Anthropogenic greenhouse CO2 gas sensor based on glassy carbon modified with organoclay/ polypyrrole-alginate nanocomposites in brackish water and seawater

Abstract

Schematic presentation of the detection of CO 2 using a glassy carbon sensor (GCS) and modified glassy carbon sensor (MGCS) based on organoclay/polypyrrole-alginate (OC/Ppy-A) nanocomposite via cyclic voltammetry. • An anthropogenic greenhouse CO 2 gas sensor was successfully fabricated. • The sensor exhibited remarkable conductivity and electrocatalytic activity. • Low detection limits and a wide linearity range were observed. • The sensor was successfully applied to detect CO 2 in brackish and seawater samples. An increase in the amount of greenhouse gases around the Earth’s atmosphere generated by emissions through various sources creates a huge problem for the near future because of global warming and the consequent climate changes. This study fabricated an organoclay/polypyrrole-alginate (OC/Ppy-A) nanocomposite-modified glassy carbon sensor (MGCS), which was used for the sensitive estimation of anthropogenic greenhouse gas (CO 2 ). The efficiency of the developed sensor was investigated via cyclic voltammetry (CV) and electrochemical impedance spectroscopy. Compared with the bare glassy carbon sensor (GCS), the developed MGCS exhibited a fivefold superior CV signal for the recognition of the redox-active solution of potassium ferricyanide (K 3 [Fe(CN) 6 ]). The CV signal currents of the redox reaction of (K 3 [Fe(CN) 6 ]) were changed by changing the amount of CO 2 molecules in the measured samples. The oxidation signal of (K 3 [Fe(CN) 6 ]) linearly correlated with the CO 2 concentration in the separate ranges of 0.05–0.25 ppm (0.595–2.98 µM) and 0.25–3.5 ppm (2.98–41.67 µM) with limits of detection (S/N = 3) of 0.0165 ppm (0.196 µM, 40.569 μA/ppm) and 0.0825 ppm (0.982 µM, 1.751 μA/ppm). Additionally, the developed electrochemical MGCS exhibited appropriate repeatability, reproducibility, and stability. The proposed sensor was successfully applied for the determination of CO 2 in brackish and seawater samples in Egypt.