Distinguished Cr(VI) capture with rapid and superior capability using polydopamine microsphere: Behavior and...

Area of Science:

• Environmental Science
• Materials Science
• Chemistry

Background:

• Hexavalent chromium (Cr(VI)) poses significant ecological and human health risks.
• Effective and selective removal of Cr(VI) from contaminated water sources is crucial.

Purpose of the Study:

• To synthesize and characterize mussel-inspired polydopamine microspheres (PDA-spheres) for Cr(VI) removal.
• To evaluate the adsorption performance, selectivity, and regeneration capabilities of PDA-spheres for Cr(VI).

Main Methods:

• In situ oxidative polymerization of dopamine to form PDA-spheres.
• Batch adsorption experiments to determine optimal pH, kinetics, and selectivity.
• X-ray photoelectron spectroscopy (XPS) for surface analysis.

Main Results:

• PDA-spheres demonstrated rapid Cr(VI) adsorption, reaching equilibrium in 8 minutes.
• High selectivity for Cr(VI) was observed even in the presence of high concentrations of sulfate, nitrate, and chloride ions.
• Adsorption capacity reached 42,000 kg/kg, reducing effluent Cr(VI) from 2000 ppb to below 50 ppb.
• Effective regeneration of PDA-spheres using binary alkaline and salt mixtures was achieved.

Conclusions:

• Polydopamine microspheres are highly effective and selective adsorbents for Cr(VI) removal from water.
• The material's properties, including morphology and functional groups, contribute to its strong Cr(VI) affinity.
• PDA-spheres show great potential as an ideal material for treating Cr(VI) contaminated wastewater.