Study On The Preparation And Application Of Defluorinated Materials In Fouling Acid And The Application Conditions Of Regeneration

Since the reform and opening up,along with the development of the industry,the smelting industry has also developed rapidly,promoting the further development of heavy industry.While huge economic benefits,it also produce large amount of fouling acid.In recent years,the removal of fluorine ions in fouling acid has gradually received attention,traditional treatment methods such as chemical precipitation have apply many years.Domestic and foreign researchers start to research new ideas for removing fluorine ions and aim at recycling dilute sulfuric acid.For the smelting industry,comprehensive treatment of fouling acid is urgent requirement for enterprises to achieve sustainable development.This paper focuses on the removal of high-concentration fluoride ions from fouling acid from the smelting industry.The characteristics of fouling acid and the harm offluoride ion,the necessity of fouling acid treatment,the existence form of fluorine,and the common methods for removing fluoride ion are briefly introduced.Combination of inorganic nanomaterialss and polymer materialss to design a defluorination materials with multilayer core-shell structure.The structure of the materials is divided into three layers.the inner core inorganic nanomaterialss.nanocalcium carbonate is used to fix fluoride ions and adjust the density of the materials,the second layer is polyacrylic acid amino ester polymer.that can adsorb fluoride ions to form quaternary ammonium salt,the quaternary ammonium salt can be desorbed under heating or alkaline environment to realize recycle materials.The outermost layer is cross-linked polystyrene-(amino acrylate)-acrylamide The copolymer is the outer surface of the skeleton,in which the polyacrylamide segment has certain swelling property in the filthy acid,the smaller volume F' can enter,so most F-can be removed.The fouling acid used in this paper come from Daye Nonferrous Smelter in Hubei Province,the following aspects have been studied,the details are as follows:1.Research on the materials preparation.The staff of the research group have made exploration in the preliminary work,but there are problems in the preparation and the separation after-treatment,high cost on preparation.Therefore,it is necessary to further study and optimization of the preparation of materials.The method of emulsion polymerization and controlling the variables simultaneously in turn about the polymerization temperature,the amount of inorganic dispersant,the amount of monomer dimethylaminoethyl acrylate(DMAEA),the usage initiator dimethyl azobisisobutyrate(AIBME),the dispersion medium,the amount of monomer,the amount of acrylamide(AM),the amount of styrene(St),and the temperature of adding acrylamide(AM)were investigated to determine the best preparation method from the perspective of the removal effect of fluoride ion and adsorption capacity.The fluoride ion concentration in fouling acid is 1798.3 mg/L,the maximum adsorption capacity of the materials can reach 35.6 mg/g.2.Based on the materials preparation,Next,the application conditions of the materials are to study.Firstly,single-factor experiment is performed in turn using the control variable method,the adsorption time,fouling acid pH,dilution factor,and the amount of precipitated material on the defluorination were explored in order.Then,according to the results of single factor experiment,the amount of emulsion,processing time and pH of fouling acid were selected to carry out the experiments of three factors and five levels to determine the order of about the effect of materials.From the perspective of the adsorption capacity for fluoride ions in fouling acid,the application conditions affecting the materials were explored.When the fluoride ion concentration in this section is as high as 3531.9 mg/L,the adsorption capacity for fluoride ion is also increased,it up to 67 mg/L.The experimental results combined with the materials preparation chapter show that the materials is not only suitable for low-concentration waste acids,but also high-concentration fouling acids.The laboratory research of materials provides reference and basis for the realization of pilot and industrial applications of materials,and achieves the goal of cost savings and process optimization.3.In order to further explore the effect of other anions in fouling acids,The effects of F-,Cl-,SO42-,PO43-were explored in turn,so simulated wastewater containing different concentrations of F-,Cl-,SO42-,PO43-,the centrifuged emulsion materials are used to treat simulated wastewater.Based on the materials defluorination efficiency and adsorption capacity,the effects of various ions on the materials treatment effect were judged to better explore the materials defluorination mechanism.4.The structure of the defluorination materials determines that may can be regenerated and applied.Therefore,the desorption experiment of the materials is carried out to explore regenerative ability and the mechanism of adsorption-separation-desorption.this paper uses alkaline desorption.The results show that s NaOH solution can be used to desorb the materials,and the concentration of the sodium hydroxide solution has little effect,the materials can be recycled three times,and the fouling acid can be treated four times,the cumulative adsorption can reach 156 mg/g.5.Characterization and analysis of materials.Characterization of materials and the materials after treatment of fouling acid to explorate of the structure of materials.The characterization methods in this paper mainly include thermogravimetric analysis(TGA),scanning electron microscopy(SEM),X-ray powder diffraction(XRD),and infrared spectroscopy(IR).Combining multiple characterization methods shows that the materials have multilayer structure and can selectively adsorb fluoride ions.