[This corrects the article DOI: 10.1021/acsomega.3c09773.].
Spent lithium-ion batteries (S-LIBs) are typically discarded in landfills after their lifecycle ends, despite containing valuable materials like graphite. While much research focuses on extracting precious metals from the cathode, this study explores the recycling, recovery, and reuse of spent graphite, converting it into reduced graphene oxide (rGO) for electrochemical sensing. The rGO material demonstrated excellent sensitivity to ascorbic acid (AA) in a concentration range of 1 mM to 100 mM at pH 7.6, offering a cost-effective solution for AA detection. The recovered graphite (RG) from S-LIBs and commercial graphite (CG) was first converted into graphene oxide (R-GO, C-GO) and then reduced (R-rGO, C-rGO). This material underwent extensive structural characterization using techniques such as powder X-ray diffraction (PXRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) analysis, field-emission scanning electron microscopy (FE-SEM), and high-resolution transmission electron microscopy (HR-TEM). Electrochemical performance was evaluated through cyclic voltammetry (CV), differential pulse voltammetry (DPV). This study underscores the "waste-to-wealth" concept and supports circular economy principles by transforming electronic waste into a valuable resource. The LOD and LOQ for both the material R-rGO and C-rGO were calculated as 3.055 mM, 10.18 mM, and 3.41 mM, 11.36 mM, respectively. The rGO-based sensor not only promotes sustainable recycling but also offers a low-cost, high-performance solution for ascorbic acid detection, with potential applications in food quality monitoring, medical diagnostics, and the cosmetic industry.
We report on a highly sensitive NOx (NO and NO2) gas sensor using ZnO nanorods produced through a simple thermal evaporation method. The impact of the oxygen atmosphere on the gas detection assessment of the ZnO nanorod was conducted. An excellent sensitivity towards NO2 gas with a sensor response (R-g/R-a) of similar to 8.8 for 50 ppm at an optimum temperature (T-opt) of 250 degrees C, accompanied by a fast response/recovery time of similar to 28 s/20 s, was achieved for ZnO nanorods with 30 sccm O-2 gas flow. Further, it displayed a very good sensor response towards NO gas at T-opt of 275 degrees C. The ZnO nanorods demonstrate high selectivity towards NOx gases and stability (even after 8 months) and can detect as low as 1 ppm concentration of NO2 gas. Thus, the developed ZnO nanostructures by a single-step growth method are substantially suitable for the fabrication of highly selective dual gas NOx sensors.
The selective removal of CO2 from the flue gas remains a quite challenging due to the weak selectivity of CO2/N2 in adsorbents. Therefore, it is necessary to design an effective sorbent to improve its selectivity. This work attempts to synthesis of novel core-shell ETS-4@LSX composite via a seed-assisted hydrothermal method. In this composite structure, a small pore titanosilcate ETS-4 as a core, while a large pore aluminosilicate LSX forms the outer shell. The effects of ETS-4 seed loading (1-5 wt.%) and crystallization time on the formation and structural integrity of the core-shell architecture was systematically investigated. The structural and physicochemical properties of samples were characterized by XRD, FE-SEM, HR-TEM, EDS, FT-IR, TGA, N2 adsorption-desorption, and pore size distribution. From XRD pattern and FE-SEM results confirmed that the composite synthesized with 2 wt% ETS-4 seed and 3 h crystallization time has pure phase of ETS-4@LSX structure. HR-TEM imaging revealed uniform growth of LSX over the ETS-4 surface, resulting in the formation of a continuous shell. The 2 wt% ETS4@LSX composite demonstrated an outstanding CO2/N2 equilibrium selectivity of 81.4 at 1 bar and 303 K with five and seven times higher than that of pure LSX and ETS-4, respectively. At 20 bar, the composite achieved a CO2 uptake of 5.25 mmol g- 1 and an N2 uptake of 0.50 mmol g- 1. Dynamic adsorption study exhibited the 2 wt% ETS-4@LSX has 3.52 mmol g- 1 CO2 sorption capacity and N2 uptake capacity of 0.26 mmol g- 1. The enhanced adsorption capacity and selectivity of ETS-4@LSX are attributed to its dual-pore structure, highlighting its potential as an effective adsorbent for CO2 capture from flue gas.
Lithium iron phosphate (LiFePO4) batteries have gained popularity due to their high safety and low cost. Effective recycling processes are needed to sustain indigenous material and economic benefit. In other hand, power materials are imported for the manufacturing of batteries, which compells for the development of process for recovery of the valuable metals (Fe, P, Li, Cu, and Al) from spent LFP batteries. Leaching was carried out at optimized condition using 3 % H2SO4 and 5 % H2O2 maintaining 100 g/L pulp density at 60 degrees C. 99.99 % Fe, Li, P, Al, and Cu were recovered within 60 min of mixing time. Leaching kinetics of Li followed "Chemical reaction control dense constant size cylindrical particles" model 1-(1-X)1/2 = kct, while Fe, P, Al, and Cu adhered to a "Chemical reaction control dense constant size or shrinking spheres" model 1-(1-X)1/3 = kct. Cementation was carried out using scrap iron to recover Cu at room temperature within 40 min. Fe and P were recovered as FePO4 by precipitation. 99.99 % Al was precipitated using NaOH at pH 7.5, whereas 99.9 % Li was precipitated as Li2CO3 and Li3PO4 at pH 12 and 90 degrees C using Na2CO3 and Na3PO4.12H2O, respectively. This process is viable for recycling LFP batteries ensuring resource recovery and environmental sustainability.
