Preparation Of Fe₃O₄/Mg?OH?₂ Magnetic Composites And Its Remove Property On Copper Ions In Aqueous Solution

With the rapid development of industrial technology,more and more industrial wastewater containing heavy metal ions is discharged into the environment,and the rich magnesium resources in our country is often exported or applied only to low-end products,these problems need to be solved urgently.In this paper,the magnetic nanoparticles of four ferric oxide?Fe₃O₄?were prepared by solvent-thermal method and the Fe₃O₄/Mg?OH?₂ magnetic composites were prepared by seed deposition method.By using the corresponding characterization test method,the properties of the synthesized materials were characterized and analyzed,and some morphological factors of Fe₃O₄ and Fe₃O₄/Mg?OH?₂ magnetic composites were studied.Finally,the adsorption properties of Fe₃O₄/Mg?OH?₂ magnetic composite as remove agent on the copper-containing ion(Cu²⁺)aqueous solution were studied.The 150-350 nm size uniformity,fine appearance regularity and excellent magnetic properties were prepared by solvent-thermal method for four iron oxide particles.The effects of reaction time,molecular weight of polyethylene glycol and polyethylene glycol on the morphology of ferroferric oxide were studied.When the solvent heat reaction time reaches 4 h,the Fe₃O₄ phase is not produced.When the reaction time is 8 h,the Fe₃O₄ nanoparticles with no impurity peaks can be obtained.The addition of polyethylene glycol will affect the size of nanocrystalline and nano-spheres,when polyethylene glycol increases from 0 g to 0.35 g,the size of nano-crystalline particles becomes smaller and the size of the nanoparticles becomes larger.The molecular weight of polyethylene glycol has little effect on its morphology.A new type of flower-like magnetic composite Fe₃O₄/Mg?OH?₂ was prepared by seed deposition method.XRD,SEM,TEM,HRTEM,SAED,VSM and so on were mainly tested and analyzed.The effects of ammonia concentration,stirring speed and alkali velocity on the morphology of the composites were investigated.The iron oxide particles can be uniformly dispersed in the flower-like magnesium hydroxide matrix,the size of the composite is distributed in 3-6?m,and the specific surface area is35.641 m²·g^-1.The saturated magnetic strength of the composite was 4.2 emu g^-1 by VSM test.The flower-like magnesium hydroxide matrix in the magnetic composite is a single crystal structure.The decrease of ammonia concentration and the decrease of ammonia injection rate have the same effect on the morphology matrix of magnesium hydroxide.The reunion of samples can be improved slightly by adjusting the stirring speed,but the reunion is still very serious.The Fe₃O₄/Mg?OH?₂ composite material prepared in the third chapter is used as remove agent to study the removal of acticvated aqueous solution.The effects of magnetic composite on the removal rate of initial solution pH,contact time,initial solution concentration and removal mechanism were mainly studied.At the same time,magnetic recovery of magnetic composite materials after removal of Cu²⁺aqueous solution was also explored.When the initial Cu²⁺aqueous solution pH is chosen at pH=4,the removal rate of magnetic composite material to copper ion is the highest,which is 92.3%.When the magnetic composite material is removed for Cu²⁺for 480minutes,the Cu²⁺content in the aqueous solution would not decrease with time.The maximum removal amount of magnetic composite material for Cu²⁺solution with initial concentration of 578.4 to 1170 mg/L^-1 is 1474 mg g^-1.Through the study of the removal mechanism,it is found that the removal process may include both the adsorption process and the precipitation transformation process,and the precipitation transformation is likely to occur on the surface of the composite and the adsorption based precipitation transformation.Composite materials in the external magnetic field can be gathered in a piece and then recycled.