Chitosan-Modified Coconut Shell Activated Carbon for Efficient Hexavalent Chromium Removal from Aqueous Solution

Area of Science:

• Environmental Science
• Materials Science
• Chemical Engineering

Background:

• Hexavalent chromium (Cr(VI)) poses significant environmental and health risks.
• Conventional wastewater treatment methods often face challenges in Cr(VI) removal efficiency and cost-effectiveness.

Purpose of the Study:

• To develop and evaluate a novel composite adsorbent for efficient Cr(VI) removal from aqueous solutions.
• To investigate the adsorption mechanism and performance of the composite under various conditions.

Main Methods:

• Chitosan (CS) was used to modify coconut shell activated carbon (CAC) creating a CS-AC composite.
• Adsorption experiments were conducted to assess the effects of adsorbent dosage, initial Cr(VI) concentration, contact time, temperature, and pH.
• Kinetic and isotherm modeling were applied to understand the adsorption process.
• Regeneration studies were performed to evaluate the adsorbent's reusability.

Main Results:

• The CS-AC composite demonstrated significantly enhanced adsorption performance for Cr(VI).
• Optimal conditions yielded a Cr(VI) removal efficiency of up to 99.04%.
• The adsorption process followed pseudo-second-order kinetics and was best described by the Langmuir isotherm model.
• The composite retained over 98% removal efficiency after five regeneration cycles, indicating excellent reusability.

Conclusions:

• The CS-AC composite is a highly effective and reusable adsorbent for Cr(VI) removal.
• This material presents a promising solution for treating Cr(VI)-contaminated wastewater.
• The study highlights the potential of modified activated carbon for environmental remediation.