The applicability of ion-exchange membranes (IEMs) in chemical synthesis was discussed based on the existing literature. At first, a brief description of properties and structures of commercially available ion-exchange membranes was provided. Then, the IEM-based synthesis methods reported in the literature were summarized, and areas of their application were discussed. The methods in question, namely: membrane electrolysis, electro-electrodialysis, electrodialysis metathesis, ion-substitution electrodialysis and electrodialysis with bipolar membrane, were found to be applicable for a number of organic and inorganic syntheses and acid/base production or recovery processes, which can be conducted in aqueous and non-aqueous solvents. The number and the quality of the scientific reports found indicate a great potential for IEMs in chemical synthesis.
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To design innovative and novel optical materials with high mobility, two kinds of disubstituted derivatives for mer -tris(4-hydroxy-1,5-naphthyridinato) aluminum ( mer -AlND3) with push (EDG)–pull (EWG) substituents have been designed. The structures of mer -tris(8-EDG-2-EWG-4-hydroxy-1,5-naphthyridinato) aluminum (type I) and mer -tris(8-EWG-2-EDG-4-hydroxy-1,5-naphthyridinato) aluminum (type II) in the ground and first excited states have been optimized at the B3LYP/6-31G(D) and CIS/6-31G(D) level of theory, respectively. It can be seen from frontier molecular orbitals analysis, in all these complexes, the highest occupied molecular orbital (HOMO) is localized on the pyridine-4-ol ring of A-ligand while lowest unoccupied molecular orbital (LUMO) is on the pyridyl ring of B-ligand in ground state irrespective of electron donor/acceptor substitution present on the ligands similar to that of mer -tris(8-hydroxyquinoline) aluminum ( mer -Alq3) and parent mer -AlND3.The absorption and emission wavelengths have been evaluated at the TD-PBE0/6-31G(D) level and it can be see that all the type I derivatives show blue shift while most of the type II derivatives show red shift compared to mer -AlND3. All the disubstituted complexes have showed hypsochromic shifts in both the absorption and emission spectra when compared with the calculated absorption and emission spectra respectively of mer -Alq3. It can be seen that the reorganization energies of some of the disubstituted derivatives are comparable with mer -Alq3 and these derivatives might be good candidates for emitting materials in OLED.
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Bee pollen and bee bread from stationary apiaries in the southwest Polish Legnica-Glogow copper district (LGOM) were analyzed for Cr, Pb, Cd and As by ICP-AES. Their concentrations in both products were As > Cr > Pb > Cd. Concentrations in bee pollen were higher than in bee bread. Average Cr, Pb, As and Cd concentrations in bee products were 0.138, 0.093, 0.325, and 0.019 mg kg −1 , respectively. Chromium was the most problematic element in bee pollen because its concentration limit was exceeded in more than 50% of the samples. Differences in Cd level between bee pollen and bread were significant (p ≤ 0.05)
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Sewage Sludge Ash (SSA) is a concentrated source of phosphorus and can be successfully recycled via a number of different routes. This paper presents research results on phosphorus recovery from differently combusted sewage sludge with the use of nitric acid extraction. Different SSA forms from Polish thermal utilization stations were compared. It was revealed that sewage treatment technology as well as combustion technology influence many physical and chemical parameters of ashes that are crucial for further phosphorus recovery from such waste according to the proposed method. Presented research defines extraction efficiency, characterized extracts composition and verifies the possibility of using SSA as cheaper and alternative sources of phosphorus compounds. Gdynia, Kielce and Kraków SSA have the best properties for the proposed technology of phosphorus recovery with high extraction efficiency greater than 86%. Unsuitable results were obtained for Bydgoszcz, Szczecin Slag and Warszawa SSA. Extraction process for Łódź and Szczecin Dust SSA need to be improved for a higher phosphorus extraction efficiency greater than 80%. Phosphorus content in extracts varies from 1.6 to 103.4 g PO 4 3− per 1 dm 3 , nitrogen content was 167,4 g per 1 dm3 while the K content reached 0.2 to 2.37 g per 1 dm3. The lowest content of Fe, Ni, Cr, Cd is noted in extracts after phosphorus recovery from Gdynia SSA, where the phosphorus content is also at the highest level. The proposed solution can be considered as waste minimization technology by the rational recycling of phosphorus and could be used in industry to produce fertilizers.
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In this research Ce 3+ doped Captopril nanoparticles (Ce 3+ doped CAP-NP) were prepared by a cold welding process and have been studied. Captopril may be applied in the treatment of hypertension and some types of congestive heart failure and for preventing kidney failure due to high blood pressure and diabetes. CAP-NP was synthesized by a cold welding process. The cerium nitrate was added at a ratio of 10% and the optical properties have been studied by photoluminescence (PL). The synthesized compounds were characterized by Fourier transform infrared spectroscopy. The size of CAP-NP was calculated by X-ray diffraction (XRD). The size of CAP-NP was in the range of 50 nm. Morphology of surface of synthesized nanoparticles was studied by scanning electron microscopy (SEM). Finally the luminescence properties of undoped and doped CAP-NP were compared. PL spectra from undoped CAP-NP show a strong pack in the range of 546 nm after doped cerium ion into the captopril appeared two bands at 680 and 357 nm, which is ascribed to the well-known 5d–4f emission band of the cerium.
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The paper presents properties of nanomaterials and methods of their principal applications. Environmental aspects of using nanomaterials and reasons for their toxicity are also reviewed. The vast part of the paper is devoted to properties, application and market of silver nanoparticles. Their biocidal activity is clarified. However, silver nanoparticles may cause environmental pollution. Reasons for their toxicity have been also described.
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Epilobium genus has been confirmed as an effective source of natural antimicrobials. However, the influence of Epilobi hirsuti herba derived products on usual antibiotics activity has not been studied. In this study, several standardized Epilobi hirsuti herba extracts (EHE) were evaluated in order to asses their potential effects on usual antibiotics tested on standard Gram-positive and Gram-negative bacterial strains in vitro . The results emphasized that the bacterial strains ranged from sensitive (MIC values between 50–200 μg GAE mL -1 ) ( S. epidermidis ATCC 12228) to very resistant ( E. coli strains), E. faecalis ATCC 29212 being practically immune to EHE. In terms of synergistic interaction, Tetracycline and Ampicillin combinations lead to the most important stimulatory effects, the diameters of the inhibition zone being even 60% bigger compared to the antibiotic alone. Synergistic effects between myricetin(galloyl) derivates and Tetracycline were also revealed on P. aeruginosa and E. coli strains. Together, it clearly demonstrated not only EHE’s own antimicrobial properties, but also their capacity to influence the antimicrobial potency of some common antibiotics. These results could be useful for the area of herbal medicines and as potential candidates in managing microbial resistance, but also for physicians and pharmacists using combined antibacterial therapy.
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Potassium catalyzed isothermal coal hydrogasification was investigated, as an alternative route for synthetic natural gas production. Potassium chemisorption occurred on oxygen sites in the coal structure and was strongly affected by the solution pH and followed the Cation Exchange Capability (CEC) which is also pH-dependent. A quadratic function described the relation between the solution pH and the fraction of the chemisorbed potassium, while; the cumulative distribution function of two Weibull probability density functions correlated the solution pH with the CEC that was linearly correlated with the fraction of the chemisorbed potassium. Coal hydrogasification is strongly affected by the increased alkalinity of the impregnating solution and increased methane yields were obtained while carbon conversion was slightly affected. This was attributed to the formation of profuse K + substituted active sites that decompose under H 2 attacks and trigger scission of the aromatic rings followed by K + migration to neighboring complexes, thus, the hydrogasification reaction continuous to yield CH 4 , as codified in a three stage reaction mechanism. The relative specific hydrogasification rate was found to increase linearly with the CEC of the coal samples, suggesting that the oxygen functional groups, on which potassium is chemisorbed, act as “active sites” and are linked with the carbon’s reactivity.
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This review focuses on the chemistry and application of radium isotopes to environmental monitoring, analytical, and medicinal uses. In recent years, radium has been used primarily as a tracer to study the migration of radioactive substances in environmental systems. Tracing the naturally occurring radium isotopes in mineral and water sources allows for the determination of source location, residence time, and concentrations. An understanding of the concentration of radionuclides in our food and water sources is essential to everyone’s health as alpha particle decay is highly damaging in vivo . Due to this high radiobiological effectiveness, there is increased interest in using alpha-emitting radionuclides to prepare new, therapeutic radiopharmaceutical drugs. Selected studies from the recent literature are provided as examples of these modern applications of radium isotopes.
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The hydrothermal decomposition of actinide(IV) oxalates ( An = Th, U, Pu) at temperatures between 95 and 250 °C is shown to lead to the production of highly crystalline, reactive actinide oxide nanocrystals (NCs). This aqueous process proved to be quantitative, reproducible and fast (depending on temperature). The NCs obtained were characterised by X-ray diffraction and TEM showing their size to be smaller than 15 nm. Attempts to extend this general approach towards transition metal or lanthanide oxalates failed in the 95–250 °C temperature range. The hydrothermal decomposition of actinide oxalates is therefore a clean, flexible and powerful approach towards NCs of An O 2 with possible scale-up potential.
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A molecular dynamics (MD) simulation study of the enzymatic portion of cholera toxin; cholera toxin A-1 polypeptide (CTA1) was performed at 283, 310 and 323 K. From total energy analysis it was observed that this toxin is stable thermodynamically and these outcomes were likewise confirmed by root mean square deviations (RMSD) investigations. The Cα root mean square fluctuation (RMSF) examinations revealed that there are a number of residues inside CTA1, which can be used as target for designing and synthesizing inhibitory drugs, in order to inactivate cholera toxin inside the human body. The fluctuations in the radius of gyration and hydrogen bonding in CTA1 proved that protein unfolding and refolding were normal routine phenomena in its structure at all temperatures. Solvent accessible surface area study identified the hydrophilic nature of the CTA1, and due to this property it can be a potential biological weapon. The structural identification (STRIDE) algorithm for proteins was successfully used to determine the partially disordered secondary structure of CTA1. On account of this partially disordered secondary structure, it can easily deceive the proteolytic enzymes of the endoplasmic reticulum of host cells.
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A liquid-liquid extraction-chromogenic system for vanadium(IV, V) containing 2,3-dihydroxynaphtahlene (DN), 2,3,5-triphenyl-2H-tetrazolium chloride (TTC), water and chloroform was studied in detail. When the vanadium is in the oxidation state of IV, the extracted species are aggregates containing three 1:2:1 (V:DN:TTC) ion-pair units composed of triphenyltetrazolium cations (TT + ) and chelate anions {[V IV O(DN)(DNH)] − ( I ) and/or [V IV (OH)(DN) 2 ] − ( II )}. When the initial oxidation state of vanadium is V and the DN concentration is high, vanadium(V) is reduced by DN to a lower oxidation state, V(IV). However, at low DN concentration, vanadium(V) can enter the organic phase as a part of an ion-pair consisting of TT + and [V V O 2 (DN)] − ( III ). The ground-state equilibrium geometries of the anions I, II , and III were optimized by quantum chemical calculations using BLYP/6-31++G ⋆ . The following characteristics were determined under the optimum conditions for V IV extraction: absorption maximum λ max = 333 nm, molar absorptivity ε 333 = 2.1x10 4 dm 3 mol −1 cm −1 , Sandell’s sensitivity SS = 2.4 ng cm −2 , and fraction extracted E = 98%. The conditional extraction constant was calculated by two independent methods. The calibration graph was linear in the range 0.1-3.1 μg cm −3 (R 2 =0.9994) and the limit of detection was 0.03 μg cm −3 .
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The review presents analytical methods for determination of new oral drugs for the treatment of type 2 diabetes mellitus (T2DM), focusing on peroxisome proliferator-activated receptor gamma agonists (glitazones), dipeptidyl peptidase 4 inhibitors (gliptins) and sodium/glucose co-transporter 2 inhibitors (gliflozins). Drugs derived from prandial glucose regulators, such as glinides, are considered because they are present in some new therapeutic options. The review presents analytical procedures suitable for determination of the drugs in bulk substances, such as pharmaceuticals and biological samples, including HPLC-UV, HPLC/LC-MS, TLC/HPTLC, CE/CE-MS, spectrophotometric (UV/VIS), spectrofluorimetric and electrochemical methods, taken from the literature over the past ten years (2006-2016). Some new procedures for extraction, separation and detection of the drugs, including solid phase extraction with molecularly imprinted polymers (SPE-MIP), liquid phase microextraction using porous hollow fibers (HP-LPME), HILIC chromatography, micellar mobile phases, ion mobility spectrometry (IMS) and isotopically labeled internal standards, are discussed.
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A simple, rapid, sensitive and economic spectrofluorimetric method has been developed and validated for determination of some β-adrenergic blocking agents namely; betaxolol hydrochloride (BTX), carvedilol (CAR), labetalol hydrochloride (LBT), nebivolol hydrochloride (NEB) and propranolol hydrochloride (PRO). The method is based on the quenching effect of the cited drugs on the fluorescence intensity of eosin Y at pH 3.4 (acetate buffer). The fluorescence quenching is due to the formation of an ion-pair complex and was measured without extraction at 545 nm (λex. 301.5 nm). The factors affecting the formation of the ion-pair complex were carefully studied and optimized. Under the optimal conditions, the linear ranges for the relationship between the fluorescence quenching value and the concentration of the investigated drugs were 100-2500, 150-2500 and 50-2250 ng mL -1 for (BTX, CAR), (LBT, NEB) and (PRO) respectively. The method was validated according to ICH guidelines and was applied for determination of the cited drugs in pharmaceutical dosage forms with excellent recoveries. In addition, content uniformity testing of some commercial dosage forms was checked by the proposed method.
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The modelling of acid-base titration curves of mineral assemblages was studied with respect to basic parameters of their surface sites to be obtained. The known modelling approaches, component additivity (CA) and generalized composite (GC), and three types of different assemblages (fucoidic sandstones, sedimentary rock-clay and bentonite-magnetite samples) were used. In contrary to GC-approach, application of which was without difficulties, the problem of CA-one consisted in the credibility and accessibility of the parameters characterizing the individual mineralogical components.
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A previously developed model which effectively predicts the probability of olive oil reaching the end of its shelf-life within a certain time frame was tested for its response when the convective diffusion of oxygen through packaging material is taken in account. Darcy’s Law was used to correlate the packaging permeability with the oxygen flow through the packaging materials. Mass transport within the food-packaging system was considered transient and the relative one-dimensional differential equations along with appropriate initial and boundary conditions were numerically solved. When the Peclet (Pe) number was used to validate the significance of the oxygen transport mechanism through packaging, the model results confirmed the Arrhenius type dependency of diffusion, where the slope of the line per material actually indicated their –Ea/R. Furthermore, Pe could not be correlated to the hexanal produced in samples stored under light. Photo-oxidation has a significant role in the oxidative degradation of olive oil confirmed by the shelf-assessing test. The validity of our model for the oxygen diffusion driven systems, was also confirmed, for that reason the predictive boundaries were set. Results safely indicated the significance of applying a self-assessing process to confirm the packaging selection process for oxygen sensitive food via this model.
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A mild and sustainable synthesis of 2,2-disubstituted oxetanes has been achieved through the use of a flow microreactor system. By controlling the residence time a highly unstable intermediate such as 2-phenyloxetan-2-yl lithium can be generated and trapped with various electrophiles affording in moderate to good yields 2-substituted-2-phenyloxetanes at higher temperatures with respect to macrobatch-mode where –78 °C is required.
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The Ag deposition on TiO 2 nanoparticles (Ag-TiO 2 NPs) and N-TiO 2 nanoparticles (Ag-N-TiO 2 NPs) has been made by electrochemical methodology in view of improved antibacterial properties and enhanced photocatalytic activity under visible light irradiation. The particle size in powder and in dispersion showed similar values and good stability in aqueous medium which made them suitable for use in leather surface covering for new multifunctional properties development. The diffuse reflectance spectra of Ag-TiO 2 NPs, Ag-N-TiO 2 NPs and TiO 2 NPs have been investigated and correlated with their photocatalytic performances under UV and visible light against different silver concentrations. The leather surfaces treated with Ag-N-TiO 2 NPs showed advanced self-cleaning properties under visible light exposure through the hydrophilic mechanism of organic soil decomposition. Moreover the bacterial sensitivity and proven fungitoxic properties of Ag-N-TiO 2 NPs leads to the possibility of designing new multifunctional additives to extend the advanced applications for more durable and useable materials.
Special Issue on: Recycling by-products and waste materials to restore degraded environments, and/or use as biosorbents
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The present work investigates arsenic, antimony and tellurium sorption using iron modified peat. The results were obtained using batch tests and the sorption was studied as a function of initial metalloid concentration, pH and sorption time, as well as the presence of competing substances. The obtained results indicate that modification of peat with Fe compounds significantly enhances the sorption capacity of the sorbents used for sorption of arsenic, antimony and tellurium. The optimal pH interval for the sorption of Sb(III) is 6.5–9 and for As(V) and Sb(V) – 3–6, while As(III) and tellurium sorption using Fe-modified peat is favourable in a wider interval of 3–9. The presence of competing ions as well as HA affect sorption of metalloids on Fe-modified peat. A minor impact on the reduction of metalloid sorption was detected in the presence of nitrate, sulphate, carbonate and tartrate ions, while in the presence of phosphate and HA the sorption ability of metalloids can be considerably reduced. The obtained results of kinetic experiments indicate that sorption of metalloids on Fe-modified peat mainly occurs relying on mechanisms of physical sorption processes.
Special Issue on: Recycling by-products and waste materials to restore degraded environments, and/or use as biosorbents
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The objective of this work was to evaluate the removal of Cu 2+ and Zn 2+ in water by means of the adsorption process using three biosorbents derived from jatropha biomass (bark, endosperm and endosperm + seed coat). The experiments were performed in batch and evaluated the effect of solution pH, adsorbent mass, contact time, different initial concentrations of the metals Cu 2+ and Zn 2+ , and the temperature of the solution during the adsorptive process. By kinetics, the adsorption isotherms and thermodynamics the mechanisms that control the adsorptive process were evaluated. The optimal conditions for the realization of the adsorptive process for both metals were: solution pH of 5.0 and 8 g L -1 of adsorbent mass per volume of solution, with a contact time between adsorbent and adsorbate of 60 min. According to the Langmuir model, the maximum adsorption capacities for the bark, endosperm and endosperm + seed coat of Jatropha were, respectively, for Cu 2+ 11.541, 20.475 and 22.910 mg g -1 , and for Zn 2+ 14.852; 15.888 and 14.674 mg g -1 , with the predominance of chemisorption in monolayer. The three biosorbents derived from the biomass of Jatropha have potential for the remediation of water contaminated with Cu 2+ and Zn 2+ .
Special Issue on: Recycling by-products and waste materials to restore degraded environments, and/or use as biosorbents
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Flotation separation is mainly used for removing particulates from aqueous dispersions. It is widely used for ore beneficiation and recovering valuable materials. This paper reviews the hydrodynamics of flotation separations and comments on selected recent publications. Units are distinguished as cells of ideal and non-ideal flow. A brief introduction to hydrodynamics is included to explain an original study of the hybrid flotation-microfiltration cell, effective for heavy metal ion removal.
Special Issue on: Recycling by-products and waste materials to restore degraded environments, and/or use as biosorbents
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Mustard waste biomass was tested as a biosorbent for the removal of Pb(II), Zn(II) and Cd(II) from aqueous solution. This strategy may be a sustainable option for the utilization of such wastes. The influence of the most important operating parameters of the biosorption process was analyzed in batch experiments, and optimal conditions were found to include initial solution pH 5.5, 5.0 g biosorbent/L, 2 hours of contact time and high temperature. Kinetics analyses show that the maximum of biosorption was quickly reached and could be described by a pseudo-second order kinetic model. The equilibrium data were well fitted by the Langmuir model, and the highest values of maximum biosorption capacity were obtained with Pb(II), followed by Zn(II) and Cd(II). The thermodynamic parameters of the biosorption process (ΔG, ΔH and ΔS) were also evaluated from isotherms. The results of this study suggest that mustard waste biomass can be used for the removal of heavy metals from aqueous media.
Topical Issue on Polymer Science
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Inspired by the superhydrophobicity of juicy peach surface, on which microscale hairs are standing vertically to the surface plane, an extremely simple, inexpensive physical method is developed for fabrication of superhydrophobic polyolefin surfaces over large areas. This method includes three steps: abrasive paper scraping, adhesive tape bonding and 90° peeling. Scraping increases the roughness and enhence water contact angles (CAs) on polyolefin surfaces. It increases more when the scraped surface are bonded with adhesive types and then then 90° peeled. The CA variation depends on the types of polyolefin and abrasive paper. Superhydrophobic lowdensity polyethylene (LDPE), high-density polyethylene (HDPE) and polypropylene (PP) surfaces (CA>150°) are obtained and they all exhibit very low adhesive force and high resistance to strong acids and bases.
Topical Issue on Polymer Science
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Poly(acrylamide)-multiwalled carbon nanotubes (PAAm-MWNTs) hybrid hydrogels were prepared through the radiation-induced polymerization and crosslinking of the aqueous solution of acrylamide and well-dispersed MWNTs for the first time. The PAAm gels obtained by the radiation-induced polymerization and cosslinking showed very high mechanical strengths, and the PAAm-MWNTs hybrid hydrogels had improved mechanical properties compared with the PAAm gels, and hence the PAAm-MWNTs hybrid hydrogels showed extremely high compressive and tensile strengths. The hybrid hydrogels with water contents more than 80 wt.% usually did not fracture even at compressive strengths close to or even more than 60 MPa and strains more than 97%. And the hybrid hydrogels had very high elongations (more than 2000% in some cases), especially when the water content was high. The tensile strengths were in sub-MPa. The hybrid PAAm-MWNTs hydrogel is one of the strongest hydrogel even made.
Topical Issue on Polymer Science
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This paper presents a method for polyurethane surface functionalization for tissue engineering applications. Functionalization has been carried out by grafting acrylic acid to the polyurethane surface with the use of radical polymerization with a Ce 4+ initiator. Contrary to other papers suggesting that the presence of hydroxyl groups are essential for successful grafting via ceric ions, we propose a method with the omission of the surface hydroxylation step. The influence of reaction conditions: reaction time, reaction temperature and monomer concentration on carboxyl groups surface density has been analyzed and described. The quantity of carboxyl groups on the surface was determined with the use of the TBO method. Materials grafted with acrylic acid have been subjected to conjugation with a peptide using sulfoNHS/ EDC chemistry. Successful incorporation of the peptide has been confirmed by an ELISA assay. Additionally, for better characterization, after each step of modification materials were subjected to SEM, FTIR-ATR, XPS and contact angle measurement analysis.
Topical Issue on Polymer Science
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A new sodium coordination polymer, [Na 2 (L) 2 (H 2 O) 4 ] n (1), was synthesized by reflux reaction of p -aminobenzene sulfonic acid, p -hydroxy benzaldehyde and NaOH in ethanol/water solution and characterized by elemental analysis, UV-vis, IR and X-ray single crystal diffraction analysis. The crystal of 1 belongs to monoclinic, space group P 2 1 / c with a = 17.765(4) Å, b =10.181(2) Å, c = 8.0450(16) Å, β = 91.67(3)°, V = 1454.5(5) Å 3 , Z = 4, D c = 1.531 mg·, μ = 0.28 mm -1 , F (000) = 696, and final R 1 = 0.0327, ωR 2 = 0.0854. The molecules of 1 are extended to a 2D layer structure along ab plane. The 2D layers form 3D framework structure by the interaction of π-π stacking and hydrogen-bond interaction.
Topical Issue on Polymer Science
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This manuscript describes a novel approach for the preparation of composites based on cellulose paper (CP) modified with polypyrrole (PPy) and bromophenol blue (BPB) (CP/PPy/BPB). Cellulose fibers are suitable for uniformly retaining the polymer in its doped form, once BPB can be used as a negatively charged dye. The CP/PPy/BPB composites were characterized by Raman Spectroscopy, Scanning Electron Microscopy, Spectroscopy and Dispersive Energy, and X-ray Diffraction. After characterization, they were studied for the quantification of pH and ammonia by diffuse reflectance spectroscopy. Under varying pH, different colors were verified, which ranged from yellow to blue, and an optical response for ammonia at concentrations as high as 25 ppm. The replacement of BPB by bromothymol blue (BTB) did not produce efficient color transitions and showed no sensitivity to changes in pH and ammonia concentration.
Topical Issue on Advanced organic functional materials for practical applications
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We have developed an efficient, low temperature, synthetic route for ZnO nanoflowers (NFs) as photoanode material. This alternative route yields small flowerlike nanostructures, built from densely self-assembled tip-ended rod structures. The obtained ZnO NFs possess a large bandgap of 3.27 - 3.39 eV, enabling the generation of an average open current voltage of 0.56 V. Additionally, they show a high internal light harvesting of 14.6•10 -7 A-mol -1 . The growth mechanism and self-assembly of ZnO NFs were studied in detail by joint spectroscopic-TEM investigations. It is shown that the ZnO crystallite size increases with increasing annealing temperatures and that the stress and the improved crystallinity are induced by annealing and reduce the lattice strain and the dislocation density. The bandgaps of ZnO are affected by the lattice strain revealing an optimal region of lattice strain to gain high bandgap energies. The properties of the synthesized ZnO NFs are compared with other morphologies, i.e . ZnO spherical aggregates (SPs) and ZnO nanorods (NRs), and are tested as electrode materials in dye-sensitized solar cells.
Topical Issue on Advanced organic functional materials for practical applications
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Ahmed E. Fazary, Yi-Hsu Ju, Aisha Q. Rajhi, Ayed S. Alshihri, Mohammad Y. Alfaifi, Mohammed A. Alshehri, Kamel A Saleh, Serag Eldin I. Elbehairi, Khaled F. Fawy, Hisham S. M. Abd-Rabboh
In this work twelve novel mixed ligand complexes were synthesized. The complexes were formed between a metal ion (Cu(II), Cd(II), Mn(II), Fe(III), Ni(II), Pb(II)) and vitamins (B 3 and B 9) as primary ligands, and glycine as secondary ligand. Melting points, conductivities, and magnetic susceptibilities of the synthesized complexes were determined and the complexes were subjected to elemental analyses. The presence of coordination water molecules in the complex was also supported by TG/DTG thermal analysis. Full elucidation of the molecular structures for the synthesized mixed ligand complexes were confirmed using detailed spectroscopic IR, 1 H-, 13 C-NMR, and XRD techniques. In addition, cytotoxic and antioxidant activities of the twelve synthesized solid complexes were tested to evaluate their bioactivities.
Topical Issue on Catalysis
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We present a combined approach to photo-assisted degradation processes, in which a catalyst, H 2 O 2 and UV irradiation are used together to enhance the oxidation of Rhodamine B (RB). The heterogeneous photocatalyst was made by the process of adsorption of copper phthalocyanine tetrasulfonic acid (CuPC) onto purified spongin-based Hippospongia communis marine sponge skeleton ( Hc S). The product obtained, CuPC- Hc S, was investigated by a variety of spectroscopic (carbon-13 nuclear magnetic resonance 13 C NMR, Fourier transform infrared spectroscopy FTIR, energy-dispersive X-ray spectroscopy EDS) and microscopic techniques (scanning electron microscopy SEM, fluorescent and optical microscopy), as well as thermal analysis. The study confirms the stable combination of the adsorbent and adsorbate. For a 10 mg/L RB solution, the percentage degradation reached 95% using CuPC- Hc S as a heterocatalyst. The mechanism of RB removal involves adsorption and photodegradation simultaneously.
Topical Issue on Catalysis
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The synthesis of α-Fe 2 O 3 /SAPO-34 nano photocatalyst was the first step of this study. The α-Fe 2 O 3 nanocatalyst was synthesized applying forced hydrolysis and reflux condensation followed by solid-state dispersion that was used for supporting α-Fe 2 O 3 on SAPO-34. The next step was a characterization of the catalyst that was performed using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FT-IR). Then, for optimizing the operational parameters in Doxorubicin’s degradation process the effect of Doxorubicin concentration, the amount of α-Fe 2 O 3 /SAPO-34 nano photocatalyst, the pH, and H 2 O 2 concentration was studied via the Taguchi method. The AL 9 orthogonal array was adjusted and nine crucial runs were conducted. For calculating Signal/Noise ratio, each run was repeated three times. As the results showed, the concentration of Doxorubicin is the most effective parameter. Optimized conditions for removing the anti-cancer drug (based on Signal/Noise ratio) were Doxorubicin concentration (20 ppm), H 2 O 2 concentration (3 mol/L), catalyst amount (50 mg/L) and pH = 8.
Topical Issue on Catalysis
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The hydrogenolysis of glycerol was performed over a Pt/C catalyst in combination with several alkali metal hydroxides and their salts. LiOH was found to be an effective promoter for the selective hydrogenolysis of glycerol to 1,2-propanediol. Hydroxyl ions are the main factor to promote the reaction process by dehydration of the glyceraldehyde intermediate. Lithium ions play a role in assisting the dehydrogenation of glycerol to glyceraldehyde, because they have the right size to coordinate with the alkoxide species. A possible surface reaction mechanism involving the participation of lithium ions was proposed to account for the results obtained in the study.
Topical Issue on Catalysis
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The ruthenium(II) complex cis-[RuCl 2 (PPh 3 ) 2 (L1)] ( 1 ) where L1 = 2-(2’-pyridyl)quinoline was obtained in high yield from the reaction of [RuCl 2 (PPh 3 ) 3 ] with L1. The new compound was characterized by different spectroscopic methods including FT-IR, UV-Vis, NMR ( 1 H, 31 P) spectroscopy along with a mass spectrometric analysis (ESI-MS) and conductivity measurements. 31 P NMR spectroscopy provided evidence that the two PPh 3 ligands are orientated trans to each other in an octahedral environment. Complex ( 1 ) was tested in the transfer hydrogenation of various ketones in 2-propanol at 82 o C. The catalytic activity of ( 1 ) displayed quantitative conversions for benzophenone and 4-chloroacetophenone.
Topical Issue on Catalysis
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Natural zeolites as a raw material to prepare catalytic precursors for the oxidation reaction of linear and poly-aromatic hydrocarbons are reported in this work. The process consisted in the formation of mono- and bi-metallic species containing Co and Co-Rh on natural zeolite tuffs. The materials are analyzed by different physicochemical techniques and used as catalysts for propane and naphthalene oxidation in emissions sources. Comparatively, Rh-zeolites are the most active catalysts for propane conversion. In this case, the formation of mixed oxides seems to be conditioned by surface properties. It could also be suggested that the Rh incorporation on a non-active phase in bimetallic catalysts impacts the effectiveness of the system. In addition, the NO presence increases the activity of bimetallic materials. Rh-Co zeolite systems markedly influence the naphthalene combustion temperature. Whereas in the absence of a catalyst a conversion rate of 50% and 100% is reached at 430 °C and 485 °C, respectively. It is interesting to observe that for RhCoCli-Mor and RhCoCli catalyst the 100% conversion is reached at 250 °C.
Topical Issue on Catalysis
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The novel [Ni{(Ph 2 P) 2 N(CH 2 ) 3 Si(OCH 3 ) 3 - P , P´ }I 2 ] complex ( 1 ) was synthesized and investigated by a variety of spectroscopic methods (IR, 1 H and 31 P NMR). The molecular structure of 1 , determined by single crystal X-ray diffraction, was compared with those of the analogue [Ni{(Ph 2 P) 2 N(CH 2 ) 3 Si(OCH 3 ) 3 - P , P´ }Cl 2 ] complex ( 2 ) and the recently reported [Ni{ i CPrP) 2 NH- P , P´ }I 2 ] complex. Complexes 1 and 2 were tested as homogeneous catalysts for the oligomerization of ethylene, leading to the formation of C 4 and, to a smaller extent, C 6 products, in moderate yields.
Topical Issue on Catalysis
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Vladislav A. Sadykov, Mikhail N. Simonov, Natalia V. Mezentseva, Svetlana N. Pavlova, Yulia E. Fedorova, Aleksei S. Bobin, Yulia N. Bespalko, Arcady V. Ishchenko, Tamara A. Krieger, Tatiana S. Glazneva, Tatyana V. Larina, Svetlana V. Cherepanova, Vasilii V. Kaichev, Andrey A. Saraev, Yurii A. Chesalov, Aleksandr N. Shmakov, Anne-Cecile Roger, Andrzej Adamski
Mixed nanocrystalline Ce-Zr-O oxides (Ce/Zr = 1 or 7/3) were prepared by modified Pechini route using ethylene glycol solutions of metal salts. Detailed characterization of their real structure and surface properties by X-ray diffraction on synchrotron radiation with the full-profile Rietveld analysis, high resolution electron microscopy with elemental analysis, Raman spectroscopy, UV-Vis and X-ray photoelectron spectroscopy revealed a high homogeneity of cations distribution in nanodomains resulting in stabilization of disordered cubic phase. This provides a high dispersion of NiO loaded on these mixed oxides by wet impregnation, a high reactivity and mobility of oxygen in these catalysts and strong interaction of Ni with support in the reduced state. This helps to achieve a high activity and coking stability of developed catalysts in CH 4 dry reforming in feeds with CH 4 concentration up to 15% and CH 4 /CO 2 ratio =1.
Topical Issue on Catalysis
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Herein, we report on the homogeneous photocatalytic evolution of hydrogen by using as reductive catalysts the prismatic symmetric tris – dithiolene complexes of the tungsten, namely [W{S 2 C 2 (Ph) 2 } 3 ] ( 1 ) and its monoanion [W{S 2 C 2 (Ph) 2 } 3 ](TBA) ( 2 ). Complex 2 is fully characterized by elemental analysis, ESI-MS, IR, UV-Vis and fluorescence spectrophotometry as well as cyclic voltammetry. The photocatalytic system consists of [ReBr(CO) 3 (bpy)] as a photosensitizer, triethanolamine as a sacrificial electron donor and acetic acid as the proton source. Although the activity of the photocatalytic system is rather small (TON=18), it indicates that the homoleptic tris dithiolene complexes can act as proton reductive catalysts with their monoanion form to be more active in accordance with the findings for the bis - dithiolene complexes.
Topical Issue on Natural Products with Biological Activities: Short Communication
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The present work aimed to determine the antioxidant, metal chelating and neuroprotective potential of the unsaponifiable matter (UM) of Tetraselmis chuii to be applied to a biorefinery setting. The UM obtained via saponification from crude lipids extracted from microalgal wet biomass showed a radical scavenging activity (RSA) towards the DPPH radical of 90.7±1.3% and 57.1±1.2% at a concentration of 10 and 5 mg/mL, respectively. The UM fraction also displayed metal chelating capacity at a concentration of 5 mg/mL: 58.5±1.4% and 50.9±4.0% for copper and iron, respectively. The chemical characterization of the UM revealed significant levels of total phenolics (TPC, 13.61 mg GAE/g) and carotenoids (2.45 mg/g of β-carotene, lutein and violaxanthin). Overall, the separation of the UM containing high value metabolites might significantly upgrade the total wet biomass value in a biorefinery, allowing the exploitation of a stream with relevant antioxidant and metal chelating activities.
Topical Issue on Natural Products with Biological Activities
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The most of important crops cultivated for production of foods and feeds could be considered as plants possessing nutraceutical or medically interesting compounds, especially if can be eaten without processing. Chemical and biological parameters that were evaluated in 100 oat (Avena sativa L.) genotypes were others than those that are important in food and feed production. Contents of polyphenols and flavonoids, radical scavenging activity (DPPH), and inhibitory activities against five proteases (trypsin, thrombin, urokinase, elastase, cathepsin B) were analyzed in extracts from mature grains. The antioxidant activity (DPPH) correlated to the content of total polyphenols. Only a minority (15 from 100) of analyzed genotypes created separate subgroup with a high content of polyphenols, flavonoids, and high antioxidant activity. The best in these parameters were genotypes CDC-SOL-FI, Saul, and Avesta, respectively. Fifteen other genotypes assembled another minority subgroup (also 15 from 100) on the basis of their high inhibitory activities against tested proteases. The highest trypsin-, urokinase-, and elastase-inhibitory activities were in genotype Racoon, the best in thrombin-, and cathepsin B-inhibitory activities were genotypes Expression and SW Kerstin, respectively. Three oats genotypes – Rhea, AC Percy, and Detvan appeared in both subgroups.
Topical Issue on Natural Products with Biological Activities
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The chemical variability and antioxidant activity of the flower and leaf essential oils (EOs) of Ammoides pusilla , collected at Algeria was evaluated. The EOs were isolated by hydrodistillation and analyzed by Gas Chromatography (GC) and Gas Chromatography-Mass Spectrometry (GC-MS). Antioxidant activity was assessed by DPPH, ABTS, Reducing Power and TBARS assays. Oxygen-containing monoterpenes (54-77%) dominated all but one A. pusilla leaf EOs, and in two flower EOs (53% both). Thymol dominated in practically all leaf and flowers EOs, but cumin alcohol, p -cymene and limonene attained also relatively high percentages in some EOs. A strong negative correlation ( p <0.01) between IC 50 values of ABTS, DPPH, and hydroxyl scavenging activity and the percentages of p -cymene and cumin alcohol present in EOs were observed, showing that higher levels of these monoterpenes were responsible for the best activities found. In spite of this finding, the antagonism and/or synergism between EO components must be taken into account, since the EO activity can only be considered as a whole. Moreover, given the EOs chemical variability their use as antioxidants, should be preceded by their chemical evaluation.