Abstract Magnetite-boehmite porous ceramic composites were synthesized from magnetite and boehmite hydrosols in a course of room-temperature sol-gel transition. The proposed synthesis routine allowed producing ceramic matrices with a high degree of structure homology, realizing the full range of composites combining magnetite and boehmite phases at any mass ratio. Depending on the magnetite to boehmite ratio the total surface area of the composites can be varied from 122 to 391 m2/g while the magnetization of the composites can reach up to 88 emu/g. The synthesized composites were examined as adsorbent for Cr(VI) ions and showed the pseudo-second order sorption kinetics. The characterized adsorption behavior was in best accord with the Langmuir model, showing the maximum adsorption capacities of Cr(VI) ions up to 62.4 mg/g. Owing to their magnetic properties the magnetite-containing composites can be magnetically separated and reused for up to 5 times with only minor drop to the sorption capacity down to 89% of its initial value. These make the magnetite-boehmite composites prospective for various applications, including wastewater treatment.

中文翻译：

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用于去除重金属离子的磁铁矿-勃姆石溶胶-凝胶复合材料的室温制备

摘要 以磁铁矿和勃姆石水溶胶为原料，经过室温-溶胶-凝胶转变过程合成了磁铁矿-勃姆石多孔陶瓷复合材料。建议的合成程序允许生产具有高度结构同源性的陶瓷基体，实现以任何质量比结合磁铁矿和勃姆石相的全系列复合材料。根据磁铁矿与勃姆石的比例，复合材料的总表面积可以从 122 到 391 m2/g 不等，而复合材料的磁化强度可以达到 88 emu/g。合成的复合材料作为 Cr(VI) 离子的吸附剂进行了检查，并显示出准二级吸附动力学。表征的吸附行为最符合朗缪尔模型，显示 Cr(VI) 离子的最大吸附容量高达 62.4 mg/g。由于它们的磁性，含磁铁矿的复合材料可以被磁性分离并重复使用多达 5 次，而吸附容量仅轻微下降至其初始值的 89%。这些使磁铁矿-勃姆石复合材料具有多种应用前景，包括废水处理。