Toxicity removal by Daphinia similis assay in BTEX contaminated groundwater using nanometric TiO2/ZrO2 film and black light

Patricia P.R Donaire,Marcia R Assalin,Nelson Durán

doi:10.1088/1742-6596/1323/1/012012

Abstract

In this work, a photocatalytic tubular reactor, with a nanometric TiO2/ZrO2 film, immobilized on glass substrate, was developed in order to investigate the degradation of volatile organic compounds, such as, benzene, toluene, ethylbenzene and xylene (BTEX ) in groundwater sample, under black light irradiation (365nm). The BTEX compound were determined by solid phase microextraction (SPME) technique and analyzed by Gas Chromatography - Ionization Flame Detection (CG-FID). The efficiency of photocatalytic process was evaluated by determination of BTEX removal and toxicity, using Daphnia similis as organism-test. The influence of the initial concentration of BTEX in the degradation process was investigated. The degradation process of sample groundwater contaminated with BTEX (145μg/L) from gasoline, resulted in 90% of efficiency after 120 minutes of treatment. The toxicity (EC50-48 h) of the groundwater sample to Daphnia similis was 14.1% (10.5-19.0) for untreated samples. After 30 min of treatment, the EC50-48 h was of 84.3 (71-100%). The benzene efficiency removal was reduced in function of the increase of its initial concentrations that observation was not found for the other compounds studied.

Highlights

1.IntroductionBTEX (benzene, ethylbenzene toluene and xylenes) are Volatile Organic Compounds (VOCs) of naturally-occurring chemicals found mainly in petroleum [1]
BTEX are Volatile Organic Compounds (VOCs) of naturally-occurring chemicals found mainly in petroleum [1]
The benzene efficiency removal was reduced in function of the increase of its initial concentrations that observation was not found for the other compounds studied

Summary

1.Introduction

BTEX (benzene, ethylbenzene toluene and xylenes) are Volatile Organic Compounds (VOCs) of naturally-occurring chemicals found mainly in petroleum [1]. These compounds are found in the environment due to accidental gasoline released from underground storage tanks and pipelines [2, 3]. Dezhi et al [28] applied heterogeneous photocatalysis using TiO2 doped with Fe in the BTEX degradation [28]. A photocatalytic tubular reactor with internal glass cylinders tubes was developed in order to investigate the degradation of volatile organic compounds, such as, benzene, toluene, ethylbenzene and xylene (BTEX) from gasoline in groundwater sample. The degradation of BTEX compounds and toxicity (using Daphnia similis) were evaluated

Methods

Toxicity assay using Daphnia similis

AND DISCUSSION

Photocatalytic degradation of BTEX groundwater samples

Conclusion