Study On Adsorption And Oxidation Characteristics Of Arsenic And Antimony On Layered Phyllomanganate Mn Oxide

The effects of?-MnO₂ on As?V?and Sb?V?removal were studied by adsorption kinetics and adsorption isotherm.At the same time,the influencing factors such as the equilibrium time,pH,dosage of adsorbent,humic acid and complexing agent were studied.In addition,the process of oxidation of As???and Sb???by?-MnO₂ was studied by oxidation kinetics experiment.The oxidation of?-Mn O₂ and the characterization of?-MnO₂ were studied.The results are as follows:?1?Adsorption experimentsIn the isotherm experiment,the adsorption of As?V?and Sb?V?in?-MnO₂ was much more than 480 min at 720 min,the adsorption effect was better,and the adsorption process was more consistent with the Freundlich model.The adsorption of As?V?and Sb?V?on?-Mn O₂ decreases with the increase of pH,and the adsorption effect is better in the neutral acidic environment,and it is lower in the alkaline environment.In the kinetic experiment,the effect of?-MnO₂ on As?V?removal was better than that of Sb?V?,and the effect was more obvious when the reaction reached equilibrium.The removal rate increases with the increase of the dosage,and the removal effect is the best when the dosage is 0.5g/L.The inhibitory effect of humic acid on the removal effect was more obvious,and the inhibitory effect was more obvious than that of the early reaction.Similarly,the addition of complexing agent on the removal effect also have a certain inhibitory effect,sodium citrate inhibition than EDTA more obvious.?2?Oxidation experimentWith the initial concentration of As?III?increased its oxidation rate gradually decreased.The oxidation rate of Sb?III?is similar to that of As?III?,but its oxidation rate is faster than that of As?III?.The results of XPS,FTIR and Raman spectroscopy showed that the oxidation of?-MnO₂ with As???resulted in no obvious structural change after the surface was passivated.After the oxidation reaction with Sb???,?-MnO₂ surface of the particle morphology and composition of the elements were significantly changed.The results show that the key factor affecting the oxidation rate of Sb???is not surface passivation.In addition,it is found that Mn???may oxidize Sb???in the same way as Mn???,and MnSb₂O₆ precipitates in the reaction.