Study On Removal Of Antimony From Water By Combined Fenton Oxidation And Manganese Sand Filtration

China is the largest production country of antimony and the largest antimony emitter in the world.With the progress of the society,the problem of antimony pollution is becoming more and more serious.Aiming at the difficulty of steady antimony removal from water,this thesis studies the removal performance and mechanism of antimony by Fenton reagent(Fe²⁺/H₂O₂)and manganese sand respectively.Then,Fenton oxidation and manganese sand filtration technology were combined to remove heavy metal antimony from water.The removal efficiency of the combined system and the influencing factors of treatment were investigated to form an effective method to remove heavy metal antimony from water.The results of Fenton oxidation showed that the best removal conditions of antimony were in the conditions of Fe²⁺dosage of 5.6 mg·L^-1,Fe²⁺to H₂O₂ ratio of2:1,reaction time of 40 min at p H 4.0.Under these conditions,the removal efficiency of Sb（III）and Sb（V）by Fe²⁺/H₂O₂ was 75.8%and 68.9%,respectively.When the ratio of Fe²⁺to H₂O₂ is in the range of 2:1～8:1,the removal rate of Sb（III）and Sb（V）of the system was basically unchanged.When the concentration of Fe²⁺exceeds 5.6mg/L,the removal rate of Sb（III）and Sb（V）increased slightly with sharp increase in the residual iron concentration in solution.The removal efficiency of Sb（Ⅲ）and Sb（V）by Fe²⁺/H₂O₂ was high in the range of p H3.0～5.0.However,the removal efficiency of Sb（Ⅲ）and Sb（V）decreases significantly with the increase of p H.The removal efficiency of Sb（Ⅲ）and Sb（V）by Fenton was better than that by ferric coagulation in the range of p H3.0～5.0.XPS analysis showed that the binding force between Sb（III）and floc is higher than that of Sb（V）,which was related to the removal mechanism of Sb（III）and Sb（V）by Fenton system.The mechanism of Sb（III）removal by Fenton was the co-precipitation of Fe³⁺and Sb（III）produced by oxidation,the adsorption of Sb（III）by in situ formed iron oxide and the release of adsorbed Sb（III）into water after oxidation,while the removal of Sb（V）is mainly due to the adsorption of Sb（V）by in situ formed iron oxide.At the same time,it is found that Fenton oxidation shows a good performance on the removal of both antimony and organic substances in wastewater.The static adsorption test showed that removal of Sb（V）by manganese sand was effective in the condition of Sb（V）initial concentration of 200?g/L,the adsorbent dosage of 1.0 g/L,the p H value of 4.0,and the adsorption time of 24h.The results of manganese sand filtration experiments show that manganese sand has a good removal potential on antimony.The dynamic adsorption tests showed that the adsorption penetration curves of antimony removal obey the Logiest curve model,and the shapes of adsorption penetration curves are similar under different conditions as the"S"shape.The penetration curves obtained by dynamic filtration of manganese sand under different conditions were well fitted by Thomas model and Yoon-Nelson model with R² of 0.99 for both.The combination of Fenton oxidation and dynamic manganese sand filtration for antimony removal showed that the combination of two technology exhibited a better removal effect on antimony compared with direct manganese sand filtration without Fenton reagent.It also significantly shortens the time of Fenton reaction.Under the same conditions,the appropriate addition of Fenton reagent in the water could effectively increase the water production of the filter column.