Mpelane Siyasanga, Mketo Nomvano, Mlambo Mbuso, Bingwa Ndzondelelo, Nomngongo Philiswa N
Department of Chemical Sciences, University of Johannesburg, Doornfontein Campus, P.O. Box 17011, Doornfontein 2028, South Africa.
Analytical Facility, University of Johannesburg, P.O. Box 524, Auckland Park 2006, South Africa.
ACS Omega. 2022 Jun 23;7(27):23302-23314. doi: 10.1021/acsomega.2c01460. eCollection 2022 Jul 12.
This study describes for the first time the synthesis, characterization, and application of a MnFeO/GO core-shell nanocomposite as an adsorbent for the removal of levofloxacin (Lev) from real water samples. The formation of the proposed nanocomposite was confirmed using various characterization techniques. The structural techniques revealed a 20 nm average particle size of the MnFeO/GO core-shell nanocomposite, with a surface area of 70.7 m g, as shown by the BET results. The most influential parameters (adsorbent dosage, stirring rate, and Lev pH) that affected the adsorption process were optimized using the response surface methodology (RSM) based on a central composite design. The optimum conditions were 0.007 g, 2, and 7 for adsorbent dosage, stirring rate, and Lev pH, respectively. The adsorption behavior of Lev on the MnFeO/GO core-shell nanocomposite was examined using isotherm models, kinetics, and thermodynamics. The kinetic models demonstrated that the adsorption process was controlled by both intraparticle and outer diffusion. Furthermore, the results obtained revealed that the adsorption of Lev on MnFeO/GO was dominated by electrostatic interactions. Moreover, Dubinin-Radushkevich and Temkin isotherms confirmed that the sorption mechanism was dominated by electrostatic interactions, while Langmuir and Sips models confirmed a monolayer adsorption process. The maximum adsorption capacity of Lev onto the MnFeO/GO adsorbent was found to be 129.9 mg g. Furthermore, the thermodynamic data revealed that the adsorption system was spontaneous and exothermic. The synthesized MnFeO/GO core-shell nanocomposite showed significant recyclability and regenerability properties up to five adsorption-desorption cycles. As a proof of concept, the performance of the prepared adsorbent was evaluated for laboratory-scale purification of spiked real water samples. The prepared adsorbent significantly reduced the concentration of Lev in the real water samples and the removal efficiency ranged from 86 to 97%.
本研究首次描述了MnFeO/GO核壳纳米复合材料的合成、表征及其作为吸附剂用于从实际水样中去除左氧氟沙星（Lev）的应用。使用各种表征技术证实了所提出的纳米复合材料的形成。结构技术表明，MnFeO/GO核壳纳米复合材料的平均粒径为20 nm，BET结果显示其表面积为70.7 m²/g。基于中心复合设计，采用响应面法（RSM）优化了影响吸附过程的最具影响力的参数（吸附剂用量、搅拌速率和Lev的pH值）。最佳条件分别为吸附剂用量0.007 g、搅拌速率2和Lev的pH值7。使用等温线模型、动力学和热力学研究了Lev在MnFeO/GO核壳纳米复合材料上的吸附行为。动力学模型表明，吸附过程受颗粒内扩散和外扩散控制。此外，所得结果表明，Lev在MnFeO/GO上的吸附主要由静电相互作用主导。此外，Dubinin-Radushkevich和Temkin等温线证实吸附机制主要由静电相互作用主导，而Langmuir和Sips模型证实了单层吸附过程。发现Lev在MnFeO/GO吸附剂上的最大吸附容量为129.9 mg/g。此外，热力学数据表明吸附系统是自发的且放热的。合成的MnFeO/GO核壳纳米复合材料在多达五个吸附-解吸循环中表现出显著的可回收性和可再生性。作为概念验证，评估了制备的吸附剂对加标实际水样进行实验室规模净化的性能。制备的吸附剂显著降低了实际水样中Lev的浓度，去除效率范围为86%至97%。
