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INFLUENCE OF LIGHT SPECTRAL DISTRIBUTION ON PHOTOCATALYTIC TIO 2 COATING IN ORDER TO DECREASE AMMONIA AND METHANE EMISSION IN ANIMAL HUSBANDRIES - LABORATORY TESTING AND VERIFICATION Josef PECEN, Petra ZABLOUDILOVÁ Czech University of Life Sciences Prague, Institute of Tropics and Subtropics Kamýcka 129, Prague 6, Czech Republic, Abstract Laboratory experiments aimed at reducing ammonia, methane and carbon dioxide concentration and emissions in the air of stables were made using a sealed cylindrical container from plexiglas with a diameter of 0.48 m. Experiments were conducted to simulate the real environment conditions in the stables and they were aimed to find the reasons affecting the ammonia and methane concentrations in stables environment. The container consisted of: the source of radiation - fluorescent lamp, the active surface coated by DETOXY COLOR with photocatalytic TiO 2 and a specific measured amount of litter from the stable. The same amount of air flew through the sealed container as there was in the ventilation stable. At the output of containers there were placed sensors to measure gas concentration, relative air humidity and air temperature. The spectrum of light radiation falling on the active area with photocatalytic TiO 2 coating depended on the type of fluorescent lamp. The different types of lamps were used. The change of intensity in illumination of active area was made by shift of the opaque cover on the lamp cover. The uniformity of illumination across the surface was measured by photometer. It was found that the reduction of ammonia, methane and carbon dioxide concentration in the container atmosphere depends on the spectral distribution of light radiation, illumination of active area and partly on the type of litter as a source of measured gases as well. Rate of concentration decrease both gases is not the same for both types of litter. On the basis of obtained results from concentration rates we can state that the concentrations of the both gases differed from each other depending on the types of litter. Keywords: photocatalytic TiO 2, spectrum of light radiation, ammonia, methane, emission, litter 1. Introduction The emissions of noxious substances are still current as well as the question of their impact on the environment and perspective for their limitations. Agriculture always was, still is, and presumably, will be one of a major source of undesirable polluting substances, in particular gaseous pollutants. It is therefore a worldwide effort to reduce the quantities of these emissions. This effort is more noticeable in developed countries with stronger economies by that time. The most effective method to reduce emissions is to cut them at the source. There is a myriad of processes and procedures for achieving this goal. Lately, much attention has been focused on the function of TiO 2 and its photocatalytic properties for degradation organics and inorganic compounds. The photocatalytic properties of the TiO 2 are used in different applications [1], [2], [3], [7]. The photocatalytic process efficiency depends heavily on the specific conditions of TiO 2 applications. These are noticeably different at each individual of animal production facility. As the most important parameters influencing photocatalytic process of the TiO 2 can be indicated: illumination of the TiO 2 layer in the view of its space application in the building the active area size treated by TiO 2 TiO 2 application method and the surface quality indoor humidity and temperature The above mentioned conditions do not take into account the eventual variable properties of the TiO 2 layer and their impact on the final results include its preparation and technological refinements [4]. Experimental activity concentrated on the impact of outside parameters on the total effect (mainly influence of illumination of the TiO 2 layer). There have been therefore carried out some detail laboratory experiments with illumination of the active layer of TiO 2 in experimental vessels and with the animal production facilities as a source of the emissions. The experiment used commercially available paint DETOXY COLOR Interior with active photocatalyst based on the TiO 2. The main aim was to obtain more detailed information about the properties and ways to illuminate areas coated with the TiO 2 in relation to the characteristics of used radiation source. Some partial findings obtained from the experiments in the laboratory are on the trial base implemented in the production facilities, where monitoring is still proceeding [7]. Not all of the above mentioned conditions have a major impact on the TiO 2 photocatalytic efficiency. Due to lack of time for the experiments, it is not possible at the present time to provide more complex and reliable model of TiO 2 impact on the photocatalytic process related to particular conditions in laboratory and spatially on farm premises. 2. Material and Methods All laboratory experiments were running in the joint laboratory for measurement of ammonia emissions and greenhouse gases (CULS Prague and RIAEng Prague). The laboratory is equipped for continuous monitoring of concentration of selected gases. It is possible to measure concurrently no more than four air samples (gas mixtures) maximum, because only four experimental vessels (Fig.1) located in the digesters are available. Each vessel comprises of two acrylic cylinders. The outer cylinder with attached bottom has inner diameter 485 mm and height 500 mm and inside on the floor is a dish with the sample (source of emissions). The internal sliding cylinder, also from acrylic, extends to the sample dish, carries ventilation air over the sample on the big cylinder bottom and delivers air with emissions from the vessel to the sensors. The air velocity inside the cylinder is the same or very similar to the air velocity on the premises. Inner cylinder is connected via sliding gasket to the top cover which encloses external cylinder and thus the entire vessel. For the purposes of monitoring the TiO 2 photocatalytic process, it was inserted a vertical piece of drywall double coated with paint DETOXY COLOR Interior on one side at a height that space between the sample dish and top cover was fully blocked. To better cope with the cylinder shape, the drywall was partially cut into the vertical stripes 12 cm wide from outside. This way it was achieved good fit to the big cylinder and drywall perimeter was one half of big cylinder perimeter. Thus there was created circa 0,20 m 2 area with active layer with TiO 2 included in the used coating paint. , Olomouc, Czech Republic, EU Fig. 1 Experimental vessel with a source of light radiation The illumination source (short fluorescent lamp lenght 0.38 m, 14 W, 30 % UV-A radiation, 5 % UV-B radiation) was placed vertically inside the big cylinder. The lamp is fix connected with cylinder of vessel. The setup inside the vessel (illumination and drywall with TiO2) was given by its structure design (physical dimensions and possibilities of the vessel), and by requirement an homogeneity of illumination the illuminated area with TiO2. It is necessary to point out that for this experimental configuration in the vessel most of the light radiation was used for direct illumination area with TiO2 with the fact that the difference in the area illumination amounted ratio 1:12 (in horizontal direct), depending on the lamp distance from the illuminated area. This illumination is bigger than on the premises where real area different in size has much smaller illumination. Spectrum of the used fluorescent lamp is on Fig.2. Fig.2 Spectrum of light emitted from a fluorescent lamp 3. Results The output of all experiments in laboratory was information about concentrations of NH 3, CH 4 and CO 2 for two different litter (pig manure and dry poultry litter), with the focus on NH 3 emissions. The differences in concentration of CH 4 (in each experiment and for the different litter) were smaller, than differences in concentrations of NH 3. Concentrations of all mentioned gases were measured with analyzer 1312 Photoacoustic Multi Gas Monitor and with multiple channels sampling and dispensing apparatus 1309 D Multipoint Sample; concentration of NH 3 was simultaneously measured with semiconductor sensors SP 53 (FIS Inc.). In all series of measurements with fluorescent tubes were concentrations of NH 3 in all measurements lower in vessel with TiO 2 on and the relevant lamp, compared to the concentration in the reference vessel (without TiO 2 and no illumination by the fluorescent lamp). The bigger difference in concentrations of measured gases was observed at concentrations of NH 3 and CH 4 only. The smaller differences in concentrations level were recorded in CO 2. For the other measured gases; their concentrations were the same or with no significant differences in both vessels. Small scale experiments were carried out with another type of fluorescent lamp as well. Their spectrum content is soft. The results (decreasing of concentration of methane and ammonia) were similar but the differences between concentrations of both gases were smaller. It means that photocatalytic effect is running. The decrease of concentration was observed for both type of litter in both gases. The findings can be briefly summarized such as functioning method/way of reducing NH 3 emissions (considering the conditions of the above mentioned experiments) although it has not yet been reliably demonstrated under the same experimental conditions to work as well for light spectrum of another fluorescent lamps, with too different spectra. It was observed that both linear fluorescent lamps as light sources cause visible changes on the surface of the pigs manure sample in the vessel with TiO 2. Similar results were obtained from experiment in stable. Both places (the laboratory and the experimental stable) used the same source of light. Only intensity of illumination the area with active form of TiO 2 was different. Only one drywall plate with the active form of TiO 2 was used for all measurements and during visual surface inspection before each measurement. 4. Discussion Concentrations of NH 3, CH 4, and CO 2 were measured under laboratory conditions and the differences in their values were observed in connection with the change of experiment conditions (application of the different sources lighting-radiation and type of litter). That fully well simulates actual conditions on premises and possibilities to change these conditions. The experiments used an area with an active form of TiO 2, which has been 1.5 times greater than the area of manure sample or litter in a dish. On real-life premises the situation is similar, but this ratio may be inverted (in any cases). It depends on the premises and technology used. For the treatment of areas with TiO 2 we may almost always use a ceiling and parts of the vertical walls. Lighting in the premises aims almost always to the floor (often source of emissions) and not on the area treated by TiO 2, as it was in the laboratory experiments. This may be a major difference. On the contrary it is relatively easy to adapt lighting in the premises with appropriate spectral composition to ensure the function of TiO 2 as a photocatalytic. The main restriction here is the effect of this spectrum on the health of cattle and tending personnel; safety rules have to be respected in any case [5]. It seems that choice of the appropriate lighting or radiation source, and the minimum conditions for functioning of the photocatalytic process is a priority before examining other conditions that influence this process. Despite the short period of time and limited scope of the experimental measurements carried out, particularly in the laboratory and partly in the field, it appears that the process of photocatalysis implemented with TiO 2 operates under the conditions in particular for NH 3 emissions. Continuation of the experimental work will therefore focus on active area illumination, surface characteristics, source of light radiation and the safety of animals and tending personnel. 5. Conclusion Both type of light radiation causes photocatalytic effect with active form TiO 2 and causes decrease in concentration of NH 3 and CH 4 mainly. Decrease of mentioned gases was observed for both source of light radiation and in both type of litter. Decrease of mentioned gases was greater for poultry litter in comparison with pig manure. ACKNOWLEDGEMENT This work was supported by research project QH of Ministry of Agriculture of Czech Republic, The National Agency for Agriculture Research (NAAR). LITERATURE [1] PARK, B. Nanotechnology for Food Safety. Cereal Foods World, 2009, Vol. 54 (4), pp [2] LEE, J., PARK, H., CHOI, W. Selective photocatalytic oxidation of NH 3 to N 2 on platinized TiO 2 in water. Environmental Science and Technology, 2002, Vol. 36, Issue 24, pp [3] CHEN, R. et al. Improvement of the luminescence properties of CaTiO 3:Pr obtained by modified solid-state reaction. Powder Technology, 2009, Vol. 194, Issue 3, pp [4] ZHANG., Y. et al. Evolution mechanism of alumina nanofilms on rutile TiO 2 starting from sodium metaaluminate and the pigmentary properties, Powder Technology, 2009, Vol. 192, Issue 2, pp [5] PETERKA, F., JIRKOVSKÝ, J., SŤAHEL, P., NAVRÁTIL Z. Applications of photocatalytic nanomaterials, standartization and overview of testing methods. In conference proceedings NANOCON2009, October , Rožnov pod Radhoštěm. Tanger Ltd, Slezká Ostrava. ISBN , p [6] SOVOVÁ, T., KOČÍ, V., KOCHÁNKOVÁ, L. Ecotoxicityof nano and bulk forms of metal oxides. In conference proceedings NANOCON2009, October , Rožnov pod Radhoštěm. Tanger Ltd, Slezká Ostrava. ISBN , p [7] ZABLOUDILOVÁ, P., PECEN, J., KOSOVÁ, M., ČEŠPIVA, M., JELÍNEK, A. TiO 2 application to suppres the effect of animal production on the environment.. In conference proceedings NANOCON2009, October , Rožnov pod Radhoštěm. Tanger Ltd, Slezká Ostrava. ISBN , p
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