Supported Photocatalyst for Removal of Emerging Contaminants from Wastewater in a Continuous Packed-Bed Photoreactor Configuration

Mª Borges,Dulce García,Tania Hernández,Juan Ruiz-Morales,Pedro Esparza

doi:10.3390/catal5010077

Abstract

Water pollution from emerging contaminants (ECs) or emerging pollutants is an important environmental problem. Heterogeneous photocatalytic treatment, as advanced oxidation treatment of wastewater effluents, has been proposed to solve this problem. In this paper, a heterogeneous photocatalytic process was studied for emergent contaminants removal using paracetamol as a model contaminant molecule. TiO2 photocatalytic activity was evaluated using two photocatalytic reactor configurations: Photocatalyst solid suspension in wastewater in a stirred photoreactor and TiO2 supported on glass spheres (TGS) configuring a packed bed photoreactor. The surface morphology and texture of the TGS were monitored by scanning electron microscope (SEM). The influence of photocatalyst amount and wastewater pH were evaluated in the stirred photoreactor and the influence of wastewater flowrate was tested in the packed bed photoreactor, in order to obtain the optimal operation conditions. Moreover, results obtained were compared with those obtained from photolysis and adsorption studies, using the optimal operation conditions. Good photocatalytic activities have been observed and leads to the conclusion that the heterogeneous photocatalytic system in a packed bed is an effective method for removal of emerging pollutants.

Highlights

In recent years, one of the most important aspects of environmental research has been the water pollution from emerging contaminants (ECs) such as endocrine disrupting chemicals (EDCs), pharmaceuticals and personal care products (PPCPs)
Prior to the study of the photocatalytic process, experiments in the stirred photoreactor have been performed in order to quantify the photolytic effect of the UV light on the paracetamol degradation in wastewater and the adsorption of the emergent contaminant molecules onto the TiO2 surface
The study of the stirred photoreactor reveals that TiO2 Degussa P25 shows a good photocatalytic activity for the paracetamol removal from wastewater, reaching a high photodegradation

Summary

Introduction

One of the most important aspects of environmental research has been the water pollution from emerging contaminants (ECs) such as endocrine disrupting chemicals (EDCs), pharmaceuticals and personal care products (PPCPs). Even they can be usually found in wastewater only at trace levels; their presence in aquatic environments raises the issue of their potential effects on human health and the environment [1,2,3]. Wastewater treatment plants are designed to remove conventional pollutants, such as suspended solids and biodegradable organic compounds, but they are not designed to remove low concentrations of synthetic pollutants, such as pharmaceuticals These synthetic pollutants are resistant to conventional wastewater treatments. Paracetamol has been used as emergent contaminant model molecule, which is a common analgesic and antipyretic drug, and it is heavily used all over the world and can be found in effluent of wastewater treatment plants [23]

Results and Discussion

Experimental Section

Conclusions