Study On Preparation Of Esterified Magnetic Chitosan And Its Adsorption To Heavy Metals

For the environment,heavy metals have become a major pollutant,and they have a significant impact on ecological quality.As a fast,convenient and environmentally friendly water treatment method,the adsorption method is used as the main process for wastewater treatment in many countries.There are a large number of amino groups and carboxyl groups in chitosan?CS?.These functional groups are easy to chelate with heavy metal ions,making them a good adsorption material.However,there are many shortcomings in the adsorption process of chitosan.In view of the shortcomings of low adsorption capacity of chitosan,easy to be decomposed under acidic conditions and difficult solid-liquid separation,this article selected aspartic acid?ASP?and hydroxyethylethylenediamine triacetic acid?HEDTA?to modify chitosan A new type of adsorbent is prepared in a versatile manner.After modification,the number of amino groups and carboxyl groups in the adsorbent is increased,and then the magnetic material is connected to make it easy to separate and recover after adsorbing heavy metals,and the ideal adsorption and separation effect is obtained.After that,the adsorption conditions and adsorption mechanism were thoroughly studied.details as follows:It introduces the environmental hazards of heavy metals,explores the relevant properties of CS and the physical and chemical modification based on CS,and briefly introduces the basis for selecting topics.The modification conditions and preparation process of chitosan are described,the instruments and methods used in the preparation and characterization are introduced,and the formula used to calculate the adsorption amount under different adsorption conditions is also introduced.This paper mainly introduces the modification of chitosan by HEDTA.By connecting ferric oxide to make it magnetic,it can be quickly separated.The hydroxyethylethylenediamine triacetic acid modified magnetic chitosan?HEDTA-CS/Fe3O4?was prepared.The new adsorbent was characterized by X-ray diffraction,infrared spectroscopy,thermogravimetric analysis and other methods,and the morphological characteristics were analyzed by scanning electron microscopy.The influencing factors of HEDTA-CS/Fe₃O₄ adsorption of Cu²⁺and Cd²⁺ions were explored,and the adsorption mechanism was analyzed.Finally,the adsorption effects of HEDTA-CS/Fe₃O₄ on Cd²⁺and Cu²⁺under optimal conditions were compared.Chitosan was modified by ASP,and then Fe₃O₄ was connected to the product to obtain aspartic acid-modified magnetic chitosan?ASP-CS/Fe₃O₄?.It was characterized by infrared spectroscopy,X-ray diffraction,thermogravimetric analysis and other methods,and its morphological characteristics were analyzed by scanning electron microscopy.By changing the influencing factors of the adsorption process,ASP-CS/Fe₃O₄ was used to explore the adsorption of Cu²⁺and Cd²⁺ions,and the mechanism of adsorption was discussed and discussed.After that,the adsorption effect of ASP-CS/Fe₃O₄ on Cd²⁺and Cu²⁺under optimal conditions,and the adsorption effect of ASP-CS/Fe₃O₄ and HEDTA-CS/Fe₃O₄ on Cd²⁺were compared.