Ji, Wen-chanHu, PingWang, Xiao-yuSaji, SandraChang, TianZhu, Xin-yuYang, Fairy FanCao, Qi-gaoDang, RuiWang, Kuai-sheYin, Zongyou2022-10-242022-10-242073-4352http://hdl.handle.net/1885/276124As a potential magnetic super adsorbent in wastewater treatment, Fe3O4 has been re-searched intensively up to date. However, its key problem of poor comprehensive magnetic properties is still challenging. In this work, an effective solution to this problem has been developed by a one-step carbothermal synthesis of Fe3O4 crystals, which are merited with pure-stoichiometry (FeO-phase free), high crystallinity, small-size (~10 nm), strong magnetism and sensitive magnetic response. The unveiled saturation magnetization of Fe3O4 nanoparticles reaches as high as 90.32 emu·g−1, and the fastest magnetic response time is as short as only 5 s. Such magnetic Fe3O4 super adsorbents exhibit outstanding performance when applied as an adsorbent for wastewater treatment. They can quickly and effectively adsorb methylene blue with an adsorption capacity of 62.5 mg·g−1, which is much higher than that of Fe3O4 adsorbents prepared by other methods reported in the literature. Importantly, this capacity is refreshable after removing the adsorbed methylene blue just by ultrasonic cleaning. With such combined outstanding magnetic properties and recyclable adsorption capacity, the problems associated with the conventional adsorbent solid–liquid separation could be resolved, thus making a forward development towards industrial wastewater treatment.This work was supported by the Natural Science Foundation of China (NSFC, 51404181); the Fok Ying Tung Education Foundation (171101); the Youth Innovation Team of Shaanxi Universities (2019-2022); the Top young talents project of “special support program for high level talents” in Shaanxi Province of China (2018-2023); the ANU Futures Scheme (Q4601024); and the Australian Research Council (DP190100295, LE190100014).application/pdfen-AUCopyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.https://creativecommons.org/licenses/by/4.0/magnetismFe3O4 nanoparticlesaccurate fabricationmagnetic responsivenessadsorption202110.3390/cryst110100752021-11-28Creative Commons Attribution 4.0 International License