Synthesis Of Spinel/graphene Magnetic Adsorbents And Their Adsorption Properties

In recent years,the global water pollution is serious,especially the pollution oforganic dyes.In view of the organic dye waste water treatment,adsorption method is one of the relatively mature processing methods.But on one hand,adsorption requires adsorbent for nanoparticles with high specific surface area and the surface of the special performance;On the other hand,due to the nanoparticles size is too small,there may be a problem which is difficult to recycle,easy to cause the secondary pollution.In order to solve this problem,this subject adopts coprecipitation-reduction method,hydrothermal method,respectively,the preparation of the doped graphene with large specific surface area of composites MnFe₂O₄/GNS,CoFe₂O₄/GNS,and room-temperature magnetic nanoparticles MnFe₂O₄ spinel,CoFe₂O₄.Furthermore,using the magnetic field can quickly,efficiently and magnetically recycle.Mainly studied the synthesis conditions of different adsorbent,such as pH value,content of graphene,hydrothermal time and hydrothermal temperature,auxiliary agent content and so on,.Also,we do the experiment of adsorption of methylene blue solution,further discusses the synthetic conditions on the adsorbent.This paper uses coprecipitation-reduction method in the mixed solution of iron nitrate and manganese nitrate?cobalt nitrate?,with NaOH as precipitant,NaBH4 as a reducing agent,MnFe₂O₄/GNS?CoFe₂O₄/GNS?composite materials were synthesized under the condition of water bath.The effects of the ratio of raw materials,preparation of pH value on the influence of the morphologies and properties of the composites are studied.The mechanism of synthetic reaction is proposed.Explore their influence of rule on the adsorption properties of methylene blue and chanism.It is found that the adsorption properties for methylene blue of MnFe₂O₄/xGNS,CoFe₂O₄/xGNS increased with the concentration of GNS.But the enhancing rate slowed down.In addition,we discussed the synthesis conditions cause the influence on the adsorbent that when pH=11,the effect on adsorption is the best.To compare with,the CoFe₂O₄ magnetic nanoparticles were synthesized by the hydrothermal method in two ways.First,put ascorbic acid as reducing agent,urea as alkali source under specific temperature and reaction time,CoFe₂O₄ was synthesized and it has different shapes;Second,put sodium citrate as complexing agent,urea as alkali source,polyacrylamide as stabilizer.Hydrothermal temperature and time are adjusted for synthesizing CoFe₂O₄.Through the control variable method to discuss the performance of different variable factors on the CoFe₂O₄ adsorbent,the optimal route of composite adsorbent has been explored.