Investigation of ultrasonic effect on synthesis of nano zero valent iron particles and comparison with conventional method

Abstract

ABSTRACT In this work, a new method of the synthesis of nano zero valent iron (nZVI) is presented. Ultrasonic wave as a novel method is used to synthesize nanoparticles and the physico‐chemical properties of particles compared with conventional synthesis method. Among the various synthesis methods, chemical reduction is widely used because of its simplicity. The effect of ultrasonic power (500 W, 1000 W), FeSO 4 .7H 2 O concentration (0.02, 0.05 and 0.08 M), NaBH 4 concentrations (0.1, 0.25 and 0.4 M) and delivery rate of reducing agent on nZVI characteristics were investigated. Particle size distribution, morphology and surface composition were characterized by transmission electron microscopy, field emission scanning electron microscopy, X‐ray diffraction (XRD), Brunauer, Emmett and Teller (BET) surface area and particle size analyzer. It was found that the morphology of nanoparticles changed from spherical type to plate and needle type under high ultrasonic power. The size of 50% of nanoparticles was decreased from 90.3 to 29.9 nm under high precursor/reductant concentration and high ultrasonic power. Also, BET surface area was increased from 10 to 42 m 2 /g while using ultrasonic waves. The XRD patterns showed that the crystallinity of the nZVI prepared using ultrasonic conditions was poor because of the inadequate time for nuclei growth and crystallization. Therefore, the ultrasonic power could impose dramatic effect on the characteristics of the nanoparticles. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.