“Metal recovery from battery waste using electrospun functionalised nanofibers”
| dc.contributor.author | Tshisano Kamogelo Maureen | |
| dc.date.accessioned | 2025-09-12T10:57:48Z | |
| dc.date.available | 2025-09-12T10:57:48Z | |
| dc.date.issued | 2024 | |
| dc.description.abstract | The growing demand for lithium-ion batteries (LIBs) driven by electric vehicles (EVs) and modern electronics has emphasised the need for efficient recycling processes to recover valuable metals. Traditional recycling methods, pyrometallurgy and hydrometallurgy, offer substantial recovery rates but are limited by high energy costs and environmental impacts. To optimise the hydrometallurgy approach, other separation methods such as adsorption are considered to combat the challenges encountered by the liquid-liquid extraction (LLE) procedure. The use of nanofibers as adsorbents has gained researchers' attention because of their high surface area which enables them to effectively adsorb metals at faster kinetics. Functionalised nanofibers offer even more advantages such as selectivity towards specific metal ions. This study explores an adsorption-based approach, using Polyethylene terephthalate (PET) blended with Di-2-ethylhexyl phosphoric acid (DEHPA) ligands and electrospun into nanofibers adsorbent, as an alternative for enhancing metal recovery from spent LIBs, particularly for metals such as Ni(II), Co(II), and Mn(II). The optimal electrospinning conditions were identified as 10 weight percentage (wt.%) PET in trifluoroacetic acid (TFA) solvent, 1.0 mL/h solution flow rate, and a 15 cm distance between the needle-tip and collector. PET (10 wt.% m/v) in TFA was co-blended with DEHPA in varying amounts (5%, 10%, 15%, and 20% v/v), and electrospun into PET-DEHPA nanofibers. The electrospun PET and PET-DEHPA nanofibers were characterised by using a Scanning electron microscope (SEM), Energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy- Attenuated total reflection (FTIR-ATR), and Thermogravimetric analysis (TGA). SEM results showed an increase in nanofiber diameter from 132 ± 51 nm (pristine PET) to 215 ± 91 nm (PET-DEHPA-C4 (20% v/v)). EDS and XPS confirmed the presence of DEHPA based on the detected phosphorous (P) content. FTIR-ATR spectra displayed characteristic functional groups of DEHPA (P-O-C at 1010 cm⁻¹ and P=O at 1221 cm⁻¹). While TGA revealed the DEHPA the masses of DEHPA and PET as per nanofiber samples. XRD indicated an improvement in the nanofiber ordering from PET to PET-DEHPA nanofibers. The leaching off of ligands during the desorption of metal ions has been a challenge in the use of nanofibers. Herein, PET-DEHPA-C3 (15% v/v) nanofiber adsorbent was exposed to various concentrations of nitric acid. However, the FTIR-ATR spectra showed no spectral changes, thus confirming that the DEHPA ligand remained immobilised to the nanofibrous structure. Polyethylene terephthalate and PET-DEHPA nanofibers were assessed on their adsorption capacities towards metal ions such as Ni(II), Co(II), and Mn(II). The adsorption results obtained from ICP-OES analysis demonstrated that PET-DEHPA nanofibers significantly enhanced metal ion adsorption capacities. For PET-DEHPA-C3 (15% v/v), adsorption capacities were optimised at 60 mins contact time, pH 4, and 100 mg/L initial metal ion concentration. The adsorption capacity of PET was less than 5 mg/g towards all of the targeted metal ions while PET-DEHPA-C3 (15% v/v) adsorbed 13 mg/g (29%) Ni(II), 16 mg/g (33%) Co(II) or 21 mg/g (52%) Mn(II). Additionally, PET-DEHPA-C3 (15% v/v) nanofibers maintained their adsorption capacity over five adsorption-desorption cycles. This highlighted the potential of reusing the PET-DEHPA-C3 (15% v/v) nanofibers as adsorbents to extract valuable metals from spent LIBs. | |
| dc.identifier.uri | https://hdl.handle.net/10566/20908 | |
| dc.language.iso | en | |
| dc.publisher | University of the Western Cape | |
| dc.subject | Lithium-ion battery (LIB) | |
| dc.subject | Di-2-ethylhexyl phosphoric acid (DEHPA) | |
| dc.subject | Nanofiber | |
| dc.subject | Polyethylene terephthalate (PET) | |
| dc.subject | Nickel | |
| dc.title | “Metal recovery from battery waste using electrospun functionalised nanofibers” | |
| dc.type | Thesis |