Co/SH-based MOFs incorporated nanofiltration membranes for efficient selenium uptake in water purification

Area of Science:

• Materials Science
• Environmental Science
• Chemical Engineering

Background:

• Metal-Organic Frameworks (MOFs) show promise for water pollutant removal, but face challenges in efficiency and recovery for selenium (Se).
• Existing MOFs exhibit limitations in removing toxic selenium and are difficult to recover post-treatment.

Purpose of the Study:

• To develop a Co-MOF-74-SH material with dual active sites for enhanced selenium adsorption.
• To fabricate a multi-functional nanofiltration (NF) membrane incorporating Co-MOF-74-SH for efficient selenium removal and salt separation.

Main Methods:

• Synthesis of Co-MOF-74-SH with dual Co/S active sites.
• Immobilization of Co-MOF-74-SH into a NF membrane.
• Density Functional Theory (DFT) simulations to study Se adsorption mechanisms.
• Evaluation of membrane performance for selenium removal and salt separation.

Main Results:

• Co-MOF-74-SH demonstrated a high Se removal efficiency of 94.1% due to strong cooperative interactions between Co/S sites and selenium.
• The fabricated NF membrane achieved a remarkable Se removal of ~99.6%, significantly outperforming the original membrane (~74.4%).
• The membrane exhibited excellent divalent/monovalent salt selectivity (>80) and high water permeance (15.80 Lm⁻²h⁻¹bar⁻¹).

Conclusions:

• The developed Co-MOF-74-SH material and its incorporated NF membrane offer a highly efficient solution for selenium removal from water.
• This work provides a new avenue for designing advanced membrane materials for water purification and wastewater resource utilization.