Study On Polyamine And Crown Ether-modified Cellulose-graft-polymer

Heavy metal pollution is a serious threat to the balance of the ecological system of nature, mainly in water, thus the removal and purification of heavy metal ions in water become a widely studied topic, modified Cellulose has become the ideal material for heavy metal adsorbent, Because of its low environmental toxicity, the good adsorption effect and no secondary pollution.Modified Cellulose adsorbents have been reported a lot. This research focuses on the preparation of a variety of modified Cellulose adsorbents, which are ethylene diamine-modified Cellulose (Cell-PGMA-EDA), tetraethylenepentamine-modified Cellulose (Cell-PGMA-TEPA), crown ethers-modified Cellulose (Cell-PGMA-EDA-CROWN), crown ether-modified Cellulose (Cell-PGMA-TEPA-CROWN), compare adsorbent properties reported, and explore different adsorption properties and adsorption mechanisms adsorbent by static and dynamic adsorption.In this study, four adsorbents were successfully obtained and characterized by FT-IR spectra,1H NMR spectra and TG/DTG analysis.Subsequently, the adsorption behavior of Cu(â…¡, Ni(â…¡) and Pb(â…¡) on four adsorbents in aqueous solution has been investigated. The results are as follows:By the investigation of the static adsorption, the adsorption equilibrium between Cu(â…¡), Ni(â…¡), Pb(â…¡) and every adsorbent could be established. The data agreed well with pseudo-second-order model based on the assumption that the rate-limiting step may be chemisorption involving valency through sharing electrons between adsorbent and heavy metallic cation. The adsorption processes of Cell-PGMA-EDA and Cell-PGMA-TEPA meet the quasi-first-order kinetic model, namely the adsorption process is controlled by the diffusion step.On the study of the dynamic adsorption, adsorbent Cell-PGMA-TEPA against Ni (â…¡) adsorption effect is very prominent, and the maximum adsorption capacity is141mg g-1, which is3.45times as it reported. While the two adsorbents modified by the crown ether against Cu (â…¡), Ni (â…¡), Pb (â…¡) adsorption capacity is poor. In this study, we synthesized polyamine-modified Cellulose adsorbents and crown ether-modified adsorbent. Through the study of the adsorption behavior and comparing with the previous works, we found that adsorption of heavy metals increased with the increase of the nitrogen content of amine functional groups, and the best adsorbent for different metal ions may need to be modified by different kinds of polyamine. Crown ether-modified adsorbent for Cu (â…¡), Ni (â…¡), Pb (â…¡) adsorption is less effective.