LAUSR

Abstract This research aimed to recover oat hulls as activated carbon, using the produced adsorbent to remove the organic matter removal from landfill leachate. The organic matter content in leachate was determined by measurements of chemical oxygen demand (COD) and color. In addition, the maximum adsorptive capacities associated with the adsorbents were also determined. Adsorption batch tests were initially performed with synthetic leachate, and variables such as pH, activated carbon dose, temperature and contact time were evaluated. The effectiveness of the adsorbents was also verified for real landfill leachate. Oat hulls samples were chemically activated with phosphoric acid (impregnation ratios, 60 and 100 %) and pyrolyzed (N2 atmosphere) at 350 and 500 °C. The 100% impregnation ratio resulted in adsorbents with higher surface areas (1090–3880 m2  g−1) rather than the ratio 60 % (123–731 m2  g−1). It was found that the organic matter removal from synthetic leachate was favored by performing the adsorption tests at 20 °C, pH 4, and using a 20-g L−1 activated carbon dose. Under these experimental conditions, the activated carbon sample impregnated at 100% with phosphoric acid and pyrolyzed at 500 °C completely removed the color from leachate, and COD removal was up to 90%. Therefore, oat hulls comprise a suitable precursor for activated carbon, and its application for leachate treatment should be encouraged.