Akademik Veri Yönetim Sistemi
Chinese Journal of Chemical Engineering, cilt.90, ss.214-231, 2026 (SCI-Expanded, Scopus)
Iron (Fe) and manganese (Mn) mixed oxide composites are widely recognized for their excellent adsorption performance in wastewater treatment. However, their functionalization for simultaneous removal of both anionic and cationic contaminants remains underexplored. In this study, Fe–Mn mixed oxides were functionalized with poly(acrylic acid) (PAA) and chitosan to introduce carboxylic and amine groups respectively, forming a dual-functionalized composite (PAA–chitosan–FeMn). The material was evaluated for the adsorption of Congo red, reactive blue 19, and methylene blue from aqueous solutions using batch and fixed-bed reactor systems. The composite was characterized before and after adsorption using X-ray photoelectron spectroscope (XPS), atomic force microscope, scanning electron microscope, high-resolution transmission electron microscope, Fourier transform infrared spectroscope (FTIR), thermal gravimetric analyzer, and Raman spectroscopy. A marked enhancement in adsorption capacity was observed for all target dyes. Mechanistic investigations using XPS, FTIR, and density functional theory (DFT) indicated that the adsorption process was predominantly governed by electrostatic interactions and hydrogen bonding involving carbon, nitrogen, and oxygen functional groups. XPS analysis further confirmed the active role of Fe and Mn ions in dye binding. Comprehensive studies on adsorption isotherms, kinetics, and thermodynamics were conducted under optimized conditions. The composite exhibited a specific surface area of 27.4 to 68.4 m2·g−1 before and after dye adsorption and a point of zero charge of 6.5–6.8, facilitating effective adsorption of oppositely charged dyes at near-neutral pH. Batch adsorption experiments demonstrated maximum capacities of 95.0% to 99.7% for both dyes under optimal conditions (pH 8–10, 298 K). The PAA–chitosan–FeMn composite demonstrated high adsorption capacity, excellent stability under acidic conditions, and strong selectivity, highlighting its potential for the effective and simultaneous removal of anionic and cationic azo dyes from wastewater.