Study On Adsorption Of Heavy Metal Copper On Soybean Root Nodule

Nowadays,human production and life will discharge a large amount of non-compliance heavy metal sewage into the natural water body,and enter the soil and even the human body through the circulation of the ecosystem.This seriously threatens the balance of ecosystems and human health.Therefore,it is imperative to develop an environmentally friendly method to remove pollutants beyond the traditional physical chemistry.Microbial adsorption method is one of the most important and effective methods for the treatment of heavy metals due to its high efficiency,easy operation and no secondary pollutants.Nodule is a special tumor that grows on the roots of plants.It is formed from parasitic symbiotic nitrogen-fixing bacteria and is a non-toxic,inexpensive material.In this experiment,the heavy metal copper adsorption experiment was carried out by root nodule and Rhizobium isolated from root nodules,and the adsorption characteristics and morphology structure were analyzed.In this paper,root nodule was cleaned,ground and dried,and the rhizobia extracted from root nodules were isolated,purified and cultured.After that,the adsorption rates of heavy metals and copper by nodules and rhizobial bacteria at different temperatures,ion concentrations,and ph conditions were analyzed,and the scanning electron microscope was used.Scanning Electron Microscope?SEM?,Fourier Transform Infrared Spectroscopy?FT-IR?,and X-ray photoelectron spectroscopy?XPS?are used to physicochemically study root nodule cultures of root nodule bacteria.Characterization.In the adsorption experiment of the system,the optimal adsorption conditions and maximum adsorption capacity of copper and nodules were investigated.Different adsorption isotherm models,kinetic models and thermodynamic models were used to analyze the equilibrium state of adsorption and to study the nature of the adsorption process.The main research results of this thesis are as follows:?1?The optimum conditions for the adsorption of heavy metal copper by grinding ultrasonically treated nodule powders are p H6.5⁷.0,temperature 28°C,and Cu²⁺concentration is 5.0mg/L.The removal rate is 33%,and the higher the concentration,the lower the removal rate.20mg/L about 20%.With the increase of Cu²⁺concentration,the adsorption amount of nodule per unit weight increased,and the adsorption amount increased from 8.25 mg/g to 20 mg/g in the range of 5.0 to 20mg/L.The maximum adsorption capacity of root nodules obtained under the highest initial concentration?20 mg/L?was 20 mg/g.The overall surface roughness of the nodule was characterized by characterization,and it had a honeycomb-like structure with a relatively loose structure and a large internal space.The occurrence of adsorption.In the course of the reaction,it can be seen that functional groups such as amino groups,hydroxyl groups,and carboxyl groups contained in the root nodule participate in the reaction,especially the action of amino groups.This kind of adsorption accords well with the Langmuir model,and the pseudo-second-order kinetic equation is more suitable for describing the adsorption process of Rhizobium.Rhizobium sorption of copper ions is more prone to chemical adsorption?2?In the process of isolation and purification of Rhizobium,selection of suitable scribing methods has a great influence on the isolation and purification of bacteria.At the end of the experiment,an improved three-line drawing method was used.After the five separations and purifications,active rhizobia were obtained.Store frozen on slopes.Each time the experiment was performed,the stored Rhizobium had to be streaked at least twice to ensure the activity of Rhizobium.?3?Adsorption experiments of heavy metal copper with rhizobia before and after separation were carried out.The optimum adsorption conditions of 28°C,p H 6.5,too high or too low temperature and ph were not suitable for the adsorption reaction.By calculation and analysis,the rhizobial bacteria isolated and purified at different ion concentrations were superior to those obtained before separation and purification.The activity was stronger,and the highest removal rate of copper ions was 39.6%.When the concentration of copper ions continues to increase,the removal rate of copper ions decreases.The high or low ion concentration can be detrimental to the adsorption of Rhizobium.The observation of Rhizobia by scanning electron microscopy revealed that Rhizobia has a rough surface,a honeycomb-like structure,and a relatively loose structure.The adsorption behavior also follows the Langmuir model and the pseudo-second-order kinetic model.The use of rhizobia for the adsorption of heavy metal copper is better than the nodule powder adsorption.