Chemistry Weekly Seminar - Dr. Stephanie MacQuarrie

Title:

Reaping Unsown Rewards from Biochar

Low energy pyrolysis generates a solid by-product called bio-char (often < 40% yield). Currently bio-char is used as a low value soil amendment. The MacQuarrie research program investigates higher value use of bio-char providing incentive for moving towards a more sustainable model for energy production. Biochar produced through a low temperature (~400 ºC) pyrolysis of forestry waste, has been fully characterized and assessed for its metal ion adsorption capacity and compared to conventional commercially available wood-derived Norit activated carbon (NoritTM CA1 from wood). The biochar exhibited a substantially lower surface area than the activated carbon, 259 vs. 1323 m2 g-1, but displayed superior adsorption capacity for all tested metal ions. The adsorption kinetics, leaching, and recyclability of the biocarbon were examined. The binding behaviour was determined using X-ray photoelectron spectroscopy which revealed that strongly bound metal ions formed insoluble oxides in the material while less strongly bound ions were adsorbed as carboxylate chelates. The retention of endogenous surface groups greatly facilitates the adsorption of metal ions from solution, which makes this material greener, less expensive, and more effective for these particular applications. Recent endeavours include organic functionalization of biochar to generate chiral materials.