Studies On Characteristics Of Lead And Cadmium Adsorption To Organic Components Of Natural Surface Coatings

There are many methods to take heavy metals in natural water. among which biosorption is considered as a new method valued in cheap consume, high efficiency and it can save power. It is always be applied to deal with low concentration sew with heavy metals economicaly.Dong et al had found that biofilm can adsorb many kinds of heavy metals easily in natural water. In addition ,the dominant components of biofilm such as microorganism and its exopolymer all were qualified with the ability to adsorb heavy metals.though it is very complicated during the process that biofilm contact with its environments ,and all the components cant be recognized easily ,we can conclude that the organic parts play an important role during biosorption process. which included microorganism and its exopolymer and some other parts .As for microorganism ,it can almost decompose every kinds of pollution. and once some new kind of pollution appear, it can create new enzyme to deal with that pollution. we can find proper microorganism to decompose all of the pollutions under controlled conditions.Almost all the microorganism can produce its exopolymer, which can not only exchange ions but also can contact with metal ions, and combine with the heavy metals selectively. all the exopolymer can be identical or not. it is affected by many factors such as environment and other life conditions. though all the components can be identical ,but the ingredient about exopolymer can be recognized as including protein ,glucide, fatness and DNA, among them ,the glucide and DNA are considered as dominant ingredient.Many research work show that exopolymer play an important role in the process to deal with polluted water with heavy metals. so it is important to take the research work on it.In this subject ,we take the method that through the comparation of every components that adsorb heavy metals and use natural water as sample to foster targeting bacterium instead directly obtained biofilm's, for directly biofilm are restricted by many factors such as climate and season .as the result we can see that we can consider dominant bacterium obtained from natural water as the substitude that from biofilm.But after purifieding and exculture ,many matters are involved in that solution, so before we analysis each component we must separate the mixture, Including glucose from that liquid culture and some bacterium and its exopolymer.We should remove the glucose through lysis method at first, for the concentration of glucose affect adsorption result much, once the glucose was removed ,the dominant component include dominant bacterium and its exopolymer. Then we separate that two component through high speed centrifugal method, then we can obtain living body bacterium and nonliving body bacterium and its exopolymer.the obtained sterilized liquid culture involve the dominant bacterium placed at culture box for about 3 daytime. about 28 through 30 centigrade as culture temperature and after lysis and high speed centrifugal, we collect the matters at the bottom of centrifugal tube as aimed living body bacterium and if we deal with that bacterium through freezed dry method we can get the nonliving body bacterium. For that ,we can estimate how the freed-dry method affect that experiment. After that we can put up every experiments such as experiment for biosorption balance time , the effect of biosorption temperature and PH value ,the thermodynamics experiments and so on .we can compare the biosorption ability from langmuir equation result.