Cleaning of microfiltration membranes from industrial contaminants using “greener” alternatives in a continuous mode

• Porous membrane cleaning was investigated using a continuous mode system with solvent recirculation.
• Pure scCO2 and scCO2 with minor amounts of organic solvents were used as solvents.
• Effect of pressure, temperature, solvent flow, process time, and solvent composition on cleaning efficiency was investigated.
• Addition of organic solvents leads to higher process rates.
• A “greener” alternative for traditional cleaning methods is provided.

This work presents a sufficient cleaning of microfiltration membranes from industrial contaminants (oils) using supercritical fluids as alternative to industrial use of organic solvents used near their high boiling points. Supercritical carbon dioxide either as pure or with an insignificant addition of “greener” solvents such as ethyl alcohol or isopropyl alcohol were applied in this study. The cleaning process was investigated in a high pressure system with a continuous solvent flow and solvent recirculation. The effect of system pressure, temperature, solvent flow rate, solvent composition, cleaning time and type of the contaminant on cleaning efficiency was analysed. Powerful, “greener” solvents combined with CO2 gave satisfactory results in removing oils from membranes allowing to increase the process rate and cleaning efficiency, as well as reduce energy consumption of the process.

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