A feasibility study of magnetic separation of magnetic nanoparticle for forward osmosis

Abstract

It was recently reported that a UK company has developed a naturally non-toxic magnetoferritin to act as a draw solute for drawing water in forward osmosis process. The gist of this technology is the utilization of the magnetic nanoparticle and high-gradient magnetic separation for draw solute separation and reuse. However, any demonstration on this technology has not been reported yet. In this study, a feasibility test of magnetic separation using magnetic nanoparticle was therefore performed to investigate the possibility of magnetic separation in water treatment such as desalination. Basically, a magnetic separation system consisted of a column packed with a bed of magnetically susceptible wools placed between the poles of electromagnet and Fe3O4 magnetic nanoparticle was used as a model nanoparticle. The effect of nanoparticle size to applied magnetic field in separation column was experimentally investigated and the magnetic field distribution in a magnet gap and the magnetic field gradient around stainless steel wool wire were analyzed through numerical simulation. The amount of magnetic nanoparticle captured in the separator column increased as the magnetic field strength and particle size increased. As a result, if magnetic separation is intended to be used for draw solute separation and reuse, both novel nanoparticle and large-scale high performance magnetic separator must be developed.

Nonideal Solution Behavior in Forward Osmosis Processes Using Magnetic Nanoparticles

“…between nanoparticle size and osmolality using PAA-MNPs. However, Kim et al [56] found that particles smaller than 11 nm were difficult to separate from solution even with the application of a strong magnetic field, while the removal of particles larger than about 20 nm from the magnetic separator column was problematic. Additionally, the larger the mass percentage of coating material on a Fe 3 O 4 core, the lower the saturated magnetization value on a per gram of particle basis.…”

A magnetic CoFe2O4–CNS nanocomposite as an efficient, recyclable catalyst for peroxymonosulfate activation and pollutant degradation

“…12,13 Another challenge is the easy agglomeration of the NPs, which leads to poor re-suspension and reduced performance with repeated use.…”

“…Furthermore, for the small-sized CoFe 2 O 4 particles, an agglomeration would occur during their magnetic separation, and the resulting aggregates are difficult to re-disperse even with intense ultrasonication. 13,46 This explains the much poorer re-suspension of CoFe 2 O 4 than the larger-sized yet welldispersed CoFe 2 O 4 -CNS (Fig. 6 Inset).…”

Magnetic Cube‐Shaped NiFe2O4 Nanoparticles: An Effective Model Catalyst for Nitro Compound Reduction

“…Transition‐metal‐based magnetic nano‐scale particles have drawn the attention of researchers because of their particular properties such as their high surface area, low toxicity, excellent chemical stability, and biodegradability. As a result of their magnetic properties and biodegradability, they are used in drug delivery, magnetic resonance cell imaging, magnetic hyperthermia, dye adsorption, magnetic separation, wastewater treatment, and heavy‐metal removal . Such magnetic nanoparticles are also applicable as catalysts in industry .…”