【摘要】 利用三维荧光光谱(3DEEM)和傅立叶转换红外光谱(FTIR)研究了藻菌生物膜EPS与Al3+的相互作用机理.3DEEM结果表明,生物膜EPS含有3个荧光峰.其中,峰A(Ex/Em=225～235nm/300～330nm)和峰B(Ex/Em=275～280nm/325～330nm)荧光较强,属类蛋白峰,峰C(Ex/Em=335nm/432～434nm)荧光较弱,属类腐殖酸峰.峰A和峰B都能不同程度地被Al3+猝灭,它们的条件稳定常数(logK)分别为5.89和6.95.Al3+-EPS体系的峰A和峰B荧光强度明显受溶液pH值的影响.在pH为2～4之间时,荧光强度随pH的增大而增大,在4～7之间随pH的增大而减小,在7～11之间随pH增大而增大.FTIR光谱图分析表明,Al3+主要与EPS中所含的—NH—、C==O等发生强的配位作用.图6参21更多还原

【Abstract】 Three-dimensional excitation emission matrix fluorescence spectroscopy(3DEEM)and fourier transform infrared (FTIR)spectroscopy were used to study the extracellular polymeric substances(EPS)produced by alga-bacteria biofilm. Three excitation/emission(Ex/Em)fluorescence peaks at Ex/Em 225~235/300~330 nm(Peak A),275~280/325~330 nm(Peak B),and 335/432~434 nm(Peak C)were identified in the 3DEEM,respectively.Peaks A and B were referred to as protein- like fluorescence and peak C as humic-like fluorescence.The fluorescence intensity at both peaks A and B decreased as Al3+ concentration increased.The values of logK(conditional stability constant)for peaks A and B were 5.89 and 6.95,respectively. It was also found that solution pH strongly affected the fluorescence intensity at peaks A and B for the Al3+-EPS complexation. The fluorescence intensity at peaks A and B increased consistently with solution pH increasing from 2 to 4,decreased with solution pH increasing from 4 to 7,and increased again with solution pH increasing from 7 to 11.FTIR analysis demonstrated that—NH—and C==O groups in EPS were responsible for binding with Al3+.Fig 6,Ref 21更多还原