Layered double hydroxide assembled on a metal–organic framework coupled with polyaniline as pseudocapacitive anode for phosphorus capture

• Published in: Separation and purification technology 2025-02, Vol.354, Article 129370
• Main Authors: Song, Xiang, Chen, Wenqing, Mou, Haiyan, Ao, Tianqi
• Format: Article
• Language: English
• Subjects: Capacitive deionization; Layered double hydroxide; Metal-organic framework; Phosphorus; Polyaniline
• ISSN: 1383-5866
• DOI: 10.1016/j.seppur.2024.129370

[Display omitted] •LDH coupled with PANI was successfully fabricated using MOF as an LDH precursor.•LDH and PANI favor enhanced structural properties and electrochemical performance.•LDH@MOF/PANI displayed outstanding pseudocapacitive behavior for charge storage.•The interaction mechanism of phosphorus with LDH@MOF/PANI was fully elucidated. Excessive phosphorus is detrimental to supporting the proper function of aquatic ecosystems. Capacitive deionization (CDI) is an emerging, highly efficient, eco-friendly electrochemical technology that eliminates phosphorus from wastewater. In this work, a novel LDH@MOF/PANI composite was successfully fabricated by utilizing polyaniline (PANI) as a conductive substrate and metal–organic framework (MOF) as a self-sacrificial template for layered double hydroxide (LDH). The results demonstrated that LDH and PANI are favorable for improving the pore structure features, enriching the phosphorus binding sites, and strengthening the electrochemical performance of the electrode materials. Accordingly, the LDH@MOF/PANI electrode presented a superior phosphorus capture capacity than LDH@MOF and MOF. The isotherm and kinetic experiments revealed that the phosphorus capture by LDH@MOF/PANI is a chemisorption-dominated process associated with heterogeneous adsorption. The potential interference with phosphorus uptake was also assessed by focusing on several vital factors. Eventually, the possible mechanism suggested that ligand exchange, anion exchange, hydrogen bond, electrostatic attraction, and electric field assistance participate in the phosphorus uptake process. This work presents promising insight into the assembly design and rational construction of LDH-based pseudocapacitive anode for phosphorus capture.