Degradation Of Landfill Leaches Organic Substances Under Photo Catalyzer By Focused Solar Rays

Landfill is a kind of waste residue produced by human life and factory production. And the quantity of which is rapidly increasing with development of society and cities. During landfill is put under the surface of the earth ,a large quantity of landfill leaches is produced because of rain immersing,biologic ferment and physical chemistry reaction. landfill leaches is a kind of high concentration organic waste water ,which is the most harmful substance in all the garbage ramifications. It is a urgent task for human environment to treat landfill leaches.In the paper,"Y doped fiberglass substrate TiO2 photo catalyst"(YFSTPC)was applied to broaden the effective spectrum of solar rays for degradation ,and a experimental device named"solar rays tracking and focusing system",was also applied for collecting solar rays. The features of the way are : with the YFTSPC as the photo catalyst , the energy threshold for organic molecular broken is debased , and ray wavelength for photo catalyzing is broadened from ultraviolet spectrum (about 4% in total solar radiation) to visible-ultraviolet spectrum (about 50% in total solar radiation),and then ,the efficiency of solar radiation is raised about 10 times. Another usage of the transparent YFSTPC is to conducting solar rays into the inner of landfill leaches to degrade it ,and then the degradation takes place from surface to all over the whole body of the landfill leaches. A transformation has been brought about: The areas of collected solar rays from the areas of landfill leaches liquid become the areas of the convexes, so, the quantum of the collected solar rays may be enlarged by increasing the areas and number of the convexes, therefore, theoretically , the conflict between quantum of"naturally cope with way"and sequentially increasing landfill leaches may be meet. With light conducting plastic medium of"solar rays tracking and focusing system", the reaction of degradation of landfill leaches may also take place in the areas where the sun can not shine directly.Main contents are introduced in the paper: The way of fabrication and characterization of YFSTPC ; Study on the experiment of degradation of landfill leaches over YFSTPC by focused solar rays ; Study on the main factors which affect degradation including :the temperature ,the quantity of doped Y in YFTSPC, the air flux, the concentration of landfill leaches, the pH of landfill leaches, the quantum of the collected solar rays. Drawing experimental curves of relation between the removal rate and the time; Fitting the experimental curves affected by the main factors and analyzing the physical signification about the parameters in fitting formulae; Establishing the kinetic model formula for photo catalytic degradation of landfill leaches by focused solar rays.The first , YFSTPC was fabricated and characterized. A kind of smooth and transparent YFSTPC may be obtained by the experimental way , with 20-80 nm thickness ,and granularity≤50nm. The second, the of degradation was operated .The degrees and reasons of main factors which affect photo catalytic degradation of landfill leaches by focused solar rays were analyzed ,and the way for optimizing experimental conditions was introduced .Landfill leaches organic substances may be degraded by focused solar rays with the photo catalyst YFSTPC. The quantum of Y doped may obviously affect the degradation, It is better for photo catalytic degradation of landfill leaches, as the quantum of Y doped was 0.2% .The removal rates of TOC and COD were increased with the increasing of the temperature ,the collecting areas of convexes and the air flux. The removal rates of TOC and COD were gradually increased with the increasing of the air flux, but the increasing tendency and increasing extent became slow and small with the increasing of the air flux. The increasing of the collecting areas of convexes may obviously raise the efficiency of degradation .The pH of the landfill leaches affected the efficiency of degradation at the beginning of the reaction , but the affect became weak with the reaction processing. The speed of degradation was increased, but the removal rates of TOC and COD were gradually decreased, with the increasing of beginning concentration of the landfill leaches.Finally, considering some kinetic models on photo catalytic degradation of organic substances, and according to the main factors containing : temperature ,air flux, concentration of reaction, the collecting areas of convexes , etc., we obtained the kinetic general model formula for photo catalytic degradation, and those constants may be gotten by means of mathematics with experimental data, and then ,the the kinetic model formula for photo catalytic degradation of landfill leaches over YFSTPC by focused solar rays was established ,and the formula is as follow :Through 270 minutes reacting, the removal rates of TOC and COD were79.2% and 74.5%, with the condition: the landfill leaches were diluted by 40 times, the temperature was 25℃, the quantum of Y doped was 0.2% in YFSTPC, air flux was 40mL/s , the collecting areas of convexes was 125 times of its original liquid.It is a new geochemistry way to cope with landfill leaches organic substances with photo catalytic degradation over YFSTPC by focused solar rays. There are some advantages of this process :"naturally cope with", lower cost, higher efficiency .As the plan arranged ,all the samples of landfill leaches were only take from one landfill plant ,perhaps ,the experimental results were not suitable for other sites. In the following experiment, we would expend the sample collecting sites, and study on samples collecting from different areas and sites .It would be a useful exploration for the paper to cope with landfill leaches by solar rays with a new materials way.