Continuously Responsive Surface-Enhanced Raman Scattering Sensors for Long-Term On-Site Free Chlorine Monitoring in...

Area of Science:

• Environmental Science
• Analytical Chemistry
• Materials Science

Background:

• Industrialization and urbanization increase wastewater discharge, necessitating robust aquatic ecosystem monitoring.
• Accurate long-term monitoring of free chlorine (FC) at sewage outfalls is crucial but challenging.
• Over-discharged FC poses ecological risks to aquatic environments.

Purpose of the Study:

• To develop a continuously responsive sensor for long-term, on-site free chlorine (FC) monitoring.
• To address the challenge of reliable FC detection at urban sewage discharge points.
• To provide a practical solution for safeguarding aquatic ecosystems.

Main Methods:

• Fabrication of a flexible surface-enhanced Raman scattering (SERS) probe functionalized with 4-aminothiophenol (4-ATP).
• Integration of the SERS probe with a compact floating roller device for continuous signal acquisition.
• Performance evaluation including detection limit, accuracy in real-world samples, and long-term deployment tests.

Main Results:

• The developed SERS sensor demonstrated a low detection limit of 4.16 ppb for FC.
• The sensor accurately quantified FC concentrations in real-world water samples, showing high sensitivity and reliability.
• Long-term deployment at sewage treatment plant (STP) outfalls confirmed robust monitoring capabilities under environmental conditions.

Conclusions:

• The innovative SERS sensor offers a practical and accurate solution for long-term, on-site free chlorine monitoring.
• This technology has the potential to be a scalable approach for environmental monitoring applications.
• Effective FC monitoring is vital for protecting aquatic ecosystems from wastewater discharge impacts.