In the present research, bovine serum albumin-modified silica from rice husk has been prepared and examined as adsorbent for removal of the metanil yellow dye. The silica was obtained by purification of silica from the rice husk. Rice husk was heated up at 700 °C for 4 h, the obtained rice husk ash was mixed with NaOH 5% and acidified with HNO₃ 10% to obtain silica. The modification was carried out by reacting silica with bovine serum albumin, and the amine-functionalized rice husk silica was obtained. The rice husk silica and amine-functionalized rice husk silica were characterized by Fourier-transform infrared, X-ray fluorescence, scanning electron microscopy, and Brunauer–Emmett–Teller. The adsorption study was conducted using batch method and investigated some parameters such as pH, adsorbate concentration, contact time, and temperature. The maximum adsorption capacity of rice husk silica and amine-functionalized rice husk silica was 25.975 and 82.345 mg/g, respectively. The adsorption process of metanil yellow dye onto rice husk silica followed Langmuir isotherm model. Besides, the adsorption of metanil yellow dye onto amine-functionalized rice husk silica was fitted to both Langmuir and Freundlich isotherm models (R² = 0.99). The kinetic data were well described by the pseudo-second-order (R² = 0.99) indicated a chemisorption process. The thermodynamic equation showed that the adsorption of metanil yellow dye onto rice husk silica was spontaneous through an endothermic reaction, while the adsorption onto amine-functionalized rice husk silica was spontaneous through exothermic reaction.

中文翻译：

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用牛血清白蛋白（BSA）修饰稻壳二氧化硅以改善对甲硝黄染料的吸附

在本研究中，已经制备了稻壳中的牛血清白蛋白改性二氧化硅，并作为吸附剂去除了甲硝黄染料。通过从稻壳中纯化二氧化硅获得二氧化硅。将稻壳在700°C加热4 h，将获得的稻壳灰分与5％NaOH混合并用HNO ₃酸化10％获得二氧化硅。通过使二氧化硅与牛血清白蛋白反应进行改性，从而获得胺官能化的稻壳二氧化硅。稻壳二氧化硅和胺官能化稻壳二氧化硅的特征在于傅立叶变换红外光谱，X射线荧光，扫描电子显微镜和Brunauer-Emmett-Teller。吸附研究采用间歇法进行，并研究了一些参数，例如pH，吸附物浓度，接触时间和温度。稻壳二氧化硅和胺官能化稻壳二氧化硅的最大吸附容量分别为25.975和82.345 mg / g。偏甲黄染料在稻壳二氧化硅上的吸附过程遵循Langmuir等温线模型。除了，R ²  = 0.99）。动力学数据很好地描述了拟二阶反应（R ²  = 0.99），表明化学吸附过程。热力学方程表明，甲腈黄染料通过吸热反应自发吸附，而胺官能化稻壳二氧化硅通过放热反应自发吸附。