The reaction of carbonyl-to-imine/hemiaminal conversion in the atmospheric aqueous phase is a critical pathway to produce the light-absorbing N-containing secondary organic compounds(SOC).The formation mechanism of th...The reaction of carbonyl-to-imine/hemiaminal conversion in the atmospheric aqueous phase is a critical pathway to produce the light-absorbing N-containing secondary organic compounds(SOC).The formation mechanism of these compounds has been wildly investigated in bulk solutions with a low ionic strength.However,the ionic strength in the aqueous phase of the polluted atmosphere may be higher.It is still unclear whether and to what extent the inorganic ions can affect the SOC formation.Here we prepared the bulk solution with certain ionic strength,in which glyoxal and ammonium were mixed to mimic the aqueous-phase reaction.Molecular characterization by High-resolution Mass Spectrometry was performed to identify the N-containing products,and the light absorption of the mixtures was measured by ultraviolet-visible spectroscopy.Thirty-nine N-containing compounds were identified and divided into four categories(N-heterocyclic chromophores,high-molecular-weight compounds with N-heterocycle,aliphatic imines/hemiaminals,and the unclassified).It was observed that the longer reaction time and higher ionic strength led to the formation of more N-heterocyclic chromophores and the increasing of the lightabsorbance of the mixture.The added inorganic ions were proposed to make the aqueous phase somewhat viscous so that the molecules were prone to undergo consecutive and intramolecular reactions to form the heterocycles.In general,this study revealed that the enhanced ionic strength and prolonged reaction time had the promotion effect on the lightabsorbing SOC formation.It implies that the aldehyde-derived aqueous-phase SOC would contribute more light-absorbing particulate matter in the industrial or populated area where inorganic ions are abundant.展开更多
基金supported by the National Natural Science Foundation of China(Nos.21976034,42077193,92044301,and21906024)the Shanghai Municipal Health Commission Science and Research Fund(No.202040185)+1 种基金the Shanghai Pudong New District Bureau of Ecology and Environment Research Project(No.PDHJ20210008)the Guangdong Provincial Observation and Research Station for Coastal Atmosphere and Climate of the Great Bay Area(No.2021B1212050024)。
文摘The reaction of carbonyl-to-imine/hemiaminal conversion in the atmospheric aqueous phase is a critical pathway to produce the light-absorbing N-containing secondary organic compounds(SOC).The formation mechanism of these compounds has been wildly investigated in bulk solutions with a low ionic strength.However,the ionic strength in the aqueous phase of the polluted atmosphere may be higher.It is still unclear whether and to what extent the inorganic ions can affect the SOC formation.Here we prepared the bulk solution with certain ionic strength,in which glyoxal and ammonium were mixed to mimic the aqueous-phase reaction.Molecular characterization by High-resolution Mass Spectrometry was performed to identify the N-containing products,and the light absorption of the mixtures was measured by ultraviolet-visible spectroscopy.Thirty-nine N-containing compounds were identified and divided into four categories(N-heterocyclic chromophores,high-molecular-weight compounds with N-heterocycle,aliphatic imines/hemiaminals,and the unclassified).It was observed that the longer reaction time and higher ionic strength led to the formation of more N-heterocyclic chromophores and the increasing of the lightabsorbance of the mixture.The added inorganic ions were proposed to make the aqueous phase somewhat viscous so that the molecules were prone to undergo consecutive and intramolecular reactions to form the heterocycles.In general,this study revealed that the enhanced ionic strength and prolonged reaction time had the promotion effect on the lightabsorbing SOC formation.It implies that the aldehyde-derived aqueous-phase SOC would contribute more light-absorbing particulate matter in the industrial or populated area where inorganic ions are abundant.
