Applications of MW nonthermal effects.

No.	Application scenarios	Specific application	External expression of the nonthermal effects of MWs	Data that support the performance	Ref.
1	Environmental governance	The advanced treatment of organic wastewater	The nonthermal effects can improve the degradation rate of N-nitrosodimethylamine (NDMA) that is sorbed in zeolites, compared with CH.	MWs can produce hot spots, and the apparent activation energy is 18.2 kJ mol−1, which is much lower than those of common thermolysis reactions.	Hu et al.49
2		The coupling of MWs to an ultraviolet light (UV) light source can be used in the treatment of environment pollutants.	The MW nonthermal effects can enhance the TiO2 photoassisted reactions.	The relevant dynamics of the break-up of the bisphenol A (BPA) phenyl rings in the integrated MW-/photo-assisted method in the presence of TiO2 particulates system shows that the cleavage of the rings is twofold faster than that in the photo-assisted method alone (3.3 × 10−4 mmol L−1 min−1versus 1.7 × 10−4 mmol L−1 min−1).	Horikoshi et al.53
3				For P25 titania, the number of ·OH that were produced by the UV/MW method was nearly 30% greater than the number that were generated by the UV method alone. A fivefold increase in incident MW power from 3 to 16 W caused a non-insignificant increase (ca. 40%) in the number of ·OH radicals that were produced.	Horikoshi et al.15
4		The hydrolysis of WAS	The MW nonthermal effects can reduce Ea and improve the hydrolysis rate of WAS.	The Ea values of WAS hydrolysis by MWs were much lower than that of CH (22.6–31.0% of that of CH).	Byun et al.48
5	Industrial production	Improvement of the fermentation activity of Saccharomyces cerevisiae	The MW nonthermal effects can significantly decrease the fermentation time.	The sample that was treated by MW had a lower sugar content, its fermentation time was reduced by 40% and its fermentation capacity increased by approximately 30%.	Kapcsandi et al.54
6		Degumming of hemp	The MW nonthermal effects can accelerate the degumming process of hemp.	The corresponding carbon and oxygen atomic concentration ratios gradually increased from 0.35 for untreated hemp to 0.49 for the MW-treated fibre.	Tian et al.55
7		Production of high green densities and homogeneous pore size distribution ceramics	The MW nonthermal effects can increase the sintered densities significantly.	At the maximum sintered densities, MW-sintered tetragonal zirconia had nearly half the grain sizes as conventionally sintered tetragonal zirconia.	Mitsudo et al.56 and Link et al.57
8		Production of crosslinked gelatine with higher turbidity, crosslinking degree, and viscosity	The MW nonthermal effects can accelerate the crosslinking reaction of gelatine.	MW heating with simultaneous cooling increased the turbidity, crosslinking degree, and viscosity of the crosslinked gelatine by 91 FTU, 6.8%, and 0.08, respectively and endowed it with a higher molecular weight as the grey levels decreased by 9.2% (235–245 kDa), 2.3% (135–145 kDa), and 9.3% (122–132 kDa).	Wu et al.58
9		Production of GO with low wettability.	The MW nonthermal effects can decrease the wettability of GO.	MWs can cause the water uptake capability of GO to decrease by half and the contact angle of water droplets to increase from ∼29.7° to ∼69.9°.	Rasuli et al.59
10		Production of α-alumina with high densification	The MW nonthermal effects can strengthen the sintering by increasing the intensity of densification.	The final densities are 99.88% and 99.40% during MW and conventional sintering, respectively, at a heating rate of 25 °C min−1.	Zuo et al.60
11	Medical treatment	Clarification of the mechanisms of adjuvant treatment for delayed and nonunion fractures.	The MW nonthermal effects can reduce the NaCl solution viscosity by rotating dipolar water molecules to make high-frequency alterations to hydrogen bonds.	The time that was required to reduce the initial resistance of the solution by 10% was 1.7 times shorter with MWs.	Hinrikus et al.52
12		Promotion of the bioactivity of LDH	The MW nonthermal effects influence protein functions through changes in the bioactivity of LDH.	(1) The biological activity of the LDH enzyme can be increased by 40–70% using low-power MWs at 500 MHz to 30 dBm, 500 MHz to 40 dBm, and 500 MHz to 50 dBm, and the maximum increase is achieved at 900 MHz-30 dBm;	Pirogova et al.10
				(2) The biological activity of the LDH enzyme can be reduced by 2–15% using high-power MWs at 650 MHz to 30 dBm, 700 MHz to 40 dBm, and 750 MHz to 50 dBm.
13	Energy exploration (biomass)	Hydrolysis of cellulose to sugar	The MW nonthermal effects have high efficiency in the hydrolysis of cellulose compared with CH.	Under 135 W of MW irradiation, the conversion of cellulose exceeded 69.1% and the yield of the total reducing sugar reached 56.0% at 5 min of hydrolysis.	Zhai et al.61
14		Pretreatment of lignocellulosic biomass	The MW nonthermal effects can be used to pretreat lignocellulosic to change its biomass.	The MW can dissolve 10% of the hemicellulose in corn stalks in a pressurized reactor.	Bichot et al.62