AOPs FOR WATER TREATMENT

FLORES MARINA; MAIA LESCANO; PASSALIA CLAUDIO; BRANDI RODOLFO; LABAS MARISOL

ENVIRONMENTAL APPLICATIONS OF ADVANCED OXIDATION PROCESESS

KANAG-TISK PRAHA

Lugar: PRAGA; Año: 2017; p. 422 - 423

ADVANCED OXIDATION OF ACETAMINOPHEN IN WATER BY THE UV/H2O2PROCESSDue to the amount and kind of their application and use, pharmaceuticals belong to the group of environmental relevant compounds. In the last decade, these pharmaceuticals have been reported in the water cycle were some types of them may not be completely remnoved employing sewage treatments, leading to the subsequent pollution of aquatic ecosystems. Derived from data compilation in literature, the analgesic acetaminophen (AP) was selected for this study.The aim of this work is to evaluate and study the effectiveness of the UV/H2O2 process for acetaminophen (AP) degradation in water. The main variables were studied: hydrogen peroxide (HP) concentration (0- 650 mg L-1) and radiation level (0 - 100%) at constant pollutant coentration (20 mg L -1). Experimental runs were carried out in a well-stirred, annular batch reactor with a total reaction volume of 2000 cm3 and with a UV germicidal lamp (Phillips TUV 15 W emitting at 254 nm) on its central axis. The reactor has provisions for sampling, pH and temperature measurements. AP concentration was analysed by HPLC (Waters) equipped with an UV-Vis detector (λ=243 nm). The H2O2 concentration was analyzed with a spectrometric method at 350 nm, employing a Boeco S-22 Spectrometer. pH was controlled with HI 88127 Hanna pHmeter. Total Organic Carbon (TOC) was measured with a Shimadzu TOC-5000A analyzer. Chronic toxicity of AP was evaluated using a freshwater organism: Daphnia magna. Letal Concentration, LC50, and its respective 95% confidence limits were calculated using the computer program EPA -Probit version 1.5. Initially, optimum conditions were studied. It is well known that for organic pollutants, there is an optimum concentration ratio between the hydrogen peroxide and the organic substance. Results have shown that there is an optitum condition for the process employing 250 mg L -1 of the oxidant. AP concentration is not detected at t= 20 minutes and TOC conversion reaches values of 13%. In 3 hours this value raise up to 72%. The process led to significant mineralization of organic carbon, as demonstrated by a decrease in TOC concentration. Then, employing the optimum condition found, experiences were carried out by varying the radiation level. It can be oserved that the rate constant for AP degradation increases linearly with the radiation level. The linear dependence is useful in the development of the kinetic model for future purpouses. Toxicity evolution throughout the degradation process was checked on Daphnia manga indicating that the toxicity was significantly reduced after the treatment.The results revealed that UV/H2O2 exhibited high removal efficiency of AP. It can be concluded that the process is effective and feasible for AP mineralization in short periods of time and may be use for water treatment. The small remnant toxicity confirms the capability of the UV/H2O2 process to detoxify contaminated waters.