CNT supported Sm/Co-LDH for antimony adsorption and subsequent application in supercapacitor to prevent secondary pollution

Currently, the recycling of spent adsorbents stands as a significant concern, primarily due to the inherent value of these resources. Opting to repurpose these materials in the realm of energy storage not only alleviates environmental pressures but also offers a compelling alternative for combating the energy crisis. This multifaceted approach not only contributes to environmental sustainability but also yields invaluable electrode materials, thereby delivering comprehensive economic benefits. In this study, a novel fCNT-Sm/Co-LDH was synthesized via hydrothermal route which efficiently adsorbed antimony (Sb(III)) from wastewater. The expended adsorbent was reused for energy storage, mitigating secondary pollution. The fCNT-Sm/Co-LDH presented the maximum removal efficiency of 96% at 10 mg/L of initial concentration of Sb(III) at pH 8. The Sb-enriched waste adsorbent (fCNT-Sm/Co-LDH@SbOx) was further employed as an energy storage device and demonstrated outstanding performance. The electrochemical examination unveiled that the fCNT-Sm/Co-LDH@SbOx showcased the most substantial specific capacitances, reaching 850 F/g at 2 A/g. The fabricated fCNT-Sm/Co-LDH@SbOx-based symmetric supercapacitor device displayed 78 Wh/kg of energy density at 833 W/kg of power density while unveiling capacitance retention of 92% after 10,000 cycles. This research presents an efficient method for recycling used adsorbents, which can be extended to enhance eco-friendly and cost-effective reprocessing of other hazardous solid wastes, particularly for energy storage applications.