Table 2.

Representative summary of previous works on TEMPO-mediated oxidation with ultrasound assistance.

Raw material	Oxidant concentrations (per g fiber)				Sonication conditions	Nanocellulose size (nm)	Ref.
	TEMPO	NaBr	NaClO2	NaClO
Sugarcane bagasse pulp	16 mg	100 mg	–	2.0–11.0 mmol	25 kHz, 450 W, 30 min (Post-treatment)	W = 15 ± 8 L = 264 ± 69	[167]
Microcrystalline cellulose	16 mg	100 mg	–	20 mmol	20 kHz, 270 W, 120 min (Post-treatment)	W = 5.1–6.4 L = 190	[159]
Softwood kraft pulp	16 mg	100 mg	–	20 mmol	20 kHz, 270 W, 120 min (Post-treatment)	W = 3.5–3.6 L = 185	[159]
Banana pseudo-stem	16 mg	–	100 mg	10 mg	20 kHz, 1000 W, 60 min (Post-treatment)	W = 2.24 ± 0.57 L = 125 ± 28	[141]
Fique fibers	16 mg	100 mg	–	37 mmol	40 kHz, 130 W, 120 min (Simultaneous) 20 kHz, 750 W, 10 min (Post-treatment)	W = 2 L = 200–438	[169]
Coconut waste husk	0.50 mmol	–	15 mmol	11 mmol	25 kHz, 1000 W, 60 min (Post-treatment)	W = 5.6 ± 1.5 L = 150–300	[177]
W, width; L, length.