Effects Of The Physical And Chemical Properties And The Adsorption Behavior Of Veterinary Antibiotics Of Calcic Soil Affected By Natural Organic Fertilizer In Cold And Dry Areas

The addition of natural organic fertilizer can improve fertility and maintain a balance of various nutrients in the soil.However,natural organic fertilizer can also carry veterinary antibiotics that can bring risks for human health.Thus,study on the addition of natural organic fertilizer to the physicochemical properties of ash-calcite in the northwest arid area,as well as the influence of the adsorption behavior of antibiotics,fertility,and adsorption of veterinary drugs is of great significance for understanding the fate of veterinary antibiotics in sierozem.In this dissertation,the manure of cow and sheep were used as materials,and elemental analysis and infrared spectroscopy were used to characterize and analyze the composition and characteristics of collected natural organic fertilizers.Batch experiments were used to test the adsorption effect of veterinary drug antibiotics on sierozem soils affected by cow manure.The influence of manure on the adsorption performance of chlortetracycline and ciprofloxacin onto sierozem soil,as well as the kinetic model and thermodynamic model,and the influencing factors,such as temperature,pH,particle size,initial concentration,ion concentration and type,were also analyzed in the study.The results of the study are as follows:(1)Analysis of the characteristics of cow and sheep manure showed that the content of ash in sheep manure reaches 74.98%,and the content of ash in cow manure reaches 29.95%.The pore size,pore volume and specific surface area of ?sheep manure are larger than that of cow manure.Sheep manure contains more carbon and hydrogen than that in cow manure.Sheep manure contains more organic matter than that of cow manure.The manures contain hydroxyl,carboxyl,C=C double bonds,and amine groups.(2)Sheep manure by adding to the soil can increase the amount of organic matter,ammonium nitrogen,available phosphorus and available potassium in the cultivated land.The organic matter content gradually decreases from the plant growing stage to the harvesting stage.The precipitation affects the organic matter and ammonium in the soil.The rain has a great influence on levels of nitrogen,available phosphorus and available potassium.Fertilizer can quickly and effectively increase the content of nitrogen,phosphorus and potassium,but it will inhibit the growth of microorganisms in the soil and make the content of organic matter lower.Chemical fertilizer and manure application can be balanced with a long-term releasefrom fertilizer coupled with sheep manure.(3)The adsorption processes of chlortetracycline and ciprofloxacin in sierozem soil can be divided into fast reaction and slow reaction,which are in accordance with Pseudo-second-order kinetic model and Freundlich thermodynamic model.They are exothermic processes.The adsorption of chlortetracycline by calcareous soil is an exothermic process which is spontaneous and chaotic.The adsorption of ciprofloxacin on calcium carbonate is an exothermic process which is spontaneous and chaotic.The pH and particle size of the solution affected the adsorption of chlortetracycline and ciprofloxacin.The pH ranged from 3 to 10,and the adsorption amount of chlortetracycline in the sierozem soil increases rapidly and then decreases rapidly,and the adsorption amount of chlortetracycline in the sierozem soil was first.Increase after decrease.The smaller the particle size of the sierozem particles,the greater the amount of chlortetracycline and ciprofloxacin adsorbed onto sierozem.The equilibrium adsorption capacity of chlortetracycline on sierozem is slightly greater than that of ciprofloxacin,and the adsorption is mainly based on physical adsorption.As the ionic strength increases,the adsorption amount of chlortetracycline of the sierozem decreases.The adsorption capacity of chlortetracycline and ciprofloxacin on sierozem were increased with the increases of the initial concentrations of the chlortetracycline and ciprofloxacin.(4)Adding cow dung and sheep dung has no effect on the adsorption model of chlortetracycline,but it can not change the adsorption mechanism,but it can improve the saturated adsorption capacity and shorten the equilibrium adsorption time.The adsorption process of chlortetracycline on sierozem containing cow manure and sheep manure is an exothermic process that occurs spontaneously and the degree of chaos in the system is reduced.The adsorption amounts of chlortetracycline by adding the manure were greater with the increase of the initial concentration of chlortetracycline.The adsorption process of chlortetracycline on sierozem containing cow manure and sheep manure is an exothermic process that occurs spontaneously and the degree of chaos in the system is reduced.The high ionic strength has a significant effect on the adsorption of chlortetracycline and ciprofloxacin on the sierozem.Cation exchange is the main mechanism of soil adsorption of chlortetracycline.The effect of pH on the adsorption properties of chlortetracycline on the sierozem affected by the addition of cow manure is influenced by the molecular morphology of chlortetracycline.(5)The desorption amount of chlortetracycline from the sierozem is much smaller than the adsorption amount,which is mainly caused by the hysteresis of desorption.The adsorption and desorption reactions of chlortetracycline to sierozem can be divided into fast reaction and slow reaction.The desorption process of chlortetracycline reached a state of equilibrium after 2.5 hours,and the desorption process of ciprofloxacin reached equilibrium at the 8th hour.The desorption amount is proportional to the concentration of chlortetracycline and ciprofloxacin.