Highly efficient adsorption of natural organic matter from aqueous solutions by macroporous weakly basic anion exchange resin: performance, mechanism, and fixed − bed column

In this study, humic acid was used as a model pollutant to investigate the removal effect of a macroporous weakly alkaline anion exchange resin D301 on natural organic matter (NOM) in water. 3D fluorescence spectroscopy, UV - visible spectrophotometry and Fourier transform infrared (FTIR) spectroscopy were employed to analyze changes in the physical and chemical properties of humic acid solution and natural water samples before and after resin adsorption. The results showed that using humic acid as a model pollutant to simulate NOM in water is feasible. Through kinetic and thermodynamic analysis, ion exchange was identified as the dominant mechanism for the adsorption of organic matter by D301 resin. According to the Langmuir adsorption isotherm, the maximum adsorption capacity of the resin was 37.78 mg/g. The adsorption of NOM by the exchange resin effectively conformed to the Thomas, Yoon - Nelson, and BDST models, offering a reliable basis for practical application prediction. Using sodium chloride solution as the regeneration solution for D301 resin column, after several regenerations, the adsorption efficiency of the resin did not change significantly, which indicated that the anion - exchange resin can be used as an efficient and reusable adsorbent for the removal of NOM from water.