Preparation Of Multifunctional Chitosan Material And Absorbent Performance Study Of Re(?) And Ga(?)

In order to improve the biomass wastes to scare metal ions adsorption selectivity and adsorption capacity,this article takes the straw and crab shell as raw material,and the corresponding functional method and ion imprinting technique were used to prepare a series of adsorbent,and then the separation and adsorb of Re???and Ga???in aqueous solution respectively the results of the study summarized as follows:The twin material composite materials adsorbents were synthesized based on the crab shell of deacetylation?CS?and carbonize corn stalk?OCS?,and then were modified by methyl imidazole,which named N-CSOS.Results indicated the acidity in the whole range,the N-CSOS adsorption performance is the best.The N-CSOS showed a better selectivity for Re???under the condition of Cu?II??Fe????Zn?II??Mn?II?coexist.It could be observed that the maximum adsorption capacity could reach 252.15 mg·g^-1 at pH 3.The analysismechanism of XPS and FTIR confirmed that the high adsorption selectivity of anion exchange reaction ofCl-and ReO₄^-in the solution,in addition,the infrared proved that chelation has happened between C=N and ReO₄^-.In order to improve the adsorption ability of Re???,combining biomass and ion imprinting technology prepared a kind of anionic imprinting/amino functional chitosan adsorbent that the template of ammonium molybdate and ethylenediamine as the functional monomer,epichlorohydrin as crosslinking agent,which was named I-EDA-CS.Results showed thatquality ratio of the ammonium molybdate and chitosan as 1 g: 25 g 3 g: 25 g to achieve higher adsorption capacity of Re???.The maximum adsorption capacity of Re???can be up to 418.98 mg·g^-1,and much higher than not imprinted adsorbent?N-EDA-CS?for Re???.What is more important,higher than reports of commercial resin for Re???adsorption in recent years,proved that the adsorbent I-EDA-CS has the absolute advantagein for Re???of aqueous solution.The analysis results of FT-IR and XPS confirmed that the high adsorption selectivity of the I-EDA-CS attributed to the electrostatic attractionbetween R-NH₃⁺ and ReO₄^-,in addition,chelation between the+N-C-C-N and Re???anionic complexes in the “cavities”.In order to further explore high adsorption capacity and high selectivity of ion imprinting technique.Cation imprinted acrylic functional chitosan polymer?Ga???-AA-CS?was synthesized by Ga???as a template ion,acrylic acid as functional monomer,glutaraldehyde as crosslinking agent.The template ion concentration is determined of 50 mg·L^-1,which had a better adsorption effect.In different acidity of Ga???/Si?IV?,Ga???/Ge???,Ga???/Al???and Ga???/Zn?II?coexistence binary system,theadsorption selectivity of Ga???-AA-CS to Ga???was better than the adsorption effect of AA-CS.FT-IR,SEM and XPS analysis that the adsorption mechanism could be expressed by cation exchange between protonation amino of chitosan and Ga?OH?²⁺/Ga?OH?²⁺.