Thiol-Functionalized Covalent Organic Framework for Efficient Metal Ion Removal in Water Treatment

Area of Science:

• Materials Science
• Environmental Chemistry
• Water Treatment

Background:

• Advanced water treatment requires selective, efficient, and cost-effective contaminant removal methods.
• Metal ion contamination in water poses significant environmental and health risks.
• Development of novel adsorbent materials is crucial for effective water purification.

Purpose of the Study:

• To synthesize and evaluate a thiol-functionalized covalent organic framework (TPB-DMTP-COF-SH) for the adsorption of aluminum (Al³⁺), iron (Fe²⁺), and manganese (Mn²⁺) ions from water.
• To investigate the adsorption performance influenced by various parameters.
• To assess the material's potential for real-world water treatment applications.

Main Methods:

• Two-step synthesis of TPB-DMTP-COF-SH from 1,3,5-tris(4-aminophenyl)benzene (TPB) and 2,5-dimethoxyterephaldehyde (DMTP).
• Batch adsorption experiments to determine optimal pH, initial concentration, and contact time.
• Adsorption isotherm (Langmuir) and kinetic (pseudo-second-order) studies.
• Demonstration of processability into composite beads and membranes.

Main Results:

• Optimal adsorption pH: 3 for Al³⁺, 8 for Fe²⁺, and 10 for Mn²⁺.
• Maximum adsorption capacities: 3.27 mg g⁻¹ (Al³⁺), 8.5 mg g⁻¹ (Fe²⁺), and 0.67 mg g⁻¹ (Mn²⁺).
• Adsorption followed Langmuir isotherm and pseudo-second-order kinetics, indicating chemisorption.
• Equilibrium reached within 15-20 minutes.
• Successful fabrication into composite beads and membranes.

Conclusions:

• TPB-DMTP-COF-SH is a highly effective adsorbent for Al³⁺, Fe²⁺, and Mn²⁺ ions in water.
• The material exhibits excellent adsorption performance and rapid kinetics.
• Enhanced processability into beads and membranes makes it suitable for practical water treatment systems.
• This thiol-functionalized COF presents a promising, scalable solution for water purification.