Granular Activated Carbon Adsorption of 2-Methylisoborneol (MIB): Pilot- and Laboratory-Scale Evaluations

Pilot- and laboratory-scale granular activated carbon (GAC) studies were conducted to determine the extent of 2-methylisoborneol (MIB) removal from two conventionally treated waters. Two different GACs were evaluated, a wood-based carbon and a coal-based carbon. Greater MIB removal was observed with the wood-based GAC which contradicts previous studies using the powdered forms of the carbons. Equilibrium and kinetic parameters were derived from laboratory-scale adsorption isotherm and short bed adsorber (SBA) experiments, respectively, and used to describe the adsorption of MIB. However, the derived parameters were unable to accurately predict the removal of MIB in the pilot-scale columns using the homogenous surface diffusion model. This suggested that there were inherent limitations with the SBA experiments, in particular, the small volume of GAC and high filtration rates employed. Larger laboratory column experiments were shown to accurately simulate the pilot-scale columns. Adsorption still played a vital role in the removal of MIB, even though the GAC had been exhausted for the removal of organics in terms of dissolved organic carbon and ultraviolet absorbance measurements. Even after a 6-month operation, complete MIB removal was observed with up to 80% attributed to adsorption, and the remaining 20% attributed to biodegradation.