生物法处理含铁锰地下水的研究进展

生物法除铁锰理论是对地下水接触氧化法除铁锰工艺中过滤单元氧化过滤机制的新认识,在不改变接触氧化法工艺的基础上,形成了以培养和维护滤层中铁锰细菌氧化过滤水中铁锰机制的地下水生物法除铁锰新工艺,以进一步改善除锰效果,降低工程投资及运行费用,是目前该领域具有广阔发展前景的工艺。主要介绍了生物法同步除铁除锰机理,生物滤层中铁锰的氧化还原关系,Fe2+的作用和对除锰的影响,阐述了影响生物除铁除锰技术主要因素的研究现状,分析了复合型微污染地下水处理存在的问题。     

浅谈地下水除铁除锰技术

阐明了地下水中铁、锰的危害及去除机理,介绍了自然氧化法、接触氧化法、生物法三种除铁除锰技术,指出了除铁除锰技术应用中目前存在的部分问题.     

锰基催化剂催化氧化VOCs技术的研究进展

针对挥发性有机化合物(VOCs)有毒有害、污染大气等问题,开展了锰系催化剂催化氧化VOCs的分类研究。探讨了单一锰氧化物、锰基复合氧化物、一些特殊的锰基氧化物、锰基负载型催化剂以及锰系单体的催化活性及其影响因素、形貌结构和催化特点等,并对锰系催化剂的改进合成方法提出了建议,为未来锰系催化剂的研究发展提供了方向。     

曝气生物滤池同步除铁锰和氨氮

在实验室条件下,采用双层陶粒滤料曝气生物滤池工艺,以受氨氮污染的原生铁锰地下水作为研究对象,研究了模拟微污染地下水中铁、锰和氨氮的去除,分析了滤速变化对滤池中铁、锰和氨氮同步去除的影响及铁、锰和氨氮浓度沿滤层深度的变化。结果发现当滤速突然增加时,滤池经过2～3 d的培养后,出水铁、锰和氨氮均可达标;当滤速由0.74 m·h^-1逐渐增加到3 m·h^-1时,水中铁与氨氮的浓度一般都在滤层深度0.75 m处即可达标,但锰浓度达标的滤层深度却由0.75 m增加到1.60 m。     

臭氧催化氧化-活性炭处理微污染源水

通过连续流试验比较了载锰颗粒活性炭催化臭氧氧化（催化氧化）与臭氧氧化及其后续活性炭过滤对微污染松花江水的处理效能。处理效率最高时,催化氧化对CODMn、UV254、DOC及三卤甲烷生成潜能的平均去除率分别为59.7%、75.8%、40.8%和42.4%,分别是臭氧氧化的3.6、1.4、5.0和2.8倍。随着时间的增加,催化氧化对有机物平均去除率下降,降低程度依次为：UV254〉CODMn〉DOC。催化氧化-活性炭工艺对水力负荷变化有较强的适应能力。臭氧氧化后水中氨氮浓度上升,而催化氧化后稍有下降,同时催化氧化后续活性炭对氨氮的平均去除率在80%左右,比臭氧氧化后续活性炭去除率高而且更加稳定。     

铁锰复合氧化膜对水中双酚A的去除及影响因素

前期研究已发现表面负载铁锰氧化膜的石英砂滤料,对水中常见污染物（氨氮、铁、锰等）具有较高的催化氧化能力。本文利用中试过滤系统研究成熟滤料对水中双酚A（BPA）的去除能力,同时考察进水中Mn²⁺的负荷变化对去除水中BPA的影响。结果表明：该系统在仅有BPA负荷时,可去除ΔC_BPA为0.48mg/L,去除率高达95.6%,消耗溶解氧（DO）为5.44mg/L;进水中同时投加BPA和Mn²⁺,当Mn²⁺浓度达到2.0mg/L时,在滤柱前65cm处即可去除ΔC_BPA为0.56mg/L,BPA在后半段无法有效去除。由扫描电子显微镜（SEM）可知,BPA氧化后生成了某种物质,阻塞在氧化膜的孔隙结构中,造成滤料板结,同时发现少许氧化膜裂开脱落;能谱仪（EDS）能谱图显示投加BPA后,C、O元素的含量分别由之前的12.14%、18.50%增加到21.10%、22.58%,而Mn元素由之前的63.18%减少至42.49%,导致氧化膜表面锰氧化物减少;X射线光电子能谱（XPS）能谱图显示,在不同阶段氧化膜的主要化学形态为Mn₃O₄和MnFe₂O₄,而投加BPA后,有机物[—CH₂—H(OH)]_n覆盖在氧化膜表面及空隙中,降低了氧化膜表面的有效活性位,导致了BPA去除效果下降。     

接触氧化除锰机理及工艺流程

较详细地介绍了接触氧化除锰机理及工艺流程，并对影响接触氧化除锰效果的主要因素进行了分析。     

化学除锰技术研究进展

介绍了接触氧化法、试剂氧化法、电化学法除锰的效果、有关参数及作用机理,阐述了接触氧化法中常用滤料锰砂、石英砂、河砂、沸石等优缺点、除锰效果及作用机理,叙述了以高锰酸钾、氯、过氧化氢和臭氧为氧化剂的试剂氧化法除锰的反应条件及处理效果,分析了电化学法处理含锰废水的技术水平及除锰效能。展望了未来的发展方向:认为接触氧化法应集中在生物作用机理上,并针对生物机理培养特定菌种接种高效的活性滤膜;试剂氧化法可放在联合接触氧化法处理含锰废水上;电化学法可着重于微生物电解池以及微生物燃料电池的研究上。除锰技术结合生物能的研究意义重大。     

高锰酸盐药剂预氧化去除受污染地下水中铁、锰

通过单因子试验考察了进水pH、预氧化时间及原水本底成分对高锰酸钾、高锰酸盐复合药剂(PPC)预氧化去除受污染地下水中铁、锰效果的影响.试验结果表明,在使用KMnO4及PPC预氧化时,进水无需调节pH便能取得较好的铁、锰去除效果;综合技术经济因素考虑,PPC及KMnO4的预氧化时间应定为10 min;原水本底成分极大地影...     

锰氧八面体分子筛的制备及应用研究进展

锰氧八面体分子筛具有多孔结构、温和的表面酸碱性、混合价态的锰离子和优异的离子交换性,被广泛应用于多相催化、电池材料和吸附材料等领域。本文介绍了锰氧八面体分子筛的化学组成,对其孔结构、氧化还原性能及酸碱性等理化性质予以总结,简述了水热法、回流法、微波法、溶胶-凝胶法和固相法等常用制备方法。锰氧八面体分子筛可应用于CO催化氧化、有机物催化氧化、CO₂活化利用和费托合成等催化领域,尤其对CO和挥发性有机物有较高的氧化活性,在电池材料和吸附材料等非催化领域也有重要的应用前景。最后指出了当前锰氧八面体分子筛研究中存在的问题,未来工作应探索更高效的合成方法,深入认识其催化作用机理,进一步拓宽该材料的应用范围。     

Alumina supported manganese oxides for the low-temperature selective catalytic reduction of nitric oxide with ammonia

Alumina supported manganese oxides exhibit a high and selective activity for the catalytic reduction of nitric oxide with ammonia (SCR) between 385 and 575 K. Samples with 3–15 wt.-% manganese were studied at space velocities between 22 000–116 000 h⁻¹ and at standard conditions of 500 ppm NO, 550 ppm NH₃ and 2% O₂. Manganese acetate results in a better dispersion of the manganese oxide on the support and a higher specific catalyst activity than manganese nitrate as precursor, for which crystalline structures could be detected. Temperature-programmed reduction revealed that acetate yields Mn₂O₃ and nitrate mainly MnO₂ on the γ-alumina support. The nitric oxide conversion per amount of manganese is fairly independent of the loading for the catalysts prepared from each precursor. The use of ¹⁵NH₃ reveals that it reacts in a 1:1 molar ratio with nitric oxide towards ¹⁵NN and/or ¹⁵NNO. The SCR activity (to nitrogen) is strongly dependent on the oxygen partial pressure, whereas water inhibits reversibly. Lattice oxygen of the catalyst is not able to maintain the SCR reaction in the absence of oxygen. The nitrous oxide formation is independent of the oxygen partial pressure, but increases with increasing manganese loading and with temperature, resulting in lower selectivities for nitrogen formation. The nitrogen and nitrous oxide formation probably occur at different sites. Above 525 K ¹⁵NH₃ oxidation occurs, yielding mainly ¹⁵N₂O and ¹⁵NO, depending on the temperature. The nitrous oxide is not further reduced by ammonia over this type of catalyst. The addition of tungsten to the catalyst increases the selectivity for nitrogen considerably. The stability of the ex-acetate catalyst is good, for at least 600 h the activity remained constant. The catalysts are sensitive towards sulphur dioxide, the ex-acetate catalysts the least, due to the strong interaction with the alumina support, as is revealed by TPR.     

The catalytic oxidation of ammonia: influence of water and sulfur on selectivity to nitrogen over promoted copper oxide/alumina catalysts

The CuO/Al₂O₃ system is active for ammonia oxidation to nitrogen and water. The principal by-products are nitrous oxide and nitric oxide. Nitrous oxide levels increase with the addition of various metal oxides to the basic copper oxide/alumina system. Addition of sulfur dioxide to the reaction stream sharply reduces the level of ammonia conversion, but has a beneficial effect on selectivity to nitrogen. Added water vapour has a lesser effect on activity but is equally beneficial in terms of selectivity to nitrogen. The CuO/Al₂O₃ is also active for the selective catalytic reduction of nitric oxide by ammonia, but this reaction is not effected by sulfur dioxide addition. A mechanism for ammonia oxidation to nitrogen is proposed wherein part of the ammonia fed to the catalyst is converted into nitric oxide. A pool of monoatomic surface nitrogen species of varying oxidation states is established. N₂ or N₂O are formed depending upon the average oxidation state of this pool. An abundance of labile lattice oxygen species on the catalyst surface leads to overoxidation and to N₂O formation. On the other hand, reduced lability of surface lattice oxygen species favours a lower average oxidation state for the monoatomic surface nitrogen pool and leads to N₂ formation.     

Simultaneous SO x /NO x removal in a fluidized bed reactor using natural manganese ore

In this experiment, the simultaneous removal of SO₂ and NO from flue gases was investigated through the use of natural manganese ore as a sorbent‐catalyst in a fluidized bed reactor. Selective catalytic reduction behavior was determined as a function of the sulfation degree within the temperature range from 100 °C to 500 °C. The natural manganese ore showed a high activity in the production of nitrogen and water by the reaction of nitric oxide with ammonia and oxygen up to around 200 °C. At higher temperatures, the nitric oxide removal efficiency decreased due to the oxidation of ammonia by oxygen. With the increase of sulfation degree, the temperature at which the maximum selective catalytic reduction of nitric oxide appears gradually increased, however the maximum nitric oxide removal efficiency decreased. Additionally, we investigated the removal efficiency of sulfur dioxide and nitric oxide with reaction time in a batch fluidized bed reactor within a temperature range of 350 °C to 500 °C. As the reaction temperature increased, the adsorption capacity of sulfur dioxide increased, but the nitric oxide removal efficiency decreased. © 2001 Society of Chemical Industry     

高铝粉煤灰负载锰基催化剂的催化氧化NO性能研究

氮氧化物催化氧化是烟气脱硝技术的一个重要发展方向。本工作以具有球形镂空结构的预处理后高铝粉煤灰为载体,以硝酸锰为活性组分源,采用溶胶凝胶法制备锰基NO氧化催化剂,采用扫描电镜(SEM)、X射线衍射仪(XRD)、N2物理吸附、H2程序升温还原分析仪(H2-TPR)和X射线光电子能谱(XPS)等分析测试手段对催化剂的NO催化氧化性能进行深入研究。结果表明,载体粒径、锰负载量、硝酸锰凝胶煅烧温度以及NO催化氧化温度对催化剂催化活性均有较大影响。当载体粒径在100~200目(150~75 μm)、锰负载量为8wt%、硝酸锰凝胶煅烧温度为500℃、NO催化氧化温度290℃时,NO催化氧化效果最好,氧化率达到77.8%。SEM结果显示,溶胶凝胶法制备的氧化锰粒子在100~200 nm,且相对均匀负载在载体上。N2-物理吸附表明,催化剂的孔结构主要为介孔,并呈现H3型回滞环。锰基催化剂上化学吸附氧Oβ的占比和Mn4+浓度随着锰负载量的增加先增大后减小,此趋势与NO催化性能变化趋势一致,表明Oβ和Mn4+是影响NO催化氧化效果的决定因素。     

溶解氧对生物滤柱中氨氮、铁、锰去除效果的影响

为了研究溶解氧变化对生物滤柱中氨氮、铁、锰去除效果的影响,将进水溶解氧从约10.5mg/L逐步降到7mg/L,本文考察了氨氮、铁、锰的变化规律。结果表明：当溶解氧为约10.5mg/L时,出水氨氮、总铁、锰分别为0.050mg/L、0.065mg/L、0.022mg/L,氨氮、铁、锰分别主要在滤层的0～1.2m、0～0.4m、0～1.2m去除。当溶解氧降到约9mg/L、8mg/L、7mg/L时,出水总铁均低于0.1mg/L;出水锰先明显升高,后又降到了0.05mg/L以下;出水氨氮分别升高到0.17mg/L、0.41mg/L、0.61mg/L。溶解氧不足时,铁主要在溶解氧充足的上部滤层去除;锰氧化菌优先利用溶解氧氧化二价锰,并且锰的氧化速率没有明显降低;氨氮的氧化速率明显降低。生物滤柱可以在较低溶解氧条件下运行,从而降低运行成本。     

青草沙水源地水质状况研究

青草沙水源地自投入运行以来,水质的质量,一直是人们迫切关心的问题。本文对上海市青草沙水源地地表水在2010年至2011年的水质状况进行了监测评价。选取了溶解氧、高锰酸盐指数、化学需氧量、五日生化需氧量、氨氮、挥发酚、石油类、总磷和总氮这九个地表水常用指标对青草沙水源地的地表水的水质状况进行了评价,研究结果表明,青草沙水源地在2010～2011年中有机综合污染指数和水质综合污染指数平均值分别为-0.2和0.8,能达到地表水Ⅱ类标准,总氮超过相应类别的标准,但其指标不直接影响到水体功能效应,水体功能没有受到明显损害,但在一定程度上受到总氮污染的制约。     

Kinetics of the selective catalytic reduction of nitric oxide with ammonia on a platinum catalyst

The selective catalytic reduction of nitric oxide with ammonia on an alumina-supported platinum catalyst has been studied by the method of differential reactor analysis. In the temperature region of 400–600 K and concentrations of 0–1000 ppm of ammonia and nitric oxide and 0–1% oxygen three reactions are important: oxidation of ammonia by oxygen to nitrogen, reduction of nitric oxide by ammonia to nitrogen and reduction of nitric oxide by ammonia and oxygen to nitrous oxide. The differential reactor data were fitted to several Langmuir—Hinshelwood models using a non-linear least squares fitting computer program. The fitted models were tested by simulation of integral reactor data. The best fits were obtained from a dual site Langmuir—Hinshelwood model involving associative adsorption of ammonia and nitric oxide on the same sites and associative adsorption of oxygen on different sites.     

Investigation of Ammonia Oxidation over Copper with In Situ NEXAFS in the Soft X-Ray Range: Influence of Pressure on the Catalyst Performance

The oxidation of ammonia over polycrystalline copper was investigated by means of in situ NEXAFS (near-edge X-ray absorption fine structure) spectroscopy in the soft X-ray range. The reaction, carried out in a 1:12 excess of oxygen, was observed by mass spectrometry. The simultaneous detection of the surface electronic structure and its catalytic performance allows correlation of different reaction products to the current surface structure of the catalyst. It is shown that a change in total pressure from 0.4 to 1.2 mbar severely affects the reaction path. Copper(I) nitride was identified as poison and a copper oxide was found to be the active phase for the selective oxidation of ammonia to nitrogen.     

掺杂元素的氧化锰基低温NH3选择性还原氮氧化物催化剂研究进展

氨气选择性催化还原技术（NH₃-SCR）是控制氮氧化物排放的有效方法,但由于传统的氧化钒催化剂起活温度偏高,存在运行成本高等不足。近年来,开发具有低温活性的高效脱硝体系成为选择性催化还原技术的研究热点。其中,氧化锰催化剂是目前研究较为广泛的低温NH₃-SCR催化剂。综述了近年来国内外关于不同掺杂元素对氧化锰基低温催化剂催化性能影响的研究进展,阐述了掺杂Ce、Fe和其他元素的锰基催化剂的低温NH₃-SCR反应性能、反应机理、抗硫抗湿性能及其工业化应用前景,展望了氧化锰基低温NH₃-SCR催化剂未来的发展方向。