Online Monitoring of Seawater Carbon Dioxide Based on an Infrared Rear Beam Splitter

Area of Science:

• Environmental Science
• Oceanography
• Analytical Chemistry

Background:

• Oceans absorb significant carbon dioxide, influencing marine ecosystems.
• Rising seawater carbon dioxide causes ocean acidification, threatening biodiversity.
• Accurate dissolved carbon dioxide monitoring is vital for marine ecosystem health.

Purpose of the Study:

• To design and validate a low-cost, portable infrared system for online seawater carbon dioxide monitoring.
• To address limitations of current large and expensive detection equipment.
• To improve understanding and protection of marine ecosystems through real-time data.

Main Methods:

• Utilized molecular theory and the HITRAN database to calculate carbon dioxide absorption spectra.
• Selected a 2361 cm^-1 wavelength for measurement.
• Implemented an infrared post-splitting method to mitigate light interference and enhance accuracy.
• Developed a system with a peristaltic pump for gas-liquid separation and concentration inversion algorithms.

Main Results:

• Achieved a standard deviation of 3.05 for gas tests and 6.04 for seawater tests.
• Demonstrated an error range within 20 ppm for carbon dioxide detection.
• Validated the system's stability, portability, and flexibility for deployment.

Conclusions:

• The developed infrared system provides a cost-effective solution for online seawater carbon dioxide monitoring.
• The system's accuracy and stability meet the requirements for assessing marine ecosystem health.
• This technology supports continuous environmental monitoring and conservation efforts for marine environments.