Preparation and Performance of a Modified Iraqi Red Kaolin Clay-Based Sorbent for Methylene Blue Removal in Acidic and Basic Solutions

In recent years, the removal of dyes from wastewater via adsorption has attracted significant interest, particularly in the development of high-performance and low-cost sorbents that function effectively in both acidic and basic solutions.The goal of the present study was to synthesize a high-performance sorbent by modifying Iraqi red kaolin clay (IRK) with cetyltrimethylammonium bromide (CTAB), exchanging the interlayer of the clay to produce a hydrophobic material (CTAB-IRK) for the elimination of methylene blue (MB).Additionally, the adsorption of MB dye by CTAB-IRK was studied, focusing on the impact of agitation time, sorbent dosage, initial MB concentration, shaker speed, and pH on the adsorption mechanism.M MB removal efficiency remained stable (87.8-98.7%)over a pH range of 2 to 10.The surface modification with CTAB enhanced the hydrophobicity and adsorption capacity of IRK, facilitating MB removal.The optimum removal efficiency (100%) was achieved with an agitation time of 120 min, a dosage of 0.05 g/100 mL, pH 7, a shaker speed of 200 rpm, and an MB concentration of 50 mg/L.The Freundlich isotherm model (R =0.926) accurately represented the isotherm data with maximum adsorption capacity of 833.33 mg/g, while the pseudo-second-order model was more applicable with kinetic data.