The Changes in Physicochemical Properties of Lacquer Wax by Physical Adsorption and UV Light

Author(s):  
Yuan-Feng He ◽  
Cheng-Zhang Wang ◽  
Yan-he Dong ◽  
Jian-Zhong Ye ◽  
Hao Zhou ◽  
...  
2018 ◽  
Vol 2018 ◽  
pp. 1-15
Author(s):  
Esthela Ramos-Ramírez ◽  
Norma Gutiérrez-Ortega ◽  
Francisco Tzompantzi ◽  
Claudia M. Gómez ◽  
Gloria del Angel ◽  
...  

A gallery of hydrotalcite-type mesoporous materials with different Mg/Al molar ratios were synthesized by the coprecipitation method. The materials were activated by heat treatment to test their activity in the photodegradation of 2,4,6-trichlorophenol under UV light irradiation. The physicochemical properties of the different synthesized and activated materials were determined using XRD, physical adsorption/desorption of N2, FTIR, SEM, DTA, and TGA. Their banned band energy was determined by UV-Vis to identify their potential to be used as a semiconductor in catalytic photodegradation processes. The results of photodegradation tests of 2,4,6-trichlorophenol showed that hydrotalcites have a high degradation capacity, up to 100% for the catalyst of Mg/Al ratio = 2, with a high mineralization capacity of 80%. The degradation capacity of most of the catalysts tested is mainly due to the presence of holes and the formation of superoxide free radicals, which are the determining species within the degradation mechanism.


Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1290 ◽  
Author(s):  
Mingyue Sun ◽  
Xiaoting Sun ◽  
Ziyuan Wang ◽  
Shuyu Guo ◽  
Guangjiao Yu ◽  
...  

Photocrosslinked gelatin methacryloyl (GelMA) hydrogels have attracted great concern in the biomedical field because of their good biocompatibility and tunable physicochemical properties. Herein, different approaches to synthesize GelMA were introduced, especially, the typical method using UV light to crosslink the gelatin-methacrylic anhydride (MA) precursor was introduced in detail. In addition, the traditional and cutting-edge technologies to characterize the properties of GelMA hydrogels and GelMA prepolymer were also overviewed and compared. Furthermore, the applications of GelMA hydrogels in cell culture and tissue engineering especially in the load-bearing tissue (bone and cartilage) were summarized, followed by concluding remarks.


2015 ◽  
Vol 365 ◽  
pp. 178-182 ◽  
Author(s):  
Sara Faiz Hanna Tasfy ◽  
Noor Asmawati Mohd Zabidi ◽  
Maizatul S. Shaharun ◽  
Duvvuri Subbarao

The present work investigates the hydrogenation of CO2 to methanol via a promoted Cu/ZnO/SBA-15 catalyst. In order to understand the effect of Mn, Zr and Pb promoters on the catalytic activity of Cu/Zn/SBA-15 catalysts, the hydrogenation of CO2 was performed in a stirred high-pressure reactor at 483K, 22.5bar, and a H2/CO2 ration of 3. The physicochemical properties of the catalysts were studied using N2 physical adsorption, TEM and H2-TPR. The characteristics of catalysts depended on the type of promoter and it influenced their catalytic performance. The Mn and Zr promoters resulted in a larger surface area of the catalyst and improved catalytic activity and methanol selectivity. However, an opposite effect was found for the Pb promoter. A 10% improvement on the CO2 conversion and 20% on the methanol selectivity was achieved due to the double promotion effect of Mn and Zr on Cu/ZnO-SBA-15 catalyst.


2021 ◽  
Vol 11 (16) ◽  
pp. 7607
Author(s):  
Souad Boumad ◽  
Antonia Infantes-Molina ◽  
Isabel Barroso-Martín ◽  
Elisa Moretti ◽  
Enrique Rodríguez-Castellón ◽  
...  

This research aims to study the possible improvement of methylene blue (MB) removal from aqueous solution by hybrid adsorbent-catalysts (AdsCats) prepared through the incorporation of activated carbon derived from Luffa cylindrica fibers (LAC) to TiO2 photocatalysts. LAC with a specific surface area of 1170 m2/g was prepared by chemical activation with phosphoric acid at 500 °C. TiO2/LAC composites with 70 and 90 wt.% Degussa P25 titania content were prepared. The materials were characterized by N2 physical adsorption, XRD, FTIR, and XPS. The AdsCats displayed a very good dispersion of TiO2 over LAC, a surface area of close to 200 or 400 m2/g, depending on the composition, and high crystallinity, showing the presence of anatase and rutile phases. MB removal was studied in two different scenarios: under UV-light after reaching adsorption equilibrium, and under UV-light once the liquid effluent and the AdsCats were in contact. The MB removal by LAC has proved to be very efficient, highlighting the predominant role of adsorption over photodegradation. The prepared AdsCats have also been compared with their components. The results showed that TiLAC hybrids have superior photocatalytic performance than P25, showing TiLAC-7/3 90% MB removal with respect to the initial concentration just after 30 min of UV light irradiation for both studied scenarios.


2013 ◽  
Vol 03 (03) ◽  
pp. 329-337 ◽  
Author(s):  
Chengzhang Wang ◽  
Yanhe Dong ◽  
Hongxia Cheng ◽  
Yuanfeng He ◽  
Jianzhong Ye ◽  
...  

Author(s):  
A. Legrouri

The industrial importance of metal catalysts supported on reducible oxides has stimulated considerable interest during the last few years. This presentation reports on the study of the physicochemical properties of metallic rhodium supported on vanadium pentoxide (Rh/V2O5). Electron optical methods, in conjunction with other techniques, were used to characterise the catalyst before its use in the hydrogenolysis of butane; a reaction for which Rh metal is known to be among the most active catalysts.V2O5 powder was prepared by thermal decomposition of high purity ammonium metavanadate in air at 400 °C for 2 hours. Previous studies of the microstructure of this compound, by HREM, SEM and gas adsorption, showed it to be non— porous with a very low surface area of 6m2/g3. The metal loading of the catalyst used was lwt%Rh on V2Q5. It was prepared by wet impregnating the support with an aqueous solution of RhCI3.3H2O.


Author(s):  
Debby A. Jennings ◽  
Michael J. Morykwas ◽  
Louis C. Argenta

Grafts of cultured allogenic or autogenic keratlnocytes have proven to be an effective treatment of chronic wounds and burns. This study utilized a collagen substrate for keratinocyte and fibroblast attachment. The substrate provided mechanical stability and augmented graft manipulation onto the wound bed. Graft integrity was confirmed by light and transmission electron microscopy.Bovine Type I dermal collagen sheets (100 μm thick) were crosslinked with 254 nm UV light (13.5 Joules/cm2) to improve mechanical properties and reduce degradation. A single cell suspension of third passage neonatal foreskin fibroblasts were plated onto the collagen. Five days later, a single cell suspension of first passage neonatal foreskin keratinocytes were plated on the opposite side of the collagen. The grafts were cultured for one month.The grafts were fixed in phosphate buffered 4% formaldehyde/1% glutaraldehyde for 24 hours. Graft pieces were then washed in 0.13 M phosphate buffer, post-fixed in 1% osmium tetroxide, dehydrated, and embedded in Polybed 812.


Author(s):  
W. Engel ◽  
M. Kordesch ◽  
A. M. Bradshaw ◽  
E. Zeitler

Photoelectron microscopy is as old as electron microscopy itself. Electrons liberated from the object surface by photons are utilized to form an image that is a map of the object's emissivity. This physical property is a function of many parameters, some depending on the physical features of the objects and others on the conditions of the instrument rendering the image.The electron-optical situation is tricky, since the lateral resolution increases with the electric field strength at the object's surface. This, in turn, leads to small distances between the electrodes, restricting the photon flux that should be high for the sake of resolution.The electron-optical development came to fruition in the sixties. Figure 1a shows a typical photoelectron image of a polycrystalline tantalum sample irradiated by the UV light of a high-pressure mercury lamp.


Author(s):  
Ś Lhoták ◽  
I. Alexopoulou ◽  
G. T. Simon

Various kidney diseases are characterized by the presence of dense deposits in the glomeruli. The type(s) of immunoglobulins (Igs) present in the dense deposits are characteristic of the disease. The accurate Identification of the deposits is therefore of utmost diagnostic and prognostic importance. Immunofluorescence (IF) used routinely at the light microscopical level is unable to detect and characterize small deposits found in early stages of glomerulonephritis. Although conventional TEM is able to localize such deposits, it is not capable of determining their nature. It was therefore attempted to immunolabel at EM level IgG, IgA IgM, C3, fibrinogen and kappa and lambda Ig light chains commonly found in glomerular deposits on routinely fixed ( 2% glutaraldehyde (GA) in 0.1M cacodylate buffer) kidney biopsies.The unosmicated tissue was embedded in LR White resin polymerized by UV light at -10°C. A postembedding immunogold technique was employed


2020 ◽  
Vol 90 (5-6) ◽  
pp. 439-447 ◽  
Author(s):  
Andrew Hadinata Lie ◽  
Maria V Chandra-Hioe ◽  
Jayashree Arcot

Abstract. The stability of B12 vitamers is affected by interaction with other water-soluble vitamins, UV light, heat, and pH. This study compared the degradation losses in cyanocobalamin, hydroxocobalamin and methylcobalamin due to the physicochemical exposure before and after the addition of sorbitol. The degradation losses of cyanocobalamin in the presence of increasing concentrations of thiamin and niacin ranged between 6%-13% and added sorbitol significantly prevented the loss of cyanocobalamin (p<0.05). Hydroxocobalamin and methylcobalamin exhibited degradation losses ranging from 24%–26% and 48%–76%, respectively; added sorbitol significantly minimised the loss to 10% and 20%, respectively (p < 0.05). Methylcobalamin was the most susceptible to degradation when co-existing with ascorbic acid, followed by hydroxocobalamin and cyanocobalamin. The presence of ascorbic acid caused the greatest degradation loss in methylcobalamin (70%-76%), which was minimised to 16% with added sorbitol (p < 0.05). Heat exposure (100 °C, 60 minutes) caused a greater loss of cyanocobalamin (38%) than UV exposure (4%). However, degradation losses in hydroxocobalamin and methylcobalamin due to UV and heat exposures were comparable (>30%). At pH 3, methylcobalamin was the most unstable showing 79% degradation loss, which was down to 12% after sorbitol was added (p < 0.05). The losses of cyanocobalamin at pH 3 and pH 9 (~15%) were prevented by adding sorbitol. Addition of sorbitol to hydroxocobalamin at pH 3 and pH 9 reduced the loss by only 6%. The results showed that cyanocobalamin was the most stable, followed by hydroxocobalamin and methylcobalamin. Added sorbitol was sufficient to significantly enhance the stability of cobalamins against degradative agents and conditions.


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