Enhanced herbicide removal using an innovative NaP1-Fe3O4-La(OH)3 zeolite: Advances in water treatment and experimental modeling

This study explores the synthesis of a novel and efficient NaP1 zeolite from Austrian fly ash (AFA), composited with Fe₃O₄ nanoparticles (NPs) and lanthanum hydroxides [La(OH)₃]. The composite's efficacy was tested for simultaneously adsorbing glyphosate (GLY), glufosinate (Glu), and aminomethylphosphonic acid (AMPA) from water solution. The inclusion of Fe₃O₄ NPs and La(OH)₃ enhanced the nanoadsorbent's rapid and effective separation capabilities. Significantly, an innovative kinetic model, the Film-Pore-[Concentration-Dependent] Surface Diffusion Model (FPCDSD), was developed to analyze adsorption mechanisms, aligning with experimental results and accurately predicting adsorption processes in single and competitive scenarios. The model used detailed calculations to evaluate mass transfer resistances, employing parameters like rotation speed, adsorbent dosage, and initial concentrations to correlate adsorption data under various conditions. The study found that adsorption capacity retained 92 % effectiveness after 10 adsorption-desorption cycles, consistent with previous research. Results indicated that electrostatic interactions, herbicide affinity for La and Fe complexes, hydrogen bonding, and surface and pore diffusion likely drive adsorption mechanisms. Laboratory tests showed that Gly achieved the Maximum Residual Level (MRL) of 0.1 μg/L as per the European directive for drinking water with 99.95 % removal efficiency, suggesting that NaP1-Fe₃O₄-La(OH)₃ is a highly effective option for water treatment.