Daniel F. Hincapié Rojas; Posidia Pineda Gómez; Andrés Rosales Rivera
Abstract
The rice process generates a large amount of husk, which can become an environmental contaminant if it does not receive an adequate management. Because rice husk is a natural source of silica, in this work silica nanoparticles were obtained as an alternative use for this residue. The synthesis was carried ...
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The rice process generates a large amount of husk, which can become an environmental contaminant if it does not receive an adequate management. Because rice husk is a natural source of silica, in this work silica nanoparticles were obtained as an alternative use for this residue. The synthesis was carried out with the incineration, acid leaching process, and particle size reduction through high-energy mechanical ball milling. For its characterization, thermal, chemical, morphological, structural and superficial area analyses were performed with thermogravimetric analysis, X-ray fluorescence method, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Nitrogen adsorption/desorption isotherm techniques. The results indicated that between 150-450°C the organic material of the rice husk was released, and above 550°C was obtained ash rich in silica. The silica purity was effectively increased to 98.48%, through acid leaching with acid nitric. The reduction of particle size by mechanical milling at 600 rpm for 3 h was achieved up to nanometer size. Most of the nanoparticles were spherical with a diameter between 14 and 28 nm. Silicon oxide was the principal structural phase of the nanoparticles corroborated by the broad peak corresponding to the (101) plane shown by XRD pattern. A substantial increase of two magnitude orders of the specific surface area of nanoparticles was reached in comparison with particles without milling. The nanosilica particles obtained from rice husk can be used for the production of high-performance silicon or they can be also used as supplementary cementitious materials.
S. K. Shukla; Anand Bharadvaja;G. C. Dubey
Abstract
Finely grinded rice husk (RH) has been treated with different alkalis (NaOH, KOH, Na2CO3 and KCO3) and a film was casted from obtained semi liquid product. The effect of various alkalis on physical properties like water absorption, swelling behavior, bulk density husk has been ...
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Finely grinded rice husk (RH) has been treated with different alkalis (NaOH, KOH, Na2CO3 and KCO3) and a film was casted from obtained semi liquid product. The effect of various alkalis on physical properties like water absorption, swelling behavior, bulk density husk has been investigated. The morphology and chemical structure were studied by Infrared spectroscopy (FT-IR), Optical microscopy and thermogravimetry (TG) techniques. The results revealed the formation of homogenous film with partial crystalline nature with better thermal stability than RH and approx half bulk density. Further, the developed film was found suitable for metal (Cu(II) and As (III) decontamination from prepared aqueous sample upto 90 and 93 % with removal capacity 2gm per sq cm.