Mercapto functionalized silica entrapped polyacrylamide hydrogel: Arsenic adsorption behaviour from aqueous solution

Area of Science:

• Materials Science
• Environmental Chemistry
• Water Treatment

Background:

• Arsenic contamination in water poses significant health risks.
• Effective and economical methods for arsenic removal are crucial for public health.
• Functionalized hydrogels offer promising adsorption capabilities for heavy metals.

Purpose of the Study:

• To synthesize and characterize a novel adsorbent material for arsenic removal.
• To evaluate the efficiency of the synthesized hydrogel in removing arsenic(III) from aqueous solutions.
• To investigate the adsorption mechanism and kinetics of arsenic(III) onto the hydrogel.

Main Methods:

• Preparation of 3-mercaptopropyl functionalized silica entrapped polyacrylamide hydrogel (MPFS-PAA).
• Characterization using FT-IR, SEM, and EDS techniques.
• Batch adsorption experiments varying contact time, initial arsenic concentration, and pH.
• Analysis of adsorption data using Langmuir and Freundlich isotherm models and pseudo-second-order kinetics.

Main Results:

• MPFS-PAA hydrogel was successfully synthesized and characterized.
• Adsorption studies demonstrated effective removal of arsenic(III).
• Langmuir isotherm yielded a maximum adsorption capacity of 92.5 μg/g at an initial concentration of 100 μg/L.
• Adsorption kinetics followed a pseudo-second-order reaction with a high correlation coefficient (R² = 99.67%).

Conclusions:

• MPFS-PAA hydrogel is a highly effective adsorbent for arsenic(III) removal from aqueous solutions.
• The adsorption process is well-described by Langmuir and Freundlich isotherms and pseudo-second-order kinetics.
• This material shows potential for practical application in water purification technologies.