Enhanced adsorption of La(III) and Ce(III) onto phytic acid modified N-(2-hydroxyethyl) acrylamide

A novel adsorbent (PHPM) was synthesized through the functionalization of N -(2-Hydroxyethyl) acrylamide (HEAA) with phytic acid (PA) and applied for the adsorption of La(III) and Ce(III) ions. The material was characterized by means of FTIR, TGA, SEM, and XPS. The present study systematically investigated the effects of contact time, adsorbent dosage, initial La(III) or Ce(III) concentration, and pH value on the adsorption capacity. The maximum theoretical adsorption capacities of PHPM for La(III) and Ce(III) were determined to be 198.0 and 186.2 mg·g −1 , respectively. The adsorption process followed the pseudo-second-order kinetic model and the Langmuir isotherm model, as further confirmed by nonlinear fitting with low RMSE and χ 2 values. Thermodynamic analysis revealed negative Δ G values, positive Δ H and Δ S values, indicating a spontaneous, endothermic, and entropy-driven process. Furthermore, PHPM demonstrated high adsorption efficiency toward La(III) and Ce(III), even in the presence of competing ions. A preliminary cost analysis indicated that the preparation of PHPM was economically feasible with low cost. The adsorbent maintained approximately 50% of its initial adsorption capacity after ten consecutive adsorption-desorption cycles. The findings demonstrate that PHPM was a promising adsorbent for the recovery of La(III) and Ce(III) from aqueous environments.