The Adsorption Of Sb(Ⅴ) In Aqueous Solution By Nano Zirconium Iron Oxide Based On Activated Carbon

Antimony(Sb)is a metalloid that is ubiquitous in the environment at trace levels.Its compounds are potentially toxic and carcinogenic.Therefore,the remediation and prevention of its pollution has always been the focus of scientific research scholars.Adsorption method is one of the common water treatment technologies,which is widely used in the removal of various pollutants.Among many adsorption materials,zirconia can remove pollutants through electrostatic attraction and ligand exchange,and has a good removal effect on Sb(Ⅴ);magnetic iron oxide can be separated quickly under the condition of an external magnetic field,but the two are in the preparation and synthesis process prone to reunion.In this study,a nano zirconium iron oxide based on activated carbon(Zr/Fe@AC)was prepared,and the material was characterized and applied to the removal of Sb(Ⅴ)in water environment.Research the dosage of adsorbent,the solution p H value,initial Sb(Ⅴ)concentration,contact time and other factors on the adsorption effect of Sb(Ⅴ)and the adsorption mechanism.The main results are as follows:(1)Activated carbon was used as the carrier,and Zr/Fe@AC nanocomposite was successfully prepared by co-precipitation-reactor method to support zirconium iron oxide.By adding metal oxides and hydroxyl groups,the number of active sites is increased,and the adsorption capacity of activated carbon for Sb(Ⅴ)is greatly improved.When the molar ratio of iron to zirconium is 1:1,Zr/Fe@AC has the best adsorption effect on the solution with the initial Sb(Ⅴ)concentration of 1 mg/L,and the removal rate is 77.11%.(2)According to the results of BET and XRD analysis,Zr/Fe@AC nanocomposite is amorphous,with larger pores and more adsorption sites than activated carbon,and its surface area is 23.99 m~2/g.The SEM analysis results show that the nanoparticles are successfully loaded on the surface of the activated carbon carrier and are evenly distributed.According to the results of VSM analysis,Zr/Fe@AC nanocomposites pass through the zero point,indicating that they do not have remanence and coercivity,indicating that they have no hysteresis loss,and the maximum saturation magnetization is 1.89 emu/mg,indicating that Zr/Fe@AC has superparamagnetism,no magnetic agglomeration,and can achieve rapid solid-liquid separation under the action of an external magnetic field.(3)A single factor experiment was used to explore the optimal adsorption conditions for nanocomposites to adsorb Sb(Ⅴ)when the initial concentration of Sb(Ⅴ)was 1 mg/L.The results show that:when the dosage of Zr/Fe@AC is 600 mg/L,the p H is 5.0,and the contact time is 180 min,the adsorption capacity of Zr/Fe@AC nanocomposite for Sb(Ⅴ)is 1.63 mg/g,The removal rate is 97.81%.In the experimental concentration range,PO43-and humic acid have a greater impact on the removal of Sb(Ⅴ).Zr/Fe@AC can still maintain high adsorption performance after being reused three times.(4)The adsorption process of Sb(Ⅴ)by Zr/Fe@AC conforms to the quasi-quadratic kinetic model and Freundlich adsorption isotherm model.The results show that the theoretical maximum adsorption capacity of Sb(Ⅴ)is 11.80 mg/g.The adsorption occurs on a heterogeneous surface.The adsorption form is multi-layer adsorption.Chemical adsorption is dominant.The adsorption process is an endothermic reaction at 288～318K.The adsorption process can proceed spontaneously within the range.Combined with the results of FT-IR analysis,it can be seen that the adsorption mechanism is:non-specific adsorption through electrostatic attraction,and specific adsorption through ligand exchange.Based on the above experimental analysis,Zr/Fe@AC can not only combine the advantages of good selective adsorption and large adsorption capacity of inorganic adsorbents,but also exert the advantages of organic carrier activated carbon material of large specific surface area and easy separation,which solves the problem of inorganic material preparation process.The problem of easy agglomeration and difficult solid-liquid separation.It not only provides feasible new ideas for antimony pollution remediation technology,but also provides necessary theoretical and technical support for the development of activated carbon modified materials and the industrial production and application of carbon-based modified adsorption materials.