Bioinspired Microgel-Loaded Smart Membrane Filtration with the Thermo- and Ion-Dual Responsive Water Gate for...

Area of Science:

• Materials Science
• Environmental Science
• Chemical Engineering

Background:

• Lead (Pb²⁺) is a pervasive environmental pollutant. Conventional membrane filtration methods like nanofiltration, ultrafiltration, and microfiltration face limitations in cost-effectively and efficiently removing dissolved ions like lead.
• Existing technologies struggle with high energy requirements or insufficient selectivity for direct ion removal, posing challenges for clean water access.

Purpose of the Study:

• To develop a smart, adsorptive filtration membrane capable of selective lead ion (Pb²⁺) removal.
• To create a membrane with a tunable water gate for efficient water purification and lead remediation.

Main Methods:

• Preparation of dual-responsive poly(N-isopropylacrylamido-co-acrylamido-benzo-18-crown-6) (PNB-5-20) microgels.
• Loading PNB-5-20 microgels onto a commercial membrane to create a smart Pb²⁺-adsorptive filtration membrane.
• Characterization of microgel properties, including temperature-responsive swelling/deswelling and Pb²⁺ adsorption capacity and selectivity.

Main Results:

• The PNB-5-20 microgel demonstrated significant temperature-responsive swelling/deswelling behavior with a volume phase transition temperature (VPTT) around 33 °C.
• The microgel exhibited high Pb²⁺ adsorption capacity (85.4 mg/g) and selectivity (Kd ~ 1000 mL/g) due to crown ether complexation.
• The presence of Pb²⁺ shifted the VPTT to 40 °C, enabling ion-responsive gate control in the functionalized membrane.

Conclusions:

• A smart membrane integrating Pb²⁺ detection, adsorption, and tunable water drainage was successfully fabricated.
• The membrane selectively captures Pb²⁺ by closing its pores and can be reopened by increasing temperature, simplifying lead-polluted water remediation.
• This intelligent membrane filtration system offers a promising, efficient, and cost-effective solution for removing lead from contaminated water sources.