Adsorption of Cr(III) and Cr(VI) ions from aqueous solutions on to modified lignin

The aim for this research is to study inexpensive and effective metal ion adsorbents from biomass sources of modified lignin to offer these adsorbents as replacements for existing commercial materials. The Cr(III) and Cr(VI) binding properties of modified lignin from wood sawdust were studied. The maximum amounts of adsorption are 9.3 and 25.0 mg/g lignin for Cr(VI) and Cr(III) ions for 240 min at 290 K, respectively. As the pH of the solution increases from 2.0 to 6.0, Cr(III) ions show an increase in adsorption to the lignin with optimum adsorption occurring between pH 4.5 and 5.5. The maximum adsorption percentage is 39.5 for Cr(VI) for 240 min at 330 K, and is 67.8 for Cr(III) for 240 min at 330 K.