Colour Changes during the Carbamazepine Oxidation by Photo-Fenton

Natalia Villota,Hussein Ahmad Qulatein,José Ignacio Lombraña,Jose María Lomas,Cristian Ferreiro,Luis Miguel Camarero

doi:10.3390/catal11030386

Abstract

The oxidation of aqueous solutions of carbamazepine is conducted using the Fenton reagent, combined with the photolytic action of a 150 W medium pressure UV lamp, operating at T = 40 °C. The effect of acidity is analysed at an interval pH = 2.0–5.0, verifying that operating at pH = 5.0 promotes colour formation (Colour = 0.15 AU). The effect of iron is studied, finding that the colour of the water increases in a linear way, Colour = 0.05 + 0.0075 [Fe]0. The oxidising action of hydrogen peroxide is tested, confirming that when operating with [H2O2]0 = 2.0 mM, the maximum colour is generated (Colourmax = 0.381 AU). The tint would be generated by the degradation of by-products of carbamazepine, which have chromophoric groups in their internal structure, such as oxo and dioxocarbazepines, which would produce tint along the first minutes of oxidation, while the formation of acridones would slowly induce colour in the water.

Highlights

The study of emerging pollutants in wastewater, as well as its treatment and elimination, are receiving great attention in recent times due to their presence in many kinds of waters and their possible repercussions on the environment [1]
This leads1a to lead partial oxidation of carbamazepine towards therecalcitrant formation of the tests shown in Figure to the formation of a tinted aqueous residue to colour precursor intermediates
Metric ratio of oxidant utilised determines the degree of oxidation achieved—that is, the stage of the carbamazepine degradation mechanism reached and, the nature of the intermediates that coexist in solution

Summary

Introduction

The study of emerging pollutants in wastewater, as well as its treatment and elimination, are receiving great attention in recent times due to their presence in many kinds of waters and their possible repercussions on the environment [1]. Conventional plants are not designed for the elimination of this type of micro-pollutants, so their removal in many cases is not complete. Based on this approach, a need arises for these studies, which seek to know the behaviour of emerging pollutants, which are selected based on European guidelines to be analysed in WWTPs. Based on this approach, a need arises for these studies, which seek to know the behaviour of emerging pollutants, which are selected based on European guidelines to be analysed in WWTPs In this way, the aim of this work is to establish indicators of contamination throughout the different phases that form the treatment systems of these plants, being a key aspect to consider the degree of elimination of these contaminants in the different treatment processes currently used

Objectives

Methods

Results

Conclusion