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For the first time catalytic systems based on HZSM-5 zeolites (Si/Al=12, 25, 40) with nanosized anatase (NA) were obtained in situ by a modified hydrothermal method and a sol-gel method. Initial HZSM-5 and NA/HZSM-5 were characterized (XRPD, XAS, FT-IR, DSC, BET, XPS, SEM, TPD) and analyzed in the reactions of propane (liquefied petroleum gas) conversion (РС; temperature range 200–870 °С) with the formation of the main products propylene (C3H6, PP) and ethylene (C2H4, ETH) and liquid ethanol conversion (EC; temperature range 150–360 °C) with the formation of diethyl ether ((C2H5)2O, DEE) and ETH. In the PC reaction the maximum selectivity (SETH = 75%) and conversion (αP = 65%) were obtained on HZSM-5(40) (650 °С). With an increase in the NA content in NA/HZSM-5 SETH value increases up to 85%. In the EC reaction SDEE/ETH~98–99% was reached on HZSM-5(25) (200 °C) and HZSM-5(40) (300 °C); the αE to ETH is comparable (94%) for all HZSM-5 (300 °C). Modification of HZSM-5 with NA leads to a shift in the EC reaction temperature to lower temperature region (αE to ETH ~98% at 280 °C) with SDEE/ETH~94–100% for NA/HZSM-5(25) and NA/HZSM-5(12) obtained by a modified hydrothermal method. It was established the relationship between HZSM-5 and NA/HZSM-5 catalytic activity and their characteristics: Si/Al, NA content and Ti coordination number (NA/HZSM-5), the content of "zeolite water" with OH groups, specific surface area, meso- and micropores volume and spherical particles size (HZSM-5), surface energy of adsorption centers (HZSM-5 and NA/HZSM-5), and hence the content of acid sites, the strength of which is also determined by the temperature of the catalytic reaction. The reaction mechanisms have been presented. The obtained NA/HZSM-5 catalysts have a higher or comparable catalytic activity to commercial ones, but low cost, ease of preparation, and versatility.

Anatase–mordenite nanocomposite was synthesized in situ and characterized by X-ray diffraction analysis, Brunauer–Emmett–Teller measurements, infrared (IR) spectroscopy, electron diffraction measurements, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and scanning and transmission electron microscopy. It was found that X-ray-amorphous anatase located in the zeolite micropores resulted in a decrease in the specific surface of anatase–mordenite compared to the initial mordenite. Anatase-containing nanoparticles in anatase–mordenite showed round shape and formed nano-associates and conglomerates. The water content in the zeolite cavities in anatase–mordenite was lower compared to mordenite. Anatase–mordenite nanocomposite exhibited higher photocatalytic activity in the model decomposition reaction of methyl orange under ultraviolet (UV) radiation and higher adsorption capacity for extraction of P(V) and As(V) ions from aqueous environment in the dark compared to the initial mordenite or anatase due to an increase in the content of active OH-groups on the nanocomposite surface compared to mordenite and an increase in the specific surface compared to anatase.

Titanium oxide(IV)/zeolite nanocomposites obtained through the introduction of Beta(25), ZSM-5(12), MOR(5), and Y(2) zeolites into the reaction mixture, during the hydrolysis of titanyl sulphate, exhibit greater photocatalytic activity in the photodegradation reactions of methyl orange under ultraviolet radiation and a higher adsorption capacity to extract P(V) and As(V) from model aqueous environments compared to zeolites and nanoscale anatase prepared in the same way. The increase in the functional properties of nanocomposites is due to a higher amount of OH groups (photocatalytic activity and adsorption capacity) and lower amount of H2O (photocatalytic activity) on their surface, which is revealed with X-ray photoelectron spectroscopy. Moreover, spherical shape of particles with smaller average sizes than those of zeolites, which are characterized by a more diverse morphology, increases the photocatalytic activity and adsorption capacity of the nanocomposites.

Environmental management accounting is a mechanism for determining and evaluating, and incorporating these cost and benefit in the day-to-day business decision making, the full spectrum of environmental costs of current production processes and the economic benefits of contamination prevention, or cleaner processes. In practice, the past 10 years have acquired significance from corporate accounting, which is the most prominent part of cost accounting. Limits were widely acknowledged of conventional financial and cost accounting techniques reflecting companies’ sustainability efforts and providing management with necessary information for sustainable business choices. Information on companies’ environmental performance may be somewhat accessible, but both domestic decision makers and those at the level of public authorities are seldom able to connect environmental information with economic variables and are essentially deprived of environmental cost information. Decision makers do thus not recognize the economic worth of natural resources as asset and the commercial and financial benefit of excellent environmental performance. Beyond ‘goodwill’ efforts, there are a number of market-based incentives for integration with decision making of environmental issues. This article provides an outline of environmental management methods and we evaluate environmental costs in terms of current economic crisis.

Zeolite Y and the NTD/Y nanocomposite, which were synthesized in situ (the addition of zeolite Y to the reaction mixture in the course of the synthesis of NTD by the sulfate method), were studied by a variety of methods. The decrease in the particle size (scanning electron microscopy) and the water content in pores (X-ray powder diffraction study, the full-profile Rietveld method, IR spectroscopy, differential scanning calorimetry), the increase in OH groups content and the decrease in the water content on the surface of zeolite (X-ray photoelectron spectroscopy) in the composition of NTD/Y compared to the initial zeolite Y were all established. A larger specific surface area of NTD/Y (Brunauer–Emmet–Teller method) compared to the initial zeolite Y is due to the fact that zeolite Y in the nanocomposite contains a smaller amount of water because of the synthesis conditions and the presence of nanocrystalline NTD on the surface of zeolite particles. It was found that NTD/Y nanocomposite exhibits a higher photocatalytic activity in the model decomposition reaction of methyl orange under UV and adsorption capacity for the extraction of P(V) and As(V) ions from aqueous media compared to the initial zeolite and pure NTD obtained under the same conditions, which differs from NTD/Y by the larger particle size, the smaller specific surface and the smaller content of OH groups and water on the surface. The role of Bronsted and Lewis centers in the realization of properties is discussed.

HZSM-5 (MFI type) of composition (Hx)[Al3+xSi12−xO24] × wH2O and nanocomposites NA/HZSM-5, NA:M/HZSM-5 (NA—nanoscale anatase; M = V, Ni, Ag) with Si/Al = 12, 25, 40, 300 (sp.gr. Pnma or P21/n; z = 8), as well as zeolites [(Ti4+xSi12−xO24] × wH2O (TS) with Si/Ti = 47, 53, 73.5 (sp.gr. Pnma) were studied by XRPD, XAS, FTIR-spectroscopy, BET, XPS, SEM, EDX, TPD, UV–VIS-spectroscopy, UV–DRS, and chemiluminescence methods. The results obtained together with photocatalytic, adsorption, antimicrobial, catalytic properties were analyzed using crystallochemical concepts and literature data. It was shown that NA or NA:M introduction into HZSM-5 leads, respectively, to the photodegradation of MeO dye in the UV region or difenoconazole in the visible range, and contributes to the appearance in the dark of adsorption (almost complete extraction of P(V), As(V), and Se(V) from aquatic environment) and bacteriostatic properties in respect to Staphylococcus epidermidis, Bacillus antracoides, and Escherichia coli for NA:Ag/HZSM-5(40, 300). The presence of titanium ions in NA nanoparticles on the HZSM-5 surface improves the catalytic activity in ethanol and propane (the best performance for NA/HZSM-5(25) and NA/HZSM-5(40), respectively) conversion. Determination of the composition (surface and bulk) and structure (statistical and local) of TS zeolites together with the found correlations made it possible to propose new catalysts in the reactions of propane, ethanol, and allyl chloride conversion.

This article presents the results of a study of three commercial titanosilicalites (TS-1, TS-1N, TS-1G) with general formula [(TixSi12-x)O24] × wH2O (MFI-type) using the X-ray study (XRPD), IR spectroscopy (FT-IR), X-ray absorption spectroscopy (EXAFS/XANES), differential scanning calorimetry (DSC), Brunauer–Emmett–Teller method (BET), UV-VIS spectroscopy. It was established that the samples contain amorphous oxygenous titanium-containing formations, which does not allow the use of quantitative elemental methods of analysis to determine the content of titanium ions in the framework. The full-profile Rietveld method was used to determine the silicate modules (Si/Ti = 53 for TS-1, Si/Ti~47 for TS-1N and TS-1G) and the coordination numbers of titanium: CNTi~5.0, CNTi = 4.5, CNTi>5.0, respectively in the structures of TS-1, TS-1N, TS-1G. The distribution of Ti4+ ions over the sites of the MFI-type structure with the orthorhombic symmetry (space group Pnma, z = 8) were found: T2, T6, T10 for TS-1, T8, T10, T5 (unlikely) for TS-1N (Т10 double positions in sinusoidal channels) and Т2, Т10, Т12, Т9 (unlikely) for TS-1G (Т10 and Т12 double positions in sinusoidal channels). The best indicators of the allyl chloride epoxidation in the epichlorohydrin process at 30 °C were achieved for TS-1N and TS-1G. A higher yield of acetaldehyde was found on the TS-1(75) sample (TS-1 sample annealed at 75 °C for 2 h) at 290 °C (non-oxidative ethanol conversion), and ethylene - on the TS-1G(500) sample (TS-1G annealed at 500 °C for 2 h) at 700 °C (propane conversion). The revealed correlations between the catalytic parameters and the characteristics of the samples studied were discussed.

NT/zeolite nanocomposites (NT - nanosized titanium(IV) oxides: η-phase and Hombifine N with anatase; zeolite: Beta(25), ZSM-5 with different modules Si/Al, MOR, or Y) have been obtained by two methods: modified cold-impregnation method (method 1) and in situ method of introduction of zeolites into the reaction mixture during the synthesis of NT by hydrolysis of TiOSO 4 ×xH 2 SO 4 ×yH 2 O or TiOSO 4 ×2H 2 O aqueous solutions (method 2), performed for the first time. According to the X-ray data, the following differences in the NT:zeolite systems under investigation have been revealed: the mixture of zeolites and NT in nanocrystalline (Hombifine N/zeolite) or amorphous states (η-phase/zeolite, except for η-phase/MOR, where NT peaks are absent) (method 1), and the mixture of Y-zeolite and amorphous NT or only Y-zeolite without NT (method 2), which indicates the different levels of interaction between NT and zeolites in the systems studied. The best characteristics of properties (photocatalytic, adsorption, and antibacterial) have been revealed in the nanocomposites synthesized by the method 2. The correlation between the photoreaction rate constant (the k value) under UV irradiation in the presence of nanocomposites ( k max for NT/ZSM-5(12)) and the type of precursor, its pH, synthesis duration, NT:zeolite ratio, organic dye composition (methyl orange or Rhodamine G) has been established. The highest degree of extraction of P(V) ions from model aqueous systems has been observed in the presence of nanocomposites with the largest total surface area of all particles ( R max = 99.48% for NT/MOR). The correlation between the sorption degree of P(V) ions and the modulus of zeolite is possible. Antibacterial activity in the dark towards Escherichia coli has been found for Y and Beta(25) zeolites and nanocomposites on their basis (methods 1 and 2) with the maximum diameter of bacterial growth inhibition (18 mm) obtained for NT/Beta(25) (method 2) synthesized only from TiOSO 4 ×xH 2 SO 4 ×yH 2 O precursor.

Nanocomposites TiO2/SiO2 with photocatalytic and adsorptive properties were prepared by codispersing of η-modification and anatase (commercial Hombifine N) and SiO2 (opal, granules, ultrafine) in ethanol (or ethanol–water mixture in the presence of chlorophylls or porphyrins) with ultrasonic treatments of the mixture (method 1) and an aqueous solution of KOH with a microwave treatment (method 2), as well as the introduction of SiO2 in the reaction mixture during the synthesis of TiO2 by brief hydrolysis of sulfate titanyl (method 3). It was found that the state of titania in the sample (X-ray amorphous or nanocrystalline) and its deposition on SiO2 nanocomposites depend on the method and the conditions of obtaining. It was established that the photocatalytic activity of nanocomposite TiO2/SiO2 (granules) (method 1) photosensitized by coproporphyrin I in the visible range and the photocatalytic activity of nanocomposite TiO2/SiO2 (opal) (method 3) in the near UV range exceed activity of the commercial sample of TiSiO4 by more than 20-fold and ~7-fold, respectively. It was shown that the nanocomposite TiO2/SiO2 (opal) significantly reduces the concentration of cations (in particular, Be, Ni, Bi) in the model water systems.

It is detected experimentally for the first time that the connection of 2D electron systems with different electrochemical potentials results in long-range (τ 50 μm) electron density disturbances. When a gated region of a Corbino sample is strongly depleted, the amplitude of the magnetoresistance oscillations caused by high density ungated regions is found to increase in direct proportion to the sample resistance, which is dominated by low-density regions with small conductivity. Experiments on samples with an artificial potential profile (antidots and etched rings) below the gate show that the observed effects are not due to contact effects.

The metal-insulator transition in a 2D electron gas of Si MOSFETs has been investigated. In the extreme quantum limit, the phase boundary in the H, Ns plane has been found to be a straight line with the slope νc = 0.53 ± 0.01. Transport properties of the insulating phase have proven to be unexpectedly similar to those of the insulating phase in GaAs/AlGaAs heterostructures where magnetically induced Wigner solid formation has been reported. Strongly nonlinear current-voltage characteristics with linear V(I) dependence below some threshold voltage, Vc, and saturation at V >Vc were observed. The longitudinal resistance corresponding to the linear part of the I–V characteristics demonstrates an activated temperature dependence. Knowing the values of the threshold voltage and activation energy we obtain a characteristic length that is large compared to the distance between electrons, which excludes a single-electron picture of nonlinearity. The similarity of transport properties strongly suggests the same physical nature of the insulating phases in Si inversion layers and GaAs/AlGaAs heterostructures. However, the value of νc is somewhat surprising since, in the presence of a long-range potential, the percolation metal-insulator transition is expected at precisely this filling factor. The percolation transition is considered as an alternative explanation of the observed effects.

We report magnetotransport data of an insulating phase in silicon inversion layers in the extreme quantum limit at a Landau-level filling factor of ν≤1/2. The transport properties have proved to be unexpectedly similar to those of the insulating phase in GaAs/Al x Ga 1-x As heterostructures around ν=1/5 (for electron gas) and ν=1/3 (for hole gas) where magnetically induced Wigner solid formation has been reported. Strongly nonlinear current-voltage characteristics display threshold behavior and tend to saturate as current increases

We have investigated the charge transfer due to the change of magnetic flux in samples with a circular gate which allowed us to create an inhomogeneous electron density distribution. It has been shown that at a negative gate voltage, when the filling factors in gated and ungated regions of a sample are close to integers, nonequilibrium accumulation of charge can take place in the gated region. This gives rise to charge transfer through the sample corresponding to Hall conductivity of the ungated region with the larger number of occupied Landau levels

A Comment on the Letter by I. Glozman, C. E-Johnson, H. W. Jiang Phys. Rev. Lett. 74, 594 (1995). The authors of the Letter offer a Reply.

We investigate the transport properties of insulating phases in the 2D electron system of high-mobility AlGaAs/GaAs heterostructures of Corbino geometry at very low temperatures. We find that the nonlinear current-voltage characteristics for insulating phases in the integer and fractional quantum Hall regime and for a low-density insulating phase are very similar. The behavior of these characteristics with changing temperature and filling factor unambiguously points to the percolation metal-insulator transition as the cause for all insulating phases investigated. We propose a metal-insulator phase diagram in the ($B,{N}_{s}$) plane based on our experimental data.

We have studied the zero magnetic field resistivity of unique high- mobility two-dimensional electron system in silicon. At very low electron density (but higher than some sample-dependent critical value, $n_{cr}\sim 10^{11}$ cm$^{-2}$), CONVENTIONAL WEAK LOCALIZATION IS OVERPOWERED BY A SHARP DROP OF RESISTIVITY BY AN ORDER OF MAGNITUDE with decreasing temperature below 1--2 K. No further evidence for electron localization is seen down to at least 20 mK. For $n_s, Comment: 10 pages; REVTeX v3.0; 3 POSTSCRIPT figures available upon request; to be published in PRB, Rapid Commun