Synthesis and application of maghemite nanoparticles for water treatment: response surface method

The current study aimed at exploring potential use of maghemite nanoparticles (MNPs) synthesized via facile co-precipitation method as an adsorbent for effective water treatment. Batch adsorption studies were performed using Box–Behnken experimental design under response surface methodology to determine the effects of pH, adsorbent dose, and contact time and their interactive relationship during the adsorption process. Six water quality parameters including two physical parameters [turbidity, total dissolved solids (TDS)], one chemical parameter [chemical oxygen demand (COD)] and three heavy metals (cadmium, lead, and chromium) were selected for this study. Physicochemical properties of MNPs indicated the excellent properties of MNPs as good adsorbent. The optimized operating conditions (pH: 7, adsorbent dose: 0.75 g, and contact time: 40 min) yielded following maximum removal efficiencies for selected parameters: (89% for turbidity, 56% for TDS, 67% for COD, 79% for cadmium, 81.2% for lead, and 95.6% for chromium). Coefficient of determination (R²) depicted a good fit between experimental and predicted values whereas larger F and smaller p-values (<0.05) of all responses indicate the higher significance of mathematical model. This study demonstrated the suitability of employing MNPs as efficient adsorbent with high potentials for the removal of multiple pollutants present in water.