PVDF/SiO2-g-CDs blended membrane for fluorescence detection and adsorption of metal ions.

The preparation method of PVDF/SiO2-g-CDs blended membrane was that the silanized modified carbon dots (CDs) were grafted onto the PVDF/SiO2 blended membrane surface. The surface composition, morphology, hydrophilicity, fluorescence performance and metal ions adsorption performance of PVDF/SiO2-g-CDs blended membrane were studied. The fluorescence quenching effect of the membrane with Hg2+ and Fe3+ was obvious. The quenching mechanism was the complexation of metal ions with the functional groups of CDs including -NH2, -OH and -COOH. The optical detection limits of PVDF/SiO2-g-CDs blended membrane for Hg2+ was 1.6 nM in the linear range of 0.0025-20 μM, and the optical detection limits for Fe3+ was 2.1 μM in the linear range of 0.5-5000 μM. The maximum adsorption capacity of PVDF/SiO2-g-CDs blended membrane for Fe3+ was 47.04 mg·g-1. The adsorption of the membrane conformed to the pseudo-second-order kinetics and Langumir model, and belonged to monolayer chemical adsorption on the membrane surface. Through adsorption thermodynamic analysis, adsorption was a spontaneous endothermic process. The recovery rate of fluorescence and adsorption capacity could still be maintained above 82% after five cycles. The PVDF/SiO2-g-CDs blended membrane had the ability to regenerate. In summary, the PVDF/SiO2-g-CDs blended membrane had the dual functions of detecting and adsorbing metal ions, and had broad application prospects in sewage treatment.

Citation

Jingjing Li, Zhicheng Ji, Heyu Sun, Dongdong Zhang, Yiping Zhao, Li Chen. PVDF/SiO2-g-CDs blended membrane for fluorescence detection and adsorption of metal ions. Environmental technology. 2022 Apr;43(11):1648-1661

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PMID: 33136522

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