Synthesis of lanthanum ferrite/graphitic carbon nitride (LaFeO3/g-C3N4) composite for the efficient removal of Orange G dye from aqueous solutions

Abstract

This study investigated the adsorption performance of LaFeO₃/g-C₃N₄ (LFO/g-CN) composite material for the removal of Orange G (OG) dye from aqueous solutions. The LFO/g-CN composite, prepared by wet impregnation method from LFO phase and g-CN compound, was characterized using various techniques including Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), and Brunauer–Emmett–Teller (BET) surface area analysis. BET results revealed a significant increase in surface area from 3.7 m² g⁻¹ for LFO to 51 m² g⁻¹ for the LFO/g-CN composite. The adsorption efficiency was optimized by examining different factors affecting the adsorption process including adsorbent amount, initial pH, solution temperature, contact time and initial OG dye concentration. The maximum removal percentage of OG onto LFO/g-CN material was found to be 72% at pH 2 and 55 °C, using an adsorbent amount of 150 mg and initial OG dye concentration of 10 mg L⁻¹ during a contact time of 180 min. The pseudo-second Order (PSO) kinetic and Langmuir isotherm models accurately described the adsorption of OG on the LFO/g-CN composite. Thermodynamic analysis confirms that the adsorption process is spontaneous (\(\Delta {G}^{\circ }\hspace{0.17em}\)< 0) and endothermic (\({\Delta H}^{\circ }\) > 0). This information contributes to a better understanding of LFO/g-CN as an efficient adsorbent for dye removal, offering potential applications in wastewater treatment at elevated temperatures.