Adsorption of Remazol N. Blue RGB Dye by Calcium‐Based Adsorbents Modified With Iron–Cobalt and Triethylamine

ABSTRACT In this study, waste eggshells (ES), which are a calcium source, were used as an adsorbent in the removal of Remazol N. Blue RGB dye (Remazol N‐RGB). XRD patterns showed that all materials exhibited a crystalline structure. Metal loading and triethylamine modification enhanced the surface area, total pore volume, and mesopore diameter of CES (calcined eggshell). The surface area values were determined as 15, 169, and 138 m 2 /g for CES, FeCo@CES, and FeCo‐T@CES, respectively. FTIR spectra reflected the characteristic peaks of the materials, while SEM images proved their porous structure. The pH pzc value of materials indicated a positively charge surface, facilitating strong electrostatic interactions with dye molecules. An increase in the initial dye concentration resulted in a lower removal percentage, whereas increasing the adsorbent amount enhanced dye removal efficiency. High dye removal was achieved at low pH values. The adsorption capacities of CES and FeCo@CES were determined as 23.92 and 12.90 mg/g, respectively.