应对农业生态系统中的 PFAS.pdf

1、Addressing PFAS in AgroecosystemsWater Conservation and Management UnitUSDA-ARS,US ARID-LAND AGRICULTURAL RESEARCH CENTERHighly polarized covalent bond1.High Electronegativity of Fluorine:Short and strong bond2.Small Atomic Radius of Fluorine:Energy required to break a CF bond 563 kJ/mol.One of the

2、highest bond energies for a single carbon-element bond.3.Strength of the CF Bond:The bond between(CH)is much weaker in comparison.Energy required to break a CH bond:436 kJ/mol.(less polarized and less resistant bond).4.Comparison with CH Bond:Why forever chemicals?The high energy required to break t

3、he CF bond explains why PFAS are so persistent in the environment.They do not easily degrade through natural processes such as:hydrolysis,oxidation,or biodegradation.PFASMitigationAdsorptionMembrane FiltrationMicrobubbles/NanobubblesPhytoremediationBiocharAdsorptionGranulated Activated Carbon(GAC)Co

4、st effectiveMore effective for long chain(hydrophobic interactions)Electrostatic interactions for short chain Ion ExchangeUses pH dependent chargeCan use cation and anion exchange resinsAnion exchange resins more effective for long chainCost effective Membrane FiltrationMicrofiltration(MF)Ultrafiltr

5、ation(UF)Nanofiltration(NF)Reverse Osmosis(RO)Very high efficiencyHigh conc.permeateIncreasing pressurePhytoremediationPlant uptake and concentration from soilBiocharSoil amendment that can immobilize PFAS and prevent availabilityMicrobubbles/NanobubblesPFAS concentrates at the air/water interfaceMi

6、tigationPFAS is still thereDestruction of PFAS estimated to be$20-7,000 trillion.Global GDP is$106 trillion.PFASRemediationHydrothermal TreatmentAdvanced Oxidation/PhotocatalysisMechanochemicalThermal Destruction BiotransformationHydrothermal Treatment Thermochemical treatment us