Removal of organic pollutants from water by modified cellulose fibres

Different modified cellulose fibers were prepared and their efficiency as adsorbent for the removal of several aromatic organic compounds and three herbicides, i.e.: Alachlor (ACH), Linuron (LNR) and Atrazine (ATR), was investigated. The evolution of the adsorption capacity according to the solute structure and the modification sequence was explored. The modification was carried on under heterogeneous conditions using N,N'-carbonyldiimidazole (CDI) as an activator and different amino derivatives as grafting agent. By varying the structure of the amino derivative and the reaction sequence, different organic structures bearing diverse functional groups were generated on the surface. Evidence for the Occurrence of the surface modification was confirmed by FTIR, XPS and solid-state C-13 NMR spectroscopy. It was shown that the chemical modification of the fibers' surface greatly enhanced the adsorption capacity toward organic compound dissolved in water. The adsorption capacity evolved from 20 to 50 mu mol g(-1) for the virgin fibers to between 400 and 1000 mu mol g(-1) for the modified substrates, depending on the solute structure and the modification sequence. The efficiency of the retention property under a continuous regime was also confirmed by using a column filled with the modified fibres. Once exhausted, the column could be reused by washing its contents with ethanol, which totally extracted the trapped compounds. The regenerated column was then used in several adsorption-desorption cycles without any loss of the capacity. (c) 2009 Elsevier B.V. All rights reserved.