中文摘要：

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Al^3＋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Al^3＋猝灭，它们的条件稳定常数（logK）分别为5．89和6．95．Al^3＋-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，Al^3＋主要与EPS中所含的-NH-、C=O等发生强的配位作用．

英文摘要：

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 proteinlike fluorescence and peak C as humic-like fluorescence. The fluorescence intensity at both peaks A and B decreased as Al^3＋ concentration increased. The values of logK （conditional stability constant） for peaks A and B were 5.89 and 6.95, respectively. It was a/so found that solution pH strongly affected the fluorescence intensity at peaks A and B for the Al^3＋-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 Al^3＋.