Silica Nanoparticles (SiNPs), due to its tunable properties and composition, meets the needs in specified applications. Rice Husk (RH), an agricultural waste, abundant in amorphous silica has its extensive application in various industrial products. However, the presence of impurities in RHs makes the extraction process difficult and optimum experimental conditions are needed to achieve maximum yield with specific properties for its specified applications. In this work, Rice Husk Ash (RHA) is prepared from RH by acid leaching followed by silica gel extraction from RHA via controlled pyrolysis at three temperatures (700°C, 750°C and 800°C). Pyrolyzed RHA is then dried and pulverized to get SiNPs. Characterization of SiNPs is done using UV-Vis Spectroscopy, X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). UV-Vis Spectroscopy and XRD analysis shows that the SiNPs extracted from RHA at 750°C exhibited the highest peak at 260 nm and 2θ=26° respectively and XRD and SEM analysis show that crystallite and particle size is in close agreement with each other. The optimum temperature being 750°C, silica gel formed at a pH 6 is more stable, transparent and thicker in comparison to the silica gel formed at varied pH. Moreover, the sodium silicate sample exhibits a bright green fluorescence and the intensity of fluorescence is higher for the sodium silicate prepared at 750°C range than at any other temperature.

中文翻译：

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稻壳灰中二氧化硅纳米粒子的提取及其表征

二氧化硅纳米粒子（SiNPs）由于其可调节的特性和组成而满足特定应用的需求。稻壳（RH）是一种农业废料，富含无定形二氧化硅，已广泛应用于各种工业产品中。但是，RHs中杂质的存在使萃取过程变得困难，并且需要最佳的实验条件以实现具有特定用途特定特性的最大产量。在这项工作中，稻谷壳灰（RHA）是通过在三个温度（700°C，750°C和800°C）下通过受控的热解作用从RH进行酸浸，然后从RHA进行硅胶提取而制得的。然后将热解的RHA干燥并粉碎，得到SiNPs。使用紫外-可见光谱，X射线衍射（XRD）和扫描电子显微镜（SEM）对SiNP进行表征。θ = 26°，XRD和SEM分析表明，微晶和粒径相互接近。最佳温度为750℃，与在不同pH值下形成的硅胶相比，在pH 6时形成的硅胶更稳定，透明且更厚。此外，硅酸钠样品表现出亮绿色荧光，并且在750℃范围内制备的硅酸钠的荧光强度高于在任何其他温度下。