Abstract
The current study reports on the functionalization of Nerium oleander seed fibers (NOF) with Ethylene-Diamine (ED-NOF) and Hydrazine (HD-NOF) in order to improve their reactivity in regard with the adsorption of dyes. Fibers were characterized by FT-IR spectroscopy, elemental analysis and SEM features. The numbers of the coordinating sites per gram of each support, Ca (mmol·g−1), were 0.847 and 0.588mmol·g−1 for ED-NOF and HD-NOF, respectively. The change of the adsorbed amount of Acid Blue 161 (AB161) and Acid Red 183 (AR183) in batch system was investigated with respect to pH value, contact time, dye concentration and temperature. Maximum amounts of dye removal were achieved using ED-NOF as adsorbent and they were found to be 35mg·g−1 and 12.2mg·g−1, respectively, for AB161 and AR183. The adsorption process complies well with the pseudo first-order. The fitting of the data to the adsorption isotherms best follow the Freundlich model. The studied fibers are to be moderate for the removal of AB161 (1<n<2) and sometimes good sorbents for AR183 (n>2). The energy (E) values are, in the most cases, lower than 40kJmol−1, suggesting that the adsorption of AB161 and AR183 is physical one. The calculated adsorption energy constants (B) arranged well with the same trends observed for the effect of temperature.
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•Nerium oleander fibers were chemically modified with Ethylene-Diamine and Hydrazine.•The coordinating sites, Ca, were 0.847 and 0.588mmol·g−1 for ED-NOF and HD-NOF.•Adsorption of AB 161 and AR 183 was studied in batch mode.•Supports were moderate for AB161 (1<n<2) and good sorbents for AR183 (n>2).