Fixed-Bed Adsorption of Lead from Aqueous Solution Using Chitosan-Coated Bentonite

Area of Science:

• Environmental Science
• Materials Science
• Chemical Engineering

Background:

• Lead (Pb(II)) contamination in aqueous solutions poses significant environmental and health risks.
• Adsorption is a promising method for heavy metal removal, but efficient adsorbent materials and system optimization are crucial.
• Chitosan-coated bentonite (CCB) offers potential as an adsorbent due to its unique properties.

Purpose of the Study:

• To investigate the fixed-bed adsorption performance of chitosan-coated bentonite (CCB) for lead (Pb(II)) removal.
• To characterize CCB using Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM).
• To evaluate the influence of operational parameters (bed height, flow rate, initial concentration) on adsorption efficiency and breakthrough characteristics.

Main Methods:

• Fixed-bed column adsorption experiments were conducted using CCB.
• Parameters varied included bed height (1.3–4.3 cm), flow rate (0.20–0.60 mL/min), and initial Pb(II) concentration (500–1500 mg/L).
• Adsorption data were analyzed using kinetic column models: Thomas, Yoon-Nelson, and Clark.

Main Results:

• Lower flow rates and higher bed heights extended the time to breakthrough and exhaustion.
• Higher initial Pb(II) concentrations led to faster breakthrough and exhaustion.
• The Thomas model demonstrated excellent agreement with experimental data (R² ≥ 0.8087), accurately predicting breakthrough curves.

Conclusions:

• Chitosan-coated bentonite is an effective adsorbent for Pb(II) removal in fixed-bed systems.
• Operational parameters significantly influence the adsorption process dynamics.
• The Thomas model is highly suitable for describing Pb(II) adsorption kinetics in this fixed-bed system, aiding in process design and optimization.