Decontamination of bisphenol A and Congo red dye from solution by using CTAB functionalised walnut shell

Area of Science:

• Environmental Chemistry
• Materials Science
• Adsorption Science

Background:

• Bisphenol A (BPA) and Congo red (CR) are common water pollutants.
• Effective and sustainable adsorbents are needed for wastewater treatment.

Purpose of the Study:

• To synthesize and characterize an eco-friendly adsorbent, WNS-CTAB, for BPA and CR removal.
• To investigate the adsorption performance and mechanisms of WNS-CTAB for these pollutants.

Main Methods:

• Synthesis of cationic surfactant-modified walnut shell (WNS-CTAB).
• Characterization using FTIR, XPS, and SEM.
• Adsorption studies using isotherm (Langmuir) and kinetic (pseudo-second-order) models.
• Evaluation of reusability and binary system performance.

Main Results:

• WNS-CTAB exhibited maximum adsorption capacities of 38.5 mg/g for BPA and 104.4 mg/g for CR at 303 K.
• Adsorption followed Langmuir and pseudo-second-order models, indicating monolayer adsorption and chemisorption kinetics.
• WNS-CTAB showed good reusability over three cycles and higher selectivity for CR in a binary system.

Conclusions:

• WNS-CTAB is a promising, reusable adsorbent for removing BPA and CR from aqueous solutions.
• The adsorption mechanisms involve van der Waals, hydrophobic, and electrostatic interactions.
• WNS-CTAB demonstrates significant potential for practical wastewater treatment applications.