The Effect Of Bacillus Subtilis On The Adsorption Mechanism Of Lead Bismuth And The Ecological Effects Of Lead-related Pollution Elements

This paper explores thermodynamics and kinetics mechanism of adsorption of lead antimony compound pollutants Interaction by the Bacillus subtilis and studys the impact of the different concentrations of lead resistant bacteria Bacillus subtilis on characteristics of the lead and antimony in soil and characteristics of migration and transformation of heavy metals in soil plant system and soil diversity characteristics by Maize(Zea mays L.)pot experiment.The aim is to clarify the characteristics of environmental effects of Bacillus subtilis on Pb,Sb and other contaminated elements in soil and water,and to provide theoretical basis for the remediation and control of lead pollution.The main conclusions of this study:(1)The Bacillus subtilis dry powder preparation has a greater adsorption capacity for lead at pH 5,while the adsorption of antimony is poor.Under the optimum temperature of 35 ?,the adsorption process of lead is consistent with the Langmuir isotherm adsorption model.The adsorption process of antimony is consistent with the Freundlich isotherm adsorption model.In kinetic studies,the adsorption of lead and antimony by Bacillus subtilis tended to be pseudo two order adsorption kinetics model.The adsorption of lead and antimony by Bacillus subtilis is endothermic spontaneous process,and the spontaneous adsorption of lead is higher than that of antimony.(2)The addition of Bacillus subtilis dry powder to the culture soil promote the content of cadmium and nickel in maize seedlings,and to reduce the contents of antimony and zinc in the seedlings of maize.The active forms of Cr in rhizosphere soil increased,and the lead and nickel residue in rhizosphere soil increased,and the residual state of antimony and zinc increased,and the corresponding reduced.(3)The enrichment coefficients of antimony,cadmium and zinc are large and easy to transport from the soil to the the root of the maize,while Lead,antimony,and nickel are opposite.The transport coefficients of three elements,antimony,cadmium and zinc,are large and easy to transport from the root of the maize to the upper part of the earth.The transport coefficient of lead is small,and the ability to transport from the root to the upper part of the soil is weak.(4)The microbial species in rhizosphere soil mainly include root fungi,fungi,gram negative bacteria,eukaryotes,gram positive bacteria,anaerobic bacteria and actinomycetes.Adding Bacillus subtilis dry fungus to culture soil,the percentage of positive bacteria in rhizosphere decreased,and the percentage of Actinomyces increased.(5)The addition of Bacillus subtilis dry powder to the culture soil increase the content of organic matter in soil,and to form a variety of heavy metal crystals in rhizosphere soil.Especially the antimony,a large number of crystals were formed in the rhizosphere soil of the experimental group.(6)In view of the results of this study,Bacillus subtilis can be used as a passivating agent for the remediation of zinc and antimony contaminated soils,and also as a biological adsorbent for low lead contaminated water bodies.The main conclusions of this study are as follows:...