English June 2, 2026

Development of CNT thin film electrodes for lead ion sensing: a step toward scalable water quality monitoring

Gangwar et al. (2026): https://doi.org/10.1016/j.jelechem.2026.120284

Introduction

Heavy metal contamination in drinking water remains a major global concern because even trace concentrations can pose significant health risks. Electroanalytical sensing technologies offer rapid, sensitive, and on-site detection of these contaminants. In this article, we report a scalable and industrially viable carbon nanotube network thin-film (CNT-NTF) electrode for electrochemical detection of Pb²⁺ in water.

Carbon nanotubes grown by chemical vapor deposition were uniformly press-transferred onto PET substrates, enabling large-area, reproducible, and mass-producible sensor fabrication. The CNT-NTF sensors achieved sub-nanomolar (ppb) detection limits for Pb²⁺ with two distinct linear response ranges and reliable performance in buffer, simulated drinking water, tap water, and river water samples. The sensors detected Pb²⁺ well below WHO and US-EPA regulatory limits, maintained stable responses between 5 and 45 °C, and showed robust performance in the presence of As³⁺ and Cd²⁺.

These results demonstrate the potential of the CNT-NTF platform as a scalable and cost-effective solution for monitoring heavy-metal contamination in water systems.

Main conclusions

Proven sensing capabilities: The study successfully developed scalable carbon nanotube network thin-film (CNT-NTF) electrodes capable of detecting lead in drinking water with high sensitivity, stability, and reproducibility.
Effective performance in real water samples: The electrodes reliably detected lead concentrations below WHO and EPA guideline limits in untreated tap and river water, without requiring added supporting electrolytes, across varying temperatures and water conductivities.
Highly scalable manufacturing: The press-transfer fabrication method produced uniform and reproducible CNT films, addressing a key challenge of CNT sensor manufacturing and improving prospects for large-scale production.
Strong potential for practical deployment: The sensor maintained competitive performance even in the presence of common interfering ions (e.g., As³⁺ and Cd²⁺), making it a promising low-cost solution for real-time lead monitoring, with future work focused on automated production and field validation.