Veronica Gomez

Simultaneous determination of 76 micropollutants in water samples by headspace solid phase microextraction and gas chromatography-mass spectrometry.

This study focuses on the development of an analytical method based on headspace solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) for the simultaneous determination of 76 micropollutants in water samples. The selected micropollutants include volatile organic compounds (VOCs) (e.g. chlorobenzenes, chloroalkanes), endocrine disrupting compounds (EDCs) (e.g. bisphenol A and tributyl phosphate), odour compounds (e.g. limonene, phenol), fragrance allergens (e.g. geraniol, eugenol) and some pesticides (e.g. heptachlor, terbutryn). The experimental conditions affecting their extraction, such as the type of fibre, temperature and time of extraction, sample volume and ionic strength of the samples were optimized using HS-SPME. The method showed good linear range, reproducibility between days, repeatability and low detection limits (at ng L(-1) levels). The validated method has been applied to determine the target organic micropollutants in aqueous samples from different experimental research units of surface water, sea water, waste water and those effluents of advance membrane treatments. The optimized method showed good performance in the different types of samples studied. The analysis revealed the presence of several micropollutants at concentrations between 20 and 5000 μg L(-1), such as ethylbenzene, o-xylene, p-isopropilbenzene, D-limonene, citral and isoeugenol, due to the fact that these species are commonly used in domestic and industrial applications.

Determination and occurrence of organic micropollutants in reverse osmosis treatment for advanced water reuse.

The growing demand on water resources has increased the interest in wastewater reclamation for multiple end-use applications such as indirect and direct potable reuse. In these applications, the removal of organic micropollutants is of a greater concern than in conventional wastewater treatment. This article presents a collection of data of trace organic micropollutants in an urban wastewater treatment plant (WWTP) in North East Spain using reverse osmosis (RO) membrane treatment. The RO rejection values of the organic molecules studied with a wide range of solute size and hydrophobicity were determined. Several chromatographic methods monitoring different endocrine disrupting chemicals (EDCs), pharmaceuticals and personal care products (PPCPs) were used. Results indicated that secondary effluents from this Spanish WWTP contained most of the studied organic compounds indicating incomplete removal of organics in the conventional treatment of the plant. However, the rejection of most micropollutants was high for all three RO membrane types (low energy, high rejection, fouling resistant) tested. It was observed that some selected micropollutants were less efficiently removed (e.g. the small and polar and the more hydrophobic) and the molecular weight and membrane material influenced removal efficiencies.

Study of reverse osmosis treatment for micropollutants rejection in advanced water reuse applications

AbstractReverse osmosis (RO) membranes have made a breakthrough in waste water reclamation for the rejection of micropollutants in multiple applications such as reuse. Since these compounds are not completely eliminated using conventional treatments. This paper offers an overview of a waste water treatment plant using RO membrane treatment to study the rejection of 75 micropollutants from different families. The 75 selected micropollutants include some emerging and persistent compounds like volatile organic compounds (52), endocrine disrupting compounds (2), odor compounds (8), fragrance allergens (10), and some pesticides (3). Experimental results indicated that secondary effluents from conventional treatments contained most of the micropollutants studied; showing that conventional treatments such as activated sludge are not able to completely eliminate them. The rejection of these organic compounds was studied after the RO system. In addition, the relation between the micropollutant’s rejection, the mol...

Headspace-solid phase microextraction: useful technique to characterize volatile and semi-volatile organic compounds in water reuse applications

AbstractSample preparation is an essential step in analysis, greatly influencing the reliability and accuracy, the time and cost of analysis. Solid-phase microextraction (SPME) is a very simple and efficient, solventless sample preparation technique, which has been widely used in different fields of analytical chemistry. In this study, four different polarity SPME fibres coupled with gas chromatography-mass spectrometry have been used for the determination of volatile and semi-volatile organic substances from the reverse osmosis (RO) influent in water reuse applications and the results have been compared with those obtained with conventional liquid–liquid extraction. Adsorption of organic foulants on the membrane surface causes organic and biological fouling which also produces flow loss and consequently pressure must be high to maintain the flow. PA and PDMS/DVB/CAR were complementary fibres which together could characterize the organic compounds in the influent water. Organic compounds characterized bel...

Method for distinguishing between abiotic organic and biological fouling of reverse osmosis elements used to treat wastewater

aDow Water & Process Solutions, Dow Chemical Ibérica S.L., Tarragona 43006, Spain, email: gmassons@dow.com (G. Massons-Gassol), ggilabertoriol@dow.com (G. Gilabert-Oriol), vgomez2@dow.com (V. Gomez), vgarciamolina@dow.com (V.G. Molina) bDepartament d’ Enginyeria Química, Universitat Rovirai Virgili, Tarragona 43007, Spain, email: ricard.garcia@urv.cat cDow Water & Process Solutions, FilmTec Corporation, Edina 55439, USA, email: arrowotl@dow.com

Characterization of organic fouling in reverse osmosis membranes by headspace solid phase microextraction and gas chromatography–mass spectrometry

Adsorption of organic substances on reverse osmosis (RO) membrane surfaces may form an organic film on the membrane, known as organic fouling, and cause flow-rate loss. This problem is mostly unavoidable as no pretreatment method exists for perfect removal of possible foulants, including organic compounds resulting from undesirable bioactivity. Understanding the characteristics of fouling layers is an essential step towards overall improvement of RO membrane operations. In this study, the organic fouling in RO membranes treating the effluent of a secondary treatment from an urban wastewater treatment plant was characterized. Headspace solid phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry has been used for the first time, to provide valuable information of organic fouling. Different polarity SPME fibers were tested for this purpose. In addition, the characterization of the organic fouling obtained by HS-SPME was compared with the results obtained by extraction using several organic solvents. The results indicated that more compound families can be identified by HS-SPME than by organic solvent extraction. Moreover, complementary organic analyses were done for better understanding of the organic fouling in RO membranes, such as total organic carbon and loss on ignition.