I received my Master’s degree in chemical engineering from SU, USA. I worked as a writer and researcher for Fortune 500 company clients.
Chemical companies are always dealing with industrial hazard gasses and ways to efficiently handle them. Recently, a leak of methyl mercaptan gas – used in the manufacture of insecticide and fungicide – occurred at a DuPont chemical plant in LaPorte, Texas. Early detection of the leak wasn’t possible because the plant was not equipped with an adequate toxic gas detection system.
The motivation behind the invention of a new Technology..
Ling Xing Yi at the Nanyang Technological University, Singapore says this and another incident in Singapore in 2017 spurred the invention of a new hazardous gas detection prototype technology. A gaseous odor seeped over certain parts of the island due to the leak of volatile organic compounds from factories outside of Singapore. She (and her husband, Phang In-Yee, a scientist at the Institute of Materials Research and Engineering [IMRE]) developed the idea of identifying gasses instantly from a distance.
New Real-Time Atmospheric Monitoring Technology
Their technology consists of a laser combined with a nano-structure made of a metal-organic framework (Ag-MOF) material. The metal-organic framework (MOF), is a hollow honeycomb structure consisting of metal ions (in this case, silver, Ag in the periodic table) in the corners connected with a linker made of carbon. This structure creates traps that can capture even a small concentration of chemicals, down to parts-per-billion levels. Once the chemicals are trapped, a laser is beamed onto individual molecules, which emit a light of their own. The signal is read out in the format of a graph chart, letting you know the exact properties and structure of the chemicals accurately.
Commonly released gases like polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs), sulfur dioxide, benzene, and carbon dioxide which are carcinogenic and harmful to human health can be detected efficiently. They are commonly released from cars and engines, factories, power plants, constructions, food and cooking, mines and the agriculture industry, even universities and company laboratories.
Generally, the instruments that detect traces of a specific gas in the air are large, expensive, and energy-intensive machines. The new honeycomb structures are small, inexpensive, and energy-efficient gas sensors (having an energy intensity of 50 milliwatts, several times weaker than in other devices) can be incorporated efficiently in companies. Detecting hazardous gases in the initial stage can save lives; after 24,000 pounds of methyl mercaptan was released at Texas du Pont plant, four workers died, just one such recent incident at a du Pont plant.
What makes the technology unique is that it provides real-time atmospheric monitoring, eliminating the need for air samples. It’s portable and only takes about 10 seconds for quick gas detection. Conventional gas detecting methods like mass spectrometry require air samples with high chemical concentration to enable detection. They’re time-consuming and take hours to obtain results. The technology is also capable of detecting the gas even from 10 meters away from the gas leak area and can be engineered to reach further distances.
Other Applications ..
Researchers can also exploit AG-MOF’s porous material and ultrahigh surface area of these cage-like structures for applications in many other fields. They can do this by creating different structures with combinations of various metals and organic ligands. Applications include capturing carbon dioxide from industries, capturing radioactive nuclear waste, removing heavy metals like lead and mercury from water samples, or creating more energy-efficient air conditioners by engineering them to hold onto a large number of refrigerant gases.
Professor Wendy Lee Queen at EPFL, with colleagues at the University of California Berkeley and Lawrence Berkeley National Laboratory, treated a different MOF, known as Fe-BTC, with a polymer called polydopamine (PDA), which was pinned inside the MOF. The final MOF Fe-BTC/PDA quickly and selectively removes high amounts of heavy metals like mercury and lead from water samples. It removes about 1.6 times its weight of mercury and 0.4 times its weight of lead. Fe-BTC/PDA is capable of reducing lead concentrations down to 2 parts per billion, which is treated as drinkable water by the World Health Organization and U.S. Environmental Protection Agency.
Radioactive organic iodides in the nuclear-spent fuel waste are particularly difficult to capture. The compounds are made of iodine and hydrocarbons. Jing Li at Rutgers University modified the MOFs with reactive nitrogen at the binding sites which can further help in binding to the organic iodides from the waste. The MOF creates a molecular trap that was able to capture 71% of available radioactive material, which is 340% higher than the most common adsorbent used in clean-ups.
It will be interesting to know some facts – A study of 2015 explains that the global oil and gas industries release as much as 3.6 trillion cubic feet of natural gas into the atmosphere annually. In the year 2012, Professor Nathan Phillips from Boston University drove along the Boston roads covering a distance of 785 miles (1,263 km) with a gas sensor. He identified 3300 leaks. In 2017, it was estimated that about 15.7 million metric tons of greenhouse gases were released in Rhode Island, a third of which comes from leaks in natural gas pipes. The discovery of the new MOF material technology shows good potential as a gas detector preventing the outburst of a hazardous situation, ensuring the safety of people, and reducing emissions. Although the long-term application (life) of the technology is unknown and the technology still holds certain drawbacks. For example, the sensors do have a high fabrication cost as compared to gas chromatography. The sensor also demands the need for regular maintenance by periodic regeneration/recycling of the sensors for the removal of the gases. The life of the sensor would be another concern since they are real-time portable sensors and exposed to harsh environments continuously. Yet, studies in MOF materials can motivate the development of more such MOF material technology for wider applications.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.