TY - JOUR
T1 - Oxidative degradation of nitroguanidine (NQ) by UV-C and oxidants
T2 - Hydrogen peroxide, persulfate and peroxymonosulfate
AU - Terracciano, Amalia
AU - Koutsospyros, Agamemnon
AU - Christodoulatos, Christos
AU - Mai, Andrew
AU - Meng, Xiaoguang
AU - Su, Tsan Liang
AU - Smolinski, Benjamin
N1 - Publisher Copyright:
© 2021 Elsevier Ltd
PY - 2022/4
Y1 - 2022/4
N2 - Nitroguanidine (NQ), a component used in insensitive munitions formulations, has high solubility which often leads to highly contaminated wastewater streams. In this work, batch experiments were conducted to investigate and compare the NQ degradation by UV-based advanced oxidation processes (AOPs); hydrogen peroxide (H2O2), persulfate (PS) and peroxymonosulfate (PMS) were selected as oxidants. A preliminary evaluation of AOPs kinetics, byproducts, and potential degradation pathways were carried out and compared to NQ degradation by direct UV-C photolysis. The effects of oxidant dosage, NQ concentrations and pH were evaluated by determining the respective kinetic constants of degradation. Among the treatments applied, UV/PS showed to be a promising and effective alternative leading to faster rates of degradation respect to both oxidant dosage (25 mM) and initial NQ concentrations (≤24 mM). Nevertheless, the degradation rate of NQ by UV/PS appeared to be affected strongly by the initial pH compared to UV/H2O2 and UV/PMS, with the lowest rate overall at pH ≥ 8.0. In addition, the main byproducts from NQ degradation, guanidine and cyanamide, showed to be involved in further degradation steps only with UV/PS and UV/PMS suggesting higher degradation effectiveness of these oxidants compared UV/H2O2 and UV alone.
AB - Nitroguanidine (NQ), a component used in insensitive munitions formulations, has high solubility which often leads to highly contaminated wastewater streams. In this work, batch experiments were conducted to investigate and compare the NQ degradation by UV-based advanced oxidation processes (AOPs); hydrogen peroxide (H2O2), persulfate (PS) and peroxymonosulfate (PMS) were selected as oxidants. A preliminary evaluation of AOPs kinetics, byproducts, and potential degradation pathways were carried out and compared to NQ degradation by direct UV-C photolysis. The effects of oxidant dosage, NQ concentrations and pH were evaluated by determining the respective kinetic constants of degradation. Among the treatments applied, UV/PS showed to be a promising and effective alternative leading to faster rates of degradation respect to both oxidant dosage (25 mM) and initial NQ concentrations (≤24 mM). Nevertheless, the degradation rate of NQ by UV/PS appeared to be affected strongly by the initial pH compared to UV/H2O2 and UV/PMS, with the lowest rate overall at pH ≥ 8.0. In addition, the main byproducts from NQ degradation, guanidine and cyanamide, showed to be involved in further degradation steps only with UV/PS and UV/PMS suggesting higher degradation effectiveness of these oxidants compared UV/H2O2 and UV alone.
KW - AOP
KW - Degradation products
KW - HO
KW - Nitroguanidine
KW - Peroxymonosulfate
KW - Persulfate
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U2 - 10.1016/j.chemosphere.2021.133357
DO - 10.1016/j.chemosphere.2021.133357
M3 - Article
C2 - 34929271
AN - SCOPUS:85121908119
SN - 0045-6535
VL - 292
JO - Chemosphere
JF - Chemosphere
M1 - 133357
ER -