水中不同热解温度溶解性黑碳的光化学活性  

Photochemical activity of dissolved black carbon from different pyrolysis temperature in aqueous solution

作　　者：屠依娜 石凤丽 李英杰[1] 张志宇 田森林[1] 马艳琼 TU Yina;SHI Fengli;LI Yingjie;ZHANG Zhiyu;TIAN Senlin;MA Yanqiong(Faculty of Environmental Science and Engineering,Kunming University of Science and Technology,Kunming,650500,China;Anning Ecological and Environmental Monitoring Station,Anning,650300,China)

机构地区：[1]昆明理工大学环境科学与工程学院,昆明650500 [2]安宁市生态环境监测站,安宁650300

出　　处：《环境化学》2022年第6期2094-2102,共9页Environmental Chemistry

基　　金：国家自然科学基金(21707058);云南省优秀青年基金(2019FI004)资助.

摘　　要：为研究不同热解温度下溶解性黑碳(DBC)光化学活性与其产生活性氧物种的能力,通过自然光照研究了不同热解温度下小麦秸秆DBC光致产生其激发三重态(^(3)DBC^(*))、^(1)O_(2)、·OH和O_(2)·^(-)的能力,以及DBC光谱参数(SUVA_(254),254 nm处的紫外吸光系数;E_(2)/E_(3),254 nm和365 nm处吸光度的比值;S_(R),S_(275-295)和S_(350-400)的斜率比值)和^(3)DBC^(*)量子屈服系数(f_(TMP))、单线态氧量子产率(Φ_(^(1)o_(2)))之间的关系.结果表明,^(3)DBC^(*)的探针2,4,6-三甲基苯酚(TMP)的光解速率随热解温度的升高先增大后减少,在300℃达到最大值;^(1)O_(2)的探针糠醇(FFA)的光解速率与热解温度呈反比关系;2-羟基对苯二甲酸(·OH与对苯二甲酸反应的特征化合物)的稳态浓度在200℃和300℃优于其他热解温度,XTT-O_(2)·^(-)复合物(O_(2)·^(-)与XTT钠盐反应产物)的稳态浓度在低温热解区(200℃—400℃)明显高于500℃和600℃热解温度.量子屈服系数和量子产率计算表明,^(3)DBC^(*)的f_(TMP)值随DBC热解温度变化与TMP光解呈现类似的趋势,且在300℃和400℃具有较高的f_(TMP),DBC光谱参数计算发现400℃热解DBC具有较高的E_(2)/E_(3)值,说明该DBC含有芳香酮、醌类等有利于产生激发三重态的氧化性基团,故具有较高的^(3)DBC^(*)量子产率;因为^(3)DBC^(*)是^(1)O_(2)的前体物,400℃热解DBC也具有较高的^(1)O_(2)量子产率Φ(1o2);低温热解DBC具有较小的S_(R)值,说明该DBC富含酚羟基等还原性基团,有利于电子转移产生·OH和O_(2)·^(-).f_(TMP)、Φ(1o_(2))和E_(2)/E_(3)的拟合数据表明,f_(TMP)、Φ(1o_(2))与E_(2)/E_(3)呈正比关系,可用于预测DBC光致产生^(3)DBC^(*)和^(1)O_(2)的能力.In order to study the photochemical activity of dissolved black carbon(DBC)and its ability to produce reactive oxygen species at different pyrolysis temperatures,the photoinduced capacity of wheat straw DBC to produce its excited triplet(^(3)DBC^(*)),^(1)O_(2),·OH and O_(2)·^(-),and the relationship between spectral parameters of DBC(SUVA_(254),absorption coefficient at 254 nm;E_(2)/E_(3),absorbance ratio at 254 nm and 365 nm;S_(R),ratio of S275-295 and S350-400),quantum yield coefficient of^(3)DBC^(*)(f_(TEP))and singlet oxygen quantum yield(Φ_(^(1)o_(2)) were studied by natural light.The results showed that the photolysis rate of DBC probe 2,4,6-trimethylphenol(TMP)first increased and then decreased with the increase of pyrolysis temperature,and reached the maximum value at 300℃;the photolysis rate of^(1)O_(2) probe furfuryl alcohol(FFA)was inversely proportional to pyrolysis temperature;the steady state concentration of 2-hydroxyterephthalic acid(characteristic compound of OH reaction with terephthalic acid)at 2000 C and 300℃were better than that at other pyrolysis temperatures and the steady state concentration of XTT-O_(2)·^(-)complex(reaction product of O_(2)·^(-)with XTT sodium salt)at low temperature pyrolysis zone(200-400℃)was significantly higher than that at 500℃and 600℃.The calculation of quantum yield coefficient and quantum yield showed that the value of f_(TMP) varied with the DBC pyrolysis temperature,which showed a similar trend to TMP photolysis,and had a higher value of at 300℃and 400℃.The calculation of DBC spectrum parameters found that DBC pyrolysis at 400℃had a higher values of E_(2)/E_(3),indicating that the DBC contains aromatic ketones,quinones and other oxidizing groups which are conducive to the generation of excited triplet state,so it has a higher quantum yield of^(3)DBC^(*);because of^(3)DBC^(*)was a precursor of^(1)O_(2),DBC pyrolysis at 400℃also had the higher value of rate ofΦ_(^(1)o_(2));Low temperature pyrolysis DBC had a small value of SR,indicating tha

关 键 词：溶解性黑碳 光化学 光学性质 活性氧物种 量子产率 

分 类 号：X513[环境科学与工程—环境工程]