Asenic removal from groundwater using granular chitosan-titanium adsorbent

Area of Science:

• Environmental Science
• Materials Science
• Chemistry

Background:

• Arsenic contamination in groundwater is a significant environmental and health concern.
• Efficient and cost-effective adsorbents are needed for arsenic removal.
• Current methods face challenges in adsorbent performance and regeneration.

Purpose of the Study:

• To develop a novel granular adsorbent for arsenic removal from groundwater.
• To investigate the adsorption kinetics, isotherm, and mechanism of arsenic onto the adsorbent.
• To evaluate the performance and reusability of the adsorbent in column tests.

Main Methods:

• Fabrication of a chitosan-titanium (CS-Ti) adsorbent using the sol-gel method.
• Batch adsorption experiments to study kinetics and isotherms.
• In situ FTIR spectroscopy to analyze adsorbent composition and bonding.
• Small-scale column tests for groundwater treatment and regeneration studies.

Main Results:

• The CS-Ti adsorbent demonstrated pseudo-second-order kinetics and Freundlich isotherm behavior for As(V) adsorption.
• Amorphous TiOx within the CS-Ti structure, bonded via C-O-Ti and N-Ti, was identified as the active adsorption site.
• Column tests showed effective removal of 165.6 μg/L As in groundwater over 126 bed volumes.
• The adsorbent was successfully regenerated using 0.01 mol/L NaOH and maintained efficiency over four cycles.

Conclusions:

• The novel CS-Ti adsorbent is a promising material for efficient arsenic removal from contaminated groundwater.
• The sol-gel fabrication method provides a simple and practical route for adsorbent development.
• The adsorbent's reusability and effectiveness in column tests highlight its potential for real-world water treatment applications.