高级检索

    碳化硅掺杂的偏钛酸型锂离子吸附剂的制备

    Preparation of silicon carbide-doped metatitanate lithium-ion adsorbents

    • 摘要: H2TiO3(HTO)因具有良好的理论吸附能力、稳定性和选择性,使其成为最具应用前途的锂离子筛,但由于实际吸附量和循环稳定性等不理想,阻碍了其工业应用。本研究采用高稳定性的碳化硅(SiC)为掺杂剂,用固相法制备了SiC掺杂的锂离子吸附剂。此外,采用一系列技术对其结晶度、形貌、亲水性、比表面积、样品表面元素价态等进行了系统表征,研究了吸附等温线、热力学、动力学和循环稳定性等。结果表明:适量SiC掺杂后制备出的HTO-SiC-0.03(0.03为掺杂量)颗粒大小更加均匀,亲水性和比表面积都得到改善,氧空位显著增加,从而增加了对锂离子的吸附容量。在298 K下HTO-SiC-0.03的平衡吸附量可达40.91 mg·g−1,相比未掺杂之前吸附容量(32.96 mg·g−1)明显增加。Li+在HTO-SiC-0.03上的吸附符合Langmuir模型及伪二级动力学模型,为自发吸热过程。经过5次吸附-解吸循环后,HTO-SiC-0.03的吸附量为初始值的95.1%,具有较高的稳定性。

       

      Abstract: H2TiO3(HTO) is one of the most promising type of lithium-ion sieves due to its high theoretical adsorption capacity, excellent stability, and strong selectivity. However, its industrial application was hindered by unsatisfactory practical adsorption capacity and cycling stability. A silicon carbide (SiC)-doped lithium ion adsorbent was prepared by the solid-phase method using highly stable SiC as the dopant. The resulting material was characterized using a range of techniques to evaluate its crystallinity, morphology, hydrophilicity, specific surface area, and elemental surface valence states. Furthermore, its adsorption performance was investigated in terms of adsorption isotherms, thermodynamics, kinetics, and cyclic stability. The results indicated that after moderate SiC doping, the HTO-SiC-0.03 particles demonstrated a more uniform size distribution, improved hydrophilicity and specific surface area, as well as a significant increase in oxygen vacancies, thereby enhancing the lithium ion adsorption capacity. At 298 K, the adsorption capacity of HTO-SiC-0.03 could reach 40.91 mg·g−1, which was significantly higher than that undoped sample (32.96 mg·g−1). The Li+ adsorption on HTO-SiC-0.03 was spontaneous and endothermic, following Langmuir isotherm model and pseudo-second-order kinetic model. After five adsorption-desorption cycles, the adsorption capacity of HTO-SiC-0.03 amounted to 95.1 % of the initial value, showing high stability.

       

    /

    返回文章
    返回