Concentrated nitric acid was diluted with deionized water to create a 1.0 M HNO3 solution. In a 500 mL Erlenmeyer flask, 5.0 g of biochar was combined with 100 mL of a 1 M nitric acid solution . To prevent boil over, aluminum foil was placed over the flask before it was autoclaved for 60 minutes at 132°C and 35 pressure. The combination was filtered, then rinsed with filtered water until the pH of the rinsing water reached 6-7. The mixture was then allowed to cool to about 60 C. The functionalized biochar was then dried for 24 hours at 75 degrees Celsius in an stove and maintained in a desiccator for testing .