Synergistic zero-valent iron-based green sorption media for contaminant removal

Patent metadata

Field	Value
Publication number	US-2024091738-A1
Application number	US-202318521289-A
Country	US
Kind code	A1
Filing date	Nov 28, 2023
Priority date	Feb 1, 2022
Publication date	Mar 21, 2024
Grant date	—

Abstract

A synergistic composition can be used to treat water containing nitrogen compounds and phosphorus compounds. The synergistic composition includes iron filings, clay particles, aluminum particles, and sand particles. The iron filings, clay particles, and aluminum particles act synergistically to remove nitrogen compounds and phosphorus compounds from water. Specifically, the clay particles attract the nitrogen compounds and the phosphorus compounds to be absorbed onto a surface of the iron filings and the clay particles. The aluminum particles react with the nitrogen compounds via an oxidation reaction to form ammonia compounds, and react with the phosphorus compounds to produce aluminum phosphate. As such, the synergistic relationship between the iron filings, clay particles, and aluminum particles remove nitrogen and phosphorus compounds from water and recover the compounds in usable forms, namely, ammonia and aluminum phosphate.

First claim

What is claimed is:

1 . A composition for treating water containing one or more per- or polyfluoroalkyl substances, the composition comprising:
at most 5% (v/v) zero-valent iron particles, approximately 4% (v/v) clay particles, and approximately 91% (v/v) sand particles, wherein, during flowing an amount of water through a fixed bed filter including the composition, the zero-valent iron particles are configured to oxidize the one or more per- or polyfluoroalkyl substances via a chemical oxidation reaction to generate at least one fluorinated carbon group and an oxidation-reaction-induced byproduct, the oxidation-reaction-induced byproduct including a portion of the one or more per- or polyfluoroalkyl substances, such that the oxidation-reaction-induced byproduct has a length smaller than a length of each of the one or more per- or polyfluoroalkyl substances, thereby promoting adsorption of the oxidation-reaction-induced byproduct by hydrophilic films surrounding the zero-valent iron particles, and thereby removing an amount of the one or more per- or polyfluoroalkyl substances from the water, and wherein, during flowing the amount of water through the fixed bed filter including the composition, the zero-valent iron particles and the clay particles are configured to synergistically promote adsorption of the one or more per- or polyfluoroalkyl substances, thereby removing an amount of the one or more per- or polyfluoroalkyl substances.

2 . The composition of claim 1 , wherein the zero-valent iron particles are in a powder format.

3 . The composition of claim 1 , wherein the one or more per- or polyfluoroalkyl substances is selected from the group consisting of perfluorooctane sulfonic acid and perfluorooctanoic acid.

4 . A filtration system for treating water containing one or more per- or polyfluoroalkyl substances, the filtration system comprising:
a media chamber including a fixed bed filter comprising a homogenously mixed composition, the homogenously mixed composition including a mixture of at most 5% (v/v) zero-valent iron particles, approximately 4% (v/v) clay particles, and approximately 91% (v/v) sand particles, wherein, during flowing an amount of water through the fixed bed filter, the zero-valent iron particles are configured to oxidize the one or more per- or polyfluoroalkyl substances via a chemical oxidation reaction to generate at least one fluorinated carbon group and an oxidation-reaction-induced byproduct, the oxidation-reaction-induced byproduct including a portion of the one or more per- or polyfluoroalkyl substances, such that the oxidation-reaction-induced byproduct has a length smaller than a length of each of the one or more per- or polyfluoroalkyl substances, thereby promoting adsorption of the oxidation-reaction-induced byproduct by hydrophilic films surrounding the zero-valent iron particles, and thereby removing an amount of the one or more per- or polyfluoroalkyl substances from the water, and wherein, during flowing the amount of water through the fixed bed filter, the zero-valent iron particles and the clay particles are configured to synergistically promote adsorption of the one or more per- or polyfluoroalkyl substances through electrostatic interactions, thereby removing an amount of the one or more per- or polyfluoroalkyl substances.

5 . The filtration system of claim 4 , wherein the zero-valent iron particles are in a powder format.

6 . The filtration system of claim 4 , wherein the one or more per- or polyfluoroalkyl substances is selected from the group consisting of perfluorooctane sulfonic acid and perfluorooctanoic acid.

Assignees

• Univ Central Florida Res Found Inc

Inventors

• Chang Ni-Bin
• Reinhart Debra
• Sadmani A H M Anwar

Classifications

• B01J20/0229 Primary

  Compounds of Fe · CPC title

• B01J20/103 Primary

  comprising silica · CPC title

• B01J20/12

  Naturally occurring clays or bleaching earth · CPC title

• C02F1/288

  using composite sorbents, e.g. coated, impregnated, multi-layered · CPC title

• C02F2101/16

  Nitrogen compounds, e.g. ammonia · CPC title