MIEX®DOC resin capacity for natural organic matter (NOM) removal

The study aimed to achieve near-complete saturation of the adsorption capacity of the MIEX®DOC resin with dissolved organic compounds in order to quantitatively assess its sorption potential. The experimental procedure was conducted using a laboratory-scale continuous-flow reactor containing 25 cm³ of the MIEX®DOC adsorbent, with a packing density of approximately 500 cm³/dm³. The influent water matrix consisted predominantly of humic-type organic matter, with a concentration of approximately 9 g C/m³. Under conditions devoid of competition from inorganic anions and at a resin bed volume ratio reaching 16 000 m³/m³, the MIEX®DOC adsorbent achieved a saturation capacity of 29 g C/cm³. This saturation level can be considered proximate to the maximum adsorption capacity, as the removal efficiency of organic substances under these conditions did not exceed 2%. Furthermore, this value is consistent with the operating ion-exchange capacity of the resin for organic constituents characterized by low charge density, approximately 4 meq/g C. The adsorption saturation profile demonstrated that the application of a “high-rate” (HR) reactor enables a satisfactory quality of treated water utilizing approximately 19% of the estimated capacity of the MIEX®DOC resin. In contrast, implementation of a “high- rate counter-current” (HR-CC) reactor configuration allows for at least a twofold increase in capacity utilization, reaching approximately 40%.