Studies of chromium (VI) adsorption in Eucalyptus grandis bark

Eucalyptus spp. are the most important fiber sources for pulp and paper industries; however, substantial amounts of biomass residues are generated, among which bark is the most abundant and is currently simply burned to produce energy. Chromium (VI) is a toxic metal and there is a great concern of researchers in removing this metal from aquatic environments. In this work, we report the use of Eucalyptus barks to remove chromium (VI) of synthetic effluent. The barks were dried soon after collection and pulverized in a mill, and then stored. This material was treated according to Sarin and Pant work [1]. The adsorption test was performed by adding 75mL of synthetic effluent ( 6.83.10-4M K2Cr2O7) to 375mg of treated Eucalyptus bark and the mixture was heated to 32oC for 180 min. Every 30 minutes, 6mL of this solution was filtered and the UV-Vis spectrum of the filtrate was obtained. The MEV image of Eucalyptus bark in figure 1a shows that it is lamellar and porous material. The blue points in the figure 1b show that chromium (VI) was adsorbed on the bark surface. UV Vis analysis of the filtrate determined the concentration of chromium remaining in solution, and the calculated percentage of removal was 42%.