Sustainable repurposing of CNT decorated oxygen-deficient perovskite LaNi0.5Co0.5O3-γ for antimony removal and reuse of the spent adsorbent in high-performance supercapacitor devices

Abstract

This study presents the development of a multifunctional perovskite-based nanocomposite designed to address environmental remediation and material reuse. A novel hybrid material, LaNi_0.5Co_0.5O_3-γ/carbon nanotube (LNC/CNT), was synthesized and evaluated for its dual functionality: the removal of Sb(III) from aqueous solutions and its subsequent repurposing for energy storage applications. The LNC/CNT nanocomposite demonstrated outstanding adsorption performance, achieving a removal efficiency of 92.51 %. The adsorption process followed a pseudo-second-order kinetic model (R² = 0.996) and was well described by the Langmuir isotherm, yielding a maximum adsorption capacity of 414.99 mg/g. Following Sb(III) adsorption, the spent material was thermally treated and transformed into LNC/CNT–SbO_x, exhibiting promising potential for electrochemical reuse. In a symmetric supercapacitor configuration, the repurposed material delivered a high energy density of 70.33 Wh/kg at a power density of 1000 W/kg while maintaining 89 % of its initial capacitance after 13,000 charge-discharge cycles, indicating excellent long-term cycling stability. This work highlights a circular materials strategy that converts exhausted adsorbents into value-added functional materials, offering a sustainable and eco-friendly approach to pollutant removal and energy storage.