Transport of reactive X‐3B dye at the interface between cationic surfactant‐modified water‐quenched blast furnace slag and aqueous solution

Abstract There is an emerging interest in the utilization of low‐cost industrial wastes in sustainable pollution control. This study investigated the use of water‐quenched blast furnace slag modified by cetyltrimethyl ammonium bromide as a low‐cost adsorbent for the removal of reactive brilliant red X‐3B from an aqueous solution. The results showed that the removal efficiency increased with an increasing slag dosage and an appropriate dosage for adsorption was 8 g/L. The adsorption efficiency of X‐3B onto modified slag decreased when the pH increased from 2 to 12. The amount of dye uptake per unit of modified slag also increased with an increase in ionic strength, contact time, temperature, and initial dye concentration. The Freundlich isotherm model showed a good fit to the equilibrium adsorption data. Thermodynamic studies suggested the spontaneous and endothermic nature of the adsorption process. The adsorption kinetics followed the pseudo‐second‐order model and the rate constant increased with increasing temperature. These results can help understand the migration patterns of dye molecules at a modified slag‐water interface. It also has important implications for developing wastewater treatment techniques using low‐cost adsorbents.