BOD5荧光测定法与标准方法在地表水监测中的对比性研究

BOD₅检测是一种基于微生物的污染负荷评估,有文献证明微生物代谢物类色氨酸的荧光强度与BOD₅测量之间存在相关性. 对长江流域常州段地表水水样的荧光强度与BOD₅值之间的关系进行了探究,并通过考察浊度、pH、离子干扰和区域差异来评估荧光法应用于水质BOD₅污染评价中的潜力. 研究发现,地表水的pH和离子干扰对荧光法检测BOD₅并不构成明显影响. 区域差异对比结果t最大值为1.227,不构成显著性差异. 荧光法水样检测结果与标准方法相比,相关性系数r为0.909 9,具有明显相关性. 结果表明,荧光法应用于地表水BOD₅检测影响因素少、检测速度快、自动化程度高、结果稳定可靠,可以作为BOD₅检测的替代方法,成为表征水中可生物降解污染物污染程度的主要手段.

     

Dissolved oxygen removal from aqueous media by the chromatomembrane method

The possibilities of the new chromatomembrane method in the removal of oxygen dissolved in water are studied. The scheme of the water deoxygenation process is determined. The new reagent-free method allows production of water with oxygen content at the level of a few ppb.     

Actinide pollutants and the oxygen/water couple

The redox potential of environmental water influences the speciation of pollutants like plutonium. This potential cannot be reliably predicted from diagrams for irreversible couples like oxygen/water.Mound is operated for the U. S. Department of Energy by EG&G Mound Applied Technologies Incorporated under Contract No. DE-AC04-88DP43495.     

Adsorption of graphene for the removal of inorganic pollutants in water purification: a review

Graphene has aroused widespread attention as a new type of adsorbents due to its outstanding ability for the removal of various pollutants from aqueous solutions. This review summarizes the application of graphene-based nanomaterials as an advanced adsorbent for the removal of inorganic pollutants including anionic and cationic type. The adsorption properties, mechanisms, isotherms, kinetics, thermodynamics and regeneration of adsorbents are all summarized, and the further research trends on graphene-based nanomaterials in the removal of pollutants are also given.     

Use of high energy radiation in decomposition and removal of organic water pollutants

The present review deals with the radiation chemistry of dilute aqueous solutions of organic substances emphasizing the possibility of use of high energy radiation in wastewater treatment. Effects of radiation on biodegradability, toxicity to water organisms and changes in molecules of solutes showing resistance to biochemical degradation and toxicity to water organisms are discussed.     

功能化金属有机骨架材料去除饮用水污染物的研究进展

金属有机骨架(MOFs)材料是一类以过渡金属为中心、含杂原子的有机物为配体、通过配位作用形成的周期性网络多孔晶体材料。与其他的多孔材料相比,MOFs配体种类繁多,比表面积极大,孔径大小可调控且具有特殊(饱和或不饱和)的金属位点,在气体存储、催化、吸附与分离等领域有广阔的应用前景。近年来,功能化MOFs对污染物的富集和去除成为学者关注的热点。这是由于通过对MOFs进行功能化修饰,能够改变MOFs的孔径大小、表面带电性质等物化性质,从而实现对目标物更高效的吸附。该文综述了近年来功能化MOFs对饮用水污染物吸附的研究进展,包括饮用水污染物的类型及危害、功能化MOFs的制备方法以及去除饮用水污染物的应用,并对今后的发展前景进行了展望。     

Recent advances on dual-functional photocatalytic systems for combined removal of hazardous water pollutants and energy generation

Research on Chemical Intermediates - Photocatalytic wastewater treatment and concurrent energy production or metal ions conversion to less harmful products have great potential to address both...     

Magnetic mesoporous carbon for efficient removal of organic pollutants

Carbon materials such as activated carbons have been used in the field of water and wastewater treatments. However, the lack of mesopore and, particularly, the difficulty in recovering the spent carbon limited their applications. In this work, magnetic mesoporous carbon microspheres were synthesized by impregnating iron oxide precursors in the mesoporous carbon followed by the in situ conversion of the precursors into magnetite nanoparticles. The as-synthesized carbon microspheres with a high surface area of 742?m²/g and large mesopores of ～4.4?nm exhibited an excellent adsorption capacity for aqueous organic pollutants. The superparamagnetic microspheres with a saturation magnetization of 7.15 emu/g can be easily separated from the treated solution by external magnetic field.     

Dissolved oxygen in the bottom water of the Sea of Japan as a sensitive alarm for global climate change

The Sea of Japan, a semi-closed marginal sea (greatest depth ∼3700 m) in the northwestern-most Pacific Ocean, has an independent, deep convection system, which is driven by the formation and the sinking of cool, saline surface water towards the bottom in severe winters. Continuous measurement of dissolved oxygen using highly precise versions of the Winkler titration method has revealed 8-10% decreases in the bottom concentration of oxygen (O₂) over the past 30 years. The temporal decrease in O₂ means an imbalance between the supply of O₂ from the surface and the in situ consumption of O₂ in decomposing organic matter, suggesting that the change in the deep convection pattern of the Sea of Japan is probably caused by global climate change to reduce winter cooling of surface seawater.     

Dissolved oxygen: the electroanalytical chemists dilemma

Electroanalytical chemistry has been plagued for decades with the problems associated with dissolved oxygen. Dissolved oxygen is electrochemically reduced at potentials less negative than ?0.05 V vs. standard calomel electrode (SCE) and, therefore, interferes with detection of many species when using reductive voltammetry. Historically, electroanalytical chemists have taken the view that dissolved oxygen should be removed from the sample solution in order to overcome the interference problems. However, there are drawbacks associated with this approach, particularly when dealing with flowing solutions. More recently an alternative approach, the development of voltammetric methods which are not so prone to dissolved oxygen interference, has been taken by various workers.     

Ionic liquid–based adsorbents in indoor pollutants removal

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Dodecyl sulfate-hydrotalcite nanocomposites for trapping chlorinated organic pollutants in water

A series of hybrid organic-inorganic nanocomposite materials was synthesized by three different procedures using sodium dodecyl sulfate (DDS) and magnesium-aluminum layered double hydroxide (Mg/Al LDH with a Mg/Al molar ratio of 2 to 5). Both the pH of the exchange medium (6.5 to 10) and the Mg/Al molar ratio of the LDH affected the basal spacing, the content of DDS retained and the orientation of the DDS chains within the interlamellar space. For LDH with higher charge density (Mg/Al=2 and 3), DDS molecules likely formed a perpendicular monolayer within the LDH interlayer and the solution pH had little effect on the basal spacing, with a mean and standard deviation of 25.5+/-0.4 A. However, for LDH with lower charge density (Mg/Al=4 and 5), DDS molecules more likely formed an interpenetrating bilayer, and the basal spacing significantly increased with increasing pH, with a mean and standard deviation of 32.7+/-5.2 A. Sorption of trichloroethylene and tetrachloroethylene by DDS-LDH varied with synthesis conditions, LDH type and DDS configuration in the interlayer. DDS-Mg(3)Al-LDH had the highest affinity for both trichloroethylene and tetrachloroethylene in water, either comparable to or as much as four times higher than other clay-derived sorbents, followed by DDS-Mg(4)Al-LDH and DDS-Mg(5)Al-LDH. DDS-Mg(2)Al-LDH had the lowest sorption affinity although the highest amount of DDS. The pH of the exchange solution also affected the amount of DDS retained by the LDH as well as the sorption efficiency. Mg(3)Al-LDH has a charge equivalent area of 32.2 A(2)/charge, which allows the formation of optimal DDS configuration within its interlayer, thus resulting in the highest affinity for the chlorinated compounds. The DDS-Mg/Al-LDHs can be easily synthesized either ex situ or in situ at low temperature, indicating the feasibility of practical applications. The results obtained by controlling the synthesis procedure suggest that different arrangements of DDS molecules in the LDH interlayers can be obtained and optimized for the sorption of specific sorbates.     

Dissolved oxygen measurement with an improved amperometric cell

An improved amperometric cell for dissolved oxygen is described. The cathode material is directly deposited on the membrane in such a manner that the metal layer is sufficiently permeable for oxygen, but not porous. As there is no electrolyte layer between the cathode and the membrane, the signals are very stable. As the membrane is not subject to mechanical stresses, the diffusion pathlength, controlling the signal magnitude, is quite stable and so contributes to the overall stability of the response. This principle allows new constructions such as the flow-through cell.     

Application of near infrared spectroscopy for the determination of adsorbed p-nitrophenol on HDTMA organoclay--implications for the removal of organic pollutants from water

NIR spectroscopy has been used to measure the adsorption of p-nitrophenol on untreated montmorillonite and surfactant exchanged montmorillonite. p-Nitrophenol is characterised by an intense NIR band at 8890 cm(-1) which shifts to 8840 cm(-1) upon adsorption on organoclay. The band was not observed for p-nitrophenol adsorbed on untreated montmorillonite. Both the montmorillonite and the surfactant modified montmorillonite are characterised by NIR bands at 7061 and 6791 cm(-1). The organoclay is characterised by two prominent bands at 5871 and 5667 cm(-1) assigned to the fundamental overtones of the mid-IR bands at 2916 and 2850 cm(-1). A band at 6017 cm(-1) is attributed to the p-nitrophenol adsorbed on the organoclay. The band is not observed for the montmorillonite with adsorbed p-nitrophenol. It is concluded that p-nitrophenol is adsorbed to significantly greater amounts on the organoclay compared with the untreated montmorillonite. The implication is that organoclays are most useful for removing organic molecules from water through adsorption.     

Acrylation of pre-irradiated polypropylene and its application for removal of organic pollutants

Reactive extrusion of pre-irradiated polypropylene (PP) at different doses of gamma radiation was studied in the presence of different concentrations of acrylic acid monomer (AAc). Preliminary investigations study the feasibility or removal of organic pollutants. The optical properties and surface morphology of the grafted polypropylene were observed by FT–IR, UV/vis and scanning electron microscopy (SEM). The affinity of this membrane to the basic dye was found to be increased with increase in the dose of gamma irradiation and the ratio of acrylic acid monomer (AAc).     

Nanomaterials for electrochemical detection of pollutants in water: A review

The survival of living beings, including humanity, depends on a continuous supply of clean water. However, due to the development of industry, agriculture, and population growth, an increasing number of wastewaters is discarded, and the negative effects of such actions are clear. The first step in solving this situation is the collection and monitoring of pollutants in water bodies to subsequently facilitate their treatment. Nonetheless, traditional sensing techniques are typically laboratory-based, leading to potential diminishment in analysis quality. In this paper, the most recent developments in micro- and nano-electrochemical devices for pollutant detection in wastewater are reviewed. The devices reviewed are based on a variety of electrodes and the sensing of three different categories of pollutants: nutrients and phenolic compounds, heavy metals, and organic matter. From these electrodes, Cu, Co, and Bi showed promise as versatile materials to detect a grand variety of contaminants. Also, the most commonly used material is glassy carbon, present in the detection of all reviewed analytes.