ABSTRACT

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.

摘要

_{PVDF/SiO 2} -g-CDs共混膜的制备方法是将硅烷化改性碳点(CDs)接枝到PVDF/SiO ₂共混膜表面。_{研究了PVDF/SiO 2} -g-CDs共混膜的表面组成、形貌、亲水性、荧光性能和金属离子吸附性能。^{Hg 2+}和Fe ³⁺对膜的荧光猝灭作用明显。猝灭机理是金属离子与CDs的官能团（包括-NH ₂、-OH和-COOH）络合。_{PVDF/SiO 2} -g-CDs共混膜对Hg ²⁺的光学检测限在0.0025-20 μM的线性范围内为1.6 nM，在0.5-5000 μM的线性范围内Fe ³⁺的光学检测限为2.1 μM。_{PVDF/SiO 2} -g-CDs共混膜对Fe ³⁺的最大吸附量为47.04 mg g ^-1。膜的吸附符合准二级动力学和Langumir模型，属于膜表面的单层化学吸附。通过吸附热力学分析，吸附是一个自发的吸热过程。5个循环后荧光恢复率和吸附容量仍能保持在82%以上。PVDF/SiO ₂ -g-CDs共混膜具有再生能力。总之，PVDF/SiO ₂-g-CDs共混膜具有检测和吸附金属离子的双重功能，在污水处理中具有广阔的应用前景。