The characteristics of effluent organic matter(EfOM) from a wastewater treatment plant(WWTP) during ozonation were investigated using excitation and emission matrix(EEM)spectra, Fourier transform infrared spectroscopy...The characteristics of effluent organic matter(EfOM) from a wastewater treatment plant(WWTP) during ozonation were investigated using excitation and emission matrix(EEM)spectra, Fourier transform infrared spectroscopy(FT-IR) and high-performance size exclusion chromatography(HPSEC) at different ozone dosages. The selectivity of ozonation towards different constituents and functional groups was analysed using two-dimensional correlation spectra(2D-COS) probed by FT-IR, synchronous fluorescence spectra and HPSEC.The results indicated that ozonation can destroy aromatic structures of EfOM and change its molecular weight distribution(MWD). According to 2D-COS analysis, microbial humiclike substances were preferentially removed, and then the protein-like fractions. Terrestrial humic-like components exhibited inactivity towards ozonation compared with the above two fractions. Protein-like substances with small molecular weight were preferentially reacted during ozonation based on 2D-COS probed by HPSEC. In addition, the selectivity of ozone towards different functional groups of EfOM exhibited the following sequence:phenolic and alcoholic C\O groups > aromatic structures containing C_C double bonds >aliphatic C\H. X-ray photoelectron spectroscopy(XPS) further elucidated the preferential reaction of aromatic structures in EfOM during ozonation.展开更多
Abiotic humification is important in the formation and evolution of organic matter in soil and compost maturing processes.However,the roles of metal oxides in abiotic humification reactions under micro-aerobic remain ...Abiotic humification is important in the formation and evolution of organic matter in soil and compost maturing processes.However,the roles of metal oxides in abiotic humification reactions under micro-aerobic remain ambiguous.The aim of this study was to use non-destructive measurement methods to investigate the role of MnO_(2) in the evolution of humic substances(HSs)during oxidative polymerization of polyphenol-amino acid.Our results suggested a synergistic effect between MnO_(2) and O_(2) in promoting the polymerization reaction and identified that MnO_(2) alone had a limited ability in accelerating the transformation of fulvic acid(FA)to humic acid(HA),whereas O_(2) was the key factor in the process.Two-dimensional correlation spectroscopy(2D-COS)showed that the evolution in the UV-vis spectra followed the order of 475–525 nm>300–400 nm>240–280 nm in the humification process,indicating the formation of simple organic matter followed by FA and then HA.13C nuclear magnetic resonance(13C NMR)analysis revealed that the products under both air and N2 conditions in the presence of MnO_(2) had greater amounts of aromatic-C than in the absence of MnO_(2),demonstrating that MnO_(2) affected the structure of the humification products.The results of this study provided new insights into the theory of abiotic humification.展开更多
基金supported by the National Key Technology Support Program (No.2014BAC13B06)the National Natural Science Foundation of China (Nos.51708443,51378414)+2 种基金the National Key Research and Development Program of China (No.2016YFC0400701)the China Postdoctoral Science Foundation (No.2017M623326XB)the Program for Innovative Research Teams in Shaanxi (No.2013KCT-13)
文摘The characteristics of effluent organic matter(EfOM) from a wastewater treatment plant(WWTP) during ozonation were investigated using excitation and emission matrix(EEM)spectra, Fourier transform infrared spectroscopy(FT-IR) and high-performance size exclusion chromatography(HPSEC) at different ozone dosages. The selectivity of ozonation towards different constituents and functional groups was analysed using two-dimensional correlation spectra(2D-COS) probed by FT-IR, synchronous fluorescence spectra and HPSEC.The results indicated that ozonation can destroy aromatic structures of EfOM and change its molecular weight distribution(MWD). According to 2D-COS analysis, microbial humiclike substances were preferentially removed, and then the protein-like fractions. Terrestrial humic-like components exhibited inactivity towards ozonation compared with the above two fractions. Protein-like substances with small molecular weight were preferentially reacted during ozonation based on 2D-COS probed by HPSEC. In addition, the selectivity of ozone towards different functional groups of EfOM exhibited the following sequence:phenolic and alcoholic C\O groups > aromatic structures containing C_C double bonds >aliphatic C\H. X-ray photoelectron spectroscopy(XPS) further elucidated the preferential reaction of aromatic structures in EfOM during ozonation.
基金This manuscript is based on work supported by the National Key R&D Program of China(No.2018YFC1901405)。
文摘Abiotic humification is important in the formation and evolution of organic matter in soil and compost maturing processes.However,the roles of metal oxides in abiotic humification reactions under micro-aerobic remain ambiguous.The aim of this study was to use non-destructive measurement methods to investigate the role of MnO_(2) in the evolution of humic substances(HSs)during oxidative polymerization of polyphenol-amino acid.Our results suggested a synergistic effect between MnO_(2) and O_(2) in promoting the polymerization reaction and identified that MnO_(2) alone had a limited ability in accelerating the transformation of fulvic acid(FA)to humic acid(HA),whereas O_(2) was the key factor in the process.Two-dimensional correlation spectroscopy(2D-COS)showed that the evolution in the UV-vis spectra followed the order of 475–525 nm>300–400 nm>240–280 nm in the humification process,indicating the formation of simple organic matter followed by FA and then HA.13C nuclear magnetic resonance(13C NMR)analysis revealed that the products under both air and N2 conditions in the presence of MnO_(2) had greater amounts of aromatic-C than in the absence of MnO_(2),demonstrating that MnO_(2) affected the structure of the humification products.The results of this study provided new insights into the theory of abiotic humification.
