Preparation Of Magnetic Manganese Ferrite-based Composite Material And Their Adsorption Properties

Humic acid is widely used in the field of environment with adsorption,ion exchange and complexation properties,because of its molecule contain hydroxyl,carboxyl,carbonyl and other active groups.Activated carbon is broadly used as adsorption material,which has the character of developed pore structure,large specific surface and adsorption capacity,wide raw material sources and easy to composite with other materials.Moreover,as an adsorbent,it has the advantage of small secondary pollution,low density and low toxicity.However,pure humic acid and activated carbon as adsorbent material has certain limitations.These two kinds of materials have good dispersion in aqueous solution,but It is difficult to enrichment and separation after adsorption and increase the cost of recycling,improper use may cause secondary pollution,which limits its applications.Herein,MnFe₂O₄ was synthesized by chemical coprecipitation instead of traditional magnetic carrier Fe3O4,which effectively avoid oxidation problem of Fe???in the process of synthesis of Fe3O4,and does not need the protection of inert gas,simplify the synthesis condition,and ensures composite adsorbent has enough ferromagnetic.Humic acid or activated carbon coated or loaded with MnFe₂O₄ and synthesis a ferromagnetic composite adsorbent gives the adsorbent ferromagnetism,and makes the separation,recovery,regeneration of adsorbent become simply.This paper mainly studied the preparation of MnFe₂O₄ and humic acid,activated carbon composite material and its adsorption and regeneration performance of water pollutants.The main contents of this paper are summarized as the follows:?1?Fulvic acid coated with manganese ferrite composites?MnFe₂O₄/FA?were synthesized by chemical coprecipitation.The particle size of this composites was about 3 micron and fulvic acid content is 7%.The pHPZC of MnFe₂O₄/FA reduced to 3.12 because of FA molecule contains a large number of carboxyl that makes MnFe₂O₄/FA can use in a wide p H range.We studied the adsorption properties of C u???and Pb???systematically.It was found that the adsorbent can be separated from solution within two minutes in the low magnetic field.We investigated the influence of time,temperature and p H to the adsorption capacity.By analysis,the adsorption process conforms to pseudo-second order kinetic equation,and was about 1 h to achieve balance,so it accord with Langmuir adsorption model well.MnFe₂O₄/FA for Cu???and Pb???maximum adsorption capacity were 48.78 mg/g and 42.02 mg/g when on the room temperature and pH=7.Finally,we discussed the adsorption mechanism of MnFe₂O₄/FA for Cu???and Pb???.?2?Humic acid coated with manganese ferrite composite materials?MnFe₂O₄/HA?was synthesized by chemical coprecipitation using humic acid sodium as raw materials.The diameter of MnFe₂O₄/HA particle was about 200 nm and humic acid content was 8.94%.The BET specific surface area of MnFe₂O₄ and MnFe₂O₄/HA was 124.62m²/g and 87.95 m²/g,respectively.The saturation magnetization intensity of MnFe₂O₄ and MnFe₂O₄/HA were 41.15emu/g and 34.01emu/g.The BET specific surface area and saturation magnetization intensity of MnFe₂O₄/HA were decreased after coated HA.The equilibrium adsorption quantity rapid increases with p H value increase at the range of pH=?3-7?,while there was no much change when pH>7.The adsorption process was in keeping with pseudo-second order kinetic process from isothermal adsorption analysis,and reach adsorption equilibrium after 2h,which in line with the Langmuir adsorption model.The maximum optimal quantity was 29.94mg/g under the condition of room temperature and pH = 9.0.MnFe₂O₄/HA has good selective adsorption ability for methylene blue?MB?in the methylene blue?MB?and methyl orange?MO?mixed solution;MnFe₂O₄/HA still has a higher adsorptio n capacity in methanol and acetic acid eluent after elution regeneration six times.It indicates that MnFe₂O₄/HA has preferable performance of recycling.?3?Activated carbon loaded with manganese ferrite magnetic composite material?AC/MnFe₂O₄?was synthesized by chemical coprecipitation.The diameter of AC/MnFe₂O₄ particle was about dozens of micron and activated carbon content was 41.15%.AC/MnFe₂O₄ has an excellent adsorption in MB,MO and rhodamine B?RhB?these three types dye.The adsorption of AC/MnFe₂O₄ to MB and MO was not affected by the pH value of solution.Therefore,it has good adsorption ability in the range of pH=?3-9?.The adsorption quantity of RhB along with the increase of solution p H has a certain reduce because RhB in aqueous solution has different kinds of charge with the change of pH value,but it still keeps a good adsorption capacity.The maximum adsorption of AC/MnFe₂O₄ to MB,MO and RhB dye was 49.75 mg/g,39.68 mg/g and 36.76 mg/g,respectively.In addition,AC/MnFe₂O₄ can effectively remove MB,MO and RhB from dye wastewater.?4?We used activated carbon loaded manganese ferrite magnetic composite material?AC/MnFe₂O₄?as adsorbent and studied AC /MnFe₂O₄ adsorption performance of sulfanilamide antibiotics drugs systematically.The adsorption of AC /MnFe₂O₄ to sulfonamide?SA?was strongly influenced by the solution p H value,the adsorption quantity reduced with the increase of p H gradually,and it has well adsorption capacity under the condition of p H=?3-5?;What's more,the adsorption of AC/MnFe₂O₄ to sulfonamide?SA?was pseudo-second order kinetic process under the condition of room temperature and p H=6,conformed to the Langmuir isotherm adsorption model better,the calculated maximum adsorption capacity was 17.30 mg/g;The adsorption of AC/MnFe₂O₄to sulfonamide?SA?was gradually reduced with the increase of cycling times.