A Water-Stable Lanthanide Coordination Polymer as Multicenter Platform for Ratiometric Luminescent Sensing Antibiotics

As a hot topic of global concern, the distinguishing and detecting of antibiotic pollution is crucial owing to its adverse effect on ecosystems and human health stemming from excessive use and poor management. Herein, a water-stable lanthanide coordination polymer sensor (Dy-TCPB) with multiple emitting centers is prepared. The versatile Dy-TCPB can conveniently differentiate various antibiotics, and displays a self-calibration luminescent response to nitrofurazone (NFZ) and furazolidone (FZD). Each antibiotic exhibits notable correlation to a unique combination of the two ligand-to-Dy ion emission intensity ratios, enabling two-dimensional fingerprint recognition. Furthermore, the novel self-calibration sensor demonstrates effective recognition of NFZ and FZD with excellent sensitivity and selectivity, and detection limits as low as 0.0476 and 0.0482 μm for NFZ and FZD, respectively. The synthetic approach for the fabrication of a singular coordination polymer exhibiting multiple emissions provides a promising strategy for the development of facile and effective ratiometric sensors.     

High efficiency of Mn–Ce‐modified TiO2 catalysts for the low‐temperature oxidation of Hg0 under a reducing atmosphere

Manganese‐ and cerium oxide‐modified titania catalysts were prepared by the deposition precipitation for the removal of elemental mercury (Hg⁰) from simulated yellow phosphorus off‐gas at low temperature. In addition, these catalysts were characterized by X‐ray diffraction, Brunauer–Emmett–Teller measurements, X‐ray photoelectron spectroscopy and field‐emission scanning electron microscope to determine the surface morphology of the obtained compounds and explore their formation mechanism. The results revealed that a Mn–Ce loading and reaction temperature of 10% and 150 °C, respectively, as well as a Mn/Ce molar ratio of 2:1, led to an optimal efficiency for the oxidation of elemental mercury. Furthermore, the effects of flue gas components were investigated. The presence of O₂ clearly promoted the oxidation of Hg⁰. A CO atmosphere did not affect the Hg⁰ oxidation, when compared with N₂, whereas the presence of H₂S and water vapor inhibited the oxidation process. Furthermore, the X‐ray photoelectron spectroscopy spectra of Hg 4f revealed that the elemental mercury adsorbed by the catalyst is present as HgO. Finally, the Hg⁰ catalytic oxidation mechanism was discussed on the basis of the experimental results and characterization analysis.     

Influence Du Rapport Atomique Ca/P Initial Sur La Synthèse Sous Atmosphère Humide D’apatite

Abstract

Le comportement sous atmosphère humide des mélanges initiaux de la calcite et du di-ammonium hydrogénophosphate à différents rapport atomique (Ca/P)_initiala été étudié. L’analyse par diffraction des rayons X (DRX) montre que les produits obtenus ont tous une structure apatitique. Il montre la présence à côté de celle de l’apatite, des raies identifiables à la calcite pour des rapports atomiques initiaux supérieurs à 1.50. Par ailleurs, la spectroscopie d’absorption infrarouge (IR) révèle dans les différents cas, la présence autre que les bandes attribuables aux ions PO₄ ^3?dans une apatite, des bandes à 875 cm^?1caractéristique des groupements HPO₄ ^2?dans une apatite déficiente en ion calcium. De même, le traitement thermique à 1000°C des poudres synthétisés a mis en évidence que les apatites formées sont non st?chiométriques. Les analyses chimiques montrent, par ailleurs, que lorsque le rapport atomique Ca/P du mélange initial est inférieur à 1.50, l’apatite formée a un rapport atomique Ca/P égal à 1.58. Par contre, lorsque le rapport Ca/P initial est supérieur à 1.50, le produit formé est biphasique et a un rapport atomique Ca/P de 1.62. Ce rapport est dû essentiellement à la présence d’un excès de CaCO₃dans le mélange initial (DRX, IR).

Mots clés Apatite; atmosphère humide; calcite; hydrothermal; synthèse

Abstract The behavior, in a humid atmosphere, of the initial mixtures of calcite and diammonium hydrogenophosphate at different atomic ratio (Ca/P) was studied. The X-ray diffraction (XRD) analysis shows that all the products obtained have apatite structure. For initial atomic ratios greater than 1.50, the XRD analysis shows the presence of reflections different from those of apatite, which may be attributed to calcite. Analysis by infrared (IR) absorption spectroscopy allows to distinguish between the two cases: in addition to the presence of bands due to the PO₄ ^3?ions in apatite further bands at 875 cm^?1characteristic of HPO₄ ^2?in apatite deficient with respect to calcium ions are observed. Similarly, the powders synthesized by heat treatment at 1000°C showed that nonstoichiometric apatites are formed. Chemical analyses show, that when the atomic ratio Ca/P of the initial mixture is less than 1.50, the apatite formed has an atomic Ca/P ratio of 1.58. When the initial Ca/P ratio is greater than 1.50, the product formed is biphasic and has an atomic ratio Ca/P of 1.62. This result is mainly due to the presence of an excess of CaCO₃in the original mixture (XRD, IR).     

Unveiling the importance of reactant mass transfer in environmental catalysis: Taking catalytic chlorobenzene oxidation as an example

To date, investigations onto the regulation of reactants mass transfer has been paid much less attention in environmental catalysis. Herein, we demonstrated that by rationally designing the adsorption sites of multi-reactants, the pollutant destruction efficiency, product selectivity, reaction stability and secondary pollution have been all affected in the catalytic chlorobenzene oxidation (CBCO). Experimental results revealed that the co-adsorption of chlorobenzene (CB) and gaseous O₂ at the oxygen vacancies of CeO₂ led to remarkably high CO₂ generation, owning to their short mass transfer distance on the catalyst surface, while their separated adsorptions at Brönsted HZSM-5 and CeO₂ vacancies resulted in a much lower CO₂ generation, and produced significant polychlorinated byproducts in the off-gas. However, this separated adsorption model yielded superior long-term stability for the CeO₂/HZSM-5 catalyst, owning to the protection of CeO₂ oxygen vacancies from Cl poisoning by the preferential adsorption of CB on the Brönsted acidic sites. This work unveils that design of environmental catalysts needs to consider both of the catalyst intrinsic property and reactant mass transfer; investigations of the latter could pave a new way for the development of highly efficient catalysts towards environmental pollution control.     

Zur hydrogeologischen Interpretation von Isotopendaten im Zusammenhang mit Stofftransportprozessen

The migration of radionuclides and other tracers in porous layers is determined by substance transport. The physical and hydraulic basis of retardation is investigated. A definition of a factor of retardation is given, describing the ratio between the pore velocity of the water and the velocity of tracer migration. Consequences to the groundwater protection are discussed.     

Analysis and Fate of Dibenzothiophene Derivatives in the Marine Environment

Abstract

Dibenzothiophene (DBT) and related methylated derivatives are known to be among the most persistent and probably the most toxic PAH in the marine environment. Their analysis and their fate by photo-oxidation and biodegradation were studied.

The methylated DBT isomers, provided that they are resolved by high resolution GC, were used as organic markers of oil pollution in oysters. The determination of the relative distribution of the four monomethyl DBT allowed to characterize the source of pollution in an oyster-area in the North Brittany (France).

The fate of methylated DBT compounds was studied in a controlled sea-water enclosure where Arabian light oil was spilled. Analysis of the weathered oil showed that: (i) oil was degraded by photo-oxidation at a rate of 0.004% day; (ii) the half-lives of photolysis of methylated DBT was dependent upon the number of methyl groups on the aromatic nucleus: 8 days for DBT, 20 days for methyl-1 DBT and more than 2 years for trimethylated DBT. Compounds solubilized in the water column were identified as methyl-substituted dibenzothiophene sulfoxides and sulfones by HPLC with synchrofluorescence and GC-flame photometric detection.

The metabolic pathway of DBT was established in vitro. Rat microsomes transformed this substrate to DBT-5-oxide and subsequently to DBT-5-dioxide. Such an enzymatic S-oxidation was shown to be principally Cytochrome-P-450 dependent. It is suggested that the mixed-function oxidase (MFO) activity of marine species could be evaluated by this S-oxidation test in addition to the usual aryl hydrocarbon hydroxylase.     

Polybrominated diphenyl ethers (PBDEs) in marine sediment of Thermaikos Gulf,Greece

Polybrominated diphenyl ether (PBDE) concentrations were determined in marine sediment samples collected from 7 different locations around Thermaikos Gulf in north Greece. PBDEs were detected in all sampling sites and their average total concentration (ΣPBDEs) ranged from 0.26 to 4.92?ng?g^?1?d.w. Concentrations were an order of magnitude higher in locations outlining the inner part of the Gulf, which were also closer to industrial areas, sewage treatment plant discharges, the city's harbour and landfill area. These findings suggest pollution in the aquatic ecosystem from industrial and urban activities in the area. Congener profiles exhibit predominance of BDE-209, while concentrations of other PBDE congeners were usually lower, when compared to similar studies from other countries globally, indicating that Thermaikos Gulf is among the low-polluted areas. Statistical analysis showed significant differences among the higher polluted sampling stations. Statistically significant differences also existed between sampling stations with high and low PBDE concentrations. Correlations between congeners suggested local contamination sources; however, specific point sources of pollution were not established.     

Styrene-PEG (600) DMA Crosslinked Polymers for Absorption of Oil Derivatives

In this work, styrene (St) based crosslinked polymers were prepared for removal of oil derivatives from aqueous solutions. Polyethylene glycol (600) dimethacrylate (PEG (600) DMA) was used as crosslinker in synthesis of styrene based crosslinked polymers, for the first time. The polymers were characterized by FTIR, SEM, elemental analysis and solvent (toluene, chloroform and fuel-oil) absorption capacities. The effects of different reaction parameters like crosslinker type, diluents amount and the presence of pore forming agent on the absorption properties of polymers were investigated. The polymers synthesized by using PEG (600) DMA have higher solvent absorption capacity than that of synthesized by using conventional crosslinker. Furthermore, the polymers synthesized in the presence of good diluents have higher absorption capacities. The addition of pore forming agent into the reaction medium has also improved the absorption rate of polymers. The absorption capacity of polymers in different solvents is in order of chloroform > toluene > fuel-oil. It was seen that oil derivatives can be removed efficiently from water by the St-PEG (600) DMA polymers.     

重金属铊在环境介质中的分布及其迁移行为

铊是剧毒重金属元素,它在自然界中是典型的稀有分散金属。环境介质中铊的自然本底值较低,但随着铊矿床的开发和铊资源的广泛应用,岩矿石中的铊在自然力或人为作用下向环境介质中迁移。综述了铊在岩（矿）石、土壤、水体、动植物和人体中的分布,以及在上述环境介质及大气中的迁移行为。研究表明,人类活动是导致环境介质中铊含量增加的主要原因。铊在环境介质中的迁移是反复循环的复杂过程,通过风化、溶解、淋滤、吸收、沉降、固结等方式在环境介质中循环往复,从而危害环境生态和人体健康。铊污染应引起人们的普遍重视。     

光伏太阳能电池生产过程中的污染问题

日益壮大的光伏产业正在为人类发展作出积极的贡献.采用光伏发电来代替传统的发电技术,将会减少89%的空气污染.然而,在这个倡导绿色环境的时代,光伏器件生产引起的环境、健康和安全（EHS）问题也日益引起社会各界的广泛关注.认清光伏产品在生产过程中污染的真相对维持光伏产业的可持续发展有着相当重要的意义.本文综述了常见太阳能电池的EHS问题,并提出了可以减少污染的有效途径;采用生命周期评估（LCA）方法进一步比较了各种太阳能电池生产过程中污染物的排放量数据.