Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ, 07030, USA.
Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ, 07030, USA.
Chemosphere. 2022 Apr;292:133357. doi: 10.1016/j.chemosphere.2021.133357. Epub 2021 Dec 17.
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 (HO), 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/HO 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/HO and UV alone.
硝胍（NQ）是一种用于钝感弹药配方的成分，具有很高的溶解度，这往往会导致废水受到高度污染。在这项工作中，进行了批处理实验，以研究和比较基于 UV 的高级氧化工艺（AOP）对 NQ 的降解；选择过氧化氢（HO）、过硫酸盐（PS）和过氧单硫酸盐（PMS）作为氧化剂。通过初步评估 AOPs 的动力学、副产物和潜在的降解途径，并将其与直接 UV-C 光解对 NQ 的降解进行比较。通过确定各自的降解动力学常数，评估了氧化剂剂量、NQ 浓度和 pH 的影响。在所应用的处理中，UV/PS 表现出是一种有前途和有效的替代方法，与氧化剂剂量（25 mM）和初始 NQ 浓度（≤24 mM）相比，导致更快的降解速率。然而，与 UV/HO 和 UV/PMS 相比，UV/PS 对 NQ 的降解速率似乎受初始 pH 的强烈影响，在 pH≥8.0 时总体速率最低。此外，NQ 降解的主要副产物胍和氰胺仅在 UV/PS 和 UV/PMS 中显示出进一步降解步骤，这表明这些氧化剂比 UV/HO 和 UV 具有更高的降解效果。
