scholarly journals Synthesis of silica nanoparticles from rice husk ash

2018 ◽  
Vol 20 (K7) ◽  
pp. 50-54
Author(s):  
Nhung Thi Thuy Dang ◽  
Trinh Thi Ai Nguyen ◽  
Tuan Dinh Phan ◽  
Hoa Tran ◽  
Phu Van Dang ◽  
...  

Silica nanoparticles (SiO2 NPs) were synthesized from rice husk ash (RHA) by chemical treatment and calcination. The size of SiO2 NPs evaluated by transmission electron microscope (TEM) was of 20 - 50 nm and the size distribution of SiO2 NPs measured by dynamic laser scattering (DLS) was of Gaussian mode. The X-ray diffraction (XRD) pattern with only one peak at 2θ ~ 220 confirmed the amorphous phase of SiO2 NPs. The Fourier transform infrared (FTIR) and energydispersive X-ray (EDX) spectra were also used to evaluate the functional groups and the purity of SiO2 NPs. The SiO2 NPs powder with high purity could be suitably produced by calcination of acid treated RHA at 7000C for 2h. The obtained SiO2 NPs product can be potentially used for numerous purposes of application, especially as filler in paints.

2012 ◽  
Vol 174-177 ◽  
pp. 508-511
Author(s):  
Lin Lin Yang ◽  
Yong Gang Wang ◽  
Yu Jiang Wang ◽  
Xiao Feng Wang

BiFeO3 polyhedrons had been successfully synthesized via a hydrothermal method. The as-prepared products were characterized by power X-ray diffraction (XRD) pattern, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The possible mechanisms for the formation of BiFeO3 polyhedrons were discussed. Though comparison experiments, it was found that the kind of precursor played a key role on the morphology control of BiFeO3 crystals.


2022 ◽  
Author(s):  
Sunita Kumari ◽  
Dhirendra Singhal ◽  
Rinku Walia ◽  
Ajay Rathee

Abstract The present project proposes to utilize rice husk and maize cob husk ash in the cement to mitigate the adverse impact of cement on environment and to enhance the disposal of waste in a sustainable manner. Ternary concrete / MR concrete was prepared by using rise husk and maize cob ash with cement. For the present project, five concrete mixes MR-0 (Control mix), MR-1 (Rice husk ash 10% and MR-2.5%), MR-2 (Rice husk ash 10% and MR-5%), MR-3 (Rice husk ash 10% and MR-2.5%), MR-4 (Rice husk ash 10% and MR-2.5%) were prepared. M35 concrete mix was designed as per IS 10262:2009 for low slump values 0-25mm. The purpose is to find the optimum replacement level of cement in M35 grade ternary concrete for I – Shaped paver blocks.In order to study the effects of these additions, micro-structural and structural properties test of concretes have been conducted. The crystalline properties of control mix and modified concrete are analyzed by Fourier Transform Infrared Spectroscope (FTIR), Scanning Electron Microscopy (SEM), and X-Ray Diffraction (XRD). The results indicated that 10% Rice husk ash and 5% maize cob ash replaced with cement produce a desirable quality of ternary concrete mix having good compressive strength. The results of SEM analysis indicated that the morphology of both concrete were different, showing porous structure at 7 days age and become unsymmetrical with the addition of ashes. After 28 day age, the control mix contained more quantity of ettringite and became denser than ternary concrete. XRD analysis revealed the presence of portlandite in large quantity in controlled mix concrete while MR concrete had the partially hydrated particle of alite.


2016 ◽  
Vol 869 ◽  
pp. 209-214 ◽  
Author(s):  
Iara Janaína Fernandes ◽  
Daiane Calheiro ◽  
Emanuele Caroline Araújo dos Santos ◽  
Roxane Oliveira ◽  
Tatiana Louise Avila de Campos Rocha ◽  
...  

The use of rice husk ash (RHA) as filler in polymeric materials has been studied in different polymers. Research reported that RHA may successfully replace silica. The silica production process using ore demands high energy input and produces considerable amounts of waste. Therefore, the replacement of silica by RHA may be economically and environmentally advantageous, reducing environmental impact and adding value to a waste material. In this context, this study characterizes and compares RHA of different sources (moving grate and fluidized bed reactor) with commercially available silicas to assess performance as filler in polymeric materials. Samples were characterized by X-ray fluorescence, loss on ignition, X-ray diffraction, grain size, specific surface area, specific weight, and scanning electron microscopy. The results show that RHA may be used as a filler in several polymeric materials.


2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Neeraj Jain

Investigations carried out to study the effect of Cr (VI) (1000–3000 mg/l) on solidification and hydration behavior of Ordinary Portland cement (OPC) and rice husk ash (RHA) blended (10%, 20%, and 30%) cement show that addition of RHA accelerates final setting as compared to control samples (OPC) and retardation in setting time has been observed on increase in rice husk ash concentration (10%–30%). Solidification studies show that the compressive strength of controls and rice husk ash blended samples increases with increase in the curing period and maximum strength was observed with 20% RHA blended samples. With the increase in Cr (VI) concentrations, the strength of OPC and RHA blended samples decreases as compared to controls (without chromium). The results of Toxicity Characteristics Leaching Procedure (TCLP) test, (pH≅3), show that the retention capacity of OPC and RHA blended samples was in the range of 92% to 99% and the leached Cr (VI) concentration was under the allowable limit (5 mg/l) of U.S. EPA. The chemistry of influence of Cr (VI) on hydration of cement was examined by X-ray diffraction which shows the formation of various crystalline phases during solidification in rice hush ash blended cement.


2012 ◽  
Vol 517 ◽  
pp. 430-436
Author(s):  
J.L. Akasaki ◽  
E.J. Silva ◽  
L.C. Sousa ◽  
J.L.P. Melges ◽  
M.M. Tashima ◽  
...  

Rice production in Brazil in 2010 was approximately 12,2 million tons, and to reach that amount several planting techniques were used with different strains of rice in different rice-growing areas. Since Rice Husk Ash (RHA) is the pozzolan of vegetable origin most studied by researchers working in the area of pozzolanic materials, the present paper evaluates the influence that the form of planting, the climate, the soil, the strain of rice and the origin/amount of nitrogen-based fertilizers used in rice cultivation has on the chemical composition and crystallographic properties of RHA. The results obtained in this paper, confirm the importance of carrying out routine chemical analysis and X-Ray diffraction to maintain the quality control of the CCAs produced, because in situations of large-scale production, husks of different origins may be used.


2014 ◽  
Vol 807 ◽  
pp. 115-121 ◽  
Author(s):  
Fatihah Aplop ◽  
Mohd Rafie bin Johan

Zinc doped Cadmium Selenide Quantum Dots (CdSe/Zn QDs) were synthesized via inverse micelle technique. The absorption spectra exhibit a strong blue-shift characteristic due to quantum confinement effect. The X-ray Diffraction (XRD) pattern showed the zinc-blende phase of Zn doped CdSe QDs. Transmission Electron Microscopy (TEM) images suggested that the sizes of QDs were falls in range between 2 – 8 nm, with narrow size distribution. The TEM images also revealed that the Zn doped CdSe QDs were spherical, having a compact and dense structure. The optical bandgap of Zn-doped CdSe QDs are smaller than the undoped CdSe QDs as shown in Tauc’s plot. The fourier transform infrared spectra proves the complexion of CdSe-Zn QDs.


2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Qingfeng Sun ◽  
Yun Lu ◽  
Jinchun Tu ◽  
Dongjiang Yang ◽  
Jun Cao ◽  
...  

We report a bulky macroporous TiO2particles with cellular structure prepared in the presence of wood slices as template. Firstly, TiO2sol was coated onto the wood slices by repeated dip-coating process. Then, after calcinations at 550°C, the wood template could be removed, and the bulky TiO2structure was obtained. The prepared samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), and transmission electron microscope (TEM) techniques. XRD pattern confirmed the crystalline phase of the wood-templated TiO2is anatase phase. And interestingly, from the observation of SEM image, the wood-templated TiO2inherited the initial cellular structures of birch lumber (B. albosinensis Burk), and numerous macropores were observed in the sample. Meanwhile, the wood-templated TiO2presented a superior photocatalytic ability to decompose Rhodamine B (RhB) under ultraviolet irradiation.


2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Wilson Sacchi Peternele ◽  
Victoria Monge Fuentes ◽  
Maria Luiza Fascineli ◽  
Jaqueline Rodrigues da Silva ◽  
Renata Carvalho Silva ◽  
...  

Iron oxides that exhibit magnetic properties have been widely studied not only from an academic standpoint, but also for numerous applications in different fields of knowledge, such as biomedical and technological research. In this work, magnetite and maghemite nanoparticles were synthesized by chemical coprecipitation of FeCl2·4H2O and FeCl3·6H2O (proportion of 1 : 2) in three different cases using two bases (sodium hydroxide and hydroxide ammonium) as precipitants. The chemical coprecipitation method was selected for its simplicity, convenience, reproducibility, and low cost in the use of glassware. The nanostructured materials were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and magnetometry (VSM). The objective of this work is to study the variation in the morphological characteristics and physical properties of nanoparticles magnetic as a function of the different production processes. As observed by TEM, the materials obtained from the precipitating agent NH4OH are more uniform than those obtained with NaOH. From XRD pattern analysis, it appears that the obtained materials correspond to magnetite and maghemite and, from magnetometry VSM analysis, show high magnetization as a function of the magnetic field at room temperature, indicating that these materials are superparamagnetic.


2018 ◽  
Vol 25 (4) ◽  
pp. 15-22
Author(s):  
Abbas Y. Awad ◽  
Mohammed N. Ibrahim ◽  
Mohamed K. Hussein

A336.0 aluminum alloy used to fabricate hybrid composites using rice husk ash (RHA) and MgO particles as reinforcement. The influence of the particles on the wear behavior of A336.0 aluminum alloy as a matrix that reinforced with MgO and RHA was investigated. Firstly, the rice husk burned at 700°C and then heat treated at 1100°C for 2 hrs. The ash characterized by X-ray florescence and X-ray diffraction. Less than 53 and 125 micron are the particle sizes of MgO and RHA respectively. The hybrid composites manufactured using stir casting method in two steps. A336.0 aluminum alloy reinforced with 4:0, 3:1, 2:2, 1:3 and 0:4 of RHA: MgO with 10 wt% total reinforcement phase. Optical microscope and X-ray diffraction were used to characterize the prepared hybrid composites. Dry sliding wear, hardness, apparent density, percentage of porosity and coefficient of friction were examined. Results indicated that porosity, apparent density and hardness enhanced with increasing MgO, while increasing wt% of RHA decreased the apparent density. Results indicated that with inceasing the applied load the wear rate of the composites was enhanced. Coefficient of friction varies inversely with applied load and wt% of RHA. Hardness increased with increasing RHA while the friction coefficient and the wear rate decreased. The minimum wear rates were at 10% RHA and Al-alloy-(RHA-MgO) [3:1] composites, while the minimum friction coefficients were at 10% RHA composites.


2021 ◽  
Vol 22 (4) ◽  
pp. 11-17
Author(s):  
Haider Abbas ◽  
Ammar S. Abbas

In recent years, it has been evident that searching for alternative methods with low-price and eco-friendly features that produce high-quality adsorbents is in high demand. In the present work, Rice husk from Iraqi rice named (Amber) had been used as the primary source to produce rice husk ash (RHA) for the removal of the antibiotic metronidazole (Flagyl) from water. After optimum drying of rice husk, rice husk ash (RHA) was obtained at 600 °C using an electric oven. RHA has been investigated for properties using X-ray diffraction (XRD), porosity, and surface area (SA). The experimental work adsorption data were optimized to evaluate Langmuir and Freundlich constants. The thermodynamic parameters likely a change in Gipp's energy (ΔG), enthalpy (ΔH), and entropy (ΔS). The impacts of increasing temperature on adsorption capacity were investigated, and the results indicate that the pseudo-second-order kinetics model could be presented the dynamic adsorption data that it has. The resultant values for the heat of adsorption and the free energy indicated that adsorption of Flagyl is preferred at low temperatures.


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