Introducing an effective iron-based catalyst for heterogeneous electro-Fenton removal of Gemcitabine using three-dimensional graphene as cathode

Five natural iron minerals include hematite, magnetite, siderite, limonite and pyrite as natural sources of iron were investigated to determine the best one which has the highest catalytic ability in the heterogeneous electro-Fenton process. The process has emerged as a simple, green, cost-effective and efficient method for the removal of persistent and pathogenic anti-cancer drug pollutants like Gemcitabine. On the other hand, different effective factors like the initial concentration of Gemcitabine, the amount of pyrite as the chosen efficient iron mineral, applied current intensity, initial pH and time of treatment process were optimized using response surface methodology to represent the best experimental condition. The role of hydroxyl (•OH) and superoxide anion (•O2−) radicals was monitored using scavengers of active radicals. The degradation efficiency of Gemcitabine and total organic carbon analysis reached 98.33% and 78.2% respectively, in the optimum condition after 5 h of electrolysis. The gained high value of coefficient of 0.995 by analysis of variance indicated the reliability of the presented model. Gas chromatography–mass spectrometry analysis identified nine by-products like small molecules of acids, amides, amines and esters.