摘要
腐殖化是有机残体经微生物转化或化学氧化聚合形成腐殖质的固碳过程,产物腐植酸(HA)所具有的活性基团对污染物的环境化学行为有重要影响。天然矿物如含Mn/Fe/Al/Si的氧化物可以促进有机单体小分子物质(如多酚、还原性糖、氨基酸等)氧化聚合成HA。作为天然氧化剂,氧气可与金属氧化物协同促进非生物腐殖化,并提高产物HA质量。不同氧气浓度对金属氧化物促进的非生物腐殖化及有机质基团演化的影响尚不清楚。该研究选择儿茶酚和甘氨酸作为腐殖化前体物,分别代表多酚和蛋白质类物质降解的小分子。采用氧化铁作为腐殖化强化剂。对反应过程中的溶液及提取的HA进行紫外可见光谱(UV-Vis)、傅里叶变换红外光谱(FTIR)和X射线光电子能谱(XPS)分析。结果表明,在不同氧气浓度气氛下,有机质芳构化程度(UV_(254))依次表现为:21%氧气浓度>40%氧气浓度>0%氧气浓度。HA产量变化趋势与UV 254结果一致,且在21%氧气浓度下,HA产量较40%与0%氧气浓度提升了25%。XPS光谱分析表明:21%氧气促进了HA中胺基N向吡咯N的转化,而40%氧气浓度则促进了胺基N向酰胺N的转化,0%氧气浓度下HA仍有胺基N。FTIR分析结果表明:·OH促进芳香类物质环裂形成了HA中的含氧官能团(C O,COOH)。FTIR与UV-Vis的异质二维谱图分析结果表明,氧气促进了氨基酸转化成HA的C O基团及酰胺转化成HA的芳基与脂肪族基团。结构方程模型(SEM)分析结果表明:铁离子溶出量是影响HA产率的关键因素,21%浓度的氧气通过促进铁离子的溶出加速了有机质的聚合。此外,Fe^(2+)/Fe^(3+)与HA产率呈负相关,说明氧气通过促进铁离子的转化间接影响了腐殖化反应。氧气浓度影响了腐殖化产物的转化,进而影响了HA的产量和官能团组成。研究揭示了氧气浓度对腐殖化产物的影响,为腐殖化理论的完善提供参考。
Humification is a carbon sequestration process where organic residues are transformed into humic substances(HS)through microbial conversion or chemical oxidation and polymerization.The active functional groups present in the resulting humic acids(HA)significantly impact the environmental chemical behavior of pollutants.Natural minerals containing Mn/Fe/Al/Si oxides can facilitate the oxidative polymerization of organic monomeric small molecules(e.g.,polyphenols,reducing sugars,amino acids)into HA.Oxygen,as a natural oxidant,can synergistically enhance non-biological humification in the presence of metal oxides and improve the quality of the resulting HA.However,the mechanisms of abiotic humification enhancement by metal oxides under varying oxygen atmospheres and the impact on the evolution of organic matter remain unclear.This study used catechol and glycine as representative precursors for polyphenol and protein degradation,respectively,with iron oxide enhancing humification reactions.Solution and extracted HA samples were analyzed by ultraviolet-visible spectroscopy(UV-Vis),Fourier-transform infrared spectroscopy(FTIR),and X-ray photoelectron spectroscopy(XPS)during the reaction process.The results indicated that the aromatization of organic matter,as indicated by UV_(254),followed the order of 21%>40%>0%oxygen concentration.HA yields mirrored the UV_(254)findings,with an approximately 25%increase in HA production observed at 21%oxygen concentration compared to 40%and 0%oxygen concentrations.XPS spectroscopic analysis revealed that 21%oxygen concentration promoted the conversion of amino group N to pyrrole N in HA.In comparison,40%oxygen concentration facilitated the conversion of amino group N to amide N,and under 0%oxygen concentration,a substantial amount of amino group N remained in HA.FTIR analysis indicated that·OH generated from the aromatic compound ring cleavage contributed to oxygen-containing functional groups(C O,COOH)in HA.FTIR combined with hyperspectral 2D maps from UV-Vis suggested that oxygen's involvement promoted the conversion of amino acids into C O in HA and the transformation of amides into aromatic and aliphatic moieties in HA.Structural equation modeling(SEM)indicated that releasing iron ions was a key factor in promoting HA yield,and 21%oxygen concentration accelerated organic matter polymerization by enhancing iron ion release.Furthermore,the divalent iron/trivalent iron ratio was negatively correlated with HA yield,implying that oxygen indirectly affected humification by promoting iron ion conversion.In conclusion,changes in oxygen concentration affect the transformation of humification products,subsequently influencing HA yield and functional group composition.This study reveals the impact of oxygen concentration on humification products,offering references for refining humification theory.
作者
张颖超
毕志涛
田雯鑫
徐锐
唐首锋
石洪影
张鸿琼
ZHANG Ying-chao;BI Zhi-tao;TIAN Wen-xin;XU Rui;TANG Shou-feng;SHI Hong-ying;ZHANG Hong-qiong(School of Environmental and Chemical Engineering,Yanshan University,Qinhuangdao 066004,China;Yunnan Provincial Rural Energy Engineering Key Laboratory,Kunming 650500,China;Key Laboratory of Heavy Metal Remediation and Resource Utilization in Water Bodies in Hebei Province,Qinhuangdao 066004,China;Heilongjiang Boneng Green Energy Technology Co.,Ltd.,Harbin 150030,China;College of Engineering,Northeast Agricultural University,Harbin 150030,China)
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2024年第6期1620-1626,共7页
Spectroscopy and Spectral Analysis
基金
国家自然科学基金项目(52100167)
黑龙江省“揭榜挂帅”科技攻关项目(2022ZXJ05C02)
黑龙江省重点研发计划项目[省院共建(GA21D009)]
第一师阿拉尔市科技计划项目(2022TF02)资助。
关键词
腐殖化
氧化铁
氧气浓度
X射线光电子能谱
二维相关光谱
Humification
Iron oxide
Oxygen concentration
X-ray photoelectron spectroscopy
Two-dimensional correlation spectroscopy
