Paper Topics:study On Antimony Removal From Water By ASS And Its Adsorption Mechanism

In recent years,the problem of antimony pollution has become increasingly prominent,especially threatening the aquatic environment.After antimony enters the human body,it may cause acute diseases such as oral cavity and eyes.At present,antimony pollution has attracted people’s attention.As one of the methods of antimony removal,the adsorption method has always attracted attention due to its high efficiency,low cost and easy operation.Among many kinds of sorbents,metal oxide sorbents have relatively high adsorption performance.In addition,the accumulation of solid waste in iron and steel plants is also a major problem in environmental pollution.high iron content is the typical characteristics of iron and steel plant solid waste.Therefore,this study attempts to apply iron and steel plant solid waste to iron oxide adsorbent to remove antimony from water.The purpose of this study is to prepare adsorbents for removing Sb（V）and Sb（III）from water after washing chlorine treatment of a solid waste produced by steel works——ASS.Using scanning electron microscope,Zeta potential analyzer,X-ray diffractometer,specific surface area analyzer and other methods were used to study the characteristics of desiliconized sludge to determine the feasibility of the material adsorption of antimony.The influencing factors of ASS on the adsorption behavior of Sb（V）/Sb（III）were studied.And at the same time,the adsorption mechanism of ASS materials was determined by the adsorption isotherm equation,adsorption kinetics and other adsorption models.FTIR and XPS were used to characterize ASS before and after antimony adsorption,and the removal mechanism of Sb（III）and Sb（V）by ASS was reasonably analyzed.The main results are as follows:（1）ASS has a small particle size,mainly distributed in 1.0-10.0μm,and it has a high specific surface area,up to 61.9m²/g.The equipotential p H value was 6.98.The mineral composition of ASS is mainlyβ-Fe OOH and amorphous Si O₂,and the material surface is rich in hydroxyl groups.（2）Taking ASS as the research object,compare the effects of hydrothermal treatment time and temperature on the adsorption performance of materials,experimental results showed that the original ASS without hydrothermal treatment had the best adsorption performance.（3）The study of the adsorption performance of ASS on Sb（III）and Sb（V）shows that the adsorption effect of ASS is positively correlated with the dosage and adsorption time.The increase of adsorption temperature had a favorable effect on the adsorption of Sb（V）,but almost no effect on the adsorption of Sb（III）.（4）When the p H is in the range of 2.0-5.0,ASS has the best adsorption effect on Sb（V）at p H=3.0.In the range of 5.0-9.0,the adsorption capacity of ASS changes little.When p H>9.0,the material has the best effect on Sb（V）.The adsorption effect is rapidly reduced.When the p H is maintained at 2.0-10.0,the adsorption capacity of ASS on Sb（III）is stable at 12mg/g,and when p H>10.0,the adsorption capacity of ASS on Sb（III）gradually increases.（5）The increase of ionic intensity of solution significantly inhibited the removel effect of Sb（V）,but had no obvious effect on the adsorption of Sb（III）.CO₃^2-and PO₄^3-significantly inhibited the adsorption of Sb（V）,while NO₃^-promoted the adsorption of Sb（V）.The interference ions had little effects on the adsorption of Sb（III）.Among the interfering ions,only CO₃^2-can promote the removal of Sb（III）.The removal rate of Sb（III）was not affected by other interfering ions.（6）Various adsorption models were used to fit the adsorption process of two valence antimony.The fitting results showed that the adsorption kinetics of ASS for Sb（V）and Sb（III）accord with Elovich equation.But the fitting results of isothermal adsorption model showed that the R-P equation（R²=0.909）was suitable for Sb（V）adsorption process.And the isothermal adsorption model of Sb（III）conforms to Freundich equation（R²=0.937）.These indicated that the adsorption process of ASS to Sb is combination of physical and chemical adsorption.（7）It is speculated that the mechanism of ASS adsorption of Sb（V）/Sb（III）in water:after ASS oxidizes Sb（III）in solution to Sb（V）,the hydroxyl group inβ-Fe OOH reacts with Sb（V）.The complex is adsorbed to the surface of the ASS to be removed.