This study investigates the performance of a newly developed flow-through reactor and the utilized photocatalytic materials in two environments: a lab-scale experiment and a pilot-scale experiment in a contaminated building. The aim was to assess the removal of polycyclic aromatic hydrocarbons from the air using an innovative reactor equipped with an ultraviolet-irradiated titanium dioxide catalyst. Empirical measurements were conducted in the laboratory to revise the developed fixated titanium dioxide catalysts at different irradiances. Naphthalene and 1-methylnaphthalene elimination were used as model substances due to being the most volatile polycyclic aromatic hydrocarbons (PAH). In addition, they are often found in contaminated buildings. Tests in an office building revealed high suitability of the air cleaning system for low polycyclic aromatic hydrocarbons concentrations with a degradation of the compounds below the allowed limits of indoor air pollutants set by the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety. The degradation of the organic micropollutants proceeded without detection of by-products, so that mineralization can be assumed. Based on these observations and a large number of previous studies, detailed degradation pathways for the selected micropollutants were also established.

Supported titanium dioxide-based photocatalysts were investigated for the degradation of pharmaceuticals under irradiation with UV−A LEDs. Focus of the presented research was placed on the degradation kinetics under different matrix influences and energy flux densities of UV−A radiation. The chemical parameters, pH, orthophosphate, nitrogen concentration and background organic concentration were investigated. The results were evaluated by time-resolved measurement of the concentrations and by calculating and plotting the first-order degradation rate. The results showed clear differences in the rates of degradation of each compound, with diclofenac being the most easily degraded and metoprolol the most resistant. When the influence of energy flux density was examined, a linear relationship between degradation rate and the square root of energy flux density was confirmed. The organic background matrix has a strong influence on the degradation kinetics of the compounds. Nitrogen and orthophosphate slow down the degradation much less than the organic background matrix. Investigating the pH influence, it could be shown that almost no degradation is detected in the basic pH range. The results were illustrated with the help of a radar diagram, which can show all dependencies at a glance.

In the present work, a suitable experimental setup was developed to successfully apply advanced oxidation processes (AOP) to real groundwater matrices. This setup combines an O3-bubble column reactor with a carrier-bound TiO2/UV-system. The degradation of various chlorinated ethene and methane derivatives commonly found of chlorinated volatile organic compound polluted regional groundwater samples was investigated. Because of known issues within water remediation using AOP such as toxification by transformation products, this study aimed at complete mineralization of the contained organic micropollutants. Moreover, the influences of variable process parameters such as flow rate, ozone concentration, and radiation dose on process performance were statistically evaluated and discussed. Parameter optimization using a Box-Behnken experimental design resulted in very promising degradation rates. It was thus possible to achieve a degradation rate of at least 98% for cis-dichloroethene, trichloroethene and tetrachloroethene and 85% for trichloromethane without formation of transformation products. The results of this work open up the possibility of developing innovative technologies based on AOP, which can be universally applied even to challenging matrices such as groundwater.

Immobilized titanium dioxide catalysts were used within a photocatalytic immersion rotary body reactor, which was connected to a substream ozonation unit to remove micro-pollutants from wastewater. Within this work data on the behavior of cumulative parameters during treatment of wastewater by photocatalysis and photocatalytic ozonation are provided. The investigated parameters are spectral absorption coefficient at 254 nm (SAC254), total organic carbon (TOC) and chemical oxygen demand (COD). All experiments were carried out using secondary effluent from the same wastewater treatment plant. For the parameter SAC254, consistent concentration curves and dependencies to operational parameters of the experimental system could be measured. The measurements of the parameters TOC and COD showed greater uncertainties, although basic trends could nonetheless be observed. A good linear correlation (R2 < 0.85) between the reduction of SAC254 and 8 micro-pollutants for photocatalysis and photocatalytic ozonation was found. This confirms the suitability of the SAC254 as a control parameter for a large-scale application of a photocatalytic 4th treatment stage. A linear correlation between measured TOC and COD degradation rates was possible with a coefficient of determination of 0.58–0.86. The simultaneous decrease of TOC and COD is an indicator for a mineralization of the treated wastewater matrix.

Carrier-bound titanium dioxide catalysts were used for the photocatalytic conversion of nitrogen dioxide. In this context, inexpensive metal oxide sensors were tested for their usefulness in the investigation and characterization of the photocatalysts. UV-A light emitting diodes of wavelength 365 nm stimulated the catalysts. By dimming the light emitting diodes, the influence of the energy flux density on the conversion kinetics could be investigated. The observed conversation followed first-order kinetics. The light intensity has shown a large influence at lower irradiances. At high irradiances an increase in recombination effects can be assumed, which makes irradiances greater than 40 W/m2 inefficient. From that point on no significant increase in the rate of conversation could be measured. The photon efficiency at low irradiances was determined to be 4.55% decreasing to 0.59% at higher irradiances. The flow rate of gas passing through the catalysts appears to have a linear effect on the overall rate of conversion. This is evidenced by a constant half-life within the reactor in relation to variable flow rate. The sensors have been shown to be calibratable and sufficiently stable, which raises the possibility of using the sensors for spatially resolved measurements within reaction systems.

Persistent and mobile (PM) substances are being recognized as serious threats to water resources and drinking water suppliers have to use advanced treatment if raw waters are contaminated with such compounds. In this study, analytical methods for 25 micropollutants for which insufficient or no data on their occurrence in surface waters and on their behavior during drinking water treatment were available, were developed. More than 120 surface water samples were analyzed and laboratory tests were performed to evaluate the compounds' behavior during aerobic bank filtration (BF), activated carbon treatment, and ozonation. Ensulizole, 1,3-diphenylguanidine and 2-acrylamido-2-methylpropane sulfonic acid revealed the highest detection frequencies in the Rhine river. Concentration level and detection frequency correlated positively with the wastewater fraction. However, street run-off is likely an additional discharge pathway for 1,3-diphenylguanidine. In simulated BF, seven (six) substances could be classified as persistent (very persistent). By applying powdered activated carbon, 42% of the substances were well removed as was the case for 50% of the compounds when applying 0.2 mg/L O3. In total, eight of the substances detected in surface waters were weakly removed by at least one of the investigated removal processes and may cause problems for drinking water suppliers.

Carrier-bound titanium dioxide catalysts were used in a photocatalytic ozonation reactor for the degradation of micro-pollutants in real wastewater. A photocatalytic immersion rotary body reactor with a 36-cm disk diameter was used, and was irradiated using UV-A light-emitting diodes. The rotating disks were covered with catalysts based on stainless steel grids coated with titanium dioxide. The dosing of ozone was carried out through the liquid phase via an external enrichment and a supply system transverse to the flow direction. The influence of irradiation power and ozone dose on the degradation rate for photocatalytic ozonation was investigated. In addition, the performance of the individual processes photocatalysis and ozonation were studied. The degradation kinetics of the parent compounds were determined using liquid chromatography tandem mass spectrometry. First-order kinetics were determined for photocatalysis and photocatalytic ozonation. A maximum reaction rate of the reactor was determined, which could be achieved by both photocatalysis and photocatalytic ozonation. At a dosage of 0.4 mg /mg DOC, the maximum reaction rate could be achieved using 75% of the irradiation power used for sole photocatalysis, allowing increases in the energetic efficiency of photocatalytic wastewater treatment processes. The process of photocatalytic ozonation is suitable to remove a wide spectrum of micro-pollutants from wastewater.

Photocatalytic disintegration is a novel approach to eliminate pollution. The method utilizes the semiconductor titanium dioxide to degrade organic molecules in the presence of ultraviolet (UV) light. In this study, it is shown how the capabilities of several types of catalyst designs degrade the non-polar substance diesel fuel and the polar substance methylene blue. The floating design of foam glass coated with titanium dioxide could reduce the concentration of diesel fuel by 329 mg/L in 16 h; the submerged designs for coated glass fiber and coated steel grit could reduce methylene blue concentration by 96.6% after 4 h and 99.1% after 6 h, respectively. It could be shown that photocatalysis is a promising cost- and energy-efficient method for managing air and water pollution. It can be established as a low-technology method without requiring the use of a conventional source of energy, given an adequate amount of sun hours, or as an additional cleaning stage in water treatment plants using UV-LEDs.

Supported titanium dioxide catalysts were used in a photocatalytic flat cell reactor to remove organic micropollutants from real wastewater. Catalysts based on stainless steel mesh with a porous coating made of titanium dioxide nanoparticles with predominantly anatase modification were used. The influence of the retention time, and light output, and the effect of hydrogen peroxide on the degradation were examined. The kinetics of the degradation of the parent substances was determined by liquid chromatography-tandem mass spectrometry. As a result, first-order degradation kinetics could be confirmed for all substances. The irradiance had no linear influence on the degradation of the compounds. Hydrogen peroxides were added to the wastewater to be treated, as electron acceptors and boosters, and alone had no great oxidative effect on the parent substances. The combination of photocatalysis with the addition of hydrogen peroxide as an electron acceptor had great synergetic effects which can reduce the required energy of the process through a short retention time. The process is suitable for the removal of micropollutants from wastewater.

Anthropogene Spurenstoffe wie Arzneistoffe, Zusätze aus Körperpflegeprodukten oder Industriechemikalien und Pflanzenschutzmittel stellen die kommunale Abwasserbehandlung vor neue Herausforderungen. Oxidative Verfahren zu deren Reduk- tion, wie beispielsweise die Ozonierung, stehen im Verdacht, eine große Anzahl ungenügend einzuschätzender Transformationsprodukte zu erzeugen. Adsorptive Verfahren wie die Aktiv- kohleadsorption können bestimmte Verbindungsklassen nur un- zureichend zurückhalten. Erweiterte oxidative Verfahren (Advanced Oxidation Processes, AOP), die Hydroxylradikale als starkes Oxidationsmittel nutzen, sind bei den richtigen Bedingungen in der Lage, eine vollständige Mineralisation der organischen Mikroschadstoffe zu bewirken. Bei den im Beitrag dar- gestellten Untersuchungen wurde die photokatalytische Oxidation zur Entfernung von Arzneistoffen aus kommunalem Abwasser genutzt. Reinigungsleistung und Energieverbrauch wurden bewertet. Dabei kam ein photokatalytisch wirkender Rotations- tauchkörper zum Einsatz.

Anthropogene Spurenstoffe wie Arzneistoffe, Zusätze aus Körperpflegeprodukten oder Industriechemikalien und Pflanzenschutzmittel stellen die kommunale Abwasserbehandlung vor neue Herausforderungen. Oxidative Verfahren zu deren Reduk- tion, wie beispielsweise die Ozonierung, stehen im Verdacht, eine große Anzahl ungenügend einzuschätzender Transformationsprodukte zu erzeugen. Adsorptive Verfahren wie die Aktiv- kohleadsorption können bestimmte Verbindungsklassen nur un- zureichend zurückhalten. Erweiterte oxidative Verfahren (Advanced Oxidation Processes, AOP), die Hydroxylradikale als starkes Oxidationsmittel nutzen, sind bei den richtigen Bedingungen in der Lage, eine vollständige Mineralisation der organischen Mikroschadstoffe zu bewirken. Bei den im Beitrag dar- gestellten Untersuchungen wurde die photokatalytische Oxidation zur Entfernung von Arzneistoffen aus kommunalem Abwasser genutzt. Reinigungsleistung und Energieverbrauch wurden bewertet. Dabei kam ein photokatalytisch wirkender Rotations- tauchkörper zum Einsatz.

Diese Arbeit hat das Ziel, neue photokatalytische Materialien zu charakterisieren und bis zu einer technischen Systemlösung für die Abwasserbehandlung weiterzuentwickeln. Dazu wurden die vorhandenen Materialien detailliert untersucht und die allgemeine Kinetik des Abbaus von pharmazeutischen Substanzen bestimmt. Die Auswirkung von abwasserrelevanten chemischen Parametern auf diese Kinetik und die Mineralisationsleistung imVergleich mit anderen oxidativen Verfahren war ein weiterer Schwerpunkt der Untersuchungen. Letztlich konnten die Erkenntnisse für die Konstruktion von abwassertauglichen Reaktionssystemen genutzt und diese unter realen Bedingungen getestet sowie hinsichtlich ihrer Abwasserreinigungsleistung und energetischen Ezienz modelliert werden. Kurzzusammenfassung der Ziele: * Herstellung und Charakterisierung von trägergebundenen, photokatalytischen Materialien, * Optimierung einer Methode für die spurenanalytische Bestimmung der ausgewählten Pharmaka, * Beschreibung der Abbaukinetik der Pharmaka durch Funktionen, * Bestimmung des Einflusses von abwasserrelevanten Parametern auf die Abbaukinetik, * Entwicklung eines technischen Systems und Bestimmung des Abbauverhaltens der Pharmaka in realer Abwassermatrix (Kläranlagenablauf), * Bestimmung des Energiebedarfs des Systems

Pharmazeutische Mikroschadstoffe sind in jedem Kläranlagenablauf zu finden und werden über die Kläranlagen in die Um-welt eingetragen. Verfahren der weitergehenden Oxidation mit Hydroxylradikalen (AOP-Verfahren) können organische Schadstoffe oxidieren. Derartige Photokatalyse- und Titandioxid-basierte, trägerbasierte Photokatalysatoren sind in der Lage, pharmazeutische Mikroschadstoffe aus der Abwassermatrix zu entfernen. Dabei kann nur gereinigtes Abwasser mit einem neutralen pH-Wert sowie moderaten Konzentrationen von CSB/DOC und Gesamtphosphat ausreichend effektiv behandelt werden. Die verfahrenstechnische Lösung des photokatalytischen Rotationstauchkörpers hat sich als eine funktionale Mög-lichkeit der photokatalytischen Abwasserbehandlung erwiesen.

In der vorliegenden Arbeit wird die photokatalytische Oxidation untersucht, die zur Gruppe der Advanced Oxidation Processes gehört. Aus den Ergebnissen einer halbtechnischen Versuchsan-lage werden Auslegungs-und Betriebsparameter abgeleitet. Die photokatalytische Oxidation ist in der Lage, alle untersuchten organischen Spurenstoffe vollständig zu entfernen. Darüber hi-naus kann der DOC erheblich reduziert werden, was auf eine weitgehende Mineralisierung hindeutet. Innerhalb einer praxis-tauglicheren Verweilzeit von 35 Minuten können Bezafibrat, Carbamazepin und Diclofenac bis unter die Nachweisgrenze re-duziert werden. Für Iopromid und Metoprolol sind Abbauraten von 75 % beziehungsweise von 40 % möglich. Dabei variiert der zuzuführende Energieeintrag zwischen 12 kWh/m³ und 21 kWh/m³. Die Parameter DOC und ΔSAK 254 korrelieren in ge-eigneter Weise mit dem Spurenstoffabbau