No-Heat-Required System for Sensing Chlorine Gas


Project ID:  D2008-23



Continuous chlorine gas sensing system provides rapid, reliable, cost effective and easy to operate monitoring of ambient environments.


Value Proposition:

Chlorine gas is widely used for whitening and disinfecting in many industrial processes involving paper, fabric, water purification, and food production. Because chlorine is harmful when emitted into the environment, rapid detection of chlorine and chlorine dioxide in the air at the level of maximum permissible concentrations, 1 and 0.1 mg/m respectively, is important. In order to monitor emission of chlorine gases to the environment, continuous detection capability is necessary. Several detection methods are currently in use (e.g., solid state electrochemical sensors, phthalocyanine film sensors, gas chromatography), but practical usage and/or stability is often problematic because of the relatively high heat required and/or unsuitability for continuous monitoring.

Invention description: 

Dr. Ahalapitiya Jayatissa has developed a process to solve problems exhibited in previous systems with his sensor comprised of carbon nanotubes partially coated with a metal oxide and a source of infrared, visible or UV light positioned to illuminate a portion of the coated nanotubes which selectively enhances the sensing of chlorine gas.



1.      Functions at room-temperature

2.      Continuous monitoring capability

3.      Uses miniaturized microsensors

4.      No heat required to reset sensors after exposure to gas

5.      Highly stable­--no resistance decrease following exposure to gas

6.      Highly sensitive­--capable of detecting a trace amount of chlorine

7.      Technology includes chemical vapor deposition (CVD) system for forming carbon nanotubes


This technology has many potential applications including military use for troop protection, industrial, environmental, domestic and household monitoring in areas using chlorine as a disinfectant including (drinking water, sewage, swimming pools); manufacturers using chlorine in organic and inorganic synthesis (solvents, antifreeze, polymers, pesticides, refrigerants, rocket fuel); and pharmaceuticals and cosmetics manufacturing.


IP Status: U.S. Utility Patent # 8,414,831


Patent Information:
For Information, Contact:
Kwaku Opoku
Licensing Associate
The University of Toledo
Ahalapitiya Jayatissa
Chemical vapor deposition