Study On Adsorption Characteristics And Mechanism Of Modified Ferromanganese Compound Oxide On Arsenic

In recent years,arsenic pollution has always been a hot topic of concern and research.Adsorption method is widely used because of its high efficiency in removing arsenic from water.Therefore,it is the key to arsenic removal to prepare novel and efficient adsorption materials.In this experiment,a co-precipitation method was used to prepare iron-manganese composite metal oxides,which were modified with sulfite,manganese,and copper ions.Through dynamic experiments on modified adsorbents and characterization of adsorbent materials,The adsorption performance and reaction mechanism of arsenic after the modified adsorbent were selected to select a more efficient new adsorbent.The results and conclusions of the completed experiments are as follows:（1）The results of kinetic experiments show that the adsorption effect of ferromanganese compound oxides after Cu²⁺,Mn²⁺ and SO₃^2-modification has significantly increased.The relationship between its adsorption effect on total arsenic is expressed as:FMBO-C>FMBO-S>FMBO-M>FMBO.All four adsorbents can be well fitted using the quasi-second-order kinetic model and the Elovich model.（2）The adsorption of As by FMBO,FMBO-Cu,FMBO-S,and FMBO-M adsorbents is jointly controlled by membrane diffusion and intragranular diffusion,while intragranular diffusion is mainly mesoporous diffusion.During the long-term adsorption process,Arsenic diffusion in mesoporous is the main factor controlling the adsorption rate of modified FMBO.The adsorption rate of the modified FMBO adsorbent was significantly higher than that of FMBO.（3）The amount of copper ion added affects the adsorption effect of FMBO-Cu on arsenic.With the increase of copper ion added,the adsorption effect of total arsenic decreased.The adsorption of arsenic by FMBO,FMBO-Cu（3:1:0.33）,FMBO-Cu（3:1:3）and FMBO-Cu（3:1:1）adsorbents is jointly controlled by intra-particle diffusion and boundary layer diffusion.And...Among them,FMBO-Cu（3:1:0.33）has the fastest adsorption rate for arsenic.（4）Through XRD,BET,Zeta potential,thermogravimetry,infrared,and transmission electron microscopy,the physicochemical analysis of the surface morphology,composition,crystal form,and bond status of the adsorbent was performed.The FMBO modified adsorbent has a rough surface and a rich pore structure and has a large specific surface area.The infrared spectrum shows that the sorbent surface is rich in hydroxyl groups.（5）By comparing the results of SEM-Mapping and XPS before and after adsorption,the adsorption of As on the surface of the adsorbent mainly takes place through the substitution reactions between the contaminants and hydroxyl groups on the surface of the adsorbent.The adsorption of As on the surface of the material was confirmed by the vibration of the surface hydroxyl and the appearance of the corresponding elemental spectra.