Article
Engineering, Environmental
Peizeng Yang, Yuefei Ji, Junhe Lu
Summary: Sulfate radical (SO4 center dot-) based oxidation has great potential in wastewater treatment by transforming ammonium (NH4+) into nitrophenolic byproducts. The reaction mechanism leading to the formation of nitrophenolic byproducts, as well as the transformation of aromatic carboxylate moieties to phenolics by SO4 center dot-, has been demonstrated in the study. The widespread formation of nitrophenolic byproducts when using SO4 center dot- for onsite remediation highlights the importance of considering this factor in evaluating the feasibility of the technology.
Article
Engineering, Environmental
Longgang Chu, Long Cang, Zhaoyue Sun, Xinghao Wang, Hong Chen, Guodong Fang, Juan Gao
Summary: This study systematically investigated the formation mechanism of nitro byproducts of anthracene (ANT) during the electrokinetic (EK) chemical oxidation process. The formation of nitro-byproducts, including 14 different kinds, were observed and their nitration pathways were proposed and described. These nitro-byproducts, which have enhanced acute toxicity, mutagenic effects, and potential threat to the ecosystem, should be further studied during the EK process.
JOURNAL OF HAZARDOUS MATERIALS
(2023)
Article
Engineering, Environmental
Md Sohel Rana, Marcelo I. Guzman
Summary: The study investigates the reaction of nitrate radicals with substituted catechols, which are emitted to the atmosphere during wildfires and combustion processes. The results show that nitrocatechols, major constituents of atmospheric brown carbon, are rapidly generated through two proposed mechanisms. The findings explain the interfacial production of chromophoric nitrocatechols and their impact on the absorption properties of tropospheric particles, affecting the Earth's radiative forcing.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2022)
Article
Engineering, Chemical
Xu Gao, Peizeng Yang, Qi Zhang, Deyang Kong, Jing Chen, Yuefei Ji, Junhe Lu
Summary: This study investigates the influence of nitrite on the degradation of carbamazepine through heat activated peroxydisulfate oxidation. The presence of nitrite not only reduces the degradation rate but also changes the degradation pathway. Nitroacridines and nitrophenols were identified as products during the degradation process, highlighting the potential environmental risks of using persulfate to degrade carbamazepine in the presence of nitrite.
SEPARATION AND PURIFICATION TECHNOLOGY
(2022)
Article
Engineering, Environmental
Peizeng Yang, Li Qian, Yan Cheng, Yuefei Ji, Junhe Lu, Deyang Kong
Summary: Activated persulfate oxidation in soils containing nitrite can yield nitrophenolic byproducts, positively correlated with soil organic matter content. The presence of potential risks highlights the need for cautious use of oxidative reagents in soil remediation.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Engineering, Environmental
Jiating Liu, Peizeng Yang, Yuefei Ji, Junhe Lu
Summary: Sulfate radical-based advanced oxidation processes (SR-AOPs) have the potential to effectively degrade emerging contaminant tetrabromobisphenol S (TBBPS). However, this study found that sulfate radicals also react with ammonium, leading to the suppression of TBBPS degradation. The presence of ammonium changes the pathways and products of TBBPS degradation in SR-AOPs.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Thermodynamics
Wubin Weng, Marcus Alden, Zhongshan Li
Summary: We conducted a spectroscopic study on the chemiluminescence emission of flames containing premixed ammonia-air-oxygen. The emission was found to be caused by excited NH2* radicals in the reaction zone and dominated by NO2* chemiluminescence in fuel-lean flames and NH2* chemiluminescence in fuel-rich flames in the post-flame zone. High-resolution spectra of both types of chemiluminescence in the visible region were recorded. The spectra showed different characteristics, with the NO2* spectrum being continuous and unstructured while the NH2* spectrum consisting of distinct emission lines. Equivalence ratio was determined using integrated chemiluminescence intensities in specific wavelength ranges.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Engineering, Chemical
Gabriel Jaramillo-Soto, Samuel Alejandro Sarracino-Silva, Eduardo Vivaldo-Lima
Summary: This study experimentally addresses the kinetics of nitroxide-mediated dispersion copolymerization with crosslinking of styrene and divinylbenzene in supercritical carbon dioxide. The effect of nitroxide content on polymerization rate, evolution of molecular weight averages, gel fraction, and swelling index was studied.
Article
Engineering, Environmental
Pin Wang, Lingjun Bu, Lu Luo, Yangtao Wu, Weiqiu Zhang, Shiqing Zhou, John C. Crittenden
Summary: In this study, a novel kinetic model was developed to enrich the elementary reactions related to transformation products (TPs) in advanced oxidation processes (AOPs). The entire reaction pathways from parent organic compounds to TPs were mapped using density functional theory (DFT). The predicted concentrations of nitro-TPs obtained from the model matched previous research results, confirming the accuracy of the predictions. This research highlights the effectiveness of combining DFT and kinetic modeling in understanding TP formation and decay mechanisms in AOPs.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Engineering, Environmental
Jialin Chen, Ruina Zhang, Dong Chen, Jianyong Liu, Shanping Chen
Summary: The UV-enhanced generation of CO radical in the Fe(III)-oxalate system improves nitrate reduction to nitrogen with increased product selectivity. pH plays a key role in the NO reduction process, and higher concentrations of Fe(III) and oxalate promote NO3- removal and N-2 production.
JOURNAL OF WATER PROCESS ENGINEERING
(2021)
Article
Environmental Sciences
Xianwei Zhao, Zhuochao Teng, Junjie Wang, Xiaohui Ma, Yanhui Sun, Rui Gao, Fei Xu, Qingzhu Zhang, Wenxing Wang
Summary: This study reveals that nitric acid is formed from chlorine radical, nitrogen dioxide, and water molecules in the marine boundary layer, with the formation from a monohydrate system being thermodynamically favorable.
ATMOSPHERIC ENVIRONMENT
(2022)
Article
Chemistry, Applied
Pu Chen, Jun Xie, Zan Chen, Bi-Quan Xiong, Yu Liu, Chang-An Yang, Ke-Wen Tang
Summary: This study introduces a novel method for the preparation of 3-acylated spiro[4,5]trienones via a nitrogen-centered radical strategy, utilizing visible light-mediated acylation/ipso-cyclization of alkynes with acyl oxime esters. The approach allows for the introduction of various acyl groups into the molecules, providing a new pathway for organic synthesis.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Physical
Xulei Zhao, Yueyue Li, Junhe Lu, Lei Zhou, Jean-Marc Chovelon, Quansuo Zhou, Yuefei Ji
Summary: UV/H2O2 oxidation is an effective technology for degrading chloronitrobenzenes in water, but the generation of nitrated byproducts should be scrutinized. Experimental results and theoretical calculations can be used to optimize the UV/H2O2 treatment process for better removal efficiency of chloronitrobenzenes.
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
(2021)
Article
Environmental Sciences
Xiaoci Li, Yan Cai, Junhe Lu, Jean-Marc Chovelon, Jing Chen, Canlan Jiang, Yuefei Ji
Summary: This study compared the removal of 4-nitrophenol and the generation of chlorinated byproducts in HOCl and UV/HOCl treatment processes. The results showed that UV/HOCl was more effective in removing 4-nitrophenol and produced fewer chlorinated byproducts. The study provides insights into the transformation of nitrophenolic compounds and the formation potential of chlorinated byproducts in HOCl and UV/HOCl disinfection processes.
Article
Engineering, Environmental
Xu Gao, Qi Zhang, Ziyi Yang, Yuefei Ji, Jing Chen, Junhe Lu
Summary: UV/PDS oxidation is a promising technology for degrading organic pollutants. However, this study found that nitrate can lead to the formation of toxic nitrophenolic byproducts during the UV/PDS oxidation of natural organic matter. Nitrate is photolyzed to produce nitrite, which acts as a nitrating agent. Meanwhile, SO4•- oxidizes the phenolic moieties of NOM molecules, generating phenoxyl radicals. The phenoxyl radicals react with nitrite to generate nitrated byproducts. Additionally, the aromatic carboxyl moieties of NOM molecules can be decarboxylated upon reaction with SO4•-, contributing to the formation of nitrated byproducts. This study reveals a novel nitration mechanism specific to the UV/PDS process and raises concerns about the potential risks when this technology is used for wastewaters with high levels of nitrate.
ACS ES&T ENGINEERING
(2022)