Improved virus inactivation using a hot bubble column evaporator (HBCE)

[Display omitted] •Virus inactivation increases by raising HBCE inlet air temperature from 150° to 250 °C.•When inlet gas temperature increases, so will thickness and temperature of the heated water layer.•At 250 °C bubble coalescence inhibition (NaCl solutions) effectively inactivates viruses.•250 °C inlet gas temperature reduces thermal energy requirement to 25% of that required for boiling. An improved hot bubble column evaporator (HBCE) was used to study virus inactivation rates using hot bubble-virus interactions in two different conditions: (1) using the bubble coalescence inhibition phenomenon of monovalent electrolytes and (2) with reducing the electrostatic repulsive forces between virus and bubble, by the addition of divalent electrolytes. It is shown that the continuous flow of (dry) air, even at 150–250 °C, only heats the aqueous solution in the bubble column to about 45°–55 °C and it was also established that viruses are not significantly affected by even long term exposure to this solution temperature, as confirmed separately from water bath experiments. Hence, the effects observed appeared to be caused entirely by collisions between the hot air bubbles and the virus organisms. It was also established that the use of high air inlet temperatures, for short periods of time, can reduce the thermal energy requirement to only about 25% (about 114 kJ/L) of that required for boiling (about 450 kJ/L).