羟基氧化铁催化臭氧氧化去除水中阿特拉津

以实验室制备的羟基氧化铁(FeOOH)为催化剂,研究了其催化臭氧氧化去除水中痕量阿特拉津的效能,并对影响催化效果因素及降解机理进行了探讨。在本实验条件下,反应8 min时催化氧化阿特拉津的去除率比单独臭氧氧化高出63.2%,而FeOOH对阿特拉津的吸附量很小,结果表明,FeOOH对臭氧氧化水中的痕量阿特拉津具有明显的催化活性。探讨了催化剂投量、pH、阿特拉津初始浓度和重碳酸盐碱度对催化氧化阿特拉津的影响。催化剂最佳投量为150 mg/L,去除率随pH和阿特拉津初始浓度的增加而升高,重碳酸盐浓度为200 mg/L时催化作用受到明显抑制。通过研究叔丁醇对催化反应的影响间接推断了催化反应的机理,叔丁醇作为羟基自由基抑制剂有效地抑制了水中羟基自由基的生成和它对阿特拉津的氧化反应,间接证明这种催化作用遵循羟基自由基的反应机理。     

除草剂阿特拉津生物降解研究进展

本文综述了近年来国内外在阿特拉津降解菌及降解途径方面的研究进展 ,及在微生物产生的阿特拉津降解酶、其操作基因方面的研究现状 ,并提出了阿特拉津生物降解的研究趋势     

化学改性活性炭对水中阿特拉津的吸附去除

以5 mol/L HNO3,40%NaOH及5%H2O2对活性炭进行化学改性,采用序批式实验研究了活性炭改性前后对阿特拉津(AT)的吸附平衡特性,并以Langmuir和Freundlich模型对吸附等温线进行了拟合。结合活性炭改性前后孔结构和表面化学的变化特征,探讨了不同改性方法对AT吸附去除的影响效应。结果表明:活性炭经5 mol/L HNO3改性后对AT的吸附性能显著降低;而5%H2O2和40%NaOH改性炭对AT的吸附能力较原炭明显增强,且40%NaOH改性炭的吸附能力大于5%H2O2改性炭。原炭及改性炭对AT的吸附等温线均符合Langmuir模型。HNO3改性炭对AT吸附的降低主要是由于表面酸性基团的增加引起的;H2O2改性炭对AT吸附能力的提高主要是由于比表面积的增大引起的;而NaOH改性炭对AT吸附能力的提高是由比表面积增大和表面碱性基团增加共同作用的结果。几种改性炭和原炭对AT去除率的大小顺序依次为:NaOH改性炭>H2O2改性炭>原炭>HNO3改性炭。     

活性炭负载金属氧化物催化臭氧氧化甲硝唑

采用浸渍法制备了Fe、Ni、Ag、Ce 4种金属氧化物负载活性炭(MeOx/AC)催化剂,并用于甲硝唑(MNZ)的催化臭氧氧化降解,以考察其催化活性.在20 mg/h的臭氧投加量下,催化剂的加入(0.5 g)对MNZ(C0=5 mg/L;pH=5.5)的氧化和矿化有明显改善,其中NiOX/AC催化剂表现出较好的催化活性...     

活性炭纤维上4-氯酚及焦化废水尾水的O3催化氧化降解实验研究

选择YT-1000型活性炭纤维（ACF）作为催化剂,考察ACF与O3协同作用催化降解水溶液中4-氯酚的最佳反应条件,并将该条件应用于焦化废水生物处理尾水中难降解有机污染物的催化氧化。ACF表面具有丰富的微孔结构,对4-氯酚有良好的吸附作用,在动力学上提高了其与O3反应的起始浓度,并且在ACF表面含氧、含氮等基团的催化作用下发生氧化反应,1 L浓度为100 mg/L的4-氯酚水样中投加2 g ACF反应6 min时,吸附作用对TOC的去除率为43.4%,而ACF协同O3作用时的TOC去除率提高到72.5%,协同增效作用为67.1%;在选定的反应条件下,ACF协同O3降解焦化废水生物处理尾水,60 min时的TOC与色度的去除率分别达到56.8%和96.3%。上述研究过程证明了吸附作用与催化作用的协同能有效降解生物过程不能降解的焦化废水中惰性有机污染物。     

活性炭纤维上4-氯酚及焦化废水尾水的O3催化氧化降解实验研究

选择YT-1000型活性炭纤维（ACF）作为催化剂,考察ACF与O₃协同作用催化降解水溶液中4-氯酚的最佳反应条件,并将该条件应用于焦化废水生物处理尾水中难降解有机污染物的催化氧化。ACF表面具有丰富的微孔结构,对4-氯酚有良好的吸附作用,在动力学上提高了其与O3反应的起始浓度,并且在ACF表面含氧、含氮等基团的催化作用下发生氧化反应,1 L浓度为100 mg/L的4-氯酚水样中投加2 g ACF反应6 min时,吸附作用对TOC的去除率为43.4%,而ACF协同O₃作用时的TOC去除率提高到72.5%,协同增效作用为67.1%;在选定的反应条件下,ACF协同O₃降解焦化废水生物处理尾水,60 min时的TOC与色度的去除率分别达到56.8%和96.3%。上述研究过程证明了吸附作用与催化作用的协同能有效降解生物过程不能降解的焦化废水中惰性有机污染物。     

改性SCAC催化臭氧氧化去除布洛芬效能与反应活性位点研究

采用不同的表面改性方法(去矿化处理、氧化改性、碱改性和还原改性)对污泥基活性炭(SCAC)进行处理,分别获得了表面金属含量低、碱位低、碱性官能团含量高及Lewis碱含量高的4种改性SCAC(SCAC-D、SCAC-S、SCAC-OH和SCAC-N),对比考察了改性前后SCAC催化臭氧氧化去除布洛芬(IBP)的效能,并探讨了SCAC催化臭氧氧化反应的主要活性位点。结果表明,5种SCAC催化活性顺序为:SCAC-N > SCAC-OH > SCAC > SCAC-S > SCAC-D;金属组分减少会直接影响SCAC的催化活性,碱位减少对其催化活性的影响相对较弱,说明SCAC表面较为丰富的金属组分是其催化臭氧氧化反应的主要活性位点;增加SCAC表面碱位(Lewis碱和碱性官能团),减少表面酸性官能团有助于提高其催化活性。     

Atrazine removal by ozonation processes in surface waters

Abstract

Atrazine (6‐chloro‐N‐ethyl‐N'‐isopropyl‐1,3,5‐triazinedyl‐2,4‐diamine) was treated with ozone alone and in combination with hydrogen peroxide or UV radiation in three surface waters. Experiments were carried out in two bubble reactors operated continously. Variables investigated were the ozone partial pressure, temperature, pH, mass flow ratio of oxidants fed: hydrogen peroxide and ozone and the type of oxidation including UV radiation alone. Residence time for the aqueous phase was kept at 10 min. Concentrations of some intermediates, including deethylatrazine, deisopropylatrazine and deethyldeisopropylatrazine, were also followed. The nature of water, specifically the alkalinity and pH were found to be important variables that affected atrazine (ATZ) removal. Surface waters with low alkalinity and high pH allowed the highest removal of ATZ to be reached. There was an optimum hydrogen peroxide to ozone mass flow ratio that resulted in the highest ATZ removal in each surface water treated. This optimum was above the theoretical stoichiometry of the process. Therefore, to reach the maximum removal of ATZ in a O₃/H₂O₂ process, more hydrogen peroxide was needed in the surface waters treated than in ultrapure water under similar experimental conditions. In some cases, UV radiation alone resulted in the removal of ATZ higher than ozonation alone. This was likely due to the alkalinity of the surface water. Ozonation and UV radiation processes yield different amounts of hydrogen peroxide. Combined ozonations (O₃/H₂O₂ and O₃/UV) lead to ATZ removals higher than single ozonation or UV radiation but the formation of intermediates was higher.     

微气泡臭氧强化污泥碳源的释放过程

臭氧处理污泥后释放的碳物质可作为低碳市政污水生物处理的重要碳源补充。为突破传统臭氧处理效率低等问题,研究采用微气泡臭氧技术以强化污泥碳源释放效果。结果表明,在臭氧投加量为200 mg O3·（g SS）-1时,污泥SCOD增长了1 964 mg·L-1,为传统臭氧处理的2.1倍,DDCOD由18.1%上升至41.5%,污泥碳源释放效果显著提高。同时确定了微气泡臭氧处理在臭氧浓度为100.0 mg·L-1,污泥浓度为5 g·L-1,污泥初始pH为9的条件下,污泥碳源矿化损失较小且污泥碳源释放效果较好,在臭氧投加量为160 mg O3·（g SS）-1时污泥SCOD增长了1 923 mg·L-1,DDCOD达到41.2%。与传统臭氧处理相比,微气泡臭氧处理能提高臭氧传质效率与间接反应强度,更有利于污泥碳源的释放。     

活性炭催化臭氧氧化深度处理工艺对酵母发酵废水中有机物的去除特性分析

酵母发酵废水经过厌氧膨胀颗粒污泥床（EGSB）-好氧膜生物反应器（MBR）组合工艺处理后,仍含有较高浓度的COD,不能满足排放要求。以发酵废水处理过程中MBR处理单元的出水为研究对象,选择活性炭催化臭氧氧化作为其深度处理工艺,以活性炭吸附和单独臭氧氧化工艺作为对比,重点考察了活性炭催化臭氧氧化深度处理工艺对发酵废水中有机物的去除效能,并借助红外光谱、三维荧光光谱和气相色谱-质谱联用等方法,详细分析了发酵废水深度处理过程中有机物的变化规律。研究结果表明,活性炭催化臭氧氧化深度处理工艺对发酵废水中的芳香族化合物、具有共轭双键的有机物及色度具有良好的去除效果;并且对废水中酸类、醇类和醛类等有机物有较好的降解、转化和去除效果。此外,活性炭催化臭氧氧化工艺还可以使以烷烃、卤代烃、醇类、酯类和酮类为主的大分子有机物的含量大幅度减少。     

Degradation of atrazine by catalytic ozonation in the presence of iron scraps: performance,transformation pathway,and acute toxicity

Degradation of atrazine by catalytic ozonation in the presence of iron scraps (ZVI/O₃) was carried out. The key operational parameters (i.e., initial pH, ZVI dosage, and ozone dosage) were optimized by the batch experiments, respectively. This ZVI/O₃ system exhibited much higher degradation efficiency of atrazine than the single ozonation, ZVI, and traditional ZVI/O₂ systems. The result shows that the pseudo-first-order constant (0.0927?min^?1) and TOC removal rate (86.6%) obtained by the ZVI/O₃ process were much higher than those of the three control experiments. In addition, X-ray diffraction (XRD) analysis indicates that slight of γ-FeOOH and Fe₂O₃ were formed on the surface of iron scrap after ZVI/O₃ treatment. These corrosion products exhibit high catalytic ability for ozone decomposition, which could generate more hydroxyl radical (HO^?) to degrade atrazine. Six transformation intermediates were identified by liquid chromatography-mass spectrometry (LC-MS) analysis in ZVI/O₃ system, and the degradation pathway of atrazine was proposed. Toxicity tests based on the inhibition of the luminescence emitted by Photobacterium phosphoreum and Vibrio fischeri indicate the detoxification of atrazine by ZVI/O₃ system. Finally, reused experiments indicate the approving recyclability of iron scraps. Consequently, the ZVI/O₃ system could be as an effective and promising technology for pesticide wastewater treatment.     

污泥臭氧氧化处理过程中活菌抗药基因丰度的消减

臭氧氧化技术是一种广泛应用的污泥减量技术,然而臭氧处理能否对污泥中的抗生素抗药基因进行有效消减还不清楚。采用单叠氮溴化丙锭（propidium monoazide,PMA）预处理结合定量PCR（qPCR）方法对污泥臭氧减量过程中不同臭氧消耗量下活性污泥活菌中的四环素、氨基糖苷和大环内酯3大类共21种抗药基因的变化进行了研究。结果表明：臭氧氧化可以有效消减活性污泥活菌中21种抗药基因的绝对丰度（每毫升污泥的抗药基因拷贝数）,在臭氧消耗量0.31 g·g-1（TSS）情况下抗药基因总量降低了75.44%;尽管绝对丰度下降,污泥臭氧氧化处理过程中大量抗药基因的相对丰度（抗药基因拷贝数与细菌16S rRNA基因拷贝数的比例）逐渐增加,表明臭氧处理后污泥中耐药菌占总活菌比例可能增加,具有一定的抗性传播风险;Ⅰ型整合子是抗药基因水平转移的重要遗传元件,其绝对丰度同样随着臭氧消耗量增加而降低,而相对丰度逐渐上升。     

污泥基活性炭催化臭氧氧化对氯苯甲酸效能

以城市污水处理厂剩余污泥和玉米芯为原料,用氯化锌活化法制备出污泥基活性炭(SCAC),研究了其催化臭氧氧化去除水中对氯苯甲酸(p-CBA)的效能和机理,同时,考察了臭氧浓度、SCAC投量、p-CBA初始浓度以及自由基抑制剂叔丁醇的加入对SCAC催化活性的影响。实验结果表明,SCAC的加入可以显著提高臭氧对p-CBA的氧化去除效果,在反应初期尤为明显,反应1.0 min时p-CBA的去除率由单独臭氧氧化的26.1%提高到SCAC催化臭氧氧化的60.2%。SCAC催化臭氧氧化对p-CBA的去除率随臭氧浓度的增加和p-CBA初始浓度的减小而增加。此外,在一定范围内增加催化剂的投量可以增加p-CBA的去除率。叔丁醇的加入显著减弱了SCAC催化臭氧氧化降解p-CBA的效能,表明SCAC催化臭氧氧化反应的主要活性物种为羟基自由基(·OH)。     

锰氧化物改性活性炭去除空气中甲醛

为了提高活性炭材料对于气相甲醛的处理性能,采用浸渍法制得了负载锰氧化物的颗粒活性炭(MnOx/GAC).通过静态去除实验,比较了不同制备条件及环境因素对MnOx/GAC去除甲醛性能的影响.结果表明,在负载锰氧化物后,MnOx/GAC对甲醛的去除性能有明显提高.在实验考察范围内,当锰氧化物含量为0.98%,焙烧温度为380℃时,MnOx/GAC对于甲醛的去除性能最佳,单位处理量较未负载时提高了1倍.具备较多大孔结构的果壳炭较椰壳炭更适合作为MnOx/GAC的载体.MnOx/GAC对气相甲醛具有持续的去除能力,锰氧化物对富集在活性炭孔内的甲醛起到了催化降解作用.室内低温低湿的处理环境有利于MnOx/GAC对甲醛的去除.     

阿特拉津在土壤中的环境行为研究进展

概述了阿特拉津在土壤中的迁移、降解及其对植物的影响等环境行为,阐述了土壤组成、土壤pH值以及温度、湿度等因素对各种环境行为过程的影响,并结合目前国内外的研究现状,提出了阿特拉津环境行为新的研究方向。     

Agro-waste biosorbents: Effect of physico-chemical properties on atrazine and imidacloprid sorption

Low cost agro-waste biosorbents namely eucalyptus bark (EB), corn cob (CC), bamboo chips (BC), rice straw (RS) and rice husk (RH) were characterized and used to study atrazine and imidacloprid sorption. Adsorption studies suggested that biosorbents greatly varied in their pesticide sorption behaviour. The EB was the best biosorbent to sorb both atrazine and imidacloprid with K_F values of 169.9 and 85.71, respectively. The adsorption isotherm were nonlinear in nature with slope (1/n) values <1. The Freundlich constant Correlating atrazine/imidacloprid sorption parameter [K_F.(1/n)] with the physicochemical properties of the biosorbents suggested that atrazine adsorption correlated significantly to the aromaticity, polarity, surface area, fractal dimension, lacunarity and relative C-O band intensity parameters of biosorbents. Probably, both physisorption and electrostatic interactions were responsible for the pesticide sorption. The eucalyptus bark can be exploited as low cost adsorbent for the removal of these pesticides as well as a component of on-farm biopurification systems.     

活性炭纤维对水中典型除草剂的吸附行为

实验研究了活性炭纤维对水中敌草隆、阿特拉津的吸附行为,考察了温度、酸碱度、流速对这两种除草剂的吸附影响,采用碱液进行了活性炭纤维的再生。实验结果表明,在实验条件下,温度越高,吸附量越大,敌草隆最佳吸附pH范围在弱酸性区间,阿特拉津最佳吸附pH范围在中性区间。在动态吸附中,流速增大,吸附效果越来越差。采用浓度较小的碱液处理,活性炭纤维再生效果明显。     

Effect of the alkyl chain length on the anaerobic biodegradability and toxicity of quaternary ammonium based surfactants

The anaerobic biodegradability and toxicity to methanogenic gas production of different alkyl chain length homologs of quaternary ammonium based surfactants were examinated. Two series of these cationic surfactants were selected: alkyl trimethyl ammonium and alkyl benzyl dimethyl ammonium compounds. A simple anaerobic gas production test containing municipal digester solids as a source of anaerobic bacteria was used. Under the applied methanogenic conditions, the cationic surfactants tested showed a very poor primary biodegradation and no evidence of any extent of ultimate biodegradation was observed. The toxicity of quaternary ammonium based surfactants to methanogenic gas production decreased with increasing the alkyl chain length.     

催化臭氧氧化染料溶液的研究

采用催化臭氧化技术降解染料废水,以甲基紫溶液为目标污染物,研究了过渡型金属离子的类型,Fe2+的浓度,溶液初始pH值,染料浓度和正丁醇等因素对其降解率的影响。实验结果表明:臭氧氧化甲基紫溶液的过程中,加入一定浓度的过渡型金属离子对甲基紫的去除具有促进作用;当臭氧浓度为16 mg/L,一定浓度范围内,Fe2+催化臭氧化的效果随着浓度的增加而增加,但Fe2+浓度为13 mg/L时,甲基紫的降解率下降;在酸性范围时,pH值增大其降解率会减小;染料浓度增加,甲基紫的降解率减小,但是其绝对降解值会增加;正丁醇的加入抑制氧化反应的进行,甲基紫的降解率下降,说明催化臭氧化过程中有羟基自由基产生。染料降解过程符合一级反应动力学规律。     

三维多孔碳海绵催化臭氧氧化有机染料

针对目前催化臭氧氧化催化剂效率较低、易损失等缺点,通过高温煅烧制备了三聚氰胺碳海绵,以廉价易得的三聚氰胺泡沫直接碳化制备出柔性碳海绵,探讨其在催化臭氧氧化降解印染废水反应中的应用潜力;采用SEM观察、比表面积测定、傅里叶红外光谱和X-射线光电子能谱对碳化前后泡沫进行了表征,探讨了碳化前后泡沫微观结构的变化与催化降解印染废水性能与机理。结果表明：氮气氛围下高温煅烧获得了兼具微孔/介孔结构的三维碳骨架,为催化反应提供充分暴露的活性位点和高效的传质通道;在催化臭氧氧化染料的过程中,973 K下制备的碳泡沫呈现出最为优异的催化活性,显著高于均相臭氧氧化和常规活性炭催化臭氧氧化;自由基捕获实验表明催化过程由羟基自由基(·OH)所主导,超氧自由基(·O₂^-)则发挥了次要作用;富含多孔结构的碳海绵对于活性自由基的生成起到了积极贡献,从而在实际印染废水处理中具有良好的降解性能。研究为开发低成本的三维碳材料用于催化臭氧降解有机污染废水提供了新思路。