Real-time monitoring of dissolved oxygen in water at different depths in Nanjing Geography Institute

[ Instrument Network Instrument Development ] Dissolved oxygen is an important factor in maintaining the health of lake ecosystems. The dissolved oxygen concentration in lake waters fluctuates frequently with water depth, and there may even be cases where the dissolved oxygen concentration in the surface of the water body is saturated and the bottom is anaerobic. Therefore, research to determine the dissolved oxygen content of water at different depths is of great significance for environmental monitoring, water quality assurance, water ecological restoration, aquatic ecosystem assessment and aquaculture.

In recent years, microbial electrochemical technology has developed rapidly, providing a new biosensing method; among them, sediment microbial electrochemical technology is a microbial electrochemical technology that can break through the theory and realize specific applications. The sediment microbial electrochemical technique is simple in construction, the anode is buried in the reducing sediment, the cathode is placed at the air-water interface, and the external circuit between the anode and the cathode is connected to the load. The mechanism of action is that the organic matter in the anode region is oxidatively decomposed by the electrogenic microorganism, and the generated electrons are sent to the anode, and then the external circuit reaches the cathode to form a current, and the proton is transferred to the cathode through the aqueous solution, and reacts with oxygen to form water.

According to the reaction mechanism of the electrochemical anode and cathode of the sediment microbial organism, Dr. Song Na of the Jianghelong team of the Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, designed a new structure of microbial electrochemical group with single anode and multiple cathodes that do not interfere with each other. The use of dissolved oxygen concentration in the water body will affect the principle of electrical signal output from the microbial electrochemical process, and the dissolved oxygen concentration in different depths of water can be monitored simultaneously. The device and equipment developed can realize simultaneous online monitoring of water bodies of different depths with only one instrument, low operation and maintenance cost, stable operation and sensitive response. At present, the main influencing parameters of the sensor device have been optimized through laboratory experiments, and verified by the in-situ test of the lake, the device can be stably operated in the field for a long time.

This result has been granted the invention patent (patent number CN201410614945.2) and published in the Science of the total environment journal under the title of a sediment microbial fuel cell-based biosensor for simultaneous online monitoring of dissolved oxygen concentrations along various depths in lake water. The review experts believe that this is a novel and intelligent sensor design.

The work was funded by the National Natural Science Foundation of China and the Innovation Crossing Team of the Chinese Academy of Sciences.

(Original title: Progress in real-time monitoring of dissolved oxygen in different depths of lakes at the Nanjing Institute of Geography)