Toward Recycling of Marine Debris - Analysis of Microplastics Using FTIR and EDX -

Importance of the topic

Marine plastic debris, including disused fishing nets, poses significant ecological and economic challenges. Abandoned nets drift in oceans, entangle marine life and contribute to microplastic pollution. Recycling these materials supports a circular economy, reduces environmental impact and recovers valuable resources such as polymers and metal coatings.

Study objectives and overview

This application note presents a case study analyzing fishing nets collected on beaches in Majorca (Spain) and Texel (The Netherlands), as well as nets from a recycling facility. Using FTIR and EDX techniques, the research aimed to:

• Identify polymer types in field-collected and recycled nets
• Quantify elemental additives, particularly copper protective coatings
• Demonstrate the value of combined spectroscopic methods for material sorting in recycling processes

Methodology and used instrumentation

Analyses were conducted without sample pretreatment. Two complementary techniques were employed:

• FTIR (Attenuated Total Reflection) using IRTracer™-100 coupled to a Quest diamond ATR accessory. Measurement settings: 4 cm⁻¹ resolution, 45 scans, Happ-Genzel apodization, DLATGS detector.
• Energy Dispersive X-ray Fluorescence (EDX) using EDX-8000. Conditions: Rh X-ray tube target; 50 kV for Al–U and 15 kV for C–Sc; vacuum atmosphere; 3 mm diameter beam; 50 s integration.

Main results and discussion

FTIR spectra revealed that polyethylene dominated many samples, with polypropylene and polyamides also present. Additives such as calcium carbonate and silicate appeared in some beach-collected nets. EDX analysis showed negligible copper (<0.03 wt%) in field specimens, confirming absence of protective coatings. Conversely, recycled net samples contained diverse polymers and significant Cu content (up to 15 wt% and 8 wt%), indicating nets treated with antibacterial copper coatings. This dual approach allowed clear differentiation of polymer composition and coating status.

Benefits and practical application

Combining FTIR and EDX enables rapid, non-destructive characterization of fishing net materials. Key practical advantages include:

• Efficient sorting of polymers for targeted recycling streams
• Detection and quantification of hazardous coatings (e.g., Cu) to ensure proper decontamination
• Quality control in recycled feedstock production

Future trends and potential applications

Advancements may include:

• Portable FTIR/EDX devices for in-field screening and on-site decision making
• Integration with Raman spectroscopy and imaging for microplastic identification
• Automated workflows and machine learning for rapid classification of marine debris
• Extended elemental mapping to detect additional toxic metals or pollutants

Conclusion

This study demonstrates that FTIR-ATR and EDX are complementary, effective tools for characterizing polymer composition and metal coatings in fishing nets. Their combined use supports efficient recycling, environmental monitoring and resource recovery from marine debris.

References

1. Hartl MGJ, Watson D, Davenport J. Biofouling in the Marine Aquaculture Industry, with Particular Reference to Finfish – Current Status and Future Challenges. Marine Estate Research Report (AQU/06/03); Nov. 2006.
2. Nikolaou M, Neofitou N, Skordas K, Castritsi-Catharios I, Tziantziou L. Fish farming and anti-fouling paints: a potential source of Cu and Zn in farmed fish. Aquaculture Environment Interactions. 2014;5:163–171.