A CHEAPER CARBON DIOXIDE DETECTION ALTERNATIVE

The increase of CO2 in the Earth's surface has been damaging the ecosystem and gradually changing the climate, and faced with these adversities researchers are being concerned by the challenge of developing sustainable and effective technologies for the capture, storage and sequestration of CO2. A good solution is the consumption of this component through photosynthetic microorganisms, such as microalgae, which in addition to performing this function very well, also manufacture products with high added value. But to quantify and optimize the amount of CO2 that will be supplied to them, it is necessary to use CO2 sensors. An alternative to high-cost commercial sensors ($ 6,500.00), is presented in this paper using a sensor developed for Arduino, MQ-135, which is very affordable ($ 8.00), other models also allow use in Arduino such as the MG-811 ($ 76.00) that can offer even more precision. Using the MQ-135 sensor, it was possible to estimate with good precision the fraction of CO2 in the sample tested, having a linear correlation with the commercial signal with R² of 0.99. This methodology provides an accessible solution to quantify the molar fraction of CO2 fixed in a bioprocess.