Caffeine, riboflavin and curcumin amended clays for PFAS binding

Area of Science:

• Environmental Chemistry
• Materials Science
• Computational Chemistry

Background:

• Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants often found with other toxins.
• Clays are effective sorbents, but their capacity for PFAS removal can be enhanced.
• Previous work showed choline and carnitine amendments improve clay's PFAS sorption.

Purpose of the Study:

• To computationally screen safe chemical compounds for amending clays to improve PFAS sorption capacity.
• To identify specific supplements that enhance clay's ability to bind PFAS under acidic conditions.
• To experimentally validate the efficacy of designed clay-amendment systems for PFAS removal.

Main Methods:

• Computational simulations were used to screen potential clay amendments from a library of safe chemical compounds.
• Selected amendments were computationally evaluated for their potential to bind PFAS.
• Experimental sorption studies were conducted on parent clays and amended clays (caffeine, riboflavin, curcumin).

Main Results:

• Caffeine-, riboflavin-, and curcumin-amended clays demonstrated enhanced binding of various PFAS compared to unmodified clays.
• Caffeine-amended clay significantly increased GenX binding capacity from 0.15 to 1.17 mol/kg and PFOS binding by 125%.
• Riboflavin-amended clay showed enhanced binding for GenX (120%), PFOA (23%), and PFOS (70%).

Conclusions:

• Amending clays with caffeine and riboflavin are effective strategies for enhancing PFAS sorption, particularly under acidic conditions.
• The study provides atomistic insights into the mechanisms of enhanced PFAS binding by amended clays.
• This combined computational and experimental approach offers a novel pathway for designing improved sorbent materials for diverse toxins.