Chemical Modification of Bagasse-Based Mesoporous Carbons for Chromium(III) Ion Adsorption

AIMS: Modified bagasse-based mesoporous carbons were prepared for the efficient chromium(III) ion adsorption and removal from aqueous solutions. METHODS: Mesoporous carbons were prepared from bagasse with H3PO4 activation and subsequently oxidized with nitric acid and modified with ethylenediamine. RESULTS: The results showed that the modified carbon was rich in mesopores, oxygen and nitrogen-containing groups, and the Cr(III) adsorption capacity was greatly improved after modification, which was found to be higher than both pristine and oxidized carbons. The Cr(III) adsorption capacity on modified carbon was significantly influenced by the solution pH, and the optimum pH was 6 with the maximum Cr(III) adsorption capacity up to 24.61mg/g, which was almost 3 times higher than that for pristine carbon. Thermodynamic results manifested the adsorption was spontaneous and endothermic. Kinetic rates fitted the pseudo-second-order model very well. XPS study indicated the amino group was a key factor of the high efficient adsorption.