Zewide Yigezu Temesgen, Yemata Temesgen Atnafu, Ayalew Adane Adugna, Kedir Hawi Jihad, Tadesse Asab Alemneh, Fekad Asmarech Yeshaneh, Shibesh Alemayehu Keflu, Getie Fentahun Adamu, Tessema Tegen Dagnew, Wubieneh Tessera Alemneh, Kululo Wondmagegn Wonago, Mihiret Muluken Tilahun
Department of Chemical Engineering, Bahir Dar Institute of Technology, Bahir Dar University, P.O. Box 26, Bahir Dar, Ethiopia.
Department of Chemical Engineering, Dire Dawa University, P.O. Box 1362, Dire Dawa, Ethiopia.
Sci Rep. 2025 Jan 2;15(1):132. doi: 10.1038/s41598-024-83724-6.
This work aimed to extract silica from combination of rice husk (RH and Rice straw (RS) by optimizing the ash digesting process parameters with the aid of response surface methodology (RSM). The effects of three independent ash digestion process factors like sodium hydroxide concentration (1-3 M), temperature (60-120 °C) and time (1-3 h), for silica production from the mixture of rice husk (RH) and rice straw (RS) were studied. A quadratic model was used to correlate the interaction effects of the independent variables for maximum silica production at the optimum process parameters by employing central composite design (CCD) with RSM. The work indicates that the temperature is the most significant parameter among the model terms, followed by NaOH concentration, then time for digestion of ash for silica production. It may be because of the larger F-value for temperature, which influences to high extent of ash digestion for silica production. The proximate analysis discovered that RH/RS possessed compositions of high ash, volatile matter and fixed carbon content whereas low moisture content, i.e., 20.5 ± 0.46, 67.1 ± 0.78, 15.8 ± 0.35 and, 6.6 ± 0.37 wt.%, correspondingly. The characterization of RH/RS and silica were performed by employing thermogravimetric (TG) and differential thermal (DT), Fourier transforms infrared spectroscopy (FTIR), X-ray fluorescence spectroscopy (XRF) and Brunner-Emmet-Teller (BET) for confirmation of the silica production. Hence, this current study concludes that silica materials obtained from RH/RS (with purity > 97.35 wt.%) may be new materials in the Si-C-O system that may be used in construction, ceramics and silica gel that helps to absorb moisture.
本研究旨在借助响应面法（RSM）优化灰分消化工艺参数，从稻壳（RH）和稻草（RS）的混合物中提取二氧化硅。研究了氢氧化钠浓度（1 - 3 M）、温度（60 - 120 °C）和时间（1 - 3 h）这三个独立的灰分消化工艺因素对稻壳（RH）和稻草（RS）混合物生产二氧化硅的影响。采用二次模型，通过中心复合设计（CCD）与RSM关联自变量的相互作用效应，以在最佳工艺参数下实现最大二氧化硅产量。研究表明，在模型项中温度是最显著的参数，其次是氢氧化钠浓度，然后是灰分消化生产二氧化硅的时间。这可能是因为温度的F值较大，对二氧化硅生产的灰分消化程度影响较大。近似分析发现，RH/RS具有高灰分、挥发物和固定碳含量的组成，而水分含量较低，分别为20.5±0.46、67.1±0.78、15.8±0.35和6.6±0.37 wt.%。通过热重（TG）和差热（DT）、傅里叶变换红外光谱（FTIR）、X射线荧光光谱（XRF）和布鲁诺 - 埃米特 - 泰勒（BET）对RH/RS和二氧化硅进行表征，以确认二氧化硅的生产。因此，本研究得出结论，从RH/RS获得的二氧化硅材料（纯度>97.35 wt.%）可能是Si - C - O系统中的新材料，可用于建筑、陶瓷和有助于吸收水分的硅胶。
