Commentary on "Solvent-mediated construction of phosphate/carboxyl bifunctional hyper-cross-linked polymers for highly efficient uranium removal from aqueous solutions (https://doi.org/10.1016/j.jhazmat.2026.141094)".

This commentary reassesses the thermodynamic, kinetic, and equilibrium modeling presented in the recent study on a phosphate/carboxyl bifunctional hyper-cross-linked polymer for uranium adsorption. While the synthesis and characterization of the material are commendable, several interpretive limitations affect the physicochemical conclusions drawn from the data analysis. First, we identify a dimensional inconsistency in the calculation of standard thermodynamic parameters via the van't Hoff equation, emphasizing the necessity of a dimensionless equilibrium constant. Second, we clarify the fundamental mathematical distinction between empirically derived equilibrium capacity (qe) and theoretically extrapolated maximum capacity (Qmax). Third, we discuss the conceptual limitation of using pseudo-second-order kinetic fits to infer microscopic coordination mechanisms, because such fits describe only the time dependence of uptake and do not identify the nature of the adsorbate-surface interaction. Finally, we examine the limited mechanistic specificity of applying homogeneous Langmuir interpretations to complex, heterogeneous cross-linked networks. Clarifying these physicochemical frameworks is important for the accurate scale-up of environmental separation technologies.