La0.9Sr0.1FeO3 perovskite, prepared by the microwave-assisted method, was capped with cetyl trimethyl ammonium bromide (CTAB) cationic surfactant, and applied as a sorbent for the removal of the anionic Congo red (CR) dye from aqueous solutions. X-ray diffraction (XRD) patterns showed that the perovskite structure was not affected by capping; however, the particle size increased. There was a hipsochromic shift in the value of λmax of the CR absorption spectrum in the presence of CTAB, which indicated the formation of an oppositely charged dye-surfactant complex. The adsorption efficiency of CTAB-capped La0.9Sr0.1FeO3 was independent of the pH of the solution-equilibrium was reached after a few minutes. The value of the maximum adsorption capacity, qm, was 151.52 mg.g-1, which was 10-times higher than that of the pure perovskite. The proposed sorbent maintained its excellent sorption ability in the presence of the sample matrix; therefore, it can be regenerated and reused with unchanged performance.
Keywords: Adsorption; Capping; Congo red dye; Surfactant; Ternary perovskites; Water decontamination.