title: The mineralisation of methamidophos using ionised AN air water treatment pilot system and ultraviolet irradiation.
abstract: The degradation of methamidophos in pure bi-distilled water (with initial concentration 5 mg L(-1), pH = 7 at the beginning) was studied. For the first time, 2 ionised air water treatment pilot systems (IAPS-1, -2, no additives) were set up (Figs. 1 and 2). The degradation of methamidophos was carried out with only the IAPS-2 and with two different ultraviolet (UV) lamps: high- and low-pressure mercury lamps (HP and LP, with or without H202). The kinetics of these oxidative processes was investigated. The highest rate constant was reached by the LP, 0.2% H2O2 (k = 0.7524min(-1), t 1/2 = 0.9min), followed closely by both treatments with the HP, 0.2% H202 (k = 0.6328min(-1), t 1/2 = 1.1 min) and LP, 0% H202 (k = 0.4749min(-1), t 1/2 = 1.5 min). The lowest rate constants were achieved from the HP, 0% H202 process (k = 0.0303min(-1), t 1/2 = 22.9min) and from the IAPS-2 (k = 0.0117 min(-1), t 1/2 = 59.2min). The mineralisation of methamidophos was confirmed by the determination of the anions produced including NO3-, PO4(3-) and SO4(2-) during and at the end of each experiment. The toxicity of water samples before, during and after the experiments was tested with Daphnia test.
authors.affiliation: Department of Chemistry, AG Thiemann, Institute of Physical and Environmental Chemistry, University of Bremen, Germany. dang@uni-bremen.de
authors.forename: Dang Quang
authors.initials: DQ
authors.lastname: Hung
authors.forename: Jens
authors.initials: J
authors.lastname: Wohlers
authors.forename: Wolfram
authors.initials: W
authors.lastname: Thiemann
mesh_terms: D000390:Air Ionization; D000818:Animals; D002852:Chromatography, Ion Exchange; D003621:Daphnia / Q000187:drug effects; D008401:Gas Chromatography-Mass Spectrometry; D007700:Kinetics; D008903:Minerals / Q000737:chemistry; D009946:Organothiophosphorus Compounds / Q000737:chemistry* / Q000494:pharmacology / Q000528:radiation effects*; D010084:Oxidation-Reduction; D010865:Pilot Projects; D013997:Time Factors; D014466:Ultraviolet Rays; D018508:Water Purification / Q000379:methods*
chemical_list: D008903:Minerals; D009946:Organothiophosphorus Compounds; C014655:methamidophos