Development of eco-friendly and low-energy self-regenerative fiber material to recover valuable metals from industrial wastewater
Development of fiber-based adsorbent material to recover valuable metals from industrial wastewater. Minimize toxic chemicals and energy use by eliminating the need to replace and regenerate materials.
image: Fig. 1. Structure and concept of SRF. (a) Schematic illustration of fabricating PAN/PMMA fibers using a dry-jet wet spinning machine. The diameter of the PAN/PMMA fiber was readily controlled by regulating the injection rate and rolling speed. Information on the diameter of the fibers is summarized in table S1. Illustrations representing the physicochemical structure of (b) the PAN/PMMA fiber and (c) the SRF. (d) A series of courses for self-regeneration in which crystal layers are repetitively formed-detached on an SRF surface. The heavy metal ions and counter-anions induced nuclei for crystal growth, resulting in the formation of crystal layers. The crystal layers are self-detached from the SRF surfacevia collisions with each other, non-sticky surfaces, and the curvature of the fiber, and new crystals grow on the SRF surface in which the crystal layers are detached. (e) SEM image of the SRFs immersed in 1,000 ppm copper nitrate solution for 1 h. The three self-detachment aspects of the copper crystal layer, i.e., collision between the crystal layers, a non-sticky surface, and curvature of the SRF, were observed. Scale bar: 100 μm (f) Snapshot images show the course of self-detachment of crystal layers from an SRF via (g) non-sticky surface formation, (h) collision, and (i) surfacecurvatureduring an elapsed time of 55 min (Ci of 100 ppm and no pH adjustment). Scale bar: 200 μm.
Credit: Korea Institute of Science and Technology(KIST)
Technology to recover valuable metals from wastewater generated in various industries such as plating, semiconductors, automobiles, batteries, and renewable energy is important not only for environmental protection but also for economic reasons. In Korea, chemicals are mainly added to wastewater to precipitate heavy metal ions in the form of oxides, but accidents such as leakage of hazardous chemicals have occurred one after another, so it is necessary to develop more eco-friendly technologies.
Against this backdrop, the Korea Institute of Science and Technology (KIST) announced that Dr. Jae-Woo Choi's team at the Water Resource Cycle Research Center has developed a fiber-like metal recovery material that can recover metal ions in water by adsorbing and crystallizing the metal, and the recovered metal crystals can desorb and regenerate themselves.
KIST research team has developed a semi-permanent adsorption material by utilizing the phenomenon that metal ions in water crystallize when certain chemical functional groups are fixed on the surface of a fiber-like material and introducing a technology to remove the formed crystals. When tested with copper ions, the maximum adsorption amount of existing adsorbents is only about 1,060 mg/g, but by utilizing the developed material, near-infinite adsorption performance can be secured.
In addition, existing high-performance adsorbents are in the form of small granules with diameters ranging from a few nanometers to tens of micrometers, making it difficult to utilize them underwater, but the metal recovery material developed by the KIST research team is in the form of fibers, making it easy to control underwater, making it easy to apply to actual metal recovery processes.
“Since the developed material is based on acrylic fibers, it is not only possible to mass produce it through a wet spinning process, but also to utilize waste clothing,” said Dr. Jae-woo Choi of KIST. “The wastewater recycling technology will help reduce the industry's dependence on overseas sources of valuable metals that are in high demand.”
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KIST was established in 1966 as the first government-funded research institute in Korea. KIST now strives to solve national and social challenges and secure growth engines through leading and innovative research. For more information, please visit KIST’s website at https://eng.kist.re.kr/
The research, funded by the Ministry of Science and ICT (Minister Jong-ho Lee) through the Leading Project for Material Innovation (2020M3H4A3106366), Sejong Science Fellowship (RS-2023-00209565), and KIST Institutional Unique Project (2E32442), was published on October 16, 2023 in the international journal Advanced Fiber Materials.