The transport of ionic species through nanochannels plays an important role in the basic research and practical application of nanofluidic devices. Here, a visualized CdSe@ZIF-8/PAA nanochannel membrane was created by employing in situ growth of zeolite imidazole skeleton (ZIF-8) and CdSe quantum dots (CdSe QDs) on a porous anodized aluminum oxide (PAA) membrane surface using CdSe QDs, 2-methylimidazole, and zinc nitrate as the precursor solvents. ZIF-8 is a kind of metal−organic framework, a microporous material that possesses strong metal adsorption capacity. In addition, CdSe quantum dots have fluorescent properties. The nanochannel membrane detects copper ions (Cu 2+ ) by quenching the fluorescence intensity by the interaction between Cu 2+ and Se and S atoms. The direct potential of 5 V was applied to achieve Cu 2+ enrichment at the nanochannel interface, and the fluorescence change was observed. The CdSe@ ZIF-8/PAA nanochannel membrane has a good linear range of concentration (0.01 pM−1 μM) for Cu 2+ detection. With the help of nanochannel enrichment, its detection limit reaches 4 fM. In addition, this nanochannel membrane has good selectivity for Cu 2+ .

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Many oil adsorption materials are composed of nonrenewable raw materials, and their disposal can increase resource consumption and cause new environmental pollution. In this paper, the carbonized Eichhornia crassipes (CEC) were immobilized with Fe3O4 magnetic nanoparticles and modified with 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane (PFOS) to prepare an oil adsorption material, referred to here as CEC/Fe3O4/PFOS. The magnetic and mechanical strength of the CEC was enhanced by adding Fe3O4 magnetic particles, which enable it efficient to dispose the oil/water solution. CEC/Fe3O4/PFOS shows high porosity (83.53%), low skeletal density (0.487 g/cm3), excellent magnetism, ultrahigh oil absorption capacity (49.94–140.90 g/g), hydrophobic performances with a water contact angle of 150.1 ± 2.3°, and a sliding angle of 10.5°. It is worth noting that the material can be recycled, and the absorbed oil is obtained by distillation. Therefore, this work may provide a candidate for solving the problem of oil pollution using E. crassipes.