Product for PFAS adsorption

A method of producing a product for adsorbing at least one PFAS from a liquid, the method comprising:

• selecting a sepiolite as feed material, wherein prior to surface treatment the sepiolite selected as feed material contains 16-20 wt. % moisture, as measured by Loss on Ignition (LOI);
• surface treating the sepiolite with a quaternary amine surface coating solution, the quaternary amine surface coating solution including (i) a mono-quaternary amine compound, the mono-quaternary amine compound comprising one or more mono-quaternary amines that attach to the surface of the sepiolite or (ii) a di-quaternary amine compound, the di-quaternary amine compound comprising one or more di-quaternary amines that attach to the surface of the sepiolite;
• and
• surface treating the sepiolite with a mercapto surface coating solution, the mercapto surface coating solution including a surface coating agent that includes one or more mercapto groups that chemically bond to the surface of the sepiolite,
• wherein the product produced has a surface area in the range of 76-276 m2/g as measured using the BET method,
• wherein when the quaternary amine surface coating solution includes the mono-quaternary amine compound, the product is free of di-quaternary amines,
• wherein when the quaternary amine surface coating solution includes the di-quaternary amine compound, the product is free of mono-quaternary amines.

A method for adsorbing at least one PFAS in a liquid, the method comprising:

• contacting the liquid with a product comprising sepiolite that has been surface functionalized with (a) a quaternary amine surface coating solution that includes a mono-quaternary amine compound or a di-quaternary amine compound, the mono-quaternary amine compound comprising one or more mono-quaternary amines that attach to the sepiolite surface, the di-quaternary amine compound comprising one or more di-quaternary amines that attach to the sepiolite surface and (b) a surface coating agent that includes one or more mercapto groups that chemically bond to the sepiolite surface;
• and
• separating the product from the liquid to recover a resultant liquid that has a lower amount of PFAS than the liquid had prior to the mixing,
• wherein the weight percentage of the components of the product includes:
• 76-97 wt. % sepiolite, 1-16 wt. % of (i) one or more mono-quaternary amines or (ii) one or more di-quaternary amines, and 0.5-8 wt. % surface coating agent that includes the one or more mercapto groups,
• wherein when the quaternary amine surface coating solution includes one or more mono-quaternary amine compounds, the product is free of di-quaternary amine compounds,
• wherein when the quaternary amine surface coating solution includes one or more di-quaternary amine compounds, the product is free of mono-quaternary amine compounds,
• wherein the product has a surface area in the range of 76-276 m2/g as measured using the BET method,
• wherein the removal efficiency of the product for a PFAS is 10-100%, at a loading of 0.5-2 g of the product per liter of the liquid.