Anionic Dye Removal with a Thin Cationic Polyaniline Coating on Cellulosic Biomaterial.

Area of Science:

• Materials Science
• Environmental Chemistry
• Polymer Science

Background:

• Phenol red (PSP) is an anionic dye commonly found in industrial wastewater.
• Effective removal of dyes like PSP is crucial for environmental protection.
• Developing efficient and sustainable adsorbents is a key challenge in water treatment.

Purpose of the Study:

• To develop novel adsorbent materials by grafting polyaniline (PANI) onto Posidonia (POS) fibers.
• To investigate the adsorption efficiency of these POS@PANI materials for phenol red (PSP) removal from aqueous solutions.
• To characterize the structural properties and binding affinities of the synthesized adsorbents.

Main Methods:

• Synthesis of polyaniline-grafted Posidonia fibers (POS@PANI) via copolymerization.
• Characterization of POS@PANI-ES and POS@PANI-EB adsorbents.
• Adsorption experiments to determine binding percentage, kinetics, and capacity for PSP.
• Fitting experimental data to Langmuir and Volmer adsorption models.

Main Results:

• POS@PANI-ES and POS@PANI-EB showed rapid adsorption of PSP, with binding percentages of 97% and 50% respectively within 15 minutes.
• Adsorption capacities for PSP were 71.5 μmol g⁻¹ for POS@PANI-ES and 37.8 μmol g⁻¹ for POS@PANI-EB.
• Adsorption followed Langmuir and Volmer models, providing thermodynamic parameters.
• Adsorption efficiency remained high (>80%) at moderate salt concentrations but decreased with higher NaCl and CaCl₂ concentrations.

Conclusions:

• Polyaniline-grafted Posidonia fibers are effective bioadsorbents for phenol red removal.
• The POS@PANI-ES form exhibits superior adsorption performance compared to POS@PANI-EB.
• These novel materials offer a sustainable and efficient approach for treating dye-contaminated wastewater.