石墨烯吸附/催化复合材料的制备及其含氟选矿废水净化性能及机理

Aiming at the purification of beneficiation wastewater with fluoride, a novel kind of composite material is proposed in this project. Graphene, prepared from natural microcrystalline graphite will be used as adsorbent substrate to support catalyst of iron-based metal organic framework. Therefore，a graphene/iron-based metal organic framework composite will be obtained. In the project, the preparation method and technology of composite will be investigated to establish the relationship between structural characters and technological parameters firstly. Secondly the fluoride adsorption performance of the composite will be studied to prove the adsorption mechanism and the route to strengthen adsorption. Thirdly the organic beneficiation reagent adsorption/catalytic performance of the composite will be studied to prove the adsorption/catalytic process and mechanism. Finally, the purification effects of the composite will be studied in both of simulated and actual environment. The project will lay a theoretical and experimental foundation for the development of new kinds of purification materials for fluoride waste, as well has important theoretical significance and practical value for the design of novel functional composites of graphene and the materialized research and application of natural graphite.

本项目研究了一种新型吸附/催化复合材料，用于含氟选矿废水的净化。以天然微晶石墨为原料制备石墨烯吸附基底材料，然后在石墨烯基底上负载铁基-金属有机框架催化剂，形成石墨烯/铁基-金属有机框架复合材料。项目首先研究该复合材料的制备方法与工艺，建立复合材料结构特征与制备工艺参数的联系。其次研究复合材料对氟离子的吸附性能，探明吸附机制和强化方法。然后研究该复合材料对有机选矿药剂的吸附/催化降解过程和机制。最后研究复合材料对模拟和实际含氟选矿废水的净化性能。本项目将为开发新型含氟废水净化材料奠定理论和实验基础，对设计新型石墨烯复合功能材料、促进天然石墨材料化研究和应用具有重要的理论意义和实用价值。

本项目进行了新型吸附/催化复合材料的制备研究，该材料以天然微晶石墨经氧化还原法制备的石墨烯为基底，在其上组装铁基-金属有机框架，可有效用于选矿废水中氟离子的高效吸附与有机选矿药剂的吸附-催化降解，主要研究内容和成果如下：.（1）对比研究不同氧化还原技术路线，发现微晶石墨浮选精矿经改进Hummers法所制备的石墨烯结构性能相对优异。对比研究七种铁基-金属有机框架材料，发现MIL-88、MIL-53吸附和催化性能相对优异。.（2）石墨烯/MIL-88对氟离子的最大吸附量可达到249 mg/g，石墨烯/MIL-53对氟离子的最大吸附量可达到227 mg/g，吸附过程符合Langmuir模型和拟二级动力学模型。.（3）石墨烯/MIL-88对油酸钠的最大吸附量可达到28.21 mg/g，石墨烯/MIL-53对油酸钠的最大吸附量可达到26.49 mg/g，吸附过程符合Langmuir模型和拟二级动力学模型。H2O2可强化石墨烯/铁基-金属有机框架复合材料催化降解油酸钠，提高去除率8%左右。.（4）最佳工艺参数条件下采用复合材料净化含氟选矿废水，净化后的氟离子浓度由23.15 mg/L下降至0.89 mg/L，pH由8.33下降至7.32，COD由21 mg/L下降至12.09 mg/L，，氟离子去除率达到96%，净化效果明显。其中石墨烯/MIL-88的净化效果优于石墨烯/MIL-53。 .（5）净化前后材料的物相组成和形貌无明显变化，复合材料稳定性较好。净化前后FTIR分析表明，油酸钠在石墨烯/铁基-金属有机框架复合材料表面发生了化学吸附。净化前后XPS分析表明，净化前后Fe2p、O1s、C1s结合能发生了显著变化，氟离子和油酸钠组分以表面络合和化学吸附形式吸附于复合材料表面，实现氟离子和油酸钠的去除。