ABSTRACT A novel film adsorbent (PVDF-PEI) was prepared by simple blending polyethyleneimine and polyvinylidene fluoride for efficient uptake Cu(II) and Pb(II) from solution. The characterization of PVDF-PEI was investigated by Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy. Moreover, the effect about adsorbent mass, solution pH, salinity, contact time, temperature and initial Cu(II) and Pb(II) concentrations was researched by batch experiments, respectively. The adsorption quantity of Cu(II) and Pb(II) was to 81.3 and 178 mg g –1 from Langmuir model under the solid-liquid ratio was 0.5 g L –1 for 8 h at 303 K. Freundlich model and Koble–Corrigan mode well predicted the adsorption isotherms while pseudo-first-order and Elovich models appropriately described the adsorption kinetic curves. The thermodynamic parameters illustrated that both processes were endothermic and spontaneous reactions with increased entropy. Cu-loaded PVDF-PEI and Pb-loaded PVDF-PEI were better regenerated by using 0.1 mol L –1 HCl and HNO 3 , respectively. The mechanisms were both complexation and ion exchange. Overall, it is referred that PVDF-PEI be promising for eliminating Cu(II) and Pb(II) from wastewater.
Hong Fan,Kefan Wang,Yangjian Ding,Yueyue Qiang,Zhuo Yang,Huan Xu,Min Li,Zewen Xu,Cheng Huang
Radiative cooling technology, which is renowned for its ability to dissipate heat without energy consumption, has garnered immense interest. However, achieving high performance, multifunctionality, and smart integration while addressing challenges such as film thickness and enhancing anisotropic light reflection remains challenging. In this study, a core–shell composite nanofiber, PVDF@PEI, is introduced and designed primarily from a symmetry-breaking perspective to develop highly efficient radiative cooling materials. Using a combination of solvent-induced phase separation (EIPS) inverse spinning and (aggregation) self-assembly methods (EISA or EIAA) and coaxial electrostatic spinning (ES), superconformal surface anisotropic porous nanofiber membranes are fabricated. These membranes exhibit exceptional thermal stability (up to 210 °C), high hydrophobicity (contact angle of 126°), robust UV protection (exceeding 99%), a fluorescence multiplication effect (with a 0.6% increase in fluorescence quantum efficiency), and good breathability. These properties enable the material to excel in a wide range of application scenarios. Moreover, this material achieved a remarkable daytime cooling temperature of 8 °C. The development of this fiber membrane offers significant advancements in the field of wearables and the multifunctionality of materials, paving new paths for future research and innovation.
Tianran Zhang,Bofeng Shi,Siyu Zhang,Mengfan Song,Jiping Wang,Lixue Zhang,Fang Kang
Due to the development of advanced electronic systems, there is an urgent need for polymer dielectric film capacitors with high breakdown strength ( E b ) and high discharge energy density ( U d ) at elevated temperatures. Herein, an all-organic blend polymer composite is fabricated by blending polyetherimide (PEI) and a trace amount of Poly(vinylidene fluoride) (PVDF), achieving nanoscale phase separation and forming interfaces between PEI and PVDF grain. The real permittivity ( ε r ) and E b of blend composites are simultaneously enhanced after PVDF introduction. It is worth noting that increasing the temperature does not reduce the E b of the PEI/xPVDF blend composite. Our Study shows that optimizing the plasticity and storage modulus of PEI/xPVDF significantly contributes to maintaining E b at elevated temperatures. Additionally, high temperatures enhance the entanglement of molecular chains at the PVDF-PEI interface, further supporting the preservation of E b . Finally, a high E b of 540 MV/m, a high U d of 5.92 J/cm 3 are achieved for the PEI/0.5PVDF blend at 150 °C. This work presents a new approach to enhance the E b of dielectric polymers by optimizing mechanical properties at high temperature, which providing a different strategy for enhancing the energy storage performance.
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