Activation of H2O2 by Amberlyst-15 resin supported with copper(II)-complexes towards oxidation of crystal violet

Copper(II) amine complexes supported on Amberlyst-15 cation resin were prepared and characterized by SEM, EDX and FTIR measurements. The kinetics of the heterogeneous oxidation of an organic dye, crystal violet, with H2O2 catalyzed by the supported catalysts was investigated in aqueous solution. The rate of reaction increases with increasing stability of the copper(II) amine complexes. The oxidation rate attained a first-order in the catalyst and the dye only at lower concentrations and second order in H2O2. A very fast formation of a peroxo-dye intermediate resulting from the interaction of H2O2 with the dye even in the presence of the catalyst was observed.     

双氧水催化氧化中Cu/γ-Al_2O_3催化剂的稳定性研究

针对废水湿式双氧水催化氧化,采用浸渍法制备Cu催化剂,研究非均相Cu催化剂在常温常压湿式双氧水催化氧化中的稳定性与失活问题。研究表明,催化剂制备条件及催化氧化反应条件对催化剂中Cu2＋溶出均有影响。研究同时表明,催化剂失活与活性组分流失和活性组分被有机中间产物覆盖有关,高温焙烧可对催化剂再生。     

Cu/Al催化剂的制备及其在环丙沙星降解反应中的应用

为解决传统Fenton法在水体通常的酸碱(pH＞6.0)条件下活性低的问题,采用水热合成法制备了掺杂Al的非均相铜基类芬顿催化剂,通过X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)及比表面与孔隙度分析(BET)等技术对其结构和形貌进行了表征;以20 mg·L⁻¹的环丙沙星(CIP)为目标污染物,研究了不同催化剂的非均相铜基类芬顿反应体系对CIP的降解效果及H₂O₂消耗量和·OH产生量的影响;探讨了Cu/Al-180催化剂投加量、H₂O₂投加量、初始pH 3个因素对Cu/Al-180催化剂的非均相类芬顿催化降解性能的影响;考察了催化剂的循环使用活性及稳定性。结果表明：不同温度下合成的Cu/Al催化剂主要组分是以CuO和少量Al₂O₃组成的介孔材料;Cu/Al-180催化剂具有较好的结晶度及均匀的颗粒状表面形貌,且对CIP具有最高的催化活性;在Cu/Al-180催化剂投加量为3.0 g·L⁻¹、H₂O₂投加量为149.55 mmol·L⁻¹、pH为5.0条件下,反应时间120 min时CIP降解率为93.3%;Cu/Al-180催化剂催化H₂O₂的pH范围明显拓展,在弱酸性和中性条件下表现出优良的催化性能;合成的Cu/Al-180催化剂经过5次连续循环使用后对CIP降解率可达64.2%,表明该催化剂具有较高的催化活性,且金属离子溶出量较少。     

A comparative study of the effects of chloride, sulfate and nitrate ions on the rates of decomposition of H2O2 and organic compounds by Fe(II)/H2O2 and Fe(III)/H2O2

The effects of chloride, nitrate, perchlorate and sulfate ions on the rates of the decomposition of hydrogen peroxide and the oxidation of organic compounds by the Fenton's process have been investigated. Experiments were conducted in a batch reactor, in the dark at pH < or = 3.0 and at 25 degrees C. Data obtained from Fe(II)/H2O2 experiments with [Fe(II)]0/[H2O2]0 > or = 2 mol mol(-1), showed that the rates of reaction between Fe(II) and H2O2 followed the order SO4(2-) > ClO4(-) = NO3- = Cl-. For the Fe(III)/H2O2 process, identical rates were obtained in the presence of nitrate and perchlorate, whereas the presence of sulfate or chloride markedly decreased the rates of decomposition of H2O2 by Fe(III) and the rates of oxidation of atrazine ([atrazine]0 = 0.83 microM), 4-nitrophenol ([4-NP]0 = 1 mM) and acetic acid ([acetic acid]0 = 2 mM). These inhibitory effects have been attributed to a decrease of the rate of generation of hydroxyl radicals resulting from the formation of Fe(III) complexes and the formation of less reactive (SO4(*-)) or much less reactive (Cl2(*-)) inorganic radicals.     

用于CWPO处理渗滤液的Cu/AC催化剂的制备及性能

采用浸渍法制备Cu负载型活性炭催化剂,运用该催化剂催化湿式氧化（CWPO）处理转运站垃圾渗滤液,以出水COD去除率为指标检测催化剂活性和稳定性。实验考察焙烧温度、焙烧时间、浸渍浓度3个因素对催化活性的影响,并对催化剂进行XRD和BET表征。结果表明：当焙烧温度为400 ℃,焙烧时间2 h,浸渍浓度0.4 mol·L-1时,催化效率最高,渗滤液COD去除率为89.9%。紫外光谱和三维荧光光谱的结果表明,用所制备的Cu负载型活性炭催化湿式氧化垃圾渗滤液,可以较好地除去垃圾渗滤液中的难降解有机物。催化剂的重复利用实验表明该催化剂稳定性良好。     

Fresnel lens to concentrate solar energy for the photocatalytic decoloration and mineralization of orange II in aqueous solution

The decoloration and mineralization of the azo dye orange II under conditions of artificial ultraviolet light and solar energy concentrated by a Fresnel lens in the presence of hydrogen peroxide and TiO(2)-P25 was studied. A comparative study to demonstrate the viability of this solar installation was done to establish if the concentration reached in the focus of the Fresnel lens was enough to improve the photocatalytic degradation reaction. The degradation efficiency was higher when the photolysis was carried out under concentrated solar energy irradiation as compared to UV light source in the presence of an electron acceptor such us H(2)O(2) and the catalyst TiO(2). The effect of hydrogen peroxide, pH and catalyst concentration was also determined. The increase of H(2)O(2) concentration until a critical value (14.7 mM) increased both the solar and artificial UV oxidation reaction rate by generating hydroxyl radicals and inhibiting the (e(-)/h(+)) pair recombination, but the excess of hydrogen peroxide decreases the oxidation rate acting as a radical or hole scavenger and reacting with TiO(2) to form peroxo-compounds, contributing to the inhibition of the reaction. The use of the response surface methodology allowed to fit the optimal values of the parameters pH and catalyst concentration leading to the total solar degradation of orange II. The optimal pH range was 4.5-5.5 close to the zero point charge of TiO(2) depending on surface charge of catalyst and dye ionization state. Dosage of catalyst higher than 1.1 gl(-1) decreases the degradation efficiency due to a decrease of light penetration.     

Performance of photocatalytic reactors using immobilized TiO2 film for the degradation of phenol and methylene blue dye present in water stream

TiO2 thin film photocatalyst was successfully synthesized and immobilized on glass reactor tube using sol-gel method. The synthesized TiO2 coating was transparent, which enabled the penetration of ultra-violet (UV) light to the catalyst surface. Two photocatalytic reactors with different operating modes were tested: (a) tubular photocatalytic reactor with re-circulation mode and (b) batch photocatalytic reactor. A new proposed TiO2 synthesized film formulation of 1 titanium isopropoxide: 8 isopropanol: 3 acetyl acetone: 1.1 H2O: 0.05 acetic acid (in molar ratio) gave excellent photocatalytic activity for degradation of phenol and methylene blue dye present in the water. The half-life time, t1/2 of photocatalytic degradation of phenol was 56 min at the initial phenol concentration of 1000 microM in the batch reactor. In the tubular photocatalytic reactor, 5 re-circulation passes with residence time of 2.2 min (single pass) degraded 50% of 40-microM methylene blue dye. Initial phenol concentration, presence of hydrogen peroxide, presence of air bubbling and stirring speed as the process variables were studied in the batch reactor. Initial methylene blue concentration, pH value, light intensity and reaction temperature were studied as the process variables in the tubular reactor. The synthesized TiO2 thin film was characterized using SEM, XRD and EDX analysis. A comparative performance between the synthesized TiO2 thin film and commercial TiO2 particles (99% anatase) was evaluated under the same experimental conditions. The TiO2 film was equally active as the TiO2 powder catalyst.     

不同晶型二氧化锰催化臭氧化降解亚甲基蓝废水

采用水溶液化学沉积法制备纳米二氧化锰,生成了δ-MnO2、γ-MnO2、α-MnO2,采用XRD、SEM和BET等手段进行了表征。以碱性染料亚甲基蓝为目标污染物,不同晶型纳米二氧化锰作吸附剂进行了静态吸附实验;在催化臭氧化亚甲基蓝的实验中,研究了溶液的pH值、催化剂的加量以及自由基引发剂与促灭剂对催化效果的影响。结果表明：3种催化剂δ-MnO2、γ-MnO2和α-MnO2的平衡吸附量分别为58.47、50.87和40.52 mg·g-1,其中δ-MnO2的吸附性能较强;3种催化剂的吸附动力学符合准二级吸附动力学。当溶液pH=11时,催化臭氧化反应体系对亚甲基蓝的降解效果最佳。在此催化臭氧化系统下,主要遵循的是羟基自由基的反应机理。δ-MnO2应用于催化臭氧化亚甲基蓝,不仅具有良好的脱色效果,并具有一定的矿化能力。     

碳纳米管电极原位产生过氧化氢及其对亚甲基蓝脱色效果

将碳纳米管固定化制成多孔疏水性导电薄膜构建电化学阴极还原体系,实现过氧化氢在阴极的原位产生。电极特性研究表明,电极在较宽的电压范围内均具有较好的活性。考察了阴极电位、电极成分、氧气流量和电解质浓度对过氧化氢原位产生的影响,在优化条件下经过120min后过氧化氢达到66．17mg／L,并探讨过氧化氢原位产生的机理。在此基础上考察原位过氧化氢氧化工艺下对亚甲基蓝的脱色效果,并分析其脱色机理。     

碳纳米管电极原位产生过氧化氢及其对亚甲基蓝脱色效果简

将碳纳米管固定化制成多孔疏水性导电薄膜构建电化学阴极还原体系,实现过氧化氢在阴极的原位产生。电极特性研究表明,电极在较宽的电压范围内均具有较好的活性。考察了阴极电位、电极成分、氧气流量和电解质浓度对过氧化氢原位产生的影响,在优化条件下经过120 min后过氧化氢达到66.17 mg/L,并探讨过氧化氢原位产生的机理。在此基础上考察原位过氧化氢氧化工艺下对亚甲基蓝的脱色效果,并分析其脱色机理。     

The role of copper(II) chloride in the formation of organic chlorine in fly ash

In the de-novo synthesis and formation of PCDD/PCDF, the transfer of inorganic chlorine to the carbonaceous material of fly ash plays an important role. Here, copper acts as a catalyst in the chlorination reaction. In experiments in the range of 250-350 degrees C under helium, we determined the stoichiometry of the chlorination reaction with model systems. Therefore, it was necessary to develop a method to quantify the copper(II) and copper(I) ions. In a combination of solid electron paramagnetic (spin) resonance spectroscopy (EPR) for Cu(I), and X-ray fluorescence spectroscopy (XRFA) analysis for Cu (total), we found a way for the quantification of copper(I) and (II). With these experiments, we can show that the chlorination reaction is relatively fast and comes to a stop under helium, after the copper(II) is reduced. The ratio between the organic chlorine formed and copper(II) reduced is, at the end of the reaction, 0.5, which is in agreement with the following reaction: 2CuCl2 + R-H-->2CuCl + R-Cl + HCl.     

Destruction of organic pollutants in reusable wastewater using advanced oxidation technology

This work studied the destruction of various M-EDTA complexes and trace organic pollutants in treated reusable wastewater under advanced oxidation using UV irradiation and ozonation. Effect of dosage of hydrogen peroxide and acidity of reaction matrices on oxidation efficiencies were investigated. The rate constant of mineralization presents a decreasing trend as Fe(III)-EDTA > Fe(II)-EDTA > Al(III)-EDTA > Pb(II)-EDTA > Na(I)-EDTA > Zn(II)-EDTA > Cu(II)-EDTA. The mineralization efficiencies using ozone alone are 15%, 40% and 15% for the water samples after reverse osmosis (RO), microfiltration (MF) and superfiltration (SF) processes, respectively. The presence of hydrogen peroxide in photochemical reaction matrixes can effectively enhance the mineralization of organic carbon species. When 150 mg l(-1) of H2O2 was added in the effluents, the mineralization markedly increased to 80%, 92% and 89%, respectively.     

硫酸铜类芬顿法去除双酚A

在水处理应用中,为解决Fenton法通常需较低pH的局限性,提出了以硫酸铜为催化剂的类芬顿反应体系,以双酚A(BPA)为目标污染物,分别考察了催化剂用量、H₂O₂用量、反应温度、BPA初始浓度和pH对BPA去除效果的影响,分析了反应过程中pH和羟基自由基浓度的变化。结果表明：在催化剂用量为0.8 g·L⁻¹、H₂O₂为78 mmol·L⁻¹、BPA为152 mg·L⁻¹、反应温度为75 ℃、反应时间为65 min的条件下,BPA和TOC的去除率分别为95.4%和85.9%;所建立的硫酸铜类芬顿反应体系,相比Fenton反应体系具有更宽的pH适应范围,可以在pH=3.0~10.1下进行反应,无需调节反应液的pH,且出水水质颜色好,成本低。以上研究结果可为有机废水的高效处理提供理论与技术支持,具有广阔的应用前景。     

The characteristics of wet air oxidation of phenol over CuOx/Al2O3 catalysts: effect of copper loading

The nature of active copper species is well-known to vary with copper loading, i.e., isolated Cu(2+) to bulk CuO. In this work, however, the effect of copper loading on the activity and the selectivity was investigated for the wet oxidation of phenol over CuO(x)/Al(2)O(3) catalysts. The activity and the mineralization selectivity of the catalysts increased with copper loading up to 7wt% and remained almost the same at a higher loading. The optimum copper loading was about 7wt% for the wet oxidation of phenol over CuO(x)/Al(2)O(3) catalysts in this work. The nature of copper species with different loading was characterized with TPR, XRD, and XANES. The chemical states of copper in the CuO(x)/Al(2)O(3) catalysts were confirmed as varying with copper loading: isolated Cu(2+) ions for 1wt%; highly dispersed Cu(2+) cluster for 5wt% and 7wt%, and bulk CuO for 10-25wt%. The stability of the CuO(x)/Al(2)O(3) catalysts with different copper loading was also studied with respect to carbonaceous deposits and copper leaching.     

The importance of atmospheric ozone and hydrogen peroxide in oxidising sulphur dioxide in cloud and rainwater

The process by which sulphur dioxide is oxidised in atmospheric droplets has been studied in laboratory experiments designed to collect a large amount of chemical data pertinent to the atmospheric situation. Thus the oxidation of sodium sulphite solutions by oxygen, ozone and hydrogen peroxide has been studied at different pH's and temperatures. In all cases the reaction is first order with respect to sulphite ion but the order with respect to oxidant differs. For oxygen the order is zero whereas the order for ozone and hydrogen peroxide is one. Varying the hydrogen ion concentration has little effect on the oxygen reaction rate between pH 6 and 9; the ozone reaction rate is inversely proportional to the square root of the hydrogen ion concentration and the hydrogen peroxide rate is almost directly proportional to the hydrogen ion concentration. These last two observations are very important since in the case of ozone it indicates that the reaction proceeds via a free radical mechanism involving hydroxyl radicals and in the case of hydrogen peroxide it is the only oxidation process of sodium sulphite so far investigated that shows a positive response to the presence of hydrogen ions.The experimental data was used to calculate the rate of sulphate formation in water droplets under atmospheric conditions for each of the three oxidants. If it is assumed that the ozone and hydrogen peroxide gas phase concentrations are initially 50 parts in 10⁹ and 1 part in 10⁹ by volume respectively, then the rates of sulphate formation are equal in cloud water at pH 5.8. Above this pH the ozone reaction is faster and below it the hydrogen peroxide reaction is faster due to the positive catalysis by hydrogen ions; the oxygen rate is unimportant by comparison at all pH's below 7. The rate of hydrogen peroxide reaction is such that substantial amounts of sulphate can still be formed rapidly in water droplets at pH values from 3 to 5, and thus this process will be very important in creating acidity in rainwater.     

The importance of atmospheric ozone and hydrogen peroxide in oxidising sulphur dioxide in cloud and rainwater

The process by which sulphur dioxide is oxidised in atmospheric droplets has been studied in laboratory experiments designed to collect a large amount of chemical data pertinent to the atmospheric situation. Thus the oxidation of sodium sulphite solutions by oxygen, ozone and hydrogen peroxide has been studied at different pH's and temperatures. In all cases the reaction is first order with respect to sulphite ion but the order with respect to oxidant differs. For oxygen the order is zero whereas the order for ozone and hydrogen peroxide is one. Varying the hydrogen ion concentration has little effect on the oxygen reaction rate between pH 6 and 9; the ozone reaction rate is inversely proportional to the square root of the hydrogen ion concentration and the hydrogen peroxide rate is almost directly proportional to the hydrogen ion concentration. These last two observations are very important since in the case of ozone it indicates that the reaction proceeds via a free radical mechanism involving hydroxyl radicals and in the case of hydrogen peroxide it is the only oxidation process of sodium sulphite so far investigated that shows a positive response to the presence of hydrogen ions.The experimental data was used to calculate the rate of sulphate formation in water droplets under atmospheric conditions for each of the three oxidants. If it is assumed that the ozone and hydrogen peroxide gas phase concentrations are initially 50 parts in 10⁹ and 1 part in 10⁹ by volume respectively, then the rates of sulphate formation are equal in cloud water at pH 5.8. Above this pH the ozone reaction is faster and below it the hydrogen peroxide reaction is faster due to the positive catalysis by hydrogen ions; the oxygen rate is unimportant by comparison at all pH's below 7. The rate of hydrogen peroxide reaction is such that substantial amounts of sulphate can still be formed rapidly in water droplets at pH values from 3 to 5, and thus this process will be very important in creating acidity in rainwater.     

臭氧催化氧化去除水中聚乙烯醇

以Fe2+、Mn2+和Cu2+为催化剂,运用臭氧催化氧化技术对水中聚乙烯醇进行去除实验。结果表明:与单独臭氧氧化比较,臭氧催化氧化对聚乙烯醇的去除效果明显提高,且与催化剂浓度相关,去除效果随Fe2+浓度的增大而提高,在35 mg/L左右达最大值,去除率为85%;随Mn2+浓度的增大而降低,最佳含量约为5 mg/L,去除率为54%;加入Cu2+催化剂,在35 mg/L时去除率为5%,其他剂量时去除效果不明显。3种催化剂投加量同为35 mg/L,反应时间3 h条件下,去除效果对比为:Fe2+ > Cu2+ > Mn2+。     

Cu/Zn非均相Fenton催化剂的制备及其对环丙沙星的降解效果

针对传统类Fenton法需在低pH范围内反应的问题,通过正交实验对以铜基为核心Cu/Zn催化剂的化学共沉淀法制备工艺进行了优化,并用XRD、SEM、BET和XPS等测试手段对优选出的催化剂进行了表征;采用单因素分析法考察了优化出的Cu/Zn非均相Fenton催化剂对环丙沙星(CIP)的催化降解效果,并对CIP的催化降解中间产物进行了检测,由此提出了可能的降解路径。结果表明：Cu/Zn金属盐摩尔比是影响Cu/Zn催化剂催化降解CIP的主要因素。优化制备的Cu/Zn催化剂主要组分是CuO,对环丙沙星具有较高的催化活性。在CIP浓度为20 mg·L⁻¹、Cu/Zn催化剂投加量为3.0 g·L⁻¹、H₂O₂投加量为149.55 mmol·L⁻¹、pH为5.0的条件下,反应90 min时CIP降解率达95.0%。所制备的Cu/Zn非均相Fenton催化剂能在pH为3.0~7.0下保持较好的催化反应活性,且氧化剂H₂O₂在反应体系中可达86.0%的利用率。Cu/Zn催化剂具有良好的稳定性和较低的金属离子浸出浓度。通过LC-MS分析,检测出了CIP的4种催化降解中间产物,并且发现CIP是从·OH攻击哌嗪环开始降解的。以上结果可为进一步探索Cu/Zn非均相芬顿催化剂降解其他类似目标污染物性能影响提供参考。     

过氧化氢与过硫酸盐强化电化学处理铜氰废水

表面处理行业废水中的铜氰络合物是废水处理的难点。电化学氧化是一种水处理中常用的方法,对于水中常见的污染物均能进行有效处理,其中,过氧化氢(H₂O₂)和过一硫酸盐(KHSO₅,PMS)是绿色清洁的氧化剂。因此,在电氧化的基础上,探索了H₂O₂和PMS对电化学处理铜氰络合物的强化效果。实验结果表明：氰根(CN⁻)和铜离子(Cu²⁺)的去除率随着H₂O₂和PMS的增加而升高;当电流密度为10 A·m⁻²、H₂O₂浓度为0.4 mol·L⁻¹、反应时间为30 min时,氰根去除率为96.12%,铜离子去除率为81.93%,其中阴极铜回收率为75.60%;当PMS浓度为0.2 mol·L⁻¹、反应时间30 min时,氰根去除率接近100%,铜离子去除率为94.83%,其中阴极铜回收率93.51%。以上研究结果表明,投加合适的药剂可以提高电氧化对铜氰络合物的处理效率。     

CuO/γ-Al_2O_3类Fenton试剂降解丁基黄药

CuO/γ-Al2O3类Fenton试剂是降解丁基黄药的优良试剂。该试剂与传统的Fenton试剂相比,提高了反应的pH值,可在较高pH（4~5）条件下反应,而传统的Fenton试剂的适宜pH值一般在3以下。采用单因素实验和正交实验相结合的方法研究了pH、催化剂投加量、过氧化氢投加量以及反应时间对丁基黄药降解效果的影响,并对催化剂的使用寿命进行了探讨。研究结果表明,反应的最佳条件为：pH为4~5,催化剂投加量为6 g/L,过氧化氢用量为30 mg/L,反应30min。在此反应条件下,丁基黄药的降解率达98%以上;影响丁基黄药降解效果的因素大小顺序为：pH〉反应时间〉H2O2用量〉催化剂投加量,其中pH对CuO/γ-Al2O3类Fenton试剂降解丁基黄药的影响最为显著。