Removing emerging e-waste pollutant DTFPB by synchronized oxidation-adsorption Fenton technology

Area of Science:

• Environmental Chemistry
• Water Treatment Technologies
• Organic Pollutant Remediation

Background:

• Liquid crystal monomers (LCMs) are emerging organic pollutants from electronic waste.
• LCMs are persistent and frequently detected in environmental matrices like landfill leachate.
• Effective remediation technologies are needed to address LCM contamination.

Purpose of the Study:

• To evaluate the feasibility, performance, and mechanism of synchronized oxidation-adsorption (SOA) Fenton technology for LCM remediation.
• To investigate the application of SOA Fenton technology in treating DTFPB-contaminated landfill leachate.
• To understand the degradation pathways and removal mechanisms of a specific LCM, 4-[difluoro(3,4,5-trifluorophenoxy)methyl]-3,5-difluoro-4'-propylbiphenyl (DTFPB).

Main Methods:

• Utilized a synchronized oxidation-adsorption (SOA) Fenton system for DTFPB remediation.
• Optimized reaction conditions including Fe2+/H2O2 molar ratio (1/4) and pH (2.5-3.0).
• Analyzed degradation kinetics using a pseudo-first-order model and identified degradation products.

Main Results:

• Hydroxyl radical oxidation degraded 93.5% of DTFPB and 5.6% of total organic carbon (TOC).
• Synchronized adsorption by in situ ferric particles achieved nearly 100% DTFPB removal and 33.4% TOC removal.
• Proposed three degradation pathways involving eight products, with hydrophobic interactions driving adsorption.

Conclusions:

• The SOA Fenton system demonstrates high efficiency in degrading DTFPB and its byproducts.
• The combined oxidation and adsorption mechanism significantly enhances pollutant removal from leachate.
• This study confirms the potential of Fenton processes for treating emerging LCM contamination in wastewater.