Picric Acid Removal from Water Using an Anion-Coordination-Based Supramolecular Organic Framework

Area of Science:

• Materials Science
• Supramolecular Chemistry
• Environmental Chemistry

Background:

• Metal ions are common in metal-organic frameworks (MOFs), but anions are rarely used in supramolecular organic frameworks (SOFs).
• Developing novel SOFs with unique coordination centers is crucial for advanced material applications.

Purpose of the Study:

• To introduce a new supramolecular organic framework (SOF) utilizing chloride anions as a key coordination component.
• To investigate the structural properties, stability, and hazardous waste removal capabilities of the novel chloride-SOF.

Main Methods:

• Synthesis of a chloride-SOF using chloride anions and a flexible oligopyrrole.
• Characterization of the SOF's thermal stability and structural integrity upon desolvation.
• Testing the efficiency of the desolvated chloride-SOF in removing picric acid from contaminated water.

Main Results:

• The synthesized chloride-SOF demonstrated reasonable thermal stability and retained its structure after desolvation.
• The material effectively reduced picric acid concentrations from 100 mg L^-1 to the ng L^-1 (ppt) level.
• Picric acid removal occurred through anion exchange and adaptive structural transformation, not solely pore selectivity.

Conclusions:

• Chloride-SOF represents a novel class of SOFs using anions as coordination centers.
• The material exhibits significant potential for hazardous waste removal, particularly for toxic organic pollutants.
• The study highlights the utility of structurally transformable SOFs in environmental remediation applications.