苯酚三维荧光光谱特征参数影响因素的研究

Influence factors on characteristic parameters of three-dimensional fluorescence spectra of phenol

用三维荧光光谱法研究了不同离子浓度,pH值对苯酚荧光光谱特征参数的影响,并探讨了腐殖酸对苯酚的荧光猝灭效应.结果表明,天然水中9种常见离子Na^+、Mg^(2+)、Ca^(2+)、K^+、NH_4^+、Cl^-、HCO_3^-、SO_4^(2-)、HPO_4^(2-)对苯酚的荧光光谱形状和荧光强度基本无影响;NO_3^-的存在会使苯酚的荧光强度发生变化,荧光强度随着NO_3浓度增大而减小.苯酚在酸性和碱性条件下的存在形式不同,致使pH值对其荧光光谱特征参数影响较大:在酸性条件下,荧光强度基本保持不变;在碱性条件下,由于羟基的电离使荧光强度很弱.腐殖酸的存在使苯酚发生荧光猝灭,采用Stem-Volmer方程修正式对实验猝灭结果进行拟合,得到的拟合结果较好,相关系数为0.9995.

Characteristic parameters of phenol were investigated at different ion concentration and pH values by three-dimensional fluorescence spectra method.In the meantime,the effect of fluorescence quenching brought by humic acid was also explored.Results showed that nine kinds of ions usually existing in natural water including Na~＋、Mg^（2＋）、Ca^（2＋）、K~＋、NH_4~＋、Cl^-、HCO_3^-、SO_4^（2-） HPO_4^（2-） had no effect on the shape of spectra and fluorescence intensity of phenol. However,the presence of NO_3^- caused the changes of fluorescence intensity,which decreased with the increasing concentration of NO_3^-.The impact of pH was significant because phenol had different forms in acidic and alkali conditions.The fluorescence intensity remained unchanged in acidic condition;in contrast,only a weak fluorescence signal was found in the alkali condition.The latter phenomena can be explained by the ionization of hydroxyl.In addition, the presence of humic acid may cause the fluorescence quenching.Finally,Stern-Volmer equation was used to fit the quenching results,and good results had been obtained with relative coefficient of 0.9995.