Formatted Title:

Surface Modified Clays for In Situ Stabilization of PFAS-Impacted Soils, Sediments and Groundwater

Background/Objectives:

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) have become environmental and health concerns due to their potential for persistence in the environment and bioaccumulation. Surface-modified clay (SMC) adsorbents are highly effective at sequestering PFAS for contaminant remediation in a wide range of environmental applications. SMC adsorbents are manufactured by modifying sodium bentonite clay with an organic modifier containing functional groups possessing a high affinity for PFAS. The surface modifiers are bound to the surface of the plate-like crystalline structure of the clay to form adsorptive inter-platelet layers or galleries. The resulting material has a high adsorptive capacity for a variety of PFAS via electrostatic and hydrophobic mechanisms. The objective is to demonstrate the versatility of the product’s use in a variety of environmental remediation scenarios.

Approach/Activities:

SMC products have been developed to efficiently remove PFAS compounds. These new materials were tailored to provide both fast adsorption kinetics along with high adsorption capacities. The modified minerals can be manufactured at different particle sizes to allow for verstatility in deployment. Powdered versions of the product can be used for mixing or injection into the soil. Granular material can be used for groundwater filtration in pump-and-treat systems. Larger size media or needle punched geotextile products can be used for sediment capping.

Results/Lessons Learned:

The new modified minerals are exhibiting higher adsorption capacities and reduced co-contaminate competition compared to traditional remediation medias such as ion exchange resin (IER) and granular activated carbon (GAC). In some instances, the new modified mineral exhibits a 5-10x higher adsorption capacity of total PFAS compounds compared to alternative media such as GAC. This work will present data from case studies that show the effectiveness and robustness of the SMC products. Several case studies will be discussed to highlight the versatility of the product for the treatment of PFAS in a wide range of complex environmental remediation applications including groundwater, stormwater, sediment capping, and soil stabilization.

Thi Hobson

Affiliation

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(Group 1, Poster Board #85) Surface Modified Clays for In Situ Stabilization of PFAS-Impacted Soils, Sediments and Groundwater