Synergistic adsorption of dibutyl phthalate by magnetic Zr/Ce bimetallic coordination polymers with Regioisomeric mixed ligands

Magnetic Zr/Ce bimetallic CPs were prepared by a hydrothermal method. • Partial Ce substitution for Zr reduces cost of the bimetallic nodes. • Phthalic acid ligand offers electron-rich aromatic rings for π-π stacking. • DBP uptake reaches 1061–1172 mg/g at 600 mg/L, surpassing most adsorbents. • Magnetic separation enables reuse; capacity drops <5% after five cycles. Phthalate esters (PAEs), as endocrine-disrupting chemicals with reproductive toxicity, pose significant challenges to environmental protection and food safety due to their widespread occurrence and persistence in the environment. In this study, three Zr/Ce bimetallic coordination polymers (CPs) were successfully synthesized via a hydrothermal method combined with a post-modification coprecipitation strategy, using tetrafluoroterephthalic acid (BDC-F₄) and phthalic acid (PA) as mixed ligands. Fe₃O₄ was subsequently deposited in situ to impart magnetic responsiveness to the materials. All three materials exhibited excellent adsorption performance toward dibutyl phthalate (DBP), with adsorption capacities of 1061, 1128, and 1172 mg/g, respectively, at an initial DBP concentration of 600 mg/L, which were higher than the theoretical maximum adsorption capacities of most adsorbents reported in the literature. The adsorption kinetics followed the pseudo-first-order model, while the adsorption isotherms were better described by the Freundlich and Temkin models. Thermodynamic analysis indicated that the adsorption process was spontaneous and exothermic and was predominantly governed by physical adsorption. After five consecutive adsorption–desorption cycles, the average decrease in adsorption capacity was approximately 2.7%, demonstrating excellent structural stability and reusability. This study integrates Zr/Ce bimetallic nodes with mixed-ligand functional regulation, providing a magnetically separable adsorbent design strategy for the efficient and selective removal of PAEs from complex aqueous matrices. Download: Download high-res image (248KB) Download: Download full-size image