Study On The Removal Of Sb（Ⅲ）from Water By Mesoporous Silica Nanoparticles

In various industries of the national economy,antimony metal,as an important alloy element,cannot be replaced.When a large amount of antimony metal is developed and used,environmental pollution is becoming more and more serious,and human health is also affected.Antimony pollution in water bodies is particularly serious,directly causing serious damage to human health,and the scope of antimony pollution in water bodies will increase with the strong fluidity of the water.In recent years,due to the serious harm caused by antimony pollution to people’s production and life,the antimony pollution control has received more and more attention.In this study,mesoporous silica microspheres were prepared by the inverse microemulsion method,and ethanol was used as the modifier to prepare mesoporous silica nanoparticle adsorbents（MSNs）to control antimony pollution.The material preparation steps are as follows:In this study,cetyl trimethyl ammonium sulfonate（CTAC）was used as the surfactant,triethanolamine（TEA）emulsifier was used as the oil phase,and deionized water was used as the water phase.Ethyl orthosilicate（TEOS）,in order to remove the remaining reactants,was washed several times by adding ethanol and collected by centrifugation.Then it was extracted twice with 0.6 wt%ammonium nitrate（NH₄NO₃）ethanol solution at 60.0℃for 6 hours each time to remove the template（CTAC-TEA）.The products obtained after ethanol-modified centrifugation are mesoporous silica nanoparticles（MSNs）.Analyze mesoporous silica nanoparticles（MSNs）by SEM,TGA,FT-IR and other characterization methods.Scanning electron microscopy revealed that the surface of mesoporous silica particles（MSNs）had clear pores.Through TGA characterization analysis,it is found that mesoporous silica particles（MSNs）have good thermal conductivity and thermal stability.Through BET characterization analysis,it was found that the specific surface area,average pore diameter and total pore volume of mesoporous silica particles（MSNs）were 713.72 m~2/g,4.0158 nm,and 1.0173 cm~3/g,respectively.Through FT-IR analysis,it was found that all characteristic peaks of the obtained mesoporous silica particles（MSNs）shifted before and after the adsorption.It is speculated that the adsorption reaction is chemical adsorption.In the static test,the adsorption performance of mesoporous silica particles（MSNs）was investigated by adjusting the p H value and dosage.The results show that the adsorbent has a p H of 6.0,an initial concentration of 150 mg/L,an initial volume of Sb（Ⅲ）solution of 100m L,and a reaction temperature of 298 k for 480 min.The adsorption capacity for Sb（Ⅲ）in water is 27.96 mg/g.Through the fitting of the quasi-first and quasi-secondary models,it is found that the quasi-secondary kinetic model describes the adsorption process of the mesoporous silica nanoparticles（MSNs）adsorbent better,and its correlation coefficient is 0.93.Langmuir and Freundlich adsorption isotherms were used to fit the adsorption process.The Langmuir fitting model can fit the adsorption process ideally under the conditions of 298 k,308 k,and 318 k（R~2=0.9801,0.9825,0.9569）.Under the condition of 298 k,the Langmuir theoretical maximum adsorption capacity of mesoporous silica nanoparticles is 31.45 mg/g,which is slightly larger than the maximum adsorption capacity obtained from actual experiments.By analyzing the adsorption process by thermodynamic parameters,it can be known that the adsorption reaction is a spontaneous reaction of exothermic and entropy reduction.By comparing the analysis effects of different desorption solutions,it is found that the effect is best when 0.5 mol/L HCl is used for regeneration.After 3 adsorption-desorption experiments,the removal efficiency of the mesoporous silica nanoparticle adsorbent is maintained at 50%Above,it has better reproducibility.The adsorption mechanism of the mesoporous silica nanoparticle adsorbent was studied through characterization analysis and adsorption experiment.It was found that the silanol on the surface of the adsorbent and heavy metal ions exchanged to generate hydrogen ions,and the product formed on the surface of the adsorbent was（RO）₃-Sb,RO-Sb-（OH）₂,RO-Sb=O three kinds.The characterization shows that the surface of the mesoporous silica particles（MSNs）adsorbent has micropores and physical adsorption,which increases the removal effect of the adsorbent.Therefore,the adsorption reaction is mainly chemical adsorption,with physical adsorption as a supplement.In summary,the mesoporous silica particles（MSNs）prepared in this study have good adsorption performance and recyclability for Sb（Ⅲ）in water,and are an ideal adsorption material.