Surface-modified γ-alumina nanoparticles for efficient adsorption of some cationic dyes from wastewater

This study explores the removal of cationic textile dyes using γ-alumina nanoparticles modified with an anionic surfactant. The nanoparticles were synthesized in the laboratory and subsequently modified with sodium dodecyl sulfate (SDS). These modified nanoparticles were utilized to eliminate two prevalent cationic dyes, basic yellow 40 and basic red 18, from aqueous solutions that emulate textile industrial effluents. Characterization analyses, including scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR), confirmed the successful synthesis and surface modification of the nanoalumina. To optimize the conditions for dye removal, a response surface methodology (RSM) was employed to evaluate the effects of contact time, dye concentration, adsorbent dosage, and solution pH at three levels each. Under optimized conditions, SDS-modified γ-alumina nanoparticles demonstrated a dye removal efficiency of over 94%. In tests with dye-spiked real samples, they maintained high adsorption efficiencies above 90%, much better than unmodified nanoparticles, which showed less than 60% efficiency. These results show that surfactant-modified nanoalumina is a strong and effective option for cleaning dye-contaminated wastewater.