High-Efficiency Recovery of Acetic Acid from Water Using Electroactive Gas-Stripping Membranes

Area of Science:

• Chemical Engineering
• Materials Science
• Environmental Science

Background:

• Resource recovery from waste is crucial for carbon neutrality and reducing fossil carbon dependence.
• Volatile fatty acids (VFAs) are valuable carbon-based resources present in various waste streams.

Purpose of the Study:

• To develop and demonstrate a novel membrane contactor for efficient VFA extraction.
• To investigate a combined direct heating and pH swing approach for enhanced VFA recovery.

Main Methods:

• Utilized a multilayer membrane contactor with carbon fiber (CF) resistive heating and a polydimethylsiloxane (PDMS) layer.
• Employed a polyaniline (PANI)-coated CF anode to create an interfacial pH swing for VFA protonation.
• Investigated gas transport mechanism via diffusion through the polymer matrix free volume.

Main Results:

• Achieved highly efficient VFA recovery by simultaneously applying pH swing and joule heating.
• Demonstrated low energy consumption of 3.37 kWh/kg for acetic acid (AA) recovery.
• Obtained an excellent AA/water separation factor of 51.55 ± 2.11 and high AA fluxes of 51.00 ± 0.82 g.m⁻²hr⁻¹.

Conclusions:

• The developed technique offers a new concept for VFA recovery, enabling efficient extraction without bulk temperature or pH modification.
• The multifunctional membrane contactor shows promising prospects for advancements in waste resource recovery and carbon neutrality goals.