Fe3O4@CNF@Zn-BTC复合材料制备及其去除水中磷的性能

针对目前如污水厂二沉池出水磷含量超标等磷污染现状，以水体中磷元素为吸附去除对象，合成了一种新型材料Fe₃O₄@CNF@Zn-BTC用于磷元素的特定吸附，由磁性纳米Fe₃O₄粒子、羧基化纤维素纳米纤维和金属有机骨架Zn-BTC在一般实验室条件下制成。CNF材料与MOFs材料的负载提升了复合材料的结晶度，进而提升复合材料的刚性和稳定性，且产生TOCNF表面—COO—和Fe以及MOFs上相关的键合，提升复合材料孔道率的同时提升了材料的刚性，极大程度上弥补了MOFs材料的刚性、稳定性短板。用SEM、FTIR、XRD、XPS和BET等对制成的Fe₃O₄@CNF@Zn-BTC进行了表征分析，并探讨了其在常温常压条件下对于水体中微量磷元素的去除效果。结果表明:对于10 mg/L的含磷水样，投加极少量Fe₃O₄@CNF@Zn-BTC材料可在常温常压60 min将磷元素含量降至0.3~0.5 mg/L，符合GB 8978—1996《污水综合排放标准》一级A标准，平均去除率高达95%。与其他如活性炭等常规除磷材料相比，Fe₃O₄@CNF@Zn-BTC材料除磷效率高，回收简单，再生性强，价廉易合成。因此，Fe₃O₄@CNF@Zn-BTC在改善磷污染环境水质方面具有巨大前景。

PREPARATION OF Fe3O4@CNF@Zn-BTC MATERIAL AND ITS PERFORMANCE IN REMOVING PHOSPHORUS FROM WATER

In view of the current situation of phosphorus pollution such as excessive phosphorus content in effluent of the secondary sedimentation tank of a sewage plant, a new material Fe₃O₄@CNF@Zn-BTC was synthesized for specific adsorption of phosphorus. It was made of magnetic nano Fe₃O₄ particles, carboxylated cellulose nanocrystals and metal organic framework Zn-BTC under general laboratory conditions. The loading of CNF material and MOFs material improved the crystallinity of the composite material, and then improved the rigidity and stability of the composite material, and produced the related bonds between TOCNF surface -COO- and Fe and MOFs, which improved the porosity of the composite material and the rigidity of the material at the same time, and overcome the shortcomings of rigidity and stability of MOFs material to a great extent. Fe₃O₄@CNF@Zn-BTC was characterized by SEM, FTIR, XRD, XPS and BET, and its removal effect on trace phosphorus in water was discussed under normal temperature and pressure. The results showed that the phosphorus content could be reduced to 0.3~0.5 mg/L by adding a small amount of Fe₃O₄@CNF@Zn-BTC at normal temperature and pressure for 60 minutes, which met the first class A standard specified in GB 18918—2002, and then the average removal rate was as high as 95%. Compared with other conventional phosphorus removal materials such as activated carbon, Fe₃O₄@CNF@Zn-BTC material had higher phosphorus removal efficiency, simpler recovery, stronger reproducibility, lower cost and easier synthesis process. Therefore, Fe₃O₄@CNF@Zn-BTC showed great prospects in improving the water quality of phosphorus polluted environment.