Application of excitation and emission matrix fluorescence (EEM) and UV–vis absorption to monitor the characteristics of Alizarin Red S (ARS) during electro-Fenton degradation process

[Display omitted] •Degradation of ARS was monitored quickly by UV–vis and EEM fluorescence spectrum.•A convenient and quick method using EEM was developed to determine the pollutants.•Degradation pathway of ARS was proposed according to the detected intermediates. Oxidative degradation of Alizarin Red S (ARS) in aqueous solutions by using electro-Fenton was studied. At first, effect of operating parameters such as current density, aeration rate and initial pH on the degradation of ARS were studied by using UV–vis spectrum, respectively. Then, under the optimal operating conditions (current density: 10.0mAcm−2, aeration rate: 1000mLmin−1, initial pH: 2.8), the identification of degradation products of ARS was carried out by using GC–MS and HPLC, meanwhile its degradation pathway was proposed according to the intermediates. Considering the location, intensity and intensity ratio of fluorescence center peak of the ARS in aqueous solution, a convenient and quick monitoring method by using excitation–emission matrix fluorescence spectrum technology was developed to monitor the degradation degree of ARS through electro-Fenton process. Furthermore, it is suggested that the developed method would be promising for the quick analysis and evaluation of the degradation degree of the pollutants with π-conjugated system.