EXPERIMENTAL MEASUREMENT OF TOTAL INORGANIC CARBON CONCENTRATIONS FROM ABSORPTION OF GAS PHASE CO2

Abstract: Sodium hydroxide solution was mixed with cyanobacteria growth media (50% RO water and 50% BG - 11) in a ratio of 1 mL of 3M NaOH per liter a of media (3mM/L) to examine the effects on CO2 solubility using air (0.038%), 0.1%, 0.5%, 1.0%, 1.5%, 2.0% and 10% CO2 under atmospheric pressure at temperatures of 25, 35, 45, and 55°C. In addition, the solubility of 0.5% and 1.0% CO2-enriched air was investigated its behavior with respect to changing of NaOH concentration. The NaOH solution played a significant role for CO2 solubility in increasing CO2 solubility holding capacity. Ratios of TIC response among 0.1%, 0.5%, 1.0%, 1.5%, and 2.0% CO2 solubility to NaOH were approximately 1 and 2 for 10.0% CO2 compared to 0.1%, 0.5%, 1.0%, 1.5%, and 2.0% CO2,which was much less than the theoretical driving force ratio of these CO2 levels. These ratios decreased with respect to increased temperature. The TIC from CO2 solubility was linearly proportional to the amount of the NaOH solution used and to the increased CO2 levels. Experimental results yielded meaningful correlations of TIC concentrations and a bulk parameter as a function of temperatures, CO2 concentrations and amounts of the NaOH concentration.

Keywords: carbon dioxide; CO2; themophilic cyanobacteria; cyanobacteria growth media; RO water; inorganic carbon; saturated TIC concentration; total inorganic carbon; TIC.