Hierarchical porous carbon electrodes derived from bimetallic MOF on cellulose fibers for Electrical-Assisted adsorption of phosphate

Abstract

Pollution caused by the excessive use of phosphate has attracted widespread attention. In this study, Zr-La MOF-derived carbon (ZLMCs) electrode was prepared to remove phosphorus from water via the electroassisted adsorption (EAA) method. The crystal structure of ZLMOF induces defects that provide active sites for phosphate uptake. In comparison to alternative adsorption materials, ZLMC-16 achieves 143.0 mg g^–1 (80 % full capacity) in one hour and 178.8 mg g^–1 in three hours. In addition, the spontaneous adsorption of phosphorus was observed to be heat-absorbing, in line with the proposed pseudo-second-order kinetics and Langmuir isotherm model. FTIR and XPS analyses indicated that chemical bonding and electrostatic gravitational forces between La/Zr-O-P play a key role in the phosphate trapping mechanism. Under electric field, PO₄^3- was rapidly transferred from the aqueous solution to the electrode surface and can reach deeper adsorption sites. Furthermore, ZLMC-16 demonstrated high selectivity for PO₄^3- in the presence of common interfering ions (SO₄^2-, Cl^-, and NO₃^–) and an efficient adsorption capacity between pH 3–7. In conclusion, our work shows that ZLMC electrodes with fiber additions have good potential for efficient phosphate removal and recovery, which will promote the application of electroassisted adsorption in wastewater treatment.