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Preparation, characterization, and utilization of cationized hemp as anion exchanger for removing permanganates and dichromate anions



Using a software experimental design strategy and through 25 experiments, steam exploded hemp bast fibers (HBF) as well as their shives were cationized by the exhaustion method using 3-chloro-2-hydroxypropyl trimethyl ammonium chloride solution. The results obtained revealed that at pH 13, raising the temperature of a bath containing 100 g/L cationizing agent aqueous solution at liquor to substrate ratio 1/15 to 80°C for 90 min produces the cationized forms of HBFs as well as their shives with percent nitrogen content 0.2240 and 0.4893 respectively. The statistical analysis for the results indicated that the percent nitrogen content is significantly influenced by factors of time, pH, and primarily the cationizing agent concentration. The cationized forms of HBFs as well as their shives, having amino contents 76 and 104 mequiv/100 g respectively, were characterized by studying their potentiometric titration and were analyzed by thermogravimetric analysis. Both of these cationized substrates were utilized as anion exchangers for adsorption of permanganate and dichromate anions from their acidic aqueous solutions. Adsorption dynamics of the removal of such anions were first-order reactions whereas the adsorption isotherms showed that the adsorption of those anions on all the aforementioned anion exchangers was favorable. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007