Sustainable silver nanoparticle-enhanced additive manufactured sensor for cadmium (II) sensing in environmental waters

Augusto, KKL ORCID: https://orcid.org/0000-0001-6109-3448, Bernalte, Elena ORCID: https://orcid.org/0000-0002-0764-789X, Crapnell, RD ORCID: https://orcid.org/0000-0002-8701-3933, Andrews, HG ORCID: https://orcid.org/0009-0007-7268-3452, Fatibello-Filho, O and Banks, CE ORCID: https://orcid.org/0000-0002-0756-9764 (2025) Sustainable silver nanoparticle-enhanced additive manufactured sensor for cadmium (II) sensing in environmental waters. Journal of Environmental Chemical Engineering, 13 (3). 116446. ISSN 2213-3437

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Abstract

The development of bespoke, high-performance conductive filament is critical to address limitations of current additively manufactured sensors. In particular, enhancing the sensitivity and reliability of this technology is vital toward their in-the-field applications such as water pollution monitoring. As such, we present the production of filament containing a mix of carbon black (CB) and graphite (G) functionalised with silver nanoparticles (AgNPs) that does not require special printing conditions, special instrumentation, or any post-print modification for the detection of cadmium (II) in environmental waters. The AgNPs are synthesised on graphite flakes using an eco-friendly, aqueous synthesis, without additional reducing agents and their presence is confirmed through SEM, EDX and XPS analysis. The AgNP loaded graphite is incorporated into a filament using recycled PLA and the bio-based plasticiser castor oil, ensuring sustainability is at the heart of the work. The electrodes produced a heterogeneous rate constant, k0, of (1.9 ± 0.2) × 10-3 cm s-1 and were applied toward the detection of cadmium (II) within buffer, tap water, and river water samples. Importantly, using electrodes straight from the print bed with no post-print modification, a Limit of Detection of 0.43 μg L-1 and a Limit of Quantification of 1.44 μg L-1 towards the sensing of cadmium (II), significantly below the worldwide targets of 3-5 μg L-1, was achievedwas achieved. This work shows a simple but effective approach to include metallic nanoparticles within conductive additive manufacturing filament and the capabilities towards monitoring heavy metal contaminants in water systems.