赤泥基非均相芬顿体系降解磺胺二甲嘧啶的影响因素及机制  

Influencing factors and mechanism for degradation of sulfamethazine using a red mud-based heterogeneous Fenton system

作　　者：谭家秀 何玉婷 刘永红[2] 华玉妹[1] 万小琼[1] TAN Jiaxiu;HE Yuting;LIU Yonghong;HUA Yumei;WAN Xiaoqiong(College of Resources and Environment,Huazhong Agricultural University,Wuhan 430070;College of Science,Huazhong Agricultural University,Wuhan 430070)

机构地区：[1]华中农业大学资源与环境学院,武汉430070 [2]华中农业大学理学院,武汉430070

出　　处：《环境科学学报》2023年第10期76-84,共9页Acta Scientiae Circumstantiae

基　　金：中央高校基本科研业务费专项资金项目(No.2662018JC053)。

摘　　要：基于赤泥的催化作用研究了非均相芬顿体系对磺胺二甲嘧啶(SMT)的降解效果.相比不同温度预处理后的赤泥,原赤泥兼备较好的经济性和SMT处理效果,体系中赤泥的最佳投加量为20 g·L^(-1).赤泥基非均相芬顿体系在较宽初始pH值范围内(3~9)均具有较高的SMT去除率,高初始pH值有利于·OH的生成.赤泥中无定形铁氧化物FeOX含量略高于结晶态铁氧化物FeDCB,两者对SMT的降解起到重要作用,对去除SMT的贡献率分别为27.5%和25.2%.通过电子顺磁共振(EPR)识别出体系中的活性物种:·OH、超氧自由基(O_(2)^(·-))和空穴(h+),三者对去除SMT的贡献率分别为35.9%、40.8%和21.2%.利用高效液相色谱-串联质谱测得降解过程的中间产物,并推测SMT的降解主要通过以下4种途径:氨基的羟基取代反应以及磺酰胺键[S-N]、嘧啶环中碳氮双键[C=N]和碳氮单键[C-N]的断裂.赤泥被循环利用3次后,体系中的SMT降解率仍在80%以上.A heterogeneous Fenton system catalysed by red mud was investigated for degradation of the sulfamethazine(SMT).Compared with red muds being pretreated under different temperatures,untreated red mud was selected due to its relatively high removal SMT ability and low cost,and its optimum dosage in the system was 20 g·L^(-1).High removal efficiency of SMT at a wide initial pH range could be achieved in the heterogeneous Fenton system with red mud,and high pH benefited•OH production.In the red mud,the content percentage of amorphous iron oxide was a little higher than that of crystalline iron oxide.Both iron oxides played a key role in the system,with amorphous and crystalline iron oxides contributing 27.5%and 25.2%to SMT removal,respectively.Three active species in the SMT degradation were identified by electron paramagnetic resonance(EPR),which are•OH,superoxide radicals(O_(2)^(•−))and holes(h^(+)),and contributed 35.9%,40.8%and 21.2%to SMT removal,respectively.Four possible pathways for SMT degradation were proposed based on the determination of intermediate degradation products with HPLC/MS/MS.The degradation pathways of SMT mainly involved hydroxyl substitution of benzene ring-linked amino groups and cleavage of the[S−N]and[C−N]bonds.After the red mud was reused for three times,the removal efficiency of SMT in the heterogeneous Fenton system remained more than 80%.

关 键 词：抗生素 赤泥 pH影响 活性物种 降解途径 

分 类 号：X703[环境科学与工程—环境工程]