Ultrasound assisted co-precipitation synthesis of Fe3O4/bentonite nanocomposite: Performance for nitrate, BOD and COD water treatment

In this research, modification of bentonite and synthesis of Fe3O4/Bentonite nanocomposite are reported in the presence of ultrasound. The samples were prepared by chemical co-precipitation and sonochemical methods and the structural order, textural, magnetic, and surface area properties were examined using XRD, FTIR, SEM, EDX, VSM, BET, and point of zero charge pH (pH(pzc)) analysis. Then the as synthesized nanocomposite was used to remove nitrate, BOD and COD from water and industrial wastewater. Batch adsorption experiments were conducted, where the influence of several parameters such as pH, contact time, adsorbent amount, and nitrate concentration were studied. According to the results, the best nitrate removal (79%) by using the prepared nanocomposite was achieved at the pH of 5, the contact time of 90 min, adsorbent amount of 0.6 g and the initial nitrate concentration of 30 mg/l. For further investigation, some tests were conducted on industrial wastewater of pharmaceutical units to evaluate the BOD and COD reduction. Using 2 g of synthesized sample, 84.88% of BOD and 88.8% of COD of the industrial wastewater were removed.