Study On The Resource Utilization And Application Mechanism Of Cyanobacteria In Chaohu Lake

Cyanobacterial bloom is a worldwide environmental problem,and its large-scale outbreak will seriously affect the aquatic ecosystem.During the massive outbreak of cyanobacterial bloom,mechanical salvage is a timely and effective control measure,which has been widely applied in China.After cyanobacteria salvage,cyanobacteria water is separated and a large amount of algal biomass is produced,which is likely to cause secondary pollution to the environment.Therefore,it is very important to find an effective way of resource utilization for cyanobacteria biomass material(BGA).In view of the above problems,on the basis of ecological investigation and a large number of experimental studies,cyanobacteria were successfully used as the nitrogen and carbon sources of flame retardant additives,a series of flame retardant additives were successful prepared.The paper also studied on the condensed structure of cyanobacteria biomass material(BGA)which were introduced into EVA composite system and the influence on flame retardant and mechanical properties.And bacause there are oxygen-containing functional groups on the surface of cyanobacteria powder,the study uses XRD?SEM?TGA?XPS and N2 adsorption/dsorption curve to analyse its physicochemical property.The ability of adsorpting uranium(?)as adsordent of cyanobacteria powder was studied in static batch adsorption experiment.Finally,using cyanobacteria powder as carrier and phosphoric acid as activating agent,we modified cyanobacteria powder by hydrothermal process with a high temperature activation at 200?.Phosphoric acid modified algal powder bio-mass carbon was prepared.Then we analyse the physicochemical property and the ability of adsorping uranium(?)of the bio-mass carbon,and the adsorption mechanism of biomass carbon from algae powder was further explored.The main contents are as follows:(1)Effect of cyanobacteria biomass material(BGA)on EVA based composite.It was found that the 10%content of BGA can improve the processability of the composites.DSC tests showed that BGA will increase the glass transition temperature of the matrix,indicating the interaction between BGA and matrix.However,TG results indicated that BGA will thermally stabilize the composite.SEM images showed that the introduction of 10%BGA in the EVA based composite system improve the mechanical properties.But high content of BGA decrease interfacial adhesion between the inorganic particles and the polymer.Due to the high content of BGA,the mechanical strength,oil resistance and insulation performance of the composites were reduced owing to damage of the internal phase interface structure of the composites.(2)The study on the removal of U(?)in the water by Cyanobacteria biomass material(BGA).Using BGA as adsorbent,the effects of pH values,ionic strength,contact time and reacting temperature on the removal of U(?)by the adsorbent were investigated.The results showed that the adsorption performance of U(?)on BGA highly depends on pH value of solution,and the ionic strength has less effect on the adsorption performance.According to the dynamics and linear correlation coefficient R2 value of isotherm,the process of U(?)adsorption on BGAs follows the pseudo-second-order kinetic equation and the Langmuir model.According to the Langmuir fitting results,the maximum adsorption capacity was 80.55 mg/g at pH 5.0.The adsorption process is an endothermic spontaneous process.The excellent adsorption of U(?)could be attributed to C-OH ion exchange and surface complexation of-COOH groups with U(?).(3)Preparation of phosphoric acid modified cyanobacteria based bio-mass carbon by hydrothermal method.Although cyanobacteria,as adsorbent,has the adsorption capacity of U(?)in solution.The adsorption capacity is still in the middle position compared with similar biomass materials.Therefore,we prepare phosphoric acid modified cyanobacteria-based activated carbon(BGA-PH)in phosphoric solution by hydrothermal treatment method.Similarly,the effects of various environmental factors in aqueous solution on the removal of U(?)by BGA-PH were investigated by static batch experiments.The results indicated that BGA exhibit excellent adsorption capacities for U(?),and the adsorption process can also be fitted by pseudo-second-order kinetic equation and the Langmuir model.The maximum adsorption capacity of U(?)on BGA-PH was 169.20 mg/g at 298K,pH=5.0.XPS analysis showed that the-OH,-COOH and phosphoric acid functional groups on the adsorbent surface reacted with U(?)during the adsorption process.This is the adsorption mechanism of U(?)removal by BGA-PH.