Research On The Key Technology Of Strengthening The Flocculation Efficiency Of Ferric Chloride By External Electric Field

As an inorganic flocculant,ferric chloride has been widely used in the field of sewage treatment.Compared with organic flocculants and aluminum salt flocculants,ferric trichloride flocculants have the advantages of wide application range and low toxicity,however,there are still problem of low flocculation efficiency.In the flocculation process of ferric chloride,the hydrolysis and polymerization of ferric ions are two important stages.As a physical method,external electric field can accelerate the process of iron ion hydrolysis and polymerization and improve the flocculation efficiency of ferric chloride flocculant.In this paper,the method of reaction molecular dynamics simulation is used to deeply study the microscopic mechanism of the effect of the external electric field on the hydrolysis and polymerization of ferric chloride,and the changes of the flocculation effect of ferric chloride under the action of the external electric field are studied by a macroscopic experiment,and the simulation results are verified by experiment data.The main research contents of this dissertation are:（1）Deprotonation reactions is an important stage in the hydrolysis process of ferric chloride.In order to further explore the micro mechanism of the effect of external electric field on the hydrolysis process of ferric chloride,the effect of external electric field on the deprotonation reactions of iron ion is studied by using the molecular dynamics simulation method,and the radial distribution function between particles,water molecular bond angle,system energy and products of the deprotonation reaction and viscosity are counted under different intensity of electrostatic field.By analyzing the changes of these data,the mechanism of external electric field accelerating deprotonation reaction is studied.（2）The polymerization efficiency of iron ion will directly affect the flocculation effect of ferric chloride.In order to further explore the micro mechanism of external electric field affecting the polymerization process of iron ion,the effect of external electric field on the polymerization reaction of iron ion is studied by using the molecular dynamics simulation method.The radial distribution function between particles,bond order,electrostatic energy,products of the polymerization products and self-diffusion coefficient are calculated under different electric fields.By studying the change of these data,the mechanism of the effect of external electric field on the polymerization of iron ion is studied from the microscopic point of view.（3）In order to verify the research conclusions of molecular dynamics simulation,experimental methods are used to study the changes in the flocculation effect of ferric chloride under the action of an external electric field.The main experimental data observed are:the p H value of the ferric chloride dilute solution and the turbidity,particle size distribution,Zeta potential,COD and TOC during the flocculation process.The results of molecular simulation are verified by experimental data,and the results show that the external electric field can accelerate the hydrolysis and polymerization process of Fe³⁺ions,and further improve the flocculation efficiency of ferric chloride.