Glutamic acid modified chitosan adsorbent as well as preparation method and application thereof

Abstract

The invention relates to a glutamic acid modified chitosan adsorbent as well as a preparation method and application thereof. The preparation method comprises the following steps: dissolving chitosan into an acetic acid solution, adding tetraethoxysilane (TEOS), carrying out stirring for 30 to 40 min, adding aqueous ammonia, carrying out stirring for 24 to 26 hours, carrying out suction filtering, washing with ethyl alcohol till the mixture is neutral, and carrying out vacuum drying to obtain CS-SiO2; mixing CS-SiO2 with the ethyl alcohol aqueous solution, adding epoxy chloropropane, carrying out refluxing at the temperature of 70 DEG C for 3 hours to obtain a product, cooling and filtering the product, washing the product with water and the ethyl alcohol, and drying the washed product to obtain an intermediate product I; and dissolving glutamic acid into a sodium carbonate solution, adding the intermediate product I, carrying out refluxing at the temperature of 80 DEG C for 24 hours to obtain a product, cooling and filtering the product, washing with distilled water till the product is neutral, and carrying out drying to obtain SiO2-CS-Glu. The adsorbent prepared based on the preparation method goes green, is environment-friendly, pollution-free and high in separation and enrichment efficiency, can avoid waste of rare earth resources, and is also applicable to selectively adsorbing scandium from a solution mixed with rare earth ions.

Description

technical field [0001] The invention belongs to the technical field of preparation of green adsorbent and extraction of rare earth metals, and in particular relates to preparation of a glutamic acid-modified chitosan adsorbent and a method for enriching rare earth ions from a low-concentration rare earth solution. Background technique [0002] Rare earth elements (REs) refer to group IIIB in the periodic table of elements, scandium (Sc) with atomic number 21, yttrium (Y) with 39, and lanthanide elements with 57 lanthanum (La)-71 lutetium (Lu), a total of ten seven elements. With the development of scientific research and technology, the application scope of rare earth elements in various functional materials has been continuously expanded, and it has gradually become the main supporting material for high-tech research and technology fields such as new energy, biology and information new materials. Since the 1990s, the rare earth industry has developed rapidly. With the str...

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Problems solved by technology

At present, the commonly used extraction agents in the rare earth industry in my country mainly include neutral TBP, P305, Cyanex923 and acidic extraction agent P507. These extraction agents are widely used in the rare earth industry, but they also have some shortcomings: TBP’s effect on metal ions The extraction distribution ratio is relatively low, and it usually needs to be extracted under the condition of strong acid and salting-out agent; although P305 has a high extraction rate and a large separation factor, but P305 contains a large amount of reducing impurities that are not easy to eliminate, and Its synthesis cost is high, which limits its application to a certain extent; Cyanex923 is difficult to synthesize and its price is high, which hinders the pace of its industrial application; acidic extractant P507 has high acidity in the stripping of heavy rare earth elements, and it is difficult to strip completely , it takes a long time for the extraction to reach equilibrium, and more ammonia nitrogen wastewater is produced after saponification, causing environmental pollution

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