Selective Phosphate Adsorption Using Topologically Regulated Binary-Defect Metal-Organic Frameworks: Essential Role...

Area of Science:

• Environmental Science
• Materials Science
• Chemistry

Background:

• Metal-organic frameworks (MOFs) and biochar (BC) composites are effective phosphate adsorbents.
• Understanding the electronic interfacial states of MOFs in BC composites is crucial for optimizing performance.
• Current strategies lack detailed insights into electronic regulation for enhanced phosphate adsorption.

Purpose of the Study:

• To develop a novel topological transformation strategy for regulating the interfacial electronic states of BC/MOF composites.
• To investigate the mechanism behind enhanced phosphate adsorption and self-healing capabilities.
• To provide new perspectives on electronic regulation for efficient phosphate removal.

Main Methods:

• Novel topological transformation strategy for BC/MOF composites.
• Characterization of electronic interfacial states and defect regulation.
• Phosphate adsorption experiments in simulated and real wastewater.
• Analysis of adsorption kinetics and capacity.
• Investigation of electron cycling and self-healing mechanisms.

Main Results:

• Optimized BC/MOFs achieved a high selective phosphate adsorption capacity (188.68 mg·g⁻¹).
• Rapid sorption kinetics (6.81 mg·(g·min⁰.⁵)⁻¹) were observed, maintained in real bioeffluent.
• Fe(III) → Fe(II) transition enhanced electron mobility, forming Mg-CUS for phosphate anchoring.
• Binary defect regulation and sp³ hybrid orbitals improved Mg-CUS and phosphate interaction.
• High electron affinity of Mg facilitated electron cycling, enabling self-healing and phosphate desorption.

Conclusions:

• The developed topological transformation strategy effectively regulates interfacial electronic states in BC/MOF composites.
• The enhanced electron mobility and specific coordination sites significantly boost phosphate adsorption capacity and kinetics.
• The self-healing capability derived from electron cycling offers a promising approach for sustainable phosphate removal and adsorbent regeneration.