The Research On Pre-treatment Of The Sample On Determination Of Heavy Metal In Landfill Leachate

With the increasing of the number of the cities,enlargement of the industry scale,increasing of the population ,the change of life style and improvement of the standard of life,the solid waste is increasingr year by year. Meanwhile,the ingredients of them have changed obviously.Due to the ignoring of attention on the basic establishment to protect the environment,the shortage of the devotion,a large number of the waste have caused great threat to the environment around them.At least 200 out of 668 cities are surrounded by waste and the number of them have reached six billion seizing about more than five thousand million square metres of land. The piled up waste and landfill Site release the deleterious gases into the air including the substance which will cause cancer and monstrosity.Meanwhile,the acidic and alkaline organic pollutants which come from the waste dissolve the heavy metals forming contamination combined by organic compound,heavy metals and pathogeny microbe.Determination of heavy metal can judge the number of heavy metal in the landfill leachate exactly ,and also have the relationship with the life aroud them .The methods of determination of heavy metal exactly is the key to analyse the pollution grade.Photo-catalytic oxidation is a method which mixes ray radiation with。The oxidant breaks up into free state with more oxidation ability under the ray radiation so as to break up a lot of organic pollutants which can not be digested easily with single oxidant. The purpose of the application of photo-catalytic oxidation on the pre-treatment of landfill leachate is to use the physical effects which come from the corporate function with catalyzer , UV irradiation,ultrasonic and catalytic oxidation to change the heavy metals in landfill leachate from unmeasurable into measurable.The methods prevent using a lot of acid and the negative effects ,such as pollution and a waste of resources which come from high temperature digestion. Therefore,this paper take TiO2 as catalyst, according to the use of the corporate function with UV irradiation,ultrasonic and catalytic oxidation to degrade landfill leachate before treatment, and then determine the heavy metal in it by AAS. Besides, commonly used methods were compared to it. Meanwhile, the effects to the degradation efficency such time of UV irradiation , the power of UV, the dosage of H2O2,pH, the roast temperature of TiO2 , the dosage of TiO2,the speed of air supply are also discussed. Proper conditions to degrade landfill leachate and the accuracy and precision of this method are discussed. At last, high effect,quick,simple,economical methods of exploring new photocatalytic oxidation of the digestion for the sample pre-treatment methods are found .Proper conditions to degrade landfill leachate were selected.Degradation efficency is more than 94%.The recovery of this method is more than 92% and RSD of this method is less than 5.00% .Meanwhile, under the corporate function with ultrasonic and catalytic oxidation to degrade landfill leachate before treatment, we can not determine the heavy metal easily by AAS because of the falling off the TiO2.