Study of adsorption reduction behavior of Ag(Ⅰ)on cured tannin cellulose-based aerogels
A valonea tannin-immobilized cellulose-based aerogel(VTCA)was prepared by introducing valonea tannin into cellulose through crosslinking reaction in the of NaOH/urea/H2O solvent system.The structure and property of VTCA was characterized by SEM-EDS,FT-IR,XRD,etc.,and the adsorption behavior for Ag(Ⅰ)in aqueous solution was also investigated.The results showed that the three-dimensional VTCA displayed obvious porous structure with a porosity of 97.95％,and exhibited good adsorption efficiency(＞75％)for Ag(Ⅰ)under a wide pH range(18).The Ag(Ⅰ)adsorption process obeyed the pseudo-second-order kinetic model and the Langmuir adsorption isotherm model.High temperature was favorable for adsorption,and the maximum theoretical adsorption capacity was 147.2mg/g.The mechanism of Ag(Ⅰ)adsorption involved two process:Ag(Ⅰ)was firstly adsorbed onto the surface of VTCA through the electrostatic attraction and chelation effects,and then in situ reduced to Ag0 by the phenolic hydroxyl group on the tannin structure.All the results revealed that VTCA owned good adsorption and reduction performance and could achieve the recycling of Ag(Ⅰ)in water.
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