This paper focused on the study of the impact of ultrasonic waves on the intensification of Ni (II) removal from aqueous solution by adsorption onto Fe3O4 nanoparticles. Co-precipitation method is used to synthesis Fe3O4 magnetic nanoparticles (MNPs) and the average size of the nanoparticles is obtained about 19 nm by SEM. Two layouts including using a shaker and ultrasonic are examined. The effects of pH, absorbent mass and initial concentration of Ni (II) on the removal efficiency of Ni (II) ions are investigated. The results depicted that by the increase in pH from 2 to 9, Ni (II) removal efficiency has the highest value at pH=9. Ni (II) removal from aqueous solution using ultrasonic needs to lower contact time than the shaker at identical conditions. The highest removal efficiencies of Ni (II) are 83.3% and 85.5% with the contact times of 100 minutes and 60 minutes, respectively using the shaker and the ultrasonic. Finally, Langmuir and Freundlich isotherm to correlate sets of experimental adsorption isotherm data were employed. However, the fitting results showed that non-linear Langmuir model could fit the data better than Freundlich model.
