氧协同菱铁矿降解微囊藻毒素机理研究  

Study on the mechanism of synergistic degradation of microcystin by oxygen and siderite

作　　者：张静 孙文倩 黄佳 牛慧斌 黄应平[2,3] 田海林 方艳芬 ZHANG Jing;SUN Wen-qian;HUANG jia;NIU Hui-bin;HUANG Ying-ping;TIAN Hai-lin;FANG Yan-fen(School of Biology and Pharmacy,China Three Gorges University,Yichang 443002,China;College of Hydraulic and Environmental Engineering,China Three Gorges University,Yichang 443002,China;Engineering Research Center for Ecology and Environment of the Three Gorges Reservoir Area,China Three Gorges University,Yichang 443002,China)

机构地区：[1]三峡大学生物与制药学院,湖北宜昌443002 [2]三峡大学水利与环境学院,湖北宜昌443002 [3]三峡库区生态环境教育部工程研究中心三峡大学,湖北宜昌443002

出　　处：《岩石矿物学杂志》2022年第1期177-184,共8页Acta Petrologica et Mineralogica

基　　金：国家自然科学基金(22076098,22136003,21972073,21677086);111引智项目(D20015);湖北省引智项目(2019BJH004);中国博士后基金(2018M640721)。

摘　　要：已知在无氧条件下天然矿物菱铁矿能成功水解微囊藻毒素-LR(MC-LR),然而实际应用过程中难以避免水中溶解氧(O_(2))的存在,因此有必要深入研究不同溶氧量(DOC)条件下菱铁矿对MC-LR降解的影响。本文通过在无氧和有氧条件下菱铁矿对MC-LR的降解实验,发现在有氧条件下(溶氧量1.62~21.87 mg/L),MC-LR的降解速率均比无氧条件(k_(0)=0.03016 mg·L^(-1)·h^(-1))高且其降解速率随O_(2)含量增加而依次增加,当O_(2)加入量为1.0 mL(溶氧量21.87 mg/L)时,菱铁矿对MC-LR降解速率最大(0.08334 mg·L^(-1)·h^(-1)),为无氧条件下的2.76倍。通过外加腐殖酸(humic acid,HA)和自由基进行捕获实验,发现FeCO_(3)能直接活化O_(2)产生超氧自由基(·O_(2)^(-)),以实现对MC-LR的氧化,但外加HA抑制了菱铁矿对MC-LR的选择性水解。MC-LR降解中间产物的液质联用(LC-ESI/MS)分析结果表明,在有氧条件下,MC-LR的水解位点先后发生在Mdha—D-Ala和Adda—L-Arg肽键,在菱铁矿表面Fe^(Ⅱ)活化O_(2)产生的·O_(2)^(-)的氧化作用下,水解产物继续发生羟基化及脱羧反应,最终转化为小分子醛。It has been found that siderite(FeCO_(3))could directly hydrolyze microcystin-LR(MC-LR)under anaerobic conditions in previous studies.However,oxygen(O_(2))could not be completely avoided during application process.Therefore,it is urgent to study the effect of dissolved oxygen content(DOC)on the degradation efficiency of MC-LR by siderite.The results showed that the degradation rate of MC-LR under O_(2) conditions(DOC=1.62~21.87 mg/L)is higher than that under anaerobic conditions(k_(0)=0.03016 mg·L^(-1)·h^(-1)),and its degradation rate increased with the increase of O_(2) content.When the volume of O_(2) added was 1.0 mL(DOC=21.87 mg/L),siderite showed the highest degradation rate of MC-LR(0.08334 mg·L^(-1)·h^(-1)),which was 2.76 times higher than that without O_(2).According to humic acid(HA)additions and radical capture experiments,it indicated that siderite could directly activate O_(2) to produce superoxide radical(·O_(2)^(-)),facilitating the oxidation of MC-LR.However,the addition of HA inhibits the selective hydrolysis of MC-LR by FeCO_(3).Finally,the LC-ESI/MS analysis of MC-LR degradation intermediates showed that under aerobic conditions,the hydrolysis sites of MC-LR occurred in Mdha—D-Ala and Adda—L-Arg peptides.Bond,under the oxidation of(·O_(2)^(-))produced by the activation of O_(2) by Fe^(Ⅱ)on the FeCO_(3) surface,the hydrolyzed product continues to undergo hydroxylation and decarboxylation reactions,and is finally converted into small molecular aldehydes.

关 键 词：微囊藻毒素(MCs) 氧协同 水解 机理 菱铁矿 

分 类 号：P578.4[天文地球—矿物学] P579[天文地球—地质学]