Geoscience meets Nanotechnology: A Pathway of Environmental Monitoring

Geoscience meets Nanotechnology: A Pathway of Environmental Monitoring

Ornprapa P. Robert,
Dept. of Environmental Science, Faculty of Science
Silpakorn University -Thailand
Ashok Vaseashta
Strategic S&T Advisor and Fellow, U.S. Department of State,
Norwich University Applied Research Institutes
Washington -United States
Honda Kiyoshi
International Digital Earth Applied science research center
Chubu Institute for Advanced Studies, Chubu Univ.

Growing environmental pollution, depleting natural resources and the threat of climate change has moved the research community to come out with a smarter, non-conventional way in managing those issues. Find out how Thailand is using nanotechnology to curb such issues.

Climate change has been recognized as one of the most top global concern nowadays. The primary causes are because of too rapid economic growth, urbanization and industrialization in large populated cities. Bangkok metropolitan is one of the most polluted cities. It is threatening our concerns in environmental pollution, natural resource and climate change. Hence, vulnerability assessments, appropriate spatial planning and alert response system are keys issues of climate adaptation and number of sensing systems and meteorological stations are required to place in cities. Conventional pollution monitoring system, for example in air, gives excellent resolution and is under Environmental Protection Agency (EPA) Standard, nevertheless it is costly, approximately 31K US$ per one type of air pollutant, bulky in size, difficult in controlling the process, insubstantial, and seldom be used in real time. Hence, this current system is not practical to extend air pollution monitoring.

Geoscience Information System together with nanotechnology makes it possible for us to develop unsophisticated inexpensive and practical system for mitigation, monitoring and controlling environmental pollution. We have developed and employed nanosensors in detecting pollutants both in air and water.

Why nanotechnology?

There is an easy way to explain how nanotechnology can be applied in environment pollution mitigation, monitoring and controlling. In terms of sensor’s sensing area, specifically when we apply sensing materials of 5 by 5 micron, we retrieve total sensing area of 2.5×10-11 m2. With the same sensing materials, if sensing objects such as nanotube of 30 nm diameter is supplemented, we can enhance total sensing area up to 500 times. Moreover if we decrease diameter of nanotube to 15 nm, we can increase total sensing area about 1000 times. The next question is what increasing total sensing area means to environmental pollution detection?

Enviromental Pollution Detector

Here is explanation; to detect gas and vapors, response of a nanomaterials based sensor is relied on reactions replacement of atoms at the sensing surface of these materials establishing on a change of the resistance of the oxide. Depending on free electron density in space charge layer, the depletion region is increased. Since electric properties are influenced by the depletion layer, variation in electrical conductivity indicates sensor response. The sensitivity and response of nanomaterials is highly dependent on the roughness of the substrate, thus increasing surface area is able to improve sensors’ sensitivity or sensor response.

From those reasons mentioned above, we have developed applications and platforms, involving web-connected devices for detecting biological and chemical agents in water (Vaseashta, 2014), and monitoring pollution in air based Open Geo-Spatial Consortium (OGC) Standard (Chinnachodteeranun, Honda, Witayangkurn and Parnichkun 2013; Robert, Rahman, Honda, Shreshtha and Vaseashta, 2011). Fundamentally, when OGC standards are implemented by different developers, to register and replace new sensors is very simply to deploy which is called plug and play system. In Figure 1, it is demonstrated our system comprising fivefold; (1) SensorNode (2) TransferingNode (3) SOS station (4) Alert Response System and (5) Web User Interface. Water and air mounted sensors are connected to microcontroller as data processing and transferring node using

X-Bee connectivity. Sensor data are transferred to SOS station based Cloud service. Due to its importance of various data acquisition for environmental monitoring and controlling, interoperability of data integration is obtainable in our applications. Different data resources from CloudSense, meteorological data and satellite data can be acquired and further analyzed using standard web service such as OGC’s SOS, WCS, and so forth, which ensures the interoperability of the system and environmental database. The results of analysis, visualization and prediction are then provided to users both in mobile and personal computer applications via web user interface. This emerging developed water and air monitoring and controlling system is capable of making implementation of knowledge in geoscience and nanotechnology uncomplicated and practical which enhances national mitigating and controlling in environmental pollution.

Figure 1 Plug and Play Water and Air Quality Monitoring System using

Cloud based Nanosensors