印钞废水处理工艺的改进实验

印钞废水属高浓度难降解有机废水,对环境污染严重。鉴于现有处理工艺出水普遍不达标的情况,通过对比实验确定了改进方案:超滤浓缩液离心出水在进入接触氧化池前,增加新的处理单元(Fenton氧化-混凝)。Fenton氧化最佳条件:FeSO4.7H2O投加量14 g/L,H2O2的投加量34 mL/L,初始pH值6.0,氧化反应时间1.5h,温度18.8℃;混凝过程最佳条件:PAC投加量4 g/L,PAM(5‰)投加量10 mg/L,pH值7。新增单元对废水中COD去除率接近80%,可生化性提高1.6倍,色度降低36%。     

Methanotrophic community structure of aged refuse and its capability for methane bio-oxidation

Aged refuse from waste landfills closed for eight years was examined and found to contain rich methanotrophs capable of biooxidation for methane. Specially, community structure and methane oxidation capability of methanotrophs in the aged refuse were studied. The amount of methanotrophs ranged 61.97 103–632.91 103 cells/g (in dry basis) in aged refuse from Shanghai Laogang Landfill. Type I and II methanotrophs were found in the aged refuse in the presence of sterilized sewage sludge and only Type I methanotrophs were detected in the presence of nitrate minimal salt medium (NMS). The clone sequences of the pmoA gene obtained from the aged refuse were similar to the pmoA gene of Methylobacter, Methylocaldum, and Methylocystis, and two clones were distinct with known genera of Type I methanotrophs according to phylogenetic analysis. Aged refuse enriched with NMS was used for methane biological oxidation and over 93% conversions were obtained.     

Complete catalytic oxidation of o-xylene over Ce02 nanocubes

The activities of CeO2 nanocubes calcined at different temperatures were tested for catalytic oxidation of o-xylene. Using CeO2 nanocubes as catalysts, complete catalytic oxidation of o-xylene was achieved below 210℃. The CeO2 nanomaterials were characterized by means of BET, X-ray diffraction (XRD), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM). From the TEM images, all Ce02 nanocubes displayed cubic morphology irrespective of calcination temperature. The HRTEM images revealed that these nanocubes were enclosed by reactive {001}planes, which may contribute to the intrinsically catalytic property of o-xylene oxidation. The higher activity of Ce02 nanocubes calcined at 550℃ than those calcined at above 550℃ was attributed to their smaller crystallite size and larger surface area. The influences of reaction conditions were also studied, which found that a higher reaction temperature was necessary for complete catalytic oxidation of o-xylene at higher weight hourly space velocity (WHSV) and o-xylene concentration.     

Ti/SnO2-Sb2O5/PbO2阳极电化学氧化降解苯甲酸研究

文章研究了TI/SnO2-Sb2O5/Pbo2在两室电解池中氧化降解苯甲酸的性能,主要考察了电流密度、初始pH值、初始苯甲酸浓度和支持电解质这四个参数对TOC去除效率的影响。实验表明在电流密度为30 mA/cm2,初始苯甲酸浓度为0.5 mmol/L,支持电解质(Na2SO4)为0.1mol/L的条件下,经过6 h反应...     

Fenton氧化在废水处理中的应用

综述了近年来Fenton氧化在废水处理领域的应用状况,对Fenton试剂氧化的机理和主要影响因素:温度、pH、反应时间、H2O2和Fe2+的投加量、H2O2/Fe2+量比以及反应动力学模型进行了简要介绍.最后探讨了Fenton氧化技术在废水处理领域现存不足之处及今后的发展趋势.     

Cu-K型低温碳烟氧化催化剂的合成及表征

柴油机排放中碳烟的低温氧化是近年来研究的热点.通过原位合成法制备Cu2K/Al2O3和CuK／Al2O3两种碳烟氧化催化剂,并采用低温氮吸附/脱附实验、X射线衍射、X射线光电子能谱、程序升温氧化对其结构进行系统表征,并用U碳模拟柴油机碳烟,研究其催化活性,评测其对柴油机排气中碳烟颗粒的净化效果.研究表明,Cu2K/Al...     

控制游离氨实现单级自养生物脱氮的研究

通过实时调控SBR反应器内的游离氮浓度的控制策略,实现以亚硝化作用和厌氧氨氧化作用协同的单级自养生物脱氮工艺.实验分成亚硝酸菌富集和厌氧氨氧化菌混合接种2个阶段,SBR内的温度始终保持在(31±2)℃.亚硝酸菌富集阶段,pH值稳定在7.8左右,通过调节进水氩氮浓度(56～446 mg·L-1)实现FA浓度的变化,从而实...     

氧化沟处理煤矿低浓度生活污水运行控制技术探讨

本文给出了济三煤矿生活污水水量和水质情况,以及采用卡鲁塞尔氧化沟处理该低浓度生活污水的工艺流程和特点。详细描述了实际运行过程中培养和驯化适应低浓度生活污水优势菌种的几个步骤,以及防止和控制污泥膨胀和老化的方法。运行试验结果表明：采用污泥回流比150%、控制氧化沟未端溶解氧（DO）1.5 mg/L,能取得最佳的CODcr去除率和总氮（TN）去除率,分别为76.7%和79.8%。     

氧化沟工艺污水处理厂的调试运行

以安徽某县污水处理厂的改良氧化沟工艺调试为例,采用自然培菌和间歇培养相接合的方式进行调试,结果表明方法可行。在进水COD100mg/L时,MLSS在1500mg/L时,出水COD、NH4-N均可取得较好的处理效果。同时对调试过程中的各环节如人员培训、带负荷试车、污泥培养等进行了详细阐述,并确定了各工艺段的控制参数。     

Effects of metal and acidic sites on the reaction by-products of butyl acetate oxidation over palladium-based catalysts

Catalytic oxidation is widely used in pollution control technology to remove volatile organic compounds. In this study, Pd/ZSM-5 catalysts with different Pd contents and acidic sites were prepared via the impregnation method. All the catalysts were characterized by means of N2 adsorption- desorption, X-ray fluorescence （XRF）, HE temperature programmed reduction （H2-TPR）, and NH3 temperature programmed desorption （NH3-TPD）. Their catalytic performance was investigated in the oxidation of butyl acetate experiments. The by-products of the reaction were collected in thermal desorption tubes and identified by gas chromatography/mass spectrometry. It was found that the increase of Pd content slightly changed the catalytic activity of butyl acetate oxidation according to the yield of CO2 achieved at 90%, but decreased the cracking by-products, whereas the enhancement of strong acidity over Pd-based catalysts enriched the by-product species. The butyl acetate oxidation process involves a series of reaction steps including protolysis, dehydrogenation, dehydration, cracking, and isomerization. Generally, butyl acetate was cracked to acetic acid and 2- methylpropene and the latter was an intermediate of the other by-products, and the oxidation routes of typical by-products were proposed. Trace amounts of 3-methylpentane, hexane, 2-methylpentane, pentane, and 2-methylbutane originated from iso4merization and protolysis reactions.