Phosphorus adsorption in paddy water by immobilized Ce-MOFs: performance, mechanism analysis, and dynamic adsorption
摘要
In this study, a novel cerium-based metal-organic framework (Ce-Fum MOFs) was synthesized using plant-derived fumaric acid as a ligand. The Ce-Fum was immobilized onto a composite mixture of bacterial cellulose (BC) and sodium carboxymethyl cellulose (CMC), resulting in the Ce-Fum700-BC-CMC100 adsorbent. The material was used for phosphorus adsorption in water, addressing challenges related to adsorbent recovery and ligand competition, achieving a capacity of 67.35 mgP/g, surpassing most immobilized adsorbents, and demonstrating significant resistance to pH fluctuations, humic acid, and high concentrations of coexisting anions. The optimized process conditions forecasted a 99.83% phosphorus removal efficiency from real water samples. Batch adsorption experiments, complemented by X-ray photoelectron spectroscopy (XPS), two-dimensional Fourier transform infrared correlation spectroscopy (2D-FTIR-COS), and molecular dynamics (MD) simulations, revealed that ligand exchange, complexation, and electrostatic attraction are the predominant mechanisms governing phosphorus adsorption, with complexation contributing 75–83% to phosphorus removal across the pH range of 3.0–10.0. The reaction sequence is as follows: ligand exchange > complexation > electrostatic attraction. The performance of the adsorbent in real water samples and under dynamic adsorption conditions further reinforces its applicability in practical wastewater treatment processes. This study provides valuable insights into enhancing the practical application of MOFs and improving phosphorus recovery efficiency.