Preparation of two-dimensional pine pollen derived carbon sheets by rapid microwave carbonization for efficient MCDI desalination

Abstract

Membrane capacitive deionization (MCDI) has garnered significant attention in recent years due to its ability to effectively mitigate the co-ion effect in traditional CDI desalination processes, thereby substantially enhancing the desalination capacity. In this study, pine pollen with unique natural morphology was used as a biomass precursor, and two-dimensional carbon sheets with hierarchical pore structures were prepared through a one-step rapid microwave carbonization and KOH activation process. Due to its wrinkled two-dimensional morphology, abundant defects and micropores, and chemical composition rich in oxygen-containing functional groups and nitrogen element, the carbon sheets exhibit excellent desalination performance. In the MCDI system (applied voltage of 1.8 V, flow rate of 11 mL min−1, and initial NaCl solution concentration of 700 ppm), an adsorption capacity of up to 89.86 mg g−1 was achieved, and the adsorption rate reached up to 1.50 mg g−1 min−1. Therefore, the pine pollen-derived carbon in this study exhibits outstanding capacitive deionization desalination performance and demonstrates great potential for practical applications.