Nanobubble technology: An environmentally sustainable approach for gas dissolution and water chemistry modulation

This study investigates the dissolution behaviour of different gases (O₂, O3, CO₂, H₂, N₂, and air) in nanobubble (NB) form in pure water. The experiment was conducted in a pure water-filled tank equipped with sensors to monitor pH, dissolved CO2 (DCO2), dissolved O2 (DO), dissolved H2 (DH), dissolved O3 (DO₃), oxidation-reduction potential (ORP), and electrical conductivity. The influence of the NBs in pure water was continuously monitored by measuring the parameters throughout the experiment. The findings highlight that NBs play a crucial role in rapid gas dissolution in water and change the water chemistry. For instance, CO2 NBs reduced the pH of water from 6.8 ± 0.2 to 4.2 ± 0.2 within 20 min of CO2-NBs generation, and DCO2 concentration reached >1500 mg/L in 30 min. DO concentration was noted as 31.6 ± 3.0 mg/L and 51.8 ± 5.0 mg/L, with O2 and O3 NBs infusion, respectively. H₂ and N₂ gases were easily able to replace the inherent DO saturated with air and reduced the DO concentration to 2.3 ± 0.1 and 1.8 ± 0.1 mg/L. The study suggests the potential industrial applications of NB technology in processes like wastewater treatment, enhanced gas solubility, and disinfection because of the unique physicochemical properties of NBs. This report might provide valuable insights for further investigations about physicochemical properties and performances of various gas NBs on water chemistry and their potential usage in environmental sustainability.