Grantee Research Project Results
Final Report: A Low-cost Hanheld Sulfur Dioxide Tester with a Hybrid Nanomaterials-based Sensor Chip
EPA Contract Number: 68HERC21C0048Title: A Low-cost Hanheld Sulfur Dioxide Tester with a Hybrid Nanomaterials-based Sensor Chip
Investigators: Hill, James
Small Business: NanoAffix Science LLC
EPA Contact: Richards, April
Phase: II
Project Period: April 1, 2021 through March 31, 2023 (Extended to March 31, 2024)
RFA: Small Business Innovation Research (SBIR) - Phase II (2021) Recipients Lists
Research Category: SBIR - Air Monitoring and Remote Sensing , Small Business Innovation Research (SBIR)
Description:
Air pollution is a challenging and pervasive issue to address because of the myriad of health issues that are caused by acute and chronic exposure. Current testing techniques do not utilize a sufficient number of locations or testing frequency to adequately monitor potential problems. The purpose of this research project was to develop air monitoring technology for detecting sulfur dioxide (SO2) at point-of-use with an inexpensive and portable detector. The SO2 that is currently found in the air that we breathe is primarily produced through volcanic eruptions, the burning of petroleum products, and the refining of ores. Additionally, there are a number of industrial processes that generate SO2 gas as a by-product to produce things that we use every day from paper to food preservation. Chronic exposure to low concentrations of SO2 and acute exposure to high concentrations of SO2 are known to cause respiratory and cardiovascular illnesses. Current testing methods do not have adequate sensitivity and portability as handheld devices only detect ppm levels of SO2 and large stationary equipment is expensive and immovable. This is impractical for broadening the areas tested and increasing the testing frequency. Thus, there is a need for a simple and inexpensive handheld tester for monitoring exposure to SO2.
Summary/Accomplishments (Outputs/Outcomes):
The NanoAffix handheld tester uses graphene-based sensors coated with mixed metal oxide probes and communicates via Bluetooth with a smartphone application. Graphene has unique beneficial properties that enable the improved sensitivity. Graphene has excellent electronic sensitivity and small changes to the surface can lead to measurable changes in conductivity. The mixed metal oxide nanoparticles provide the selectivity for preferentially detecting SO2 and the chemical interactions are reversible so the sensor can be used for recording many measurements rapidly. These nanoparticles are synthesized hydrothermally, and spin coated onto the sensor surface. The resulting sensor chips show sensitivity to low SO2 concentrations on the order of 10 ppb and demonstrates the reversibility of the sensor surface and the ability to rapidly make measurements in minutes. This design uniquely combines the electronic sensitivity of graphene with the selectivity of the mixed metal oxide nanoparticles toward SO2 to produce a portable device that is capable of making rapid measurements in minutes on someone’s smartphone.
Conclusions:
NanoAffix has developed an innovative handheld tester that is relatively inexpensive and can easily be carried to various locations to perform rapid onsite tests using the smartphone app. This device could be used to monitoring SO2 at various locations within or near a manufacturing operation that produces SO2, to monitor levels of SO2 used during the food preservation process, or to monitor SO2 produced by vehicle emissions at various locations throughout a city or other types of environmental monitoring.
Through the SBIR Phase II project, NanoAffix has gained an in-depth understanding of the customer ‘ecosystems’ where our device might be best employed. Two key customer segments to further explore for our portable handheld device are industries here in the US where SO2 is purposefully used for food production, preservation and cold-storage as well as international locations where SO2 still remains an environmental air quality concern. To realize scalable manufacturing, we have identified and vetted a local contract manufacturer of electronic devices that is wholly capable of taking our proof-of-principle ‘rough’ prototype and engineering a first- generation customer-ready device with a reasonable cost of goods. We aim to have a small number (< 20) of these devices built and deploy them into the field for use by early-adopters identified in our customer discovery. This will allow us to gain more feedback directly from end users and thus make refinements in preparation for a full manufacturing scale-up and launch of our finished product. NanoAffix’s Phase II project results and preliminary prototype have enabled us to attract and close a modest investment from an angel investor.
SBIR Phase I:
A Low-Cost Handheld Sulfur Dioxide Tester with a Hybrid Nanomaterials-Based Sensor Chip | Final ReportThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.