Volatile Sieving Using Architecturally Designed Nanochannel Lamellar Membranes in Membrane Desalination

Area of Science:

• Materials Science
• Environmental Engineering
• Chemical Engineering

Background:

• Thermally driven membrane processes are promising for hypersaline wastewater treatment.
• Challenges exist in simultaneously achieving high volatile rejection and water flux.

Purpose of the Study:

• To develop a novel thermo-osmosis-evaporation (TOE) system for effective hypersaline wastewater treatment.
• To enhance membrane performance for separating volatile and nonvolatile contaminants.

Main Methods:

• Utilized molecular intercalation-regulated graphene oxide (GO) as a thermo-osmotic selective layer.
• Constructed interlaminar nanochannels in GO membranes by confining small molecules and incorporating polymers.
• Integrated the GO layer with a hydrophobic poly(vinylidene fluoride) fibrous membrane for thermo-evaporation.

Main Results:

• Achieved 100% rejection of NaCl and 97.41% rejection of volatile phenylamine.
• Demonstrated a water permeance of 63.80 L m⁻² h⁻¹ at a 40 °C temperature difference.
• Outperformed previously reported GO-based membranes in separation efficiency.

Conclusions:

• The polymer network within GO interlayers facilitates efficient separation of ions and volatile molecules.
• Enlarged nanochannels reduce vapor diffusion resistance, enhancing water flux.
• The developed TOE system shows significant potential for complex hypersaline wastewater treatment.