Ultrasonic irradiation as a green production route for coupling crystallinity and high specific surface area in iron nanomaterials

authors	Kamali, M; Costa, MEV; Otero-Irurueta, G; Capela, I
nationality	International
journal	JOURNAL OF CLEANER PRODUCTION
author keywords	Nano zero valent iron; Iron oxide nanoparticle; Ultrasonic irradiation; Crystallinity; Specific surface area; Taguchi method
keywords	ZERO-VALENT IRON; NANO; NANOPARTICLES; REDUCTION; REMOVAL; OPTIMIZATION; DEGRADATION; ADSORPTION; MAGNETITE; OXIDES
abstract	Coupling high crystallinity with high specific surface area in engineered nanomaterials is imperative whenever both chemical endurance regarding particle dissolution and a large specific surface area are needed for environmental clean-up purposes. Gathering both properties in the same particulate system is not trivial. In this work, A L-9 orthogonal array of experiments was used to assist a liquid-phase reduction method aiming to synthesize zero valent iron nanoparticles (nZVI) that could offer a large specific surface area while presenting a well-developed crystalline structure. The experimental variables included the reductant addition rate, the precursor (Fe+3) concentration, the (reductant/Fe3+) ratio, (R), and also the application of ultrasonic irradiation (UI) to the precipitating medium. The results show that NaBH4/FeCl3 ratio and Fe+3 concentration have opposite effects on the specific surface area of the synthesized particles whereas the effect of reductant addition rate is negligible. Moreover, the introduction of UI in the precipitation process benefits considerably the surface area of the particles while preserving or even enhancing the crystallinity of the precipitated nanomaterials. The effects of UI were interpreted in the frame work of the classical nucleation theory. This work raises the potential of UI as an environmentally friendly method to be applied to other precipitation systems which could end up in finer powder particles with better crystallinity. (C) 2018 Elsevier Ltd. All rights reserved.
publisher	ELSEVIER SCI LTD
issn	0959-6526
isbn	1879-1786
year published	2019
volume	211
beginning page	185
ending page	197
digital object identifier (doi)	10.1016/j.jclepro.2018.11.127
web of science category	Green & Sustainable Science & Technology; Engineering, Environmental; Environmental Sciences
subject category	Science & Technology - Other Topics; Engineering; Environmental Sciences & Ecology
unique article identifier	WOS:000457952400015