Nezami Shanli, Ghaemi Ahad, Yousefi Taher
School of Chemical, Petroleum and Gas Engineering, Iran University of Science and Technology, Narmak, Tehran, 16846, Iran.
Nuclear Fuel Cycle Research School, Nuclear Science and Technology Research Institute, Tehran, Iran.
Sci Rep. 2024 Dec 4;14(1):30221. doi: 10.1038/s41598-024-82186-0.
TiCT is synthesized from TiAlC by two common methods, HF and HF in situ. The synthesis approach is very practical regarding the structure, morphology, space between layers, type and number of surface-active sites and its specific surface. XRD, SEM, EDS, FTIR and BET analyzes were used to investigate the structure, morphology, type and number of surface-active sites. Under the operating conditions of cesium initial concentration ~ 150 ppm, ambient temperature, pH ~ 7.00 and time of 60 min, the cesium adsorption intensity with TiCT-HF and TiCT-HF in situ was obtained as 194 and 219.5 mg.g, respectively. The structural results of modification with KHPO show that in this modification, in addition to the increase of hydroxyl functional groups, the distance between the layers has also increased and the cesium adsorption intensity has increased to 338.75 mg.g under the above operating conditions. Meanwhile, in modification with Chitosan by increasing the frequency of functional groups and specific surface up to 3 times the effective specific surface of TiCT-HF in situ, no significant change in the cesium adsorption intensity has been observed (247.5 mg.g). Experiments were conducted to evaluate the effect of parameters of initial concentration of Cs (250 - 50 ppm), time (30-60 min), ambient temperature (298.15-318.15 K), solution pH (3.0-11.0) with the help of RSM design. RSM results show that the pH parameter is one of the most important parameters affecting the cesium adsorption intensity with TiC(OH) and TiC(OH)-KHPO. Also, with the increase in temperature, the adsorption intensity should increase. It is shown in the isotherm modeling that R matches well with the Freundlich isotherm model, which is based on the layered structure of TiC(OH) and TiC(OH)-KHPO and the presence of active sites with different energy levels, which leads to heterogeneous adsorption. The consistency will be of the adsorbent selectivity investigation shows that the Cs hydration radius plays a decisive role in its high adsorption potential. Reduction of MXene by 0.1 M HCl was carried out in 3 steps. The experimental results show that 15% absorption has been achieved in the third stage. The results of structural analysis show that its structure has not changed and the reduction of active sites as a result of washing with acid has led to a decrease in adsorption.
TiCT由TiAlC通过两种常见方法合成，即氢氟酸法（HF）和原位氢氟酸法（HF in situ）。该合成方法在结构、形态、层间距、表面活性位点的类型和数量及其比表面积方面非常实用。采用X射线衍射（XRD）、扫描电子显微镜（SEM）、能谱分析（EDS）、傅里叶变换红外光谱（FTIR）和比表面积分析仪（BET）分析来研究结构、形态、表面活性位点的类型和数量。在铯初始浓度约为150 ppm、环境温度、pH约为7.00以及时间为60分钟的操作条件下，TiCT-HF和原位TiCT-HF对铯的吸附强度分别为194和219.5 mg/g。用KHPO改性的结构结果表明，在这种改性中，除了羟基官能团增加外，层间距也增大了，并且在上述操作条件下铯吸附强度增加到338.75 mg/g。同时，在用壳聚糖改性时，通过将官能团频率和比表面积提高到原位TiCT-HF有效比表面积的3倍，未观察到铯吸附强度有显著变化（247.5 mg/g）。借助响应曲面法（RSM）设计进行实验，以评估铯初始浓度（250 - 50 ppm）、时间（30 - 60分钟）、环境温度（298.15 - 318.15 K）、溶液pH（3.0 - 11.0）等参数的影响。RSM结果表明，pH参数是影响TiC(OH)和TiC(OH)-KHPO对铯吸附强度的最重要参数之一。此外，随着温度升高，吸附强度应增加。等温线模型表明，R与弗伦德利希等温线模型匹配良好，这基于TiC(OH)和TiC(OH)-KHPO的层状结构以及不同能级活性位点的存在，导致非均相吸附。吸附剂选择性研究的一致性表明，铯水合半径在其高吸附潜力中起决定性作用。用0.1 M盐酸对MXene进行还原分三步进行。实验结果表明，在第三阶段实现了15%的吸附。结构分析结果表明其结构未发生变化，酸洗导致活性位点减少，从而使吸附量下降。
