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121.
Cost-effective separation of oil and immiscible organic contaminants from water has become an urgent challenge to protect aquatic and human life from devastating effects. Therefore, it has become imperative to develop super-selective materials for efficiently separating oil from water. In this work, a superhydrophobic surface has been formed that consists of a silane@polystyrene-coated polypropylene fibrous network (silane@PS-PPF) for efficient separation of accidentally spilled oil from water. The superhydrophobic PPFs were designed by a simple, cost-effective two-step process that includes photochemically controlled polymerization of styrene and subsequent dip coating in octadecyltrichlorosilane solution. The hydrophobic surface (CA=129°±4°) of the PS coated PPF after treating with silane was turned into a superhydrophobic body (CA=161°±2°). The achieved silane@PS-PPF fibrous network selectively allowed the fast permeation of the oils and non-polar organic liquids by altogether rejecting water during operation. The separation efficiency for various oils from the contaminated water was 96 to 99%, with a high flux in the range of 7606±312 L m−2h−1 to 9870±151 L m−2h−1. Apart from being used as a filter, the silane@PS-PPF was also used as an oil absorber and has shown an absorption capacity in the range of 1185 to 1535% for various oils. We anticipate that the developed silane@PS-PPF, due to its facile synthetic route, cost-effectiveness, and high performance, can be effectively used in oily wastewater treatment and clean-up of large oil spills from water. 相似文献
122.
Allen W. Burton Stacey I. Zones Saleh Elomari 《Current Opinion in Colloid & Interface Science》2005,10(5-6):211-219
In this review we discuss the roles that inorganic and organic components play in the synthesis of high-silica zeolites. We discuss the effects that heteroatom identity, heteroatom substitution, and SDA shape have on synthesis products. Then we summarize recent developments in zeolite synthesis that have been made by performing syntheses in concentrated fluoride media and by using germanium as a tetravalent heteroatom. Finally, we examine the combined roles that framework stability, framework/SDA interactions, and silanol defects may have in determining phase selectivity. 相似文献
123.
124.
Speckle noise arises in imaging systems that use coherent or partially coherent illumination. We demonstrate that such noise may be reduced by use of bayesian filters. The usual assumption that speckle noise is approximately equivalent to multiplicative image noise is replaced with an exact analysis. 相似文献
125.
P.R. Elliston F. Habbal N. Saleh G.E. Watson K.W. Blazey H. Rohrer 《Journal of Physics and Chemistry of Solids》1975,36(9):877-881
Magnetic and optical measurements in the layer compound NaCrO2 are reported. This compound is antiferromagnetic with Tn = 46±2 K and θ = ?400±30 K. Broad antiferromagnetic resonances are observed which cannot be interpreted on any simple model. Optical absorption data are consistent with the appearance of antiferromagnetism. Non-intrinsic fluorescence has also been observed. 相似文献
126.
127.
The role played by optical interference in determining the propagation of pulses in multimode fibers is examined under conditions of mode independence and mode coupling. Single pulses and pulse-pairs generated by a source that has arbitrary temporal and spatial coherence are considered, and the role played by the spatial integration at the detector, which effectively is a form of spatial incoherence, is investigated. It is shown that three forms of optical interference may result under different conditions of source spatiotemporal coherence—intramodal, intermodal, and interpulse interference. These effects change the profile of received pulses in a, in general, nonlinear way. 相似文献
128.
R.M. Saleh J.M. Abd El Kader A.A. El Hosary A.M. Shams El Din 《Journal of Electroanalytical Chemistry》1975,62(1):297-310
The dissolution of Cu in solutions of HNO3 of different concentrations has been studied by the thermometric method. Starting from the initial temperature, Ti, the temperature—time curves exhibit an induction period followed by a rapid rise in temperature to a maximum value, Tm, attained t min after the start of the reaction. Tm increases and t decreases with increase of the acid concentration, M. ΔT (i.e.Tm ? Ti) and the reaction number (R.N. = (Tm ? Ti)/t) vary with M according to: ΔT = k(M ? M0) and R.N. = A1Mn, where k, M0, A1 and n are constants.The effect of varying concentrations of HCl, H2SO4 and H3PO4 on the R.N. of Cu in 3.5 M HNO3 was examined. Small amounts of these acids lower the R.N. (inhibition) due to the displacement of an active species on the surface of the metal by the anion of the acid. Larger additions of the acids accelerate dissolution. The concentration at which the added acid changes from corrosion-inhibitor to accelerator varies as HCl < H2SO4 < H3PO4. This sequence is considered to parallel the strength of adsorption of the respective anions. The results of experiments with salt additions confirm this view; all salts act only as dissolution-retardants. Calculations pertaining to the effect of the various ions on the R.N. support the conclusion that the dissolution of Cu in HNO3 is autocatalytic in nature, and depends on the [H+]/[NO3?] ratio.Cu does not dissolve in air-free, cold HCl. Attack takes place, however, in the presence of KNO3. Under these conditions attack is of the pitting- rather than the general type. The temperature rises suddenly after an incubation period, which decreases in length with increase of the amount of the added salt.Proof of the involvement of HNO2 in the autocatalytic cycle of Cu dissolution in HNO3 is obtained from the results of urea additions to the solution. 相似文献
129.
An electrochemical detector cell having a dropping-mercury working electrode and an Ag/ AgCl reference electrode is examined with reference to applications in flow-injection analysis and high-performance liquid chromatography. The working electrode, fed by a horizontal capillary, is capable of delivering mercury at fast dropping rates which can be varied by a control device in the cell. Examples of application to inorganic and organic electroreducible species are considered and advantages and limitations relative to other electrochemical detector devices are discussed. 相似文献
130.
Some nitrogen screening constants and their anisotropies are calculated within the CNDO/S level of approximation. Satisfactory agreement is found with available experimental data in most cases. In general the reported results are in closer agreement with experiment than are those found from ab initio calculations. The calculated data for the isoelectronic molecules N2O and CH2N2 would be in better agreement with experiment if the assignments of the two nitrogen nuclei were reversed in both cases. A reasonable correlation is obtained with some observed nitrogen chemical shifts. Contributions arising from electronic transitions are reported for N2, HCN, CH3CN, CH3NC, NO2+ and NO2?. 相似文献