Restoring PFAS-Laden GAC With Innovative Solvent-Based Method

Granular activated carbon adsorption and regeneration is used successfully for the treatment of wastewater contaminated with organic and inorganic compounds such as per- and polyfluoroalkyl substances (PFAS), sulfides, surfactants, heavy metals, pesticides and others.

At the time of this study, the only method of regenerating spent granular activated carbon (GAC) was to reactivate it at temperatures greater than 1000 ^◦C. Unfortunately, this method uses large amounts of energy and can be very expensive.

Our team of subject matter experts (SMEs) put their minds together to find a way to regenerate contaminated GAC while preserving energy and financial resources.

We identified two different organic alcohol-based solvents as possible regenerant solutions for effective GAC regeneration. Column tests were then performed on these solvents using GAC that was contaminated with PFAS perfluorooctanoic acid (PFOA) and perfluorooctanoic sulfonate (PFOS). 

What We Found

One solvent-base mix (SBM) emerged as the most successful compound for regenerating activated carbon, achieving a 93% PFOA and 65% PFOS removal in lab samples.

In addition, we found that solvent regenerated GAC removed PFAS more effectively than virgin GAC, even after several cycles of solvent regeneration.

Sorption and Removal of PFOA/PFOS across 3 cycles of solvent regeneration.

Taking this pioneering research one step further, our team created a technology solution with a growing number of commercial applications. This solution reduces operating costs in a multitude of ways, including uptime, reduced transportation needs, lower cost disposal, and less energy required due to on-site GAC renewal.

The Battelle GAC RENEW™ Granular Activated Carbon Regeneration Technology is truly an example of environmental science that saves time, money, and energy.