Enhancing the Ammonia Selectivity by Using Nanofiber PVDF Composite Membranes Fabricated with Functionalized Carbon...

Area of Science:

• Environmental Science
• Materials Science
• Chemical Engineering

Background:

• Membrane distillation (MD) is used for ammonia recovery from anaerobic digestion (AD) effluent.
• Hydrophobic membranes lack selectivity, leading to high energy use due to water evaporation.

Purpose of the Study:

• To enhance ammonia and water selectivity in MD processes for AD effluent treatment.
• To develop functionalized carbon nanotube (CNT)/polyvinylidene fluoride (PVDF) nanofiber membranes.

Main Methods:

• Fabrication of CNT/PVDF nanofiber membranes via electrospinning.
• Investigation of CNT type and content effects on membrane performance.
• Measurement of contact angles, ammonia nitrogen transfer coefficient, and ammonia separation factor.

Main Results:

• CNTs were successfully incorporated into PVDF nanofibers.
• Composite membranes exhibited higher contact angles (up to 138°) than commercial membranes.
• Ammonia nitrogen transfer coefficient doubled compared to commercial membranes (3.41 × 10^-6 m/s).
• Carboxylated CNT composite membranes showed superior ammonia separation factors (47% and 25% higher than commercial and neat PVDF, respectively).

Conclusions:

• Functionalized CNTs significantly enhance the selectivity of PVDF membranes for ammonia recovery.
• The developed CNT/PVDF membranes offer a promising, energy-efficient solution for AD effluent treatment.
• This study presents a novel method for improving ammonia and water selectivity in membrane-based wastewater treatment.