Advanced analysis via statistical physics model to study the efficiency of catechol removal from wastewater using...

Area of Science:

• Environmental Chemistry
• Materials Science
• Adsorption Science

Background:

• Catechol is a phenolic compound and a common pollutant in industrial wastewater.
• Activated carbon derived from biomass offers a sustainable adsorbent material.
• Brazil nut shell is an underutilized agricultural waste suitable for adsorbent production.

Purpose of the Study:

• To prepare and characterize Brazil nut shell activated carbon (BNAC).
• To investigate the adsorption properties of BNAC for catechol removal from aqueous solutions.
• To elucidate the adsorption mechanism using statistical physics and thermodynamic analysis.

Main Methods:

• Preparation and characterization of activated carbon from Brazil nut shells.
• Experimental quantification of catechol adsorption isotherms at varying pH and temperature.
• Fitting adsorption data to monolayer models and statistical physics calculations.
• Analysis of thermodynamic parameters (entropy, internal energy, Gibbs free energy).

Main Results:

• Maximum catechol adsorption capacity ranged from 89.98 to 103.16 mg/g.
• Adsorption was found to be exothermic, with capacity increasing with temperature up to 55°C.
• Catechol molecules adsorbed with nonparallel orientations (n > 1), indicating multilayer interactions.
• Calculated molar adsorption energies (19.04–22.37 kJ/mol) suggest a physisorption process.
• Adsorbent exhibited unimodal pore size and site energy distributions.

Conclusions:

• Brazil nut shell activated carbon is an effective adsorbent for catechol removal.
• The adsorption process is spontaneous, exothermic, and driven by physisorption mechanisms.
• The study provides insights into the adsorption mechanism and adsorbent characteristics for water treatment applications.