Hierarchical Porous Carbon Derived from Aminated Lignin for High-Performance Capacitive Deionization

Global freshwater scarcity has intensified the demand for high-efficiency desalination technologies. Capacitive deionization (CDI) has garnered significant attention for its simple structure and low energy consumption. The development of high-performance electrode materials is the key to enhancing the CDI efficiency. In this study, the aminated lignin is synthesized via a Manish reaction using diethanolamine and formaldehyde solution. The aminated lignin is modulated by graphene oxide (GO) successfully to prepare a hierarchically porous carbon (LC-DG) material. The LC-DG exhibits excellent capacitive properties, achieving a specific capacitance of 156 F·g–1 at 1 A·g–1. In a 500 mg·L–1 NaCl solution under an applied voltage of 1.2 V, the LC-DG achieves an electrosorption capacity of 23.79 mg·g–1. The desalination capacity remains at 21.55 mg·g–1 after 50 adsorption–desorption cycles with a capacity retention rate of 90.60%. This study provides a new approach to enhance the performance of biomass-derived carbon materials in CDI applications.