School of Chemical and Biomedical Engineering , Nanyang Technological University , 62 Nanyang Drive , 637459 Singapore.
State Key Laboratory of Pollution Control and Resource Reuse, School of Environment , Nanjing University , Nanjing 210023 , P. R. China.
Environ Sci Technol. 2019 Jul 16;53(14):8342-8351. doi: 10.1021/acs.est.9b02355. Epub 2019 Jun 27.
About 3.93 billion tons of wastewater containing heavy metal complexes are discharged (e.g., from the electroplating industry) every year in China alone. It is challenging to appropriately treat such wastewaters. Here, a multifunctional composite nanowires BaTiO@graphene was designed based on Comsol simulations and made into 3D millimeter-sphere in order to facilitate practical application. Results indicate 100% of Cu-EDTA was decomplexed in situ via piezoelectric potential by BaTiO@graphene. Notably, the addition of graphene sharply increased the surface potential (from 19.8 ± 0.97 to 96.8 ± 1.48 mV) of BaTiO@graphene by its flexoelectric effect then effectively promoted piezoelectric electrons to be separated and transferred, which favors the piezoelectric catalysis. Moreover, the released Cu(II) from Cu-EDTA decomplexation were recovered simultaneously via the interaction on graphene groups. This method efficiently recovered Cu(II) to avoid the consumption of massive chemical reagents and the generation of secondary hazardous solid waste containing heavy metal ions, compared with the conventional oxidative decomplexation/precipitation strategy for heavy metal complexes removal. Piezoelectric catalysis paves a new possibility for advanced oxidation in wastewater treatment.
仅中国每年就排放约 39.3 亿吨含重金属络合物的废水（例如来自电镀行业）。妥善处理此类废水极具挑战性。在此，基于 Comsol 模拟设计并制成 3D 毫米球的多功能复合纳米线 BaTiO@graphene，以方便实际应用。结果表明，BaTiO@graphene 通过压电电势可原位将 100%的 Cu-EDTA 去络合。值得注意的是，通过挠曲电效应，石墨烯的添加急剧增加了 BaTiO@graphene 的表面电势（从 19.8±0.97 mV 增加到 96.8±1.48 mV），从而有效促进了压电电子的分离和转移，有利于压电催化。此外，Cu-EDTA 去络合释放的 Cu(II) 通过与石墨烯基团的相互作用可被同时回收。与传统的氧化去络合/沉淀策略相比，这种方法可有效回收 Cu(II)，避免使用大量化学试剂和产生含有重金属离子的二次危险固体废物。压电催化为废水处理中的高级氧化开辟了新的可能性。
