二氧化钛复合型催化剂制备及其微波辅助催化氧化甲苯性能

实验采用溶胶凝胶法和传统浸渍法制备了TiO2-分子筛复合载体及复合载体负载过渡金属与稀土元素催化剂,通过微波辅助催化氧化甲苯的性能实验考察其催化活性.结果表明,复合TiO2明显提高了载体结构的稳定性与耐温性,并使过渡金属铜(Cu)、锰(Mn)和稀土元素铈(Ce)等活性组分在催化剂表面的分散更均匀;在复合载体吸附、吸波性能与多相活性组分催化的共同作用下,Cu-Mn-Ce/TiO2-分子筛催化剂微波辅助催化氧化甲苯的完全燃烧温度仅为175℃,此时甲苯去除率可达99％;15 h的连续性实验表明,TiO2复合型催化剂具有良好的催化活性与稳定性.由催化剂表征分析结果可知,活性组分颗粒的均匀分布与铜、锰氧化物及铜锰尖晶石固溶物等活性相的存在促进了甲苯的催化氧化,锐钛矿型TiO2较高的电子迁移速率与催化剂孔径的增大均有助于甲苯的氧化降解.     

UV-H_2O_2联用工艺去除水中阿特拉津的研究

采用间歇式反应器考察了UV-H2O2高级氧化技术去除水中阿特拉津的效果及其影响因素,并进行了相关的反应动力学研究。结果表明,在pH值6.9,阿特拉津初始浓度500μg/L,紫外辐照强度172μW/cm2时,H2O2投加量50mg/L,反应10min后,阿特拉津的去除率90%。UV-H2O2联用工艺对阿特拉津的降解符合一级反应动力学。H2O2在该联用工艺降解阿特拉津中具有双重作用,一方面,当H2O2投加量较小时,一级反应速率常数随H2O2投加量的增加基本呈现线性增加的趋势;另一方面,当H2O2浓度增加到一定程度(90mg/L)后,阿特拉津的降解速率随H2O2浓度的变化已不明显,而H2O2浓度为102mg/L时,则出现了抑制作用。     

A photolysis coefficient for characterizing the response of aqueous constituents to photolysis

UV photolysis and UV based advanced oxidation processes (AOPs) are gaining more and more attention for drinking water treatment. Quantum yield (ø) and molar absorption coefficient (ε) are the two critical parameters measuring the effectiveness of photolysis of a compound. The product of the two was proposed as a fundamental measure of a constituent’s amenability to transformation by photolysis. It was shown that this product, named the photolysis coefficient, k _p , can be determined using standard bench tests and captures the properties that govern a constituent’s transformation when exposed to light. The development showed the photolysis coefficient to be equally useful for microbiological, inorganic and organic constituents. Values of k _p calculated by the authors based on quantum yield and molar absorption coefficient data from the literature were summarized. Photolysis coefficients among microorganisms ranged from 8500 to more than 600000 and are far higher than for inorganic and organic compounds, which varied over a range of approximately 10 to 1000 and are much less sensitive to UV photolysis than the microorganisms.     

工业废水催化湿式氧化处理的研究

采用系列贵金属-半导体氧化物催化剂,在高压釜中250℃液相条件下对焦化厂等工业废水以及由氨、吡啶等组成的模拟废水进行液相氧化试验。结果发现几种催化剂对不同污染物有不同序列的催化氧化活性,其净化作用有各自的选择性。WT-501催化剂对氨和有机污染物均有高活性,焦化废水经WT-501催化氧化处理后’COD、NH_3分別从9302mg/L和5230mg/L降至619mg/L和47mg/L,去除率高达93.2％和99％。     

沿面放电氧化液相亚硫酸铵

为了解决湿式氨法烟气脱硫生成不稳定亚硫酸铵（（NH4）2SO3）副产物的问题,设计了以不锈钢弹簧和溶液分别作为高压和低压电极的沿面放电系统,对液相（NH4）2SO3的氧化进行了研究。空气从反应器上方进入后经放电区域形成活性物质,再由底部的曝气头鼓入溶液并与（NH4）2SO3发生反应。比较了沿面放电处理与传统曝气处理的氧化效率,考察了放电电压、载气气量和初始浓度等因素对（NH4）2SO3氧化的影响。结果表明,沿面放电对（NH4）2SO3有显著的氧化效果;优化条件下的（NH4）2SO3氧化率接近100%;溶液中（NH4）2SO4与（NH4）2SO3的浓度比小于1时有利于（NH4）2SO3的氧化。     

Fenton氧化水中间氯硝基苯的动力学与机制研究

结合Fenton氧化反应动力学模型研究了Fenton氧化水中间氯硝基苯(m-ClNB)的影响因素和降解机制.结果表明:(1)反应初始pH、H2O2浓度、Fe2+浓度、污染物初始浓度和反应温度对m-ClNB的降解均有明显影响.在反应初始pH为3.5、m-ClNB初始摩尔浓度为0.444mmol/L、H2O2摩尔浓度为21.55mmol/L、Fe2+摩尔浓度为0.054mmol/L、反应温度为(25土1)℃的条件下,m-ClNB的去除效果较好.(2)建立了Fenton氧化m-ClNB的准一级反应动力学模型,且m-ClNB的降解与该模型拟合良好.基于不同反应温度时的准一级反应速率常数(kap),得到了m-ClNB降解的阿累尼乌斯公式,且活化能为36.51kJ/mol.(3)气相色谱(GC)/质谱(MS)和高效液相色谱(HPLC)/MS分析表明,Fenton氧化m-ClNB的主要产物有4-氯-2-硝基苯酚及其同分异构体、羟基乙酸、草酸、丁二酸、丙二酸、6-氯己酸、乙醛酸、2,2-二羟基丙二酸和2-乙基丙二酸等.     

Oxidative removal of acetaminophen using zero valent aluminum-acid system: Efficacy, influencing factors, and reaction mechanism

Commercial available zero valent aluminum under air-equilibrated acidic conditions (ZVAl/H⁺/air system) demonstrated an excellent capacity to remove aqueous organic compounds. Acetaminophen (ACTM), the active ingredient of the over-the-counter drug Tylenol^®, is widely present in the aquatic environment and therefore the treatment of ACTM-contaminated water calls for further research. Herein we investigated the oxidative removal of ACTM by ZVAl/H⁺/air system and the reaction mechanism. In acidic solutions (pH < 3.5), ZVAl displayed an excellent capacity to remove ACTM. More than 99% of ACTM was eliminated within 16 hr in pH 1.5 reaction solutions initially containing 2.0 g/L aluminum and 2.0 mg/L ACTM at 25 ± 1\textcelsius. Higher temperature and lower pH facilitated ACTM removal. The addition of different iron species Fe⁰, Fe²⁺ and Fe³⁺ into ZVAl/H⁺/air system dramatically accelerated the reaction likely due to the enhancing transformation of H₂O₂ to HO. via Fenton's reaction. Furthermore, the primary intermediate hydroquinone and the anions formate, acetate and nitrate, were identified and a possible reaction scheme was proposed. This work suggested that ZVAl/H⁺/air system may be potentially employed to treat ACTM-contaminated water.     

城市污水条件下ASBR厌氧氨氧化的启动与脱氮性能

采用ASBR在城市污水条件下进行厌氧氨氧化的启动与脱氮性能研究。实验接种好氧硝化污泥,在温度为(35±1)℃、HRT为24 h、pH为7.3～8.5的条件下经过130 d的培养,成功启动了厌氧氨氧化反应。实验结果表明,厌氧氨氧化反应稳定运行时,TN容积负荷平均为0.179 kg/(m3.d),NH4+-N、NO2--N和TN去除率分别达到了95.30%、91.30%和76.28%。启动期和稳定运行期NH4+-N、NO2--N去除量和NO3--N生成量的比值分别达到1∶1.54∶0.25和1∶1.27∶0.27;稳定运行期进出水pH差值由启动时的0.85下降到0.24。启动期反硝化和厌氧氨氧化反应同时存在而在稳定运行期厌氧氨氧化发展成为主导反应。MLSS和MLVSS/MLSS先减少后增加,反映了启动过程中硝化细菌、反硝化细菌的衰亡和厌氧氨氧化菌逐渐富集的过程,这与反应器的宏观运行效果相一致。     

Treating solid dairy manure using microwave-enhanced advanced oxidation process

The microwave enhanced advanced oxidation process (MW/H₂O₂-AOP) was used to treat separated solid dairy manure for nutrient release and solids reduction. The MW/H₂O₂-AOP was conducted at a microwave temperature of 120°C for 10 minutes, and at three pH conditions of 3.5, 7.3 and 12. The hydrogen peroxide dosage at approximately 2 mL per 1% TS for a 30 mL sample was used in this study, reflecting a range of 0.53–0.75 g H₂O₂/g dry sludge. The results indicated that substantial quantities of nutrients could be released into the solution at pH of 3.5. However, at neutral and basic conditions only volatile fatty acids and soluble chemical oxygen demand could be released. The analyses on orthophosphate, soluble chemical oxygen demands and volatile fatty acids were re-examined for dairy manure. It was found that the orthophosphate concentration for untreated samples at a higher % total solids (TS) was suppressed and lesser than actual. To overcome this difficulty, the initial orthophosphate concentration had to be measured at 0.5% TS.     

Microwave enhanced advanced oxidation process for treating dairy manure at low pH

This study investigated the treatment of dairy manure using the microwave enhanced advanced oxidation process (MW-AOP) at pH 2. An experimental design was developed based on a statistical program using response surface methodology to explore the effects of temperature, hydrogen peroxide dosage and heating time on sugar production, nutrient release and solids destruction. Temperature, hydrogen peroxide dosage and acid concentration were key factors affecting reducing sugar production. The highest reducing sugar yield of 7.4% was obtained at 160°C, 0 mL, 15 min heating time, and no H₂O₂ addition. Temperature was a dominant factor for an increase of soluble chemical oxygen demand (SCOD) in the treated dairy manure. The important factors for volatile fatty acids (VFA) production were microwave temperature and hydrogen peroxide dosage. Temperature was the most important parameter, and heating time, to a lesser extent affecting orthophosphate release. Heating time, hydrogen peroxide dosage and temperature were significant factors for ammonia release. There was a maximum of 96% and 196% increase in orthophosphate and ammonia concentration, respectively at 160°C, 0.5 mL H₂O₂ and 15 min heating time. The MW-AOP is an effective method in dairy manure treatment for sugar production, nutrient solubilisation, and solids disintegration.