New sulfonated covalent organic framework for highly effective As(III) removal from water

Area of Science:

• Environmental Chemistry
• Materials Science
• Water Treatment

Background:

• Arsenic(III) contamination in water poses significant risks to human health and ecosystems.
• Effective removal of toxic metals from water is crucial for environmental protection.

Purpose of the Study:

• To synthesize and evaluate a novel adsorbent, TFPOTDB-SO3H, for the efficient removal of arsenic(III) ions from aqueous solutions.
• To investigate the adsorption performance, kinetics, thermodynamics, and reusability of the synthesized adsorbent.

Main Methods:

• Synthesis of TFPOTDB-SO3H via the combination of 2,5-diaminobenzenesulfonic acid and 2,4,6-tris-(4-formylphenoxy)-1,3,5-triazine.
• Batch adsorption experiments to determine the effect of pH, contact time, and co-existing anions.
• Analysis of adsorption kinetics using the quasi-second order model and isotherms using the Langmuir model.
• Thermodynamic studies and cyclic adsorption-desorption tests to assess reusability.

Main Results:

• TFPOTDB-SO3H achieved a high removal rate of 97.1% for As(III) within 10 minutes at pH 8 and room temperature.
• The maximum adsorption capacity was found to be 344.8 mg/g, with minimal impact (1-7% reduction) from co-existing anions.
• Adsorption followed pseudo-second order kinetics and Langmuir isotherm, indicating monolayer chemisorption.
• The adsorbent maintained 88.86% uptake efficiency after 4 adsorption-desorption cycles, demonstrating excellent reusability.

Conclusions:

• TFPOTDB-SO3H is a highly effective and reusable adsorbent for the removal of As(III) from wastewater.
• The material exhibits excellent adsorption capacity, rapid kinetics, and stability, making it a promising candidate for practical water treatment applications.
• The study highlights the potential of functionalized triazine-based materials for mitigating arsenic pollution.