scholarly journals Synthesis of Selenium-Containing Polystyrene Microspheres and Using as Catalyst for Oxidation of Acrolein

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1632
Author(s):  
Yuanyuan Zhang ◽  
Xiangqiang Pan ◽  
Jian Zhu

Selenium-containing polystyrene (DSe-PS) microspheres were synthesized by soap-free emulsion polymerization using 1,2-bis(2,3,5,6-tetrafluoro-4-vinylphenyl)diselane (FVPDSe) and divinylbenzene (DVB) as crosslinking agents. The particle size of the obtained DSe-PS was characterized by a scanning electron microscope and dynamic light scattering. The results showed that the diameter of the obtained DSe-PS microspheres could be adjusted by changing the ratio of the monomer and crosslinker/water. The diselenide moiety in the obtained DSe-PS microspheres could be oxidized to seleninic acid by H2O2 which can catalyze the oxidation of acrolein. The oxidized DSe-PS microspheres exhibited higher catalytic activity and selectivity to methyl acrylate in a model oxidation of acrolein.

2021 ◽  
Vol 02 (01) ◽  
Author(s):  
Siti Khadijah Hubadillah ◽  
◽  
Norsiah Hami ◽  
Nurul Azita Salleh ◽  
Mohd Riduan Jamalludin ◽  
...  

The purpose of this work is to study the effect of kaolin particle size for the preparation of low cost ceramic membrane suspension and ceramic membrane structure. Kaolin particle size is categorized into two categories; i) ≤ 1µm and ii) ≥ 1 µm. The suspension is prepared via stirring technique under 1000 rpm at 60°C. The particle size of kaolin is characterized using field emission scanning electron microscope (FESEM) and the prepared suspension is characterized in term of its viscosity. Results indicate that the particle size gave significant effect to the viscosity of ceramic membrane suspension. Preliminary data showed that kaolin with particle size ≤ 1µm resulted ceramic membrane with dense structure.


2019 ◽  
Vol 25 (05) ◽  
pp. 1183-1194
Author(s):  
Mandy C. Nevins ◽  
Richard K. Hailstone ◽  
Eric Lifshin

AbstractPoint spread function (PSF) deconvolution is an attractive software-based technique for resolution improvement in the scanning electron microscope (SEM) because it can restore information which has been blurred by challenging operating conditions. In Part 1, we studied a modern PSF determination method for SEM and explored how various parameters affected the method's ability to accurately estimate the PSF. In Part 2, we extend this exploration to PSF deconvolution for image restoration. The parameters include reference particle size, PSF smoothing (K), background correction, and restoration denoising (λ). Image quality was assessed by visual inspection and Fourier analysis. Overall, PSF deconvolution improved image quality. Low λ enhanced image sharpness at the cost of noise, while high λ created smoother restorations with less detail. λ should be chosen to balance feature preservation and denoising based on the application. Reference particle size within ±0.9 nm and K within a reasonable range had little effect on restoration quality. Restorations using background-corrected PSFs had superior quality compared with using no background correction, but if the correction was too high, the PSF was cut off causing blurrier restorations. Future efforts to automatically determine parameters would remove user guesswork, improve this method's consistency, and maximize interpretability of outputs.


Clay Minerals ◽  
2011 ◽  
Vol 46 (3) ◽  
pp. 515-523 ◽  
Author(s):  
Youjun Deng ◽  
M. G. Tenorio Arvide

AbstractThe objective of this study was to build an automated size fractionator to process up to 16 samples at one time. Most parts used in the apparatus are inexpensive items, available from lawn irrigation, household appliance and aquatic pet supply stores. The device can be used to extract different silt and clay fractions by changing sedimentation time. A bentonite, a kaolin and an ironoxide-rich Oxisol were fractionated by this instrument to sequentially extract particles that have sizes equivalent to <2 µm, <5 µm, <10 µm and <20 µm quartz spheres. A laser diffraction particle size analyser revealed size differences in the different fractions and also showed that the silt fractions contained particles having slightly larger sizes than the assumed diameters of spherical quartz. Scanning electron microscope examination suggested that the greater particle size was mainly due to the non-spherical shapes of the particles and a reduced bulk density of the porous aggregates.


2020 ◽  
Vol 866 ◽  
pp. 115-124
Author(s):  
Zhan Kui Wang ◽  
Ming Hua Pang ◽  
Jian Xiu Su ◽  
Jian Guo Yao

In this paper, a series of chemical mechanical polishing (CMP) experiments for magnesia alumina (Mg-Al) spinel were carried out with different abrasives, and the materials removal rate (MRR) and surface quality was evaluated to explore their different effects. The scanning electron microscope (SEM) and laser particle size analyzer were also employed to test the micro-shape and size distribution of abrasives. Then, the mechanism of different effects with different abrasives was analyzed in CMP for Mg-Al spinel. Those experimental results suggest that different subjecting pressure ratios of abrasives to polishing pad with different abrasive are the key factors leading to difference polishing performances in CMP.


2012 ◽  
Vol 463-464 ◽  
pp. 760-763
Author(s):  
Zhen Zhao Pei ◽  
Hong Bin Xu ◽  
Yi Zhang

Nanoparticles of Cr2O3 were successfully obtained via hydrothermal reduction of CH3OH. The oxidant and chromium source was CrO3. The process needs no stirrer or surfactant and the CrO3 concentration was 0.83mol/L. The obtained products were loosely agglomerated Cr2O3 nanoparticles with the average size of 29 to 79 nm. Influences of reactant ratios and calcination temperatures on the specific surface area and average particle size were discussed. And the morphology of nanoparticles was investigated by use of field-emission scanning electron microscope.


2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Qiuxiang Zhang ◽  
Xinhua Liu ◽  
Yankun Ren ◽  
Lifeng Wang ◽  
Yuan Hu

Aiming to study the effect of particle size on the wear property of magnetorheological fluid (MRF), experiment materials, preparation process, and test methods are elaborated, and three different MRF samples consisting of particles of different size are prepared. Test experiments are carried out and the effect of particle size on the wear property of MRF is discussed. Moreover, the microstructures of particles extracted from MRF obtained before and after the wear experiments are observed by scanning electron microscope (SEM). Experimental results show that the particle size has a significant effect on wear property of MRF. Furthermore, the MRF with particles of 1.5–2.8 μm diameter on average is good for the requirement of engineering applications.


2013 ◽  
Vol 860-863 ◽  
pp. 956-959
Author(s):  
Xing Hua Liang ◽  
Lin Shi ◽  
Yu Si Liu ◽  
Tian Jiao Liu ◽  
Chao Chao Ye ◽  
...  

The High Potential Material Lini0.5Mn1.5O4 was Synthesized via Solid-State Reaction.The Surface Morphology and Particle Size of the Sample were Observed by Scanning Electron Microscope(SEM).The Crystal Structure of the Sample was Collected and Analyzed through X-Ray Diffractometry(XRD).The Sample was Charaterized by Charge-Discharge Tests.Results Indicated that the Cycling Retention Rate was about 80%,after being Charge-Diacharged at a Rate of 0.1C in a Voltage of 3.45-4.77V for 10 Times.Compared with Limn2O4,LiNi0.5Mn1.5O4 has good cycle performance.Both of LiNi0.5Mn1.5O4 structure were space group of Fd3m.


2011 ◽  
Vol 194-196 ◽  
pp. 2164-2168 ◽  
Author(s):  
Bai Kun Wang ◽  
Hao Ding ◽  
Yun Xing Zheng ◽  
Ning Liang

The amorphous silica was prepared from the alkali wastewater rich in Na2O•nSiO2 produced in manufacturing process of zirconium oxychloride (ZrOCl2). The composition and microstructure of amorphous silica were studied by X-ray diffraction, X-ray fluorescence and scanning electron microscope, respectively. The results showed that the amorphous silica was mainly composed of uncrystallized substance, and the silica content was 96.4%. Its whiteness was 97.5% and the particle size was between 100nm and 200nm without agglomeration. The specific surface area of the amorphous silica was 531.9 m2/g, and its pore volume and diameter were 0.945 cm3/g and 4.94 nm, respectively.


2017 ◽  
Vol 9 (2) ◽  
pp. 1-7 ◽  
Author(s):  
MAA Khan ◽  
MS Saha ◽  
S Sultana ◽  
AN Ahmed

Generally white carbon black in a form of silica is used instead of carbon black as reinforcing filler for rubber compounding. In the present research white carbon black was prepared from rice husks in cost effective method with direct incineration of acid leaching rice husk. The physico-chemical properties of rice husk and the product of white carbon black obtained from rice husk were investigated by Thermogravimetry, Particle size analyzer, Scanning electron microscope; Fourier transformed infrared radiation (FTIR), X-ray fluorescence and X-ray difractometry analyses. It was found that the decomposition of organic constituents of rice husk was revealed by Thermo gravimetric and carbon, hydrogen, nitrogen, sulpher (CHNS) analyses. The FTIR spectrum showed presence of Si-O-Si band with a strong peak at 1085 cm-1. The analysis of particle size and scanning electron microscope demonstrated that the produced white carbon black represent different size of 112 ?m to 0.01 ?m with very small nano-particle and amorphous structure. The amorphous structure of product was also confirmed by XRD pattern. The high pure product as 99.9% was confirmed by XRF analysis. These types of product have potential application as filler in rubber compounding.J. Environ. Sci. & Natural Resources, 9(2): 1-7 2016


2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Rani Oktaviani Saraswati ◽  
Ahmad Ni'matullah Al-Baarri ◽  
Heni Rizqiati ◽  
Anang Mohamad Legowo ◽  
Yoyok Budi Pramono ◽  
...  

This study aimed to analyze the magnification of visual image upon SEM analysis for determining the optimum view in order to obtain proper information of SEM image in ginger emulsion. The treatment in this research are without carrageenan, with iota carrageenan and with kappa carrageenan. Emulsion of ginger Graphical display testing according to using the Scanning Electron Microscope (SEM) method. The research showed that ginger emulsion with and without carrageenan were able to be seen clearly and the particle size were able to detected at a range 0.5-5 µm. The sample with iota carrageenan provided the information of separation among particles and it could not be seen clearly on the sample with kappa carrageenan. The low magnification of 250 times provided beneficial information to obtain the environment of particle.


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