Preparation of mesoporous TiO2/CNT nanocomposites by synthesis of mesoporous titania via EISA and their photocatalytic degradation under visible light irradiation

Stabilized mesoporous TiO₂ was synthesized by evaporation induced self assembly (EISA) method and mechanically incorporated into single-walled carbon nanotubes (SWCNT) with different ratios. The physicochemical properties of the nanocomposites (mesoporous TiO₂/SWCNT) materials were investigated by Brunauer–Emmett–Teller (BET) measurement, X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray (EDX), photoluminescence (PL) and ultraviolet–visible (UV–Vis) spectroscopy measurements. The catalytic activity of mesoporous TiO₂ and nanocomposites were assessed by examining the degradation of rhodamine B as model aqueous solution under visible light. CNTs are facilitating the photocatalytic activity of mesoporous TiO₂ in the degradation of rhodamine B efficiently.     

Current Applications of Magnetic Nanomaterials for Extraction of Mycotoxins,Pesticides, and Pharmaceuticals in Food Commodities

Environmental pollutants, such as mycotoxins, pesticides, and pharmaceuticals, are a group of contaminates that occur naturally, while others are produced from anthropogenic sources. With increased research on the adverse ecological and human health effects of these pollutants, there is an increasing need to regularly monitor their levels in food and the environment in order to ensure food safety and public health. The application of magnetic nanomaterials in the analyses of these pollutants could be promising and offers numerous advantages relative to conventional techniques. Due to their ability for the selective adsorption, and ease of separation as a result of magnetic susceptibility, surface modification, stability, cost-effectiveness, availability, and biodegradability, these unique magnetic nanomaterials exhibit great achievement in the improvement of the extraction of different analytes in food. On the other hand, conventional methods involve longer extraction procedures and utilize large quantities of environmentally unfriendly organic solvents. This review centers its attention on current applications of magnetic nanomaterials and their modifications in the extraction of pollutants in food commodities.     

Recent advances in the formation mechanisms of organized mesoporous materials

Since the discovery of the organized mesoporous solids by Mobil Oil Co. scientists, numerous patents and papers dealing with the synthesis, mechanisms of formation, properties and applications of these exciting solids have been published. A better understanding in the mechanisms of formation has been achieved through the use of in situ techniques of investigation. It appears that the mechanism depends much on the experimental conditions of synthesis. Even if the interaction between the inorganic precursor and the organic template is the key factor in the control of the formation of these materials, none of the proposed mechanisms provides an exclusive and definitive answer.     

Vapor–liquid equilibrium of carbon dioxide with diethyl methylmalonate,diethyl ethylmalonate and diethyl n-butylmalonate at elevated pressures

Vapor–liquid equilibrium (VLE) data for binary mixtures of CO₂ with homologous esters of diethyl methylmalonate, diethyl ethylmalonate, and diethyl n-butylmalonate at 308.2, 318.2, and 328.2 K, respectively, over the pressure range 1.4–8.4 MPa were measured using a semi-flow apparatus. New gas solubility data for CO₂ in esters are presented, and the Henry’s law constants for CO₂ in these esters are evaluated by employing the Krichevsky–Ilinskaya (KI) equation. The VLE data were also correlated using the Soave–Redlich–Kwong and the Peng–Robinson equations of state (EOSs) with various types of mixing rules. It is shown that EOS with both the van der Waals mixing rules and the two adjustable parameters yield satisfactory correlation results.     

Radiolysis of alkyl benzene sulfonat (ABS) in aqueous solution

Degradation of alkyl benzene sulfonate (ABS) in aerated aqueous solution irradiated with gamma radiation with doses up to 1.8 kGy were studied. The degree of degradation, pH change, the effect of pH on the degradation, COD values and the degradation products were determined. The degradation of ABS increases with the increase of doses and decreases with the increase of ABS concentration. The degradation was somewhat more efficient in slightly acidic and neutral solutions than at basic pH oxalic acid was detected by HPLC as degradation product.     

Role of backpulsing in fouling minimization in crossflow filtration with ceramic membranes

Effect of backpulsing on crossflow filtration of different process streams was studied. Laboratory scale experiments were conducted with synthetic electroplating wastewater containing Cr(OH)₃ suspension. Porous ceramic membranes of various pore sizes (0.05–5.0 μm) were evaluated. Filtration experiments with and without backpulsing show that backpulsing is effective in minimizing membrane fouling. Up to five-fold increase in steady-state permeate flux and 100% flux recovery were observed. Theoretical aspects are reviewed to develop a better understanding of the critical parameters associated with high-pressure backpulsing.Pilot and commercial scale operating results on several industrial applications, such as yeast filtration, process slurry filtration and oily wastewater filtration are presented. Data analysis shows the critical importance of backpulsing in reducing long-term membrane fouling while allowing the realization of high product recovery. Optimization of process parameters with backpulsing typically results in higher flux and reduces the total capital cost required to achieve the desired production rate.     

Pentacyclic Triterpenoids,Phytosteroids and Fatty Acid Isolated from the Stem-bark of Cola lateritia K. Schum. (Sterculiaceae) of Cameroon origin; Evaluation of Their Antibacterial Activity

The phytochemical investigation on the chemical constituents of dichloromethane-methanol (1:1) stem-bark extract of Cola lateritia K. Schum. (Sterculiaceae) led to the isolation and characterization of five pentacyclic triterpenoids, one fatty acid and two phytosteroids. The compounds were identified as heptadecanoic acid (1), maslinic acid (2), betulinic acid (3), lupenone (4), lupeol (5), friedelin (6), β-stigmasterol (7) and ß-sitosterol-3-O-ß-D-glucoside (8). Their structures were determined by NMR analysis (¹H, ¹³C, DEPT-135, COSY, HMBC and HSQC), high-resolution mass spectrometry (HR-ESI-MS) and comparisons with published data in the literature. This work, to the best of our knowledge, is the first isolation and identification of these compounds in pure forms from Cola lateritia. Also, compounds 1–3 are reported for the first time from Cola genus. In vitro antibacterial activity of the isolated compounds (1–8) and the crude extract were evaluated against Bacillus subtilis, Staphylococcus epidermidis, Enterococcus faecalis, Mycobacterium smegmatis, Staphylococcus aureus, Enterobacter cloacae, Klebsiella oxytoca, Proteus vulgaris, Klebsiella pneumonia, Escherichia coli, Proteus mirabilis and Klebsiella aerogenes with streptomycin, nalidixic acid and ampicillin as standard antibacterial drugs. Compound 2 was active against E. faecalis (MIC = 18.5 µg/mL), and it was 6.9 and 28 times lower and active than that of streptomycin (MIC 128 µg/mL) and nalidixic acid (MIC > 512 µg/mL) respectively. All the isolated compounds and crude extract showed significant activities against the tested bacterial strains.     

Study on the synthesis,morphology and structural analysis of fly ash–cyclodextrin composite

This study investigates the surface morphology, structure analysis and the effect on the porosity and particle size of a new composite prepared using fly ash with α and β cyclodextrins. The dry mix and solution methods were used to synthesize these composite samples. The X-ray diffraction analysis shows the new peaks that indicate the interaction between the materials. These results are in agreement with the Fourier transform infrared spectroscopic analysis that suggested the possibility of interaction of fly ash particles with cyclodextrin. Morphology changes between the composite material and the constituent materials were observed using the scanning electron microscopic. The porosity and particle size analyses show the significant changes with respect to preparation methods.     

一些二茂铁苯基亚胺化合物的合成与表征

通过回流对应的二茂铁苯胺和芳香醛的混合物的同样路径合成了一系列新颖的二茂铁苯基亚胺化合物(5~12)。当暴露于空气时化合物5~12稳定,不发生任何分解。所有化合物均用¹H、¹³C NMR,MS,IR,UV-Vis和元素分析表征。还报导了化合物N-(3-bromo-2-hydroxylbenzylidene)-4-ferrocenylimine(10)的单晶结构,其结晶属单斜晶系P2₁/c空间群。