Table 4.

Byproducts/end-products of HMX degradation via different treatment approaches.

Treatment Approach	HMX Degradation Byproducts (Intermediate/End-Products)	References
Biodegradation of HMX by Planomicrobium flavidum	NO2−, methylenedintramine, and N-methyl-N,N′-dinitromethanediamine	[4]
Alkaline hydrolysis	NO2−, N2O, NH3, N2, and HCOOH	[1]
Bioaugmentation using Janibacter cremeus, an immobilized mixture of calcite and cocopeat for bioaugmentation.	Nitroso derivatives (5-hydroxy-4-nitro-2,4-diazapentanal and NDAB (further breaks down to HCHO)	[8]
Biodegradation by sediment microorganisms	Mononitroso derivatives	[85]
Degradation by TiO2 photocatalysis	NO3−, NO2−, and NH4+	[38]
Reduction by nZVI	Formaldehyde/methanol/hydrazine/dimethyl hydrazine	[40]
Electro-assisted Fenton treatment of HMX	HCOOH, NO3−, NH4+, andCO2	[25]
Biodegradation under the mixed electron-acceptor condition	Under mixed electron-acceptor conditions, the major metabolites were CHCl3 and CH3OH. Under methanogenic, fermenting, sulfate, and nitrate-reducing conditions, mono-, di-, and tri-nitroso derivatives were produced from HMX	[7]
Fenton oxidation	NO3− and N2	[30]
Xanthine oxidase catalyzed biotransformation	NO2−, methylenedinitramine (MDNA), 4-nitro-2,4-diazabutanal (NDAB), HCHO, N2O, HCOOH), and NH4+	[9]
Nitrite and nitrate	NO2− and NO3−	[31]
Photocatalytic degradation	NO2−, NO3−, and NH4+	[43]
Reduction by zero-valent Iron	HCHO, NH4+, N2O, and NH2NH2	[29]