FeMoO Composite from Groundwater Iron Sludge for Organic Pollutant Removal from Aqueous Media

This study reports the synthesis of FeMoO-based nanocomposites derived from groundwater deironing sludge via solution combustion synthesis using different organic reducing agents. X-ray diffraction analysis revealed that the phase composition is strongly dependent on the reducing agent, with FeMoO4 as the dominant phase (up to 52%) accompanied by Fe2O3, Fe3O4, MoO3, and MoO2, indicating incomplete phase formation under combustion conditions. Morphological analysis showed aggregated nanoparticles with sizes predominantly in the range of 5−110 nm (median: 14.6 nm). The materials exhibited high photocatalytic activity toward degradation of organic dyes, with the glycine-derived sample achieving #x3e;97% removal efficiency, supported by correlation analysis demonstrating a positive relationship between the FeMoO4 content and catalytic performance, while individual oxide phases showed negative contributions. Oil sorption tests revealed that FeMoO-rich samples exhibit the highest sorption capacity, reaching 0.97 g/g, with a strong correlation (r = 0.841) between the FeMoO4 fraction and oil uptake, indicating the critical role of mixed Fe−Mo−O bonding in controlling wettability and adsorption behavior. However, after five sorption−regeneration cycles, a huge decrease in capacity (to 0.08 g/g) was observed. Antibacterial tests demonstrated moderate inhibition of Gram-positive and Gram-negative bacteria. Overall, the results show that FeMoO-based materials exhibit multifunctional properties for wastewater treatment, while their performance is critically governed by the phase composition and structural stability under cyclic operation.