Current Issue : January - March Volume : 2019 Issue Number : 1 Articles : 5 Articles
Lignin, a renewable source of aromatic chemicals in nature, has attracted increasing\nattention due to its structure and application prospect. Catalytic solvolysis has developed as\na promising method for the production of value-added products from lignin. The liquefaction\nprocess is closely associated with heating methods, catalysts and solvents. Microwave assisted\nlignin liquefaction in hydrogen donor solvent with the presence of catalysts has been confirmed\nto be effective to promote the production of liquid fuels or fine chemicals. A great number of\nresearchers should be greatly appreciated on account of their contributions on the progress of\nmicrowave technology in lignin liquefaction. In this study, microwave assisted liquefaction of\nlignin in a hydrogen donor solvent is extensively overviewed, concerning the effect of different\nsolvents and catalysts. This review concludes that microwave assisted liquefaction is a promising\ntechnology for the valorization of lignin, which could reduce the reaction time, decrease the reaction\ntemperature, and finally fulfill the utilization of lignin in a relatively mild condition. In the future,\nheterogeneous catalysts with high catalytic activity and stability need to be prepared to achieve the\nneed for large-scale production of high-quality fuels and value-added chemicals from lignin....
Ce/BiVO4 nanocomposites photocatalyst was synthesized by direct feeding\nmicrowave synthesis method, using bismuth nitrate (Bi (NO3)3·5H2O), cerium\nnitrate hexahydrate (Ce (NO3)3·6H2O) and ammonium metavanadate (NH4VO3)\nas raw material and sodium dodecyl sulfate (SDS) as surfactant. The X-ray\ndiffractometer (XRD) and the scanning electron microscopy (SEM) technology\nwere used to characterize the Ce/BiVO4 nanocomposites. We investigated\nthe photocatalytic activity of the as-prepared photocatalyst, and methyl\norange was used as organic pollutant. The results show that the Ce/BiVO4\nnanocomposite was a good photocatalyst under visible light. In 100 ml of 5\nmg/L methylene orange solution, when the catalyst calcined at 673 K was 0.1\ng, hydrogen peroxide was 0.5 ml, pH was 2.0, and the degradation ratio of catalyst\nfor methylene orange reached 90.26% within 70 min....
Due to its unique properties such as high hardness, light transmittance, thermal\nconductance, chemical stability and corrosion resistance, diamond has\ndrawn tremendous attention in last two decades. These specific properties\nmade diamond film a promising material for cutting tools, microwave windows,\nheat sinks for electronic devices and diamond electrodes. However, the\ndiamond film with grain sizes at microscale usually exhibits high surface\nroughness and hinders its applications in the microelectro mechanical system\n(MEMS) and biological field because it is difficult to be polished by mechanical\nand chemical methods. With the development of the chemical vapor deposition,\nthe nanocrystalline diamond (NCD) film has been fabricated and\nfound new applications. The grain size of NCD film is in the range of 10 to\n100 nm, which inherits the properties of the diamond and possesses the\nunique properties of the nanoscale materials, and the morphology of the NCD\nfilm is granular or needle-like structure. The microwave plasma chemical vapor\ndeposition (MPCVD) has been regarded as the most promising method to\ndeposit NCD film at low temperature. Compared to the hot filament CVD,\nMPCVD can grow high quality NCD film avoiding of the contamination from\nthe filament materials. The MPCVD technique has high plasma density to activate\ncarbonaceous compound and grow NCD film in high growth rate and\nlow substrate temperature. The unique properties of NCD film, such as the\nsuperior electrical, mechanical and biological properties facilitate their application\nin various fields. The biological application, especially as a biocompatible\ncoating, mainly includes the joint replacement implants and protective\ncoatings and the ophthalmological prosthesis....
In this study, polyaniline and Fe3O4 (PAN@Fe3O4) hybrids are fabricated and their microwave absorption property is studied.\nPAN@Fe3O4 hybrids are fabricated by the in situ aniline polymerization at spherical of Fe3O4 which is prepared by the\nsolvothermal process. Fourier-transform infrared spectrophotometer (FTIR), X-ray diffraction (XRD), and X-ray photoelectron\nspectroscopy (XPS) are applied to confirm the composition of the fabricated PAN@Fe3O4 hybrids. The morphologies of\nPAN@Fe3O4 hybrids are studied by scanning electron microscope (SEM) and transmission electron microscopy (TEM). The\ncontent of polyaniline in the PAN@Fe3O4 hybrids is calculated by thermogravimetric analysis (TGA). The magnetic properties\nof PAN@Fe3O4 hybrids are characterized by vibrating sample magnetometer (VSM). The microwave absorption property of\nPAN@Fe3O4 hybrids are measured on a vector network analyzer. The research show that the microwave absorptions property\nof the obtained PAN@Fe3O4 hybrids can be adjusted by controlling the in situ aniline polymerization at spherical of Fe3O4....
Antibiotics are widely used to prevent and treat bacterial infections in livestock animals, aquaculture, and humans. However, the\nunconditional use of those drugs as a growth promoter for livestock animals and the wrong usage as a treatment for infections\nin humans has led to high antibiotics pollution, especially in water resources. The elevated presence of antibiotics in water has\nresulted in the phenomenon known as the bacterial antibiotics resistance. To prevent ecological catastrophe, continuous real time\nmonitoring of water sources is necessary. The aim of this research work is to compare the abilities of three different\ntechniques: novel electromagnetic wave spectroscopy, UV-Vis spectrophotometry, and capacitance sensing system for the real time\ndetection and quantification of antibiotics in water. Tylosin and lincomycin antibiotics were selected to the study, as both\nare regularly found in water sources. Two novel microwave sensor configurations were used: a planar sensor with interdigitated\nelectrode pattern and a hairpin resonator sensor, as a means of real-time water analysis. Reflected S11 power signals were\nanalyzed in GHz frequency range for microwave sensors. In parallel, UV-Vis spectrophotometry was used, where change in the\noptical absorbance was used as an indicator of water pollution, whereas change in the value of a capacitance in low frequency\nrange has signalled the change in the dielectric properties of the solution. It was found that in all cases the changes in the\nmeasured parameters were dependent on both the type of antibiotic present in water and on its concentration. Fusion of all\nthese techniques into a comprehensive sensing platform provides adequate real-time assessment of the water pollution with\nantibiotics and would allow adequate management of environment for safety and sustainable development. In particular, the\nlowest lincomycin samplesâ?? concentration, 0.25 ..g/l, was measured with a hairpin resonator sensor, while the lowest tylosin\nsamplesâ?? concentration, 0.20 ..g/l, was measured with an IDE sensor. Since concentration in groundwater were 0.36 ..g/l of\nlincomycin and 1.5 ..g/l of tylosin, it is demonstrating a high-sensing platform utility....
Loading....