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With the rapid development of industry, metallurgical industrial wastewater contains a large amount of precious metal "gold". Direct discharge not only causes resource waste, but also brings economic losses and environmental problems. Therefore, it is of great significance to develop efficient, economical and recyclable adsorption materials for gold recovery from wastewater. Recently, the team of Associate Professor Zhang Yi, Associate Professor He Hongxing and Researcher Nie Zhifeng from the Yunnan Provincial Key Laboratory of Metal-Organic Molecular Materials and Devices of Kunming University published a research paper entitled "An ionic liquid-modified PVC nanofiber facilitates gold recovery from wastewater by a light-enhancing effect" in the Chemical Engineering Journal. This study used electrospinning technology and chemical grafting to prepare an ionic liquid-modified polyvinyl chloride (PVC) nanofiber (IL-PVC), and demonstrated its ability to efficiently recover gold from wastewater under light-enhancing conditions.
Traditional gold recovery methods have many limitations, such as complex synthesis process, high cost, acid and alkali resistance, and difficulty in recycling. In contrast, electrospun nanofibers have the advantages of simple preparation, high cost-effectiveness, and easy recycling. Its unique long-diameter filamentous morphology provides a broad grafting area for functional adsorption sites, thereby ensuring the effectiveness and feasibility of the adsorption sites. Therefore, the development of adsorption materials based on electrospinning nanofibers is of great significance for the recycling of precious metal resources.
Material preparation and characterization: The research team prepared IL-PVC nanofibers by electrospinning technology combined with chemical grafting. Scanning electron microscopy (SEM) showed that the surface of the modified PVC nanofibers became rough and the diameter increased, indicating that the functional groups were successfully grafted. Fourier transform infrared spectroscopy (FTIR) and solid nuclear magnetic resonance 13C spectroscopy (ssNMR) further verified the successful grafting of 4,4'-bipyridine.
Adsorption performance: The experiment showed that under light conditions, the adsorption amount of Au(III) by IL-PVC within 18 hours reached 1243.75 mg/g, which was 1.6 times higher than that under dark conditions. In addition, IL-PVC showed high selectivity for Au(III) in simulated wastewater, with a distribution coefficient of up to 531.08 L/g. After six cycles of testing, the adsorption efficiency of IL-PVC remained basically unchanged, showing good cycle performance.
Adsorption mechanism: Through X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations, the research team revealed that the adsorption process mainly involves the synergistic effect of three mechanisms: electrostatics, coordination, and redox. Electrochemical and electron paramagnetic resonance (EPR) characterizations showed that photogenerated electrons promoted the reduction of Au(III), thereby enhancing the adsorption capacity of IL-PVC for gold.
Electrospinning technology has significant advantages in the preparation of high-performance adsorbent materials. The prepared nanofibers have high specific surface area, high porosity, and good flexibility, which can effectively improve the adsorption efficiency. In addition, electrospinning technology can also optimize the morphology and performance of the fibers by adjusting process parameters (such as voltage, solution concentration, collector type), thereby further improving the adsorption capacity of the adsorbent material.
This study demonstrates the great potential of IL-PVC nanofibers in recovering gold from wastewater. By combining electrospinning technology with chemical modification, the performance of the material can be further optimized and its application in precious metal recovery can be expanded. Future research can focus on the following directions:
Multifunctional integration: Combine with other functional materials (such as conductive polymers or metal oxides) to develop nanofibers with multiple adsorption functions.
Scaled application: Explore the possibility of large-scale preparation and application to meet industrial needs.
Environmental adaptability: Further improve the acid and alkali resistance and stability of the material so that it can operate efficiently in more complex industrial wastewater.
Electrospinning Nanofibers Article Source:
https://doi.org/10.1021/acsami.4c12470
