Pros and cons of different preparation methods for magnetite nanoparticles.

Method	Pros	Cons	Ref.
Co-precipitation	■ Economical precursors	■ Broad size distribution	24
	■ Mild reaction conditions	■ Low reproducibility
	■ Synthesis in H2O	■ Uncontrolled oxidation
	■ Ease surface modification
	■ Short synthesis time minutes per hours
	■ Ease formation of ferrites
	■ Ease conversion to g-Fe2O3
	■ Ease scale-up
Reverse micelle	■ Improved size control	■ Low reaction yield	26
	■ Narrow size distribution	■ Poor crystallinity
	■ Ease size tunability	■ Surfactants are difficult to remove
	■ Uniform magnetic properties
Hydrothermal reaction	■ Improved size control	■ High pressure and reaction temperature	32
	■ Narrow size distribution	■ Safety of the reactants
	■ Synthesis in H2O
	■ Tunable magnetic properties
Thermal/sonochemical decomposition	■ Narrow size distribution	■ Toxic organic solvents used	33 and 35
	■ High size control	■ High temperatures needed
	■ High crystallinity	■ Phase transfer required
	■ Possible scale-up	■ Mechanism is still under discussion
	■ Tunable magnetic properties
Sol–gel	■ Moderate temperature conditions	■ High pressure is required	29
	■ Relatively short reaction period	■ Usually needs expensive precursors
	■ Good shape control	■ High permeability
	■ Relatively narrow size distribution	■ Low wear resistance
		■ Weak bonding
Biological	■ High yield	■ Slow and laborious	38 and 39
	■ Low production cost
	■ Good reproducibility