3D printed monoliths: From powder to an efficient catalyst for antibiotic degradation

Area of Science:

• Materials Science and Engineering
• Environmental Science and Technology
• Chemical Engineering

Background:

• Growing interest in 3D printing for advanced wastewater treatment technologies.
• Need for improved effectiveness and durability in water purification methods.
• 3D printing's capability to create complex geometries with diverse material compositions.

Purpose of the Study:

• To develop and evaluate 3D printed monoliths using non-commercial iron oxide and polylactic acid (PLA) filaments for wastewater treatment.
• To investigate the impact of different monolith designs on fluid dynamics and degradation efficiency.
• To optimize oxidant dosage and assess long-term performance and catalyst stability.

Main Methods:

• Fabrication of 3D monoliths (15-Fe3O4@PLA and 15-Fe3O4@PLA-DM) from iron oxide and PLA powder blends.
• Characterization using Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), and Mössbauer spectroscopy.
• Ofloxacin degradation experiments in a continuous flow reactor, coupled with Computational Fluid Dynamics (CFD) simulations and oxidant optimization.

Main Results:

• Monoliths achieved 55% and 82% ofloxacin degradation under optimized conditions.
• The 15-Fe3O4@PLA-DM monolith maintained 67% degradation over 120 hours of continuous operation.
• A fixed-bed reactor with ground pellets achieved total ofloxacin degradation, with minimal iron leaching (<0.1 ppm).

Conclusions:

• 3D printing offers a cost-effective, reproducible, and time-saving method for developing supported catalysts compared to conventional techniques.
• The developed 3D printed iron oxide-PLA catalysts demonstrate high efficiency and stability for removing ofloxacin from wastewater.
• The minimized leaching of active sites indicates excellent catalyst adhesion to the PLA support, enhancing durability.