Functionalized Layered Double Hydroxides for PFAS Water Adsorption

The patent creates composite materials by grafting organofunctional silicon compounds onto the LDH surface, forming a hybrid structure that combines the inorganic LDH framework with organic functional groups. This composite approach enables the adsorbent to achieve high adsorption capacity for PFAS while maintaining structural integrity and manufacturability through a systematic two-step synthesis process.

The patent applies local quality modification by introducing specific organofunctional groups (such as fluorinated alkyl chains) at the surface level of the LDH particles. This localized functionalization enhances the affinity for PFAS molecules at the interface without altering the bulk properties of the LDH structure, thereby improving adsorption capacity while preserving the ease of manufacture of the base material.

The patent changes the surface chemical parameters of the LDH by grafting organofunctional silicon compounds with hydrophobic organic groups. This parameter modification transforms the surface from hydrophilic to amphiphilic or hydrophobic character, enabling better interaction with hydrophobic PFAS compounds while maintaining the overall material handling properties of the LDH structure.

The organofunctional silicon compound acts as an intermediary layer between the hydrophilic LDH surface and the hydrophobic PFAS molecules. This intermediary structure provides a bridge that facilitates interaction between incompatible phases, allowing the hydrophilic LDH to effectively adsorb hydrophobic PFAS compounds through the mediating organic functional groups.

The patent employs preliminary action by pre-synthesizing organofunctional silicon compounds with specific functional groups tailored for PFAS interaction. These pre-prepared functionalizing agents are then applied to the LDH surface in a controlled manner, enabling efficient adsorption enhancement without requiring complex in-situ functionalization procedures during the main manufacturing process.

The patent replaces mechanical mixing or physical blending methods with a chemical grafting mechanism for functionalization. The organofunctional silicon compounds chemically bond to the LDH surface through silane coupling, creating a stable covalent linkage that provides durable adsorption enhancement without requiring complex mechanical processing or post-treatment steps.