Nonylphenol polyethoxylate in hospital wastewater: a study of the subproducts of electrocoagulation.
Chromatographic procedures such as solid phase extraction and high performance liquid chromatography coupled with a fluorescence detector (SPE-HPLC-FLD), were carried out to determine the concentrations of the surfactant nonylphenol ethoxylate (9 ethylene oxide units, NP9EO) and its biodegradation product, 4-nonylphenol (NP), in samples collected from the wastewater treatment system at the University Hospital (HUSM) of the Federal University of Santa Maria. The results showed a high concentration of NP9EO in all the collected samples (0.075 - 4.12 mg L(-1)) and an almost complete absence of NP. In addition, electrocoagulation (EC) of NP9EO was carried out in aqueous solution and in the HUSM effluent. A NP9EO removal rate of 95 % was achieved from the aqueous solution, following a pseudo-first-order kinetics. Through LC-MS measurements in aqueous solutions, it was possible to determine the formation of short-chain nonylphenol ethoxylate (NPEO), such as nonyl-phenoxy acetic acid (NP1EC), after 30 min of EC. In the case of the HUSM wastewater, the NP9EO removal was 89 %, and the chemical oxygen demand (COD) abatement was 26 %. A respirometric test was conducted to measure the increase of biodegradability during the EC and the aqueous samples were found to be less readily biodegradable before the 30-min period of electrocoagulation than after it had been completed.
Department of Chemistry, Rural Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
Danielle M
DM
Henriques
Klaus
K
Kümmerer
Francieli M
FM
Mayer
Tibiriçá G
TG
Vasconcelos
Ayrton F
AF
Martins
D000535:Aluminum / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D004563:Electrochemistry; D005026:Ethylene Glycols / Q000032:analysis / Q000737:chemistry*; D005453:Fluorescence; D006761:Hospitals; D013058:Mass Spectrometry; D010636:Phenols / Q000032:analysis* / Q000737:chemistry; D052616:Solid Phase Extraction; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
D005026:Ethylene Glycols; D010636:Phenols; D014874:Water Pollutants, Chemical; C021754:terics; C025256:nonylphenol; D000535:Aluminum