Thiemann, Wolfram
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Thiemann, Wolfram
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Thiemann, Wolfram
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Item-typ:Veröffentlichung, Monitoring of organochlorine pesticides in surface waters in Hanoi and detoxification of organochlorine and organophosphorus pesticides in water by applying novel methods using ultraviolet irradation, air ionisation and solar photocatalysis(2002-04-19); ; ; This thesis can be divided into two major parts: Monitoring of selected organochlorine pesticides in surface waters in Hanoi and Study on the applying of novel Advance Oxidation Processes-AOP (Air Ionisation and Solar Photocatalytic Oxidation) for the detoxification of waters containing toxic organochlorine and organophosphorous pesticides, which are some well-known insecticides like Lindane, 4,4à ´-DDT, Methamidophos (Me) and Monocrotophos (Mo). The monitoring process was undertaken with the same procedure in two years (in the Dry Season: Nov. 1998 and in the Rainy Season: Aug. 1999) for an evaluation of the contamination of 15 organochlorine pesticides in surface waters, by sampling of 30 water samples from different sites (Red and Duong Rivers, irrigation canals, lakes and wells) on an area of à » 30 by 20 km in Hanoi and its surroundings. The photodegradation of Me and Mo was first undertaken using the 2 UV High- and Low Pressure Mercury Lamps with addition of H:sub:2:/sub:O:sub:2:/sub:, then with a new developed reactor Ionised Air Pilot System 2 (IAPS-2). The photocatalytic detoxification of Me and Mo (C:sub:0:/sub: = 10 mg l:sup:-1:/sup:) was investigated using a Lab Solar Simulated Reactor (LSSR) and a new kind of solar non-concentrating Double Skin Sheet Reactor (DSSR). 12 diverse different commercial, modified and novel photocatalysists (TiO:sub:2:/sub: at concentrations of 500 and 1000 mg l-1), which are mostly pure anatase TiO:sub:2:/sub: powder, except well-known catalyst P25 Degussa were tested with those reactors in the photocatalytic degradation of Me and Mo at different pH values of 3, 7, 12. An initial detailed possible photocatalytic oxidation mechanisms of the degradation of Me and Mo has been found by combination of a proposed general photocatalytic oxidation mechanism of an organic pollutant (assuming an initial oxidative attack by a hydroxyl radical to a methyl group) with the molecular structures of identified intermediates.Dissertation371 137 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Vorkommen und Verteilung von mittel- und schwerflüchtigen Schadstoffen in Innenräumen(2004-05-24); ; ; Topics of this dissertation are the occurrence and distribution of semivolatile and particulate harmful substances in indoor environment. The common property of these substances is their low volatility resulting in the build-up of new emission sources in burdened rooms.Primary sources of semivolatile and particulate organic substances might be building materials, residues from pest controls, furniture or open fires. Commonly occurring groups of substances were chosen for the evaluation of their distribution and ranges of burden levels in different indoor environments in order to show which substance groups might be probably determined in different kinds of buildings or rooms.The substance groups examined for this dissertation are polychlorinated biphenyls (PCB), polynuclear aromatic hydrocarbons (PAH), polychlorinated naphthalenes (PCN), phthalates and miscellanous pesticides.Another important topic for the determination of substance burdens on surfaces is taking samples from surfaces in a correct manner in order to investigate the loaded substances without loss. For evaluating efficient methods of taking samples, three selected types of surfaces (glass, coated plywood and uncoated plywood) were treated with chlorpyriphos-ethyl, pyrethrum, piperonyl butoxide and PAH. The loaded surfaces were wiped with different kinds of cloth, the cloths being analysed subsequently.Besides, material samples to defined depths were taken from both types of plywood in order to investigate the substance amounts migrated into the material related to those taken by wipe samples. Furtherto, decay curves were determined by sampling surfaces after defined time periods from a set of equally treated surfaces. Thus, the half-times of the substances while storage of the loaded surfaces under indoor conditions were estimated. As a result, rather long estimated half-times resulted for the examinated substances; even for pyrethrum which commonly is said to decay within a very short time.Dissertation286 159 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Desinfektionsverfahren in der Schwimmbeckenwasseraufbereitung unter besonderer Berücksichtigung des Elektrochemischen-Aktivierungs-Verfahrens zwecks Verbesserung der Beckenwasserqualität(2004-02-13); ; ; The principal aim of the study was the detailed survey of swimming pool water disinfection by application of the ECA-technologis (electrochemical-activation), a significant water quality improvement seen from chemical point of view was expected. Instead of delivering gaseous chlorine into swimming pools, here the disinfectant was produced by electrolysis of a dilute NaCl-solution in situ. The "hygienic parameters" represented the crucial control parameters of the investigation. During the experimental run of ECA process extremely small microbial colony numbers (1-40 per mL) were observed after several days. Escherichia coli, coliforme bacteria and Pseudomonas aeruginosa could not determined in all tests. The other central parameters for the efficiency of the disinfecting process, the redox-voltage, could not be maintained (710 - 757 mV) during the entire experimental process with the ECA above the threshold of 770 mV (pH 7,4-7,6) required by the regulations DIN 19643. The "hygienic auxiliary parameters" in DIN 19643 could be maintained by the use of conventional chlorine, because other disinfectants in DIN 19643 were not allowed. An intended significant reduction of the "Bound C-chlorine" values, that give an indication of the total chloramines - as the typical disinfection by products - content could not be achieved. This observation is supported by the observation of other disinfection by-products (DPB) carried out in parallel. The observed concentrations of trihalomethanes were below the threshold value of 20 µg/L. Presently the investigation carried out here with ECA as compared with conventional chlorine-disinfection under identical well defined conditions, resulted in no significant reduction of the trihalomethanes. A subsequent UV-light irridation of swimming pool water gave a significant reduction of "Bound Chlorine" (chloroamines) of about 24 %, where only 65 % of pool water passed the UV reactor chamber.Dissertation400 1738 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Untersuchungen zum Verhalten von insektizidhaltigen Waessern bei Prozessen der chemischen Nassoxidation(1999-09-24); ; ; The aim of the present work was the investigation of the behavior of insecticide-containing water in different wet-oxidation-processes. As model pollutants the insecticides pirimicarb and imidacloprid were selected. Destination of these investigations was the optimization of the process influencing parameters like temperature, pH-value and added concentration of oxidizing agent and/or catalyst. It could be shown, that under laboratory conditions the utilization of the different oxidation processes, the - photolytical oxidation with ultraviolet light and hydrogen peroxide, - photolytical oxidation with ultraviolet light and ozone - photocatalysis with ultraviolet light and titanium oxide, leads to a degradation of both insecticides. The evaluation of the performed toxicity tests shows that in the luminescent bacteria test for both pesticides before and after treatment no inhibition of the light intensity occurred. In the Daphnia tests however it was shown that in the case of pirimicarb the toxicity towards Daphnia mobility decreases during all irradiation experiments. In the case of imidacloprid it was shown that the with hydrogen peroxide photolytically treated samples are all on the same toxic level. In the case of the with ozone photolytically and the photocatalytically treated samples of imidacloprid the toxicity increases in the first phase of treatment. At the end of the experiments the toxicity against Daphnia was reduced below the initial value of toxicity of imidacloprid. The evaluation of the biochemical degradation, expressed by the quotient of the biological- and the chemical oxygen demand, shows, that for both pesticides for all three applications an improvement could be achieved.Dissertation297 158