO2电极和石墨电极等阳极材料.比较而言, Ti/Sb-SnO2电极具有制备工艺简单,析氧过电位较高,材料廉价和电催化性能较强等优点.然而,它的稳定性仍有待提高.因此本文制备了一种高稳定性的Ti/TiOxHy/Sb-SnO2电极,并用于处理苯胺废水.较为系统地研究了电流密度、苯胺初始浓度、pH、NaCl投加量及反应器类型对苯胺电催化氧化性能的影响,同时采用扫描电镜(SEM)、X射线衍射(XRD)和电化学测试对该电极进行了表征,并应用紫外-可见光谱、化学需氧量、电流效率及能耗对不同参数进行评定和优化. SEM及XRD结果表明, Ti/TiOxHy/Sb-SnO2电极涂层覆盖比较完全、紧实,未出现裂缝的发生,因而有利于提高电极稳定性.循环伏安测试结果表明,此电极具备较高的析氧过电位(2.0 V vs Ag/AgCl)及电化学孔隙度(76.31%),因此有利于电极催化性能的提高.苯胺电化学氧化实验结果发现,该反应符合准一级动力学模型,且高电流密度、酸性环境、适当NaCl投加量(0.2 wt%)更有利于苯胺的降解.另外, Ti/TiOxHy/Sb-SnO2电极在三维反应器中对苯胺的处理效果要远远好于在二维反应器中.可以看出, Ti/TiOxHy/Sb-SnO2电极具有较好的处理苯胺性能,可为苯胺废水处理的应用提供了一定的理论指导.     

电化学聚合漆酚铜配合物的结构及其催化性能

 将电化学聚合法得到的聚合漆酚（EPU）与氯化铜的异丙醇溶液作用制成了电化学聚合漆酚铜配合物（EPU－Cu2＋）,并用顺磁共振波谱、红外光谱、X射线光电子能谱、动态机械热分析和原子发射光谱等手段进行了表征．结果表明,该配合物中每个铜离子与EPU分子中二个链节单元的羟基发生配位,铜含量达8．63％．实验结果还表明,该配合物在Na2SO3的水体系（pH＝7）中能催化引发MMA按自由基反应历程进行聚合．     

Fe~(2+)协同热活化过一硫酸氢钾盐诱导自由基脱除NO的研究

在气液撞击流反应器中,研究了Fe~(2+)协同热活化过一硫酸氢钾盐诱导自由基脱除模拟烟气中的NO。考察了主要工艺参数(溶液温度、Fe~(2+)浓度、过一硫酸氢钾盐浓度、溶液pH值、NO入口浓度)对NO脱除效率的影响。分析检测了反应产物和自由基。基于不同系统的对比研究、反应产物检测和活性自由基的捕获,揭示了NO脱除过程的机制和反应路径。结果表明,提高溶液温度、Fe~(2+)浓度和过一硫酸氢钾盐浓度均提高了NO的脱除效率,而提高溶液pH值和NO入口浓度均降低了NO的脱除效率。Fe~(2+)和热对活化过一硫酸氢钾盐产生自由基有显著的协同效应。自由基氧化是NO脱除的主要路径,而过一硫酸氢钾盐直接氧化是次要的脱除路径。Fe~(2+)和热的协同活化体系具有比其他体系高得多的NO脱除率。     

电-多相催化反应器强化处理苯胺废水的研究

本文设计一种新型的电-多相催化反应器处理苯胺废水.考察外加电压,电解时间,初始pH值以及支持电解质浓度等工艺条件对电解效果的影响.实验表明,在外加电压30 V、电解时间l h、初始pH=7和支持电解质Na2SO4溶液浓度为800 mg/L的条件下,该反应器对苯胺有最佳的处理效果,优于单独电化学处理体系.     

Hydroxyl radicals electrochemically generated in situ on a boron-doped diamond electrode

The hydroxyl radicals electrochemically generated in situ on a boron-doped diamond (BDD) electrode have been investigated for the first time in different electrolyte media, over the whole pH range between 1 and 11. A more extensive characterisation of BDD electrochemical properties is very important to understand the reactivity of organic compounds towards electrochemical oxidation on the BDD electrode, which is related to their interaction with adsorbed hydroxyl radicals due to water oxidation on the electrode surface. An oxidation peak corresponding to the transfer of one electron and one proton was observed in pH <9 electrolytes, associated with the water discharge process and electrochemical generation of hydroxyl radicals, which can interact and enhance the electro-oxidation of organic compounds. In pH >9 electrolytes the electrochemical generation of hydroxyl radicals was not observed; ammonia buffer electrolyte gave a pH-independent peak corresponding to the ammonia oxidation reaction. Additionally, for most pH values studied, a few small peaks associated with the electrochemical interaction between non-diamond carbon species on the doped diamond electrode surface and the electrolyte were also seen, which suggests that the doped diamond is relatively unreactive, but not completely inert, and the electrogenerated hydroxyl radicals play a role as mediator in the oxidation of organics.     

Degradation of Phenol by Hydroxyl Radicals on Different Coating Lead Dioxide Electrodes

Lead dioxide electrodes on Ti substrates were prepared by thermal-deposition or electro-deposition. The amount of hydroxyl radicals generated at the electrodes prepared by the above-mentioned two methods was compared with that at the electrodes mingled with Bi or La prepared by electro-deposition. The experimental results indicate that the highest concentration of hydroxyl radicals generated by thermal-deposition, electro-deposition mingled with nothing, electro-deposition mingled with Bi or La was 0.781, 1.048, 1.838 or 2.044 μmol/L, respectively. When phenol was electrolyzed on the four electrodes at a current density of 30 mA/cm2, the removal efficiency of phenol after electrolysis for 1.5 h was 87.30%, 93.55%, 97.95% or 98.70%, TOC removal efficiency after electrolysis for 5 h was 86.76%, 94.26%, 98.53% or 99.60%, respectively. Through the degradation experiments of phenol, the amount of hydroxyl radicals was responsible for the removal efficiency of phenol. The electro-catalytic characteristics were investigated by SEM, the generation amount of hydroxyl radicals, the degradation degree of phenol and the stability and conductivity of the electrodes were also investigated. The experimental results indicate that the four electrodes all show good electro-catalytic characteristics; the electro-catalytic characteristics of the electrode mingled with La were superior to those of the other three ones, and the electrochemical degradation of phenol followed one-step reaction dynamics.     

Electrochemical oxidation and protein adduct formation of aniline: a liquid chromatography/mass spectrometry study

Historically, skin sensitization tests are typically based on in vivo animal tests. However, for substances used in cosmetic products, these tests have to be replaced according to the European Commission regulation no. 1223/2009. Modification of skin proteins by electrophilic chemicals is a key process associated with the induction of skin sensitization. The present study investigates the capabilities of a purely instrumental setup to determine the potential of commonly used non-electrophilic chemicals to cause skin sensitization by the generation of electrophilic species from the parent compound. In this work, the electrophiles were generated by the electrochemical oxidation of aniline, a basic industrial chemical which may also be released from azo dyes in cosmetics. The compound is a known sensitizer and was oxidized in an electrochemical thin-layer cell which was coupled online to electrospray ionization–mass spectrometry. The electrochemical oxidation was performed on a boron-doped diamond working electrode, which is able to generate hydroxyl radicals in aqueous solutions at high potentials. Without any pretreatment, the oxidation products were identified by electrospray ionization/time-of-flight mass spectrometry (ESI-ToF-MS) using their exact masses. A mass voltammogram was generated by plotting the obtained mass spectra against the applied potential. Oligomerization states with up to six monomeric units in different redox states of aniline were observed using this setup. This approach was extended to generate adducts between the oxidation products of aniline and the tripeptide glutathione. Two adducts were identified with this trapping experiment. Protein modification was carried out subsequently: Aniline was oxidized at a constant potential and was allowed to react with β-lactoglobulin A (β-LGA) or human serum albumin (HSA), respectively. The generated adducts were analyzed by liquid chromatography coupled to ESI-ToF-MS. For both β-LGA and HSA, aniline adducts were successfully generated and identified.     

水中天然有机物富里酸的光催化氧化研究

以粉末态TiO2为催化剂对水中天然有机物富里酸（FA）进行了光催化氧化的研究，考察了在光催化-超滤反应器中直接光氧化、曝气条件、错流速度、催化剂浓度、初始pH等因素对富里酸氧化的影响。结果表明，光催化氧化明显优于直接光氧化对富里酸的影响，另外在空气曝气、pH减小以及增大错流速度的条件下均能有效提高富里酸的去除率。     

Electro-fenton and photoelectro-fenton degradation of sulfanilic acid using a boron-doped diamond anode and an air diffusion cathode

The mineralization of sulfanilic acid has been studied by electro-Fenton (EF) and photoelectro-Fenton (PEF) reaction with UVA light using an undivided electrochemical cell with a boron-doped diamond (BDD) anode and an air diffusion cathode able to generate H(2)O(2). Organics were then oxidized by hydroxyl radicals formed at the anode surface from water oxidation and in the bulk from Fenton's reaction between generated H(2)O(2) and added Fe(2+). The UVA irradiation in PEF enhanced the production of hydroxyl radicals in the bulk, accelerating the removal of organics and photodecomposed intermediates like Fe(III)-carboxylate complexes. Partial decontamination of 1.39 mM sulfanilic acid solutions was achieved by EF until 100 mA cm(-2) at optimum conditions of 0.4 mM Fe(2+) and pH 3.0. The increase in current density and substrate content led to an almost total mineralization. In contrast, the PEF process was more powerful, yielding almost complete mineralization in less electrolysis time under comparable conditions. The kinetics for sulfanilic acid decay always followed a pseudo-first-order reaction. Hydroquinone and p-benzoquinone were detected as aromatic intermediates, whereas acetic, maleic, formic, oxalic, and oxamic acids were identified as generated carboxylic acids. NH(4)(+) ion was preferentially released in both treatments, along with NO(3)(-) ion in smaller proportion.     

The mechanism and pathway of the ozonation of 4-chlorophenol in aqueous solution

Chlorophenols (CPs) have been widely used in dif- ferent formulations as preservatives, herbicides, insec- ticides, bactericides and solvents. Parts of chlorophe- nols were released to the natural environment during the usage. As a result, many water sources were con- taminated with CPs[1,2]. Furthermore, they also can be formed during the disinfection of phenol containing water by chlorination. Several CPs are recognized as the priority pollutants by the United States EPA (En- vironmenta…     

取代基结构-活性关系对电化学降解取代苯胺的影响

以Na2SO4为支持电解质, 使用Ti/PbO2电极, 研究了带有推电子基(—CH3)和吸电子基(—NO2, —Cl)的邻或对位取代基苯胺类化合物的电催化氧化降解过程. 研究结果表明, 带有取代基苯胺类化合物的氧化降解是在羟基自由基进攻下生成氨基酚类化合物, 然后在电极表面失去电子生成苯醌继续氧化的过程. 带有推电子基团苯胺的电催化降解速度比带有吸电子基团的苯胺降解速度快, 这是因为推电子基团使苯环电子云密度提高, 有利于羟基自由基的进攻; 吸电子基团使苯环电子云密度降低, 不利于羟基自由基的进攻. 由于阴极还原反应的作用, 化学反应活性和电化学反应活性并不完全一致. 氯代苯胺在羟基自由基进攻下—Cl离去, 以Cl-离子形式进入溶液中, 被氧化生成有效氯, 加快降解反应速度. 硝基虽然是强吸电子基, 但是可以转化为对苯二胺, 进一步活化苯环, 其降解速度较快.