Hkiri Khaoula, Mohamed Hamza Elsayed Ahmed, Abodouh Mohamed Mahrous, Maaza Malik
UNESCO UNISA Africa Chair in Nanoscience and Nanotechnology, College of Graduate studies, University of South Africa, Pretoria, South Africa.
Energy Materials Laboratory, Physics Department, School of Sciences and Engineering, The American University in Cairo (AUC), New Cairo, 11835, Egypt.
Sci Rep. 2024 Nov 6;14(1):26991. doi: 10.1038/s41598-024-78491-3.
This work investigates the efficiency of green-synthesized WO nanoflakes for the removal of methylene blue dye. The synthesis of WO nanoflakes using Hyphaene thebaica fruit extract results in a material with a specific surface area of 13 m/g and an average pore size of 19.3 nm. A combined theoretical and experimental study exhibits a complete understanding of the MB adsorption mechanism onto WO nanoflakes. Adsorption studies revealed a maximum methylene blue adsorption capacity of 78.14 mg/g. The pseudo-second-order model was the best to describe the adsorption kinetics with a correlation coefficient (R) of 0.99, suggesting chemisorption. The intra-particle diffusion study supported a two-stage process involving surface adsorption and intra-particle diffusion. Molecular dynamic simulations confirmes the electrostatic attraction mechanism between MB and the (002) WO surface, with the most favorable adsorption energy calculated as -0.68 eV. The electrokinetic study confirmed that the WO nanoflakes have a strongly negative zeta potential of -31.5 mV and a uniform particle size of around 510 nm. The analysis of adsorption isotherms exhibits a complex adsorption mechanism between WO and MB, involving both electrostatic attraction and physical adsorption. The WO nanoflakes maintained 90% of their adsorption efficiency after five cycles, according to the reusability tests.
本研究考察了绿色合成的WO纳米片对亚甲基蓝染料的去除效率。使用海枣果实提取物合成的WO纳米片比表面积为13 m/g，平均孔径为19.3 nm。理论与实验相结合的研究全面揭示了亚甲基蓝在WO纳米片上的吸附机制。吸附研究表明，亚甲基蓝的最大吸附容量为78.14 mg/g。伪二级模型最能描述吸附动力学，相关系数（R）为0.99，表明为化学吸附。颗粒内扩散研究支持了一个包括表面吸附和颗粒内扩散的两阶段过程。分子动力学模拟证实了亚甲基蓝与（002）WO表面之间的静电吸引机制，计算得出的最有利吸附能为-0.68 eV。电动学研究证实，WO纳米片的zeta电位为-31.5 mV，呈强负性，粒径均匀，约为510 nm。吸附等温线分析表明，WO与亚甲基蓝之间存在复杂的吸附机制，包括静电吸引和物理吸附。根据可重复使用性测试，WO纳米片在五个循环后仍保持90%的吸附效率。
