Double Nanofoaming Enhanced Interfacial Polymerization toward Ultra-High-Performance Nanofiltration Membranes

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Polyamide (PA) nanofiltration (NF) membranes are crucial for safe drinking water production.
• A key challenge is selectively removing contaminants while retaining essential minerals.
• Cost-effective modification of NF membranes is needed for efficient water treatment.

Purpose of the Study:

• To develop high-performance NF membranes for drinking water applications using ammonia bicarbonate (AB) as an additive.
• To investigate the mechanisms by which AB modifies interfacial polymerization (IP).
• To enhance membrane permeance and selectivity for contaminant removal and mineral retention.

Main Methods:

• Modification of interfacial polymerization (IP) using ammonia bicarbonate (AB) additive.
• Comprehensive material characterization and molecular dynamics simulations.
• Performance evaluation of the NF membrane during surface water purification.

Main Results:

• AB controlled IP kinetics, induced dual nanofoaming via reaction and decomposition products (NH3, CO2).
• Optimized NF membrane (NF-AB-8) exhibited a thinner, wrinkled PA layer with improved microstructure.
• NF-AB-8 showed enhanced permeance (28.5 LMH/bar) and selective separation (K_Ca2+/DOM = 34.5), with improved anti-fouling properties.

Conclusions:

• Dual-nanofoaming mechanisms effectively enhance NF membrane performance.
• The developed NF membranes offer improved permeance and selectivity for drinking water treatment.
• This study provides insights for designing advanced NF membranes for water purification.