Surface modified leaves with high efficiency for the removal of aqueous Cr (VI)

The pollution of chromium wastewater is becoming more and more serious. Biological adsorption of hexavalent chromium (Cr (VI)) is an effective waste water treatment technology. In this work, non-treated leaves (NL), sulfuric acid modified leaves (SL), and hexadecyl trimethyl ammonium bromide (CTAB) modified leaves (CL) were used to remove Cr (VI) from the water. Indeed, leaves are highly effective and low-cost biosorbents, and were proven to achieve a recovery of resources from waste. In the batch experiments, the adsorption of Cr (VI) onto SL and CL was shown to be influenced by several factors, including the initial pH of the solution, the adsorbent dosage, and temperature. The X-ray Photoelectron Spectroscopy (XPS) results suggest that the reduction of Cr (VI) to the less harmful trivalent chromate Cr (III) occurred during the adsorption processes; this was followed by Cr (III) adsorption onto the surface of the adsorbents. The maximum adsorption capacities obtained for Cr (VI) at 35 degrees C were 170.8 and 137.9 mg/g for SL and CL at pH 2, respectively. The results show that SL and CL, as cheap and effective biosorbents of Cr (VI), realized the recycling of wastes and have good application prospects.