Study On The Determination Method Of Bacterial Number Adsorbed On The Surface Of Clay Minerals And On The Enrichment Method Of Teace Composition In Assembly Of Clay Minerals

The interaction between mineral and microorganism is a phenomenon in nature.The adsorption of bacterial cells on the surface of minerals is the basis of their interaction.In the coexistence of clay minerals and bacteria,there are free bacteria,free clay minerals and mineral complexes in the system.Therefore,there is no direct method for determining the number of adsorbed bacteria by minerals.In this paper,a series of experiments were carried out to obtain simple,highly workable and accurate bacterial surface adsorption capacity of clay minerals.The soil often contains 2 or more than 2 kinds of clay minerals,sometimes one of them is very low and even difficult to detect.In addition,in the process of Mineral chemical weathering,sometimes forming a very low content of the newborn mineral.At this point,if the sample is directly measured by XRD,the new mineral is often undetectable.Therefore,the research work need to have a trace mineral composition in the clay mineral combination to get enrichment method.To this end,this paper also carried out the work in this area.The experimental results show that method of chromogenic reagent using ninhydrin for determination of bacterial protein content can be used to determine the bacterial number.Centrifugation at 2000 rpm for 10 min can effectively separate minerals-bacteria complexes from the bacteria and minerals under free state;The adsorption capacity of three minerals for Bacillus mucilaginous is according to following sequence:montmorillonite>illite>kaolinite;The specific surface area,the precipitation rate and the charge quantity on the surface of mineral,as well as bacterial activity are the main effect factors on the adsorption capacity;The forces lead to the adsorption of bacteria on the surfaces of clay minerals are mainly from the cation bridges.And,electrostatic attraction might also play a certain role.Treatment of six mineral assemblages of kaolinite(96%)and montmorillonite(4%)by centrifugal and sedimentation methods.First sediment A,and then the supernatant at 10000 rpm speed of re centrifugation of 10 min,obtained Trace Sediment,here temporarily referred to precipitate B.XRD test showed enrichment effect,when the proportion of two minerals is different,they are easy to separate,Such as montmorillonite kaolinite montmorillonite illite kaolinite montmorillonite illite montmorillonite combination,among the major minerals in sediment A are enriched,such as montmorillonite-kaolinite and montmorillonite-illite,the small proportion of the mineral was enriched in precipitate B,such as kaolinite-montmorillonite and illite-montmorillonite.When the proportion of the two minerals is close,the separation effect is worse,such as kaolinite-illite or illite-kaolinite.The rate of mineral precipitation is directly related to the proportion of mineral precipitation.The precipitation of the three minerals is faster,and the precipitation sequence of the minerals is kaolinite>illite>montmorillonite.