二氧化氯氧化水中苯胺的反应动力学及机理研究

采用高效液相色谱技术检测苯胺浓度随时间的变化,对二氧化氯氧化苯胺的动力学规律进行了系统的研究.结果表明,ClO₂氧化苯胺的反应对于ClO₂和苯胺均为一级反应,总反应级数为二级.在pH6.86和水温(T_w)287K条件下,二级反应速率常数k值为0.11L·(mol·s)^-1,反应活化能为73.11 kJ·mol^-1,表明ClO₂氧化苯胺的反应在一般水处理条件下即可发生.酸性和碱性条件下反应速率常数k值均较中性条件下大;亚氯酸根ClO₂^-对反应速率的影响不大CC-MS检测到对氨基酚和偶氮苯2种主要反应中间产物,文中对ClO₂氧化苯胺的反应机理进行了初步探讨.     

Ru(III) catalyzed permanganate oxidation of aniline at environmentally relevant pH

Ru（Ⅲ） was employed as catalyst for aniline oxidation by permanganate at environmentally relevant pH for the first time. Ru（Ⅲ） could significantly improve the oxidation rate of aniline by 5-24 times with its concentration increasing from 2.5 to 15 μmol/L. The reaction of Ru（Ⅲ） catalyzed permanganate oxidation of aniline was first-order with respect to aniline, permanganate and Ru（Ⅲ）, respectively. Thus the oxidation kinetics can be described by a third-order rate law. Aniline degradation by Ru（Ⅲ） catalyzed permanganate oxidation was markedly influenced by pH, and the second-order rate constant （ktapp） decreased from 643.20 to 2.67 （mol/L）^-1 sec^-1 with increasing pH from 4.0 to 9.0, which was possibly due to the decrease of permanganate oxidation potential with increasing pH. In both the uncatalytic and catalytic permanganate oxidation, six byproducts of aniline were identified in UPLC-MS/MS analysis. Ru（Ⅲ）, as an electron shuttle, was oxidized by permanganate to Ru（Ⅵ） and Ru（Ⅶ）, which acted the co-oxidants for decomposition of aniline. Although Ru（Ⅲ） could catalyze permanganate oxidation of aniline effectively, dosing homogeneous Ru（Ⅲ） into water would lead to a second pollution. Therefore, efforts would be made to investigate the catalytic performance of supported Ru（Ⅲ） toward permanganate oxidation in our future study.     

用二氧化氯降解废水中的苯胺类化合物（2）──降解机理的探讨

本文在上文（１）的基础上，进一步研究了经二氧化氯处理前后ＢＯＤ＿５／ＣＯＤ的变化规律，其比值大于或接近０．３．其降解产物有醌及醌的氧化产物和ＮＨＩ．对苯胺及二氧化氯来说其．反应级数为１，整个反应为二级反应．     

Treatment of phenol wastewater by microwave-induced ClO2-CuOx/Al2O3 catalytic oxidation process

The catalyst of CuOx/Al2O3 was prepared by the dipping-sedimentation method using γ-Al2O3 as a carrier. CuO and Cu2O were loaded on the surface of γ-Al2O3, characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). In the presence of CuOx/Al2O3, the microwave-induced chlorine dioxide (ClO2) catalytic oxidation process was conducted for the treatment of synthetic wastewater containing 100 mg/L phenol. The relationships between removal percentage and initial ClO2 concentration, catalyst dosage, microwave power, contact time, initial phenol concentration and pH were investigated and the results showed that microwave-induced ClO2-CuOx/Al2O3 process could effectively degrade contaminants in a short reaction time with a low oxidant dosage, extensive pH range. Under a given condition (ClO2 concentration 80 mg/L, microwave power 50 W, contact time 5 min, catalyst dosage 50 g/L, pH 9), phenol removal percentage approached 92.24%, corresponding to 79.13% of CODCr removal. The removal of phenol by microwave-induced ClO2-CuOx/Al2O3 catalytic oxidation process was a complicated non-homogeneous solid/water reaction, which fitted pseudo-first-order by kinetics. Compared with traditional ClO2 oxidation, ClO2 catalytic oxidation and microwave-induced ClO2 oxidation, microwave-induced ClO2 catalytic oxidation system could significantly enhance the degradation efficiency. It provides an effective technology for the removal of phenol wastewater.     

沈阳市铁西区大气环境质量状况及变化趋势的分析

沈阳市铁西区大气环境质量状况及变化趋势的分析许志霞，王天玉，姜海英，于季红，许志环（沈阳市铁西区环保局）（水新一沈阳化工厂有限公司）ＴＨＥＡＩＲＱＵＡＬＩＴＹＳＴＡＴＵＡＮＤＴＨＥＣＨＡＮＧＥＴＲＥＮＤＡＮＡＬＹＳＩＳＩＮＴＩＥＸＩＤＩＳＴＲＩＣＴＳ...     

光电催化降解苯胺的研究——单槽与双槽光反应器对比

以直接热氧化制备的TiO2为催化剂，采用单双槽光反应器，研究了水中苯胺的光电催化降解行为，结果表明：氧的还原反应不是光电催化反应的速率控制步骤，但氧的还原和还原产物能加快苯胺的光电催化降解速率，单槽光电反应器中，当pH由4．38升至10．30，苯胺降解反应速率是逐渐增大。当pH大于10．30后，反应速率迅速下降，使用双槽反应器，阳极室鼓氮气时，苯胺的反应速率始终随pH的升高而下降，而不阳极室鼓空气时，苯胺反应速率在pH9.0左右时最大，在相同的气氛条件下，苯胺在单槽的光电催化反应速率大于双槽的速率，利用光电流的大小可判断反应速率的快慢，但光电流的利用效率与溶液pH，氧和电压有关。     

化学氧化技术处理硝基苯生产废水的试验

硝基苯和苯胺生产中产生的废水含有的大量硝基苯、苯胺类物质及其衍生物。这些物质的生物可降解性较差,并对生物具有毒性。对含硝基苯和苯胺的废水采用ClO2催化氧化技术进行处理后,硝基苯和苯胺的去除率均可达到95%以上,COD的去除率可以达到90%;出水中硝基苯、苯胺和COD的浓度分别降到2.5mg/L、1.5mg/L和100mg/L以下。     

光电催化降解苯胺的研究--外加电压的影响

以直接热氧化制备的TiO2为催化剂，研究了水中苯胺的光催化和光电催化降解行为。结果表明：外加阳极偏压可提高TiO2薄膜电极的光催化活性，但同时副反应速率增大更快，苯胺降解的光电流效率反而下降。     

响应面法优化水力空化强化二氧化氯降解罗丹明B研究

利用响应面法的中心组合设计方法对水力空化强化二氧化氯降解罗丹明B实验进行设计,建立了二次多项式模型,并且模型拟合性较好。对实验条件进行优化,结果表明最佳实验条件为:入口压力为0.44 MPa,反应时间为100 min,二氧化氯浓度为33.74 mg/L。在最佳条件下,罗丹明B的实际降解率为92.2%,与预测值仅差0.3%。     

Ag/TiO_2对邻硝基氯苯废水的催化氧化降解

以自制的Ag/TiO2为催化剂,过碳酸钠(SPC)作氧化剂催化氧化降解邻硝基氯苯(oCNB),考察了催化剂种类、催化剂用量、SPC用量、底物浓度、反应温度及添加无机盐对降解反应的影响。实验结果表明:当催化剂用量1.57×10-6mol、底物浓度6.35×10-4mol/L、SPC用量3.18×10-3mol、温度40℃时,降解率可达到约94%。添加碱金属与碱土金属的卤化物对反应有促进作用,降解率可达99%,因此,利用本方法可以有效降解废水中的邻硝基氯苯。根据实验结果对过碳酸钠氧化邻硝基氯苯的机理进行了推测。     

Degradation kinetics and mechanism of aniline by heat-assisted persulfate oxidation

Oxidation of aniline by persulfate in aqueous solutions was investigated and the reaction kinetic rates under different temperature, persulfate concentration and pH conditions were examined in batch experiments. The results showed that, the aniline degradation followed pseudo first-order reaction model. Aniline degradation rate increased with increasing temperature or persulfate concentration. In the pH range of 3 to 11, a low aniline degradation rate was obtained at strong acid system (pH 3), while a high degradation rate was achieved at strong alkalinity (pH 11). Maximum aniline degradation occurred at pH 7 when the solution was in a weak level of acid and alkalinity (pH 5, 7 and 9). Produced intermediates during the oxidation process were identified using liquid chromatography-mass spectrometry technology. And nitrobenzene, 4-4’-diaminodiphenyl and 1-hydroxy-1,2-diphenylhydrazine have been identified as the major intermediates of aniline oxidation by persulfate and the degradation mechanism of aniline was also tentatively proposed.     

废铁屑预处理被4-硝基苯胺污染的土壤

利用机械厂废弃铁屑和分析纯级铁粉对受4-硝基苯胺(PNA)污染土壤的修复进行了对比研究,探讨了土壤酸度和反应温度对还原效果的影响,并对反应时间、铁屑用量和土壤含水量3个影响因素进行了优化选择.实验结果表明,在1.5g含PNA浓度约为1.3×10-5mol/g的模拟污染土样中加入100mg铁屑或铁粉和0.5mL蒸馏水,在25℃下反应4h,PNA的还原率分别为99%和76%,产物均为苯二胺(PDA);铁粉仅在偏酸性土壤中对PNA有较高还原率,铁屑则在中性或弱碱性土壤中仍能保持较好的还原效果;反应温度的变化对还原效果影响不大;正交实验结果显示反应时间对PNA的还原效果影响最大,土壤含水量次之,铁屑用量影响最小。     

催化超临界水氧化技术处理香料废水研究

采用催化超临界水氧化(CSCWO)技术对香料废水进行氧化处理,研究了催化剂浓度、反应温度、压力、停留时间等因素对废水COD、TN去除效果的影响.结果表明:在超临界水中添加cu2+催化剂后有机物的去除效率与无催化剂时相比有显著的提高.香料废水中COD、TN的去除率随催化剂浓度、反应温度和压力的升高,停留时间的延长而提高....     

二氧化氯对水中流感病毒的消毒效果

通过考察MDCK细胞病变程度,研究二氧化氯(ClO₂)对水中流感病毒(包括流感病毒Ⅰ型 、流感病毒Ⅱ型和流感病毒Ⅲ型)的消毒效果.对各种试验条件,如消毒剂投加量、消毒时间 及pH值等影响因素进行了研究,并与液氯(Cl₂)消毒效果进行了对比.结果表明,ClO₂投加量为 40mg/L时,作用20min,ClO₂对试验的流感病毒具有很好的灭活效果,且在pH值为3.0～8.0的范 围内均达到很好的消毒效果.而液氯在试验的投加量、时间和pH值范围内均不能灭活流感病 毒.      

Fenton试剂氧化降解腐殖酸动力学

研究了Fenton试剂氧化降解腐殖酸废水的过程及动力学.结果表明,Fenton法能通过氧化和混凝作用有效去除腐殖酸,其中氧化降解速率主要与Fenton试剂投量、腐殖酸初始浓度和初始pH值有关,且氧化作用主要发生在反应前60 min.在pH为4.0,[Fe2+]0为5～40 mmol.L-1,[H2O2]0为40～120 mmol.L-1,[HS]0为250～1 000 mg.L-1,温度为278～318 K的实验范围内,反应初始阶段腐殖酸的氧化降解符合表观反应动力学模型.模型值与实验值吻合良好,说明该反应动力学模型能较好地描述Fenton氧化降解腐殖酸过程.Fenton氧化降解腐殖酸的初始反应活化能Ea为14.9 kJ.mol-1,说明反应较易进行.动力学模型的反应总级数为2.34,其中H2O2的反应分级数(0.86)高于Fe2+的分级数(0.47),表明H2O2浓度比Fe2+浓度对Fenton氧化降解反应的影响大.     

Fenton法处理中药废水的研究

采用Fenton氧化技术对中药废水进行实验处理,对主要操作条件及其对实验处理效果的影响进行了实验研究。主要考察了废水pH、H2O2投加量、Fe^2＋投加量及温度等对废水中CODcr去除率的影响。实验结果显示,在pH=3.0,H2O2投加量为4/5Qth,Fe^2＋浓度为7.9×10^-3mol.L-1,20℃的情况下反应80 m in后CODcr去除率可以达到71.40%,Fenton氧化反应对中药废水有比较好的处理效果,改善了废水的可生化性,有利于进一步进行生化处理。     

金属负载活性炭催化剂的稳定性研究

通过预处理、浸渍处理、改性液后处理等方式,研究开发出具有电化学反应性能的系列金属负载活性炭催化剂.分别将未改性和改性后的系列金属负载活性炭用于不同pH值下多种高浓度有机废水处理.试验结果表明,改性后的载铜及载铁活性炭催化剂经催化氧化反应后,处理出水中Cu2+离子和Fe2+离子的溶出量均可减少90％以上,苯胺及苯酚废水中COD的去除率可达50％～95％.大大提高了金属负载活性炭催化剂的稳定性,提高了催化剂的使用寿命,降低了废水处理成本.     

Study on the removal of NOx from simulated flue gas using acidic NaClO2 solution

The study on the removal of NOx from simulated flue gas has been carded out in a lab-scale bubbling reactor using acidic solutions of sodium chlorite. Experiments were performed at various pH values and inlet NO concentrations in the absence or presence of SO2 gas at 45℃. The effect of SO2 on NO oxidation and NO2 absorption was critically examined. The oxidative ability of sodium chlorite was investigated at different pH values and it was found to be a better oxidant at a pH less than 4. In acidic medium, sodium chlorite decomposed into C102 gas, which is believed to participate in NO oxidation as well as in NO2 absorption. A plausible NOx removal mechanism using acidic sodium chlorite solution has been postulated. A maximum NOx removal efficiency of about 81% has been achieved.     

双氧化剂光催化降解水中邻苯二甲酸酯类污染物

采用过硫酸钠/双氧水双氧化体系光催化氧化降解水中邻苯二甲酸酯类有机污染物,考察了过硫酸钠/双氧水的投加比例、紫外光强、溶液pH以及邻苯二甲酸二辛酯(DOP)的初始浓度等因素对降解率的影响,并在优化条件下对降解反应的动力学进行了考察。结果表明:室温下,过硫酸钠和双氧水浓度均为0.2mol/L且体积比为1:1,pH=7.0,光照距离为0.5cm,反应80min,DOP降解率达98%以上,反应动力学研究表明,过硫酸钠/双氧水双氧化体系光催化氧化降解水中DOP反应为表观一级。优于相同条件下两种氧化剂单独使用对DOP的降解效果。     

酸-碘改性壳聚糖-膨润土脱除单质汞特性及机理分析

为探明烟气中酸性气体(SO2,NO,HCl)和H2O对酸-碘改性壳聚糖-膨润土吸附剂脱除单质汞(Hg0)的影响和脱除机理,在小型固定床试验台架上开展了Hg0脱除的实验研究.结果表明:由于SO2与Hg0在吸附剂表面活性位上存在竞争吸附,SO2抑制吸附剂对Hg0的脱除.H2O和较高浓度(1000μg/m3)的NO对脱汞具有明显地促进作用.由于低温下HCl与Hg0较高的反应能垒,HCl对脱汞没有影响.与单一烟气成分影响相比,在SO2、NO、HCl和H2O的联合作用下,吸附剂的长时间脱汞性能得到大幅提高.机理分析表明壳聚糖首先被酸中的H+质子化,之后再吸附酸与KI反应生成的I2,进而有效地吸附Hg0.量子化学计算表明壳聚糖在酸性条件下对I2具有良好的吸附特性,改性壳聚糖吸附剂对Hg0具有较好的吸附能力,其吸附能约为127kJ/mol.