Searching for a solvent with a low carbon dioxide solubility
To find a solvent with low solubility for non polar gases like CO2 you have to compare the polarity of the solvents. A very polar solvent like water is the best choice. 
There's a related question here: Dissolving of non polar gases in water (liquid)

At the end of this answer I have added two links. The first one gives you the solubility of CO2 in water. According to this source, at room temperature and around atmospheric pressure of Co2, the molar fraction in water is 0.00061. 
The second link compares many other solvents. At room temperature and 1atm of CO2 the molar fraction is 0.012 in hexane that is the lowest for straight chain alkenes(Fig.1). Overall, among alkanes and cyclic alkanes, cyclohexane is the only one that at room temperature has a CO2 solubility below 0.01(fig.2).
Among aromatic hydrocarbons, you can reach a molar fraction as low as 0.006 if you use 1-Methylnaphthalene(fig.3) and this value is interestingly similar to what you can reach using methanol(you can find a graph comparing alcohols there as well(pag.129). Apparently the CO2 solubility with aromatic compounds is comparable to alcohols(polar).

With all this in mind, water is the best option and if you add salts the solubility of CO2 decreases further as you mentioned. 






Solubility of Carbon Dioxide in Water:
https://sites.chem.colostate.edu/diverdi/all_courses/CRC%20reference%20data/solubility%20of%20carbon%20dioxide%20in%20water.pdf

CARBON DIOXIDE IN NON-AQUEOUS SOLVENTS: 
https://srdata.nist.gov/solubility/IUPAC/SDS-50/SDS-50.pdf