The Synthesis And Application Of Acid Resistant Magnetic Adsorbent

As a hot topic in the field of the adsorbent,Magnetic adsorbent who has the advantages of continuous automatic operation,high removal efficiency and selectivity,facile in solid-liquid separation has been widely used in purification and enrichment of metal ions.Electrolytes of copper electro-refining contain a small amount of antimony,bismuth and iron which will seriously affect the appearance and quality of the product need to be puriied in the industry.On the one hand,although the magnetic solid adsorbent has obvious advantages in the field of metal ion purification,the traditional magnetic adsorbent has its limit in acid resistance.On the other hand,the electrolyte is a solution of copper sulfate and sulfuric acid whose nominal composition is 40-45 g/L copper and 180-200 g/L sulfuric acid.Therefore,the traditional magnetic adsorbent can not be used for purifying copper electrolyte,and the development of acid resistant magnetic adsorbent is imperative.Based on the above background and from the perspective of structure-function,we couple the structure of traditiona solid adsorbent and acid-resistant magnetic particles prepareing a novel acid-resistant magnetic adsorbent with a strong acid-resistant magnetic core and the property in adsorption of traditional adsorbent.On the basis of conventional sol-gel method,the silane coupling agent(Dimethyl diethoxysilane)with hydrophobic groups is combined with tetraethylortho silicate.By the controlling of the reaction conditions,we succefully couple the hydrophobic layer to the coating of magnetic particles.Then,we graft functional groups in the surface of the particles or package copolymer(methacrylate-divinyl benzene)by suspension polymerization before grafting functional groups which result in the two kinds of acid-resistant adsorbent for the purification of copper electrolyte.The details are shown as follow:1.Study in synthesis and adsorption of amino-methylene-phosphonic based acid-resistant magnetic adsorbentAfter coating a silicon oxide layer to the hydrophobic layer by the sol-gel method,the particles were coated with(3-aminopropyl)triethoxysilane and then graft functional groups(amino-methylene-phosphonic).The acid resistance of amino-phosphate based magnetic adsorbent was tested and characterized.The results show that the adsorbent can withstand the corrosion of lmol/L hydrochloric acid and 2.5mol/L sulfate.The adsorption of Sb(?)from 2.5 mol/L sulfuric acid solution needed four hours to reach equilibrium.The adsorption isotherm experiments show that the adsorption of antimony to the adsorbent conforms to the Langmuir adsorption model.The acid-resistant magnetic adsorbent selectively removed Sb(?)from cupric sulfate solution with 2.5 mol/L sulfuric acid with the result of selective adsorption test.The elution and regeneration of adsorbent were achieved by using lmol/L hydrochloric acid and lmol/L phosphoric acid as eluent.2.Study in synthesis and adsorption of hydroxy-pyridyl-ketone based acid-resistant magnetic adsorbentReferring to the existing polymer coating technology of magnetic particle,we coat a layer of organic polymer methyl acrylate-divinyl benzene by suspension polymerization.Another kind of acid resistant magnetic adsorbent,which can adsorb Fe(?)in strong acid solution is obtained by modifying and grafting functional group hydroxyl pyridine ketone with poly ethylene polyamine.Compared with amino phosphate based magnetic adsorbent,the adsorbent obtained higher acid resistance which can withstand the erosion of 2mol/L hydrochloric acid and 2.5mol/L sulfuric acid.The adsorption of Fe(?)from 2.5 mol/L sulfuric acid solution needed one hours to reach equilibrium.The adsorption isotherm experiments show that the adsorption of iron to the adsorbent conforms to the Freundich adsorption model.The acid-resistant magnetic adsorbent selectively removed Fe(?)from cupric sulfate solution with 2.5 mol/L sulfuric acid with the result of selective adsorption test.The elution and regeneration of adsorbent were achieved by using 1.5mol/L hydrochloric acid as eluent.