| As a metal-like element,arsenic(As)is widely distributed in the earth’s crust.It is a recognized highly carcinogenic substance.How to quickly and effectively remove arsenic in water has been a hot spot for researchers for a long time.The method proposed in this paper treats arsenic-containing wastewater.Its advantages are not only in the few types of dosing agents,low operating costs,and convenient operation.More importantly,it can promote higher precipitation efficiency and more stable wastewater discharge.Applications in the field of arsenic removal provide some reference.In this paper,the process of oxidizing and adsorbing arsenic-containing pollutants in Fe(III)-S(IV)system was studied,and p-aminophenyl arsenic acid(ASA)and sodium arsenite were used as the targets,and the initial system was prepared and optimized.Conditions(including p H,dissolved oxygen,concentration of Fe(III),S(IV),etc.).At the same time,the free radical trap was used to analyze the types of free radicals generated during the experiment,the mechanism of the oxidation process was analyzed,the oxidation path of inorganic arsenic and organic arsenic ASA was explored,the arsenic removal effect of the system in natural water and the The degradation of other common pollutants verified the practicability of the system.The SEM image shows that the new ecological iron is an amorphous nano-sized particle with excellent adsorption capacity.After As(V)is adsorbed,a stable composite can be formed.Through XPS spectrum,it was found that the valence state of As species on the surface of the adsorbent material after adsorption of pollutants is mainly +5 valence,and the valence state of Fe species is mainly +3 valence.The Fe component in the new ecological adsorption material in the system is in As(V)plays a key role in the adsorption process,there is a strong interaction between As(V)and Fe components.The free radical capture experiment analyzes the oxidation mechanism of the Fe(Ⅲ)-S(Ⅳ)system,analyzes the substances in the system that play an oxidizing role,and draws the oxidation mechanism diagram.The path of Fe(Ⅲ)-S(Ⅳ)system degradation of ASA was explored,and the intermediate products in the oxidation path of organic arsenic were analyzed.In the reaction system,ASA is first oxidized to p-aminophenol,arsenic is detached from the benzene ring,and becomes arsenite / arsenite form,and then oxidized to +5 valence arsenate / arsenate form and exists stably;Phenol continues to be oxidized into hydroquinone and p-benzoquinone,and the two maintain a certain dynamic balance.Part of the benzene ring structure of p-benzoquinone will be oxidized by free radicals to open the ring to form small molecular organics,which will be further oxidized to CO2 and mineralized.At the same time,experiments have confirmed that the system not only has a good oxidation effect on organic arsenic and trivalent arsenic,but also has an oxidation effect on other common organic substances.The practical application of the system in natural water bodies was explored.The filtered Songhua River water was used as the mother liquor to explore the arsenic-removing effect of the system under the natural background. |
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