Binary‐Grafted Chitosan‐Based Hydroxyethyl Methacrylate and Glycidyl Trimethylammonium Chloride Copolymers for Selective Removal of Kaolin Suspension and Anionic Dyes via Flocculation

This study presents the synthesis, characterization, and application of binary‐grafted chitosan‐based copolymers functionalized with hydroxyethyl methacrylate and glycidyl trimethylammonium chloride for selective magnetic flocculation. Motivated by the need for efficient, sustainable, and cost‐effective treatment technologies to address the challenges of stable colloidal suspensions and complex mineral wastewater, this work addresses the gap in binary‐functionalized magnetic flocculants capable of high performance in saline and mixed mineral systems. The developed materials were evaluated for their efficiency in the separation of kaolin from hematite and removal of anionic dyes such as Congo Red from aqueous solutions. The binary grafted copolymer CGH1 exhibited superior performance over its mono‐grafted counterparts, attributed to its enhanced hydrodynamic size, higher surface charge, and increased hydrogen bonding capability. Settling kinetics, zeta potential analysis, SEM–EDX, and Kynch settling plots demonstrated CGH1's effectiveness in both selective mineral separation and dye removal across varying pH and saline conditions. Moreover, magnetic separation under an external field further accelerated floc formation and sedimentation, underscoring the advantages of magnetic flocculation in reducing process time and improving selectivity. We believe that the findings establish a proof‐of‐concept for using quaternized chitosan derivatives in water treatment, especially in contexts involving complex mineral mixtures and dye‐laden industrial effluents.