Carboxymethyl cellulose thiol-imprinted polymers: Synthesis, characterization and selective Hg(II) adsorption.

Area of Science:

• Environmental Chemistry
• Polymer Science
• Materials Science

Background:

• Mercury (Hg(II)) is a toxic heavy metal pollutant.
• Effective removal of Hg(II) from aqueous solutions is crucial for environmental protection.
• Ion-imprinted polymers offer selective adsorption capabilities.

Purpose of the Study:

• To develop and evaluate sulfur-containing ion-imprinted polymers (S-IIPs) for Hg(II) removal.
• To investigate the adsorption mechanism, capacity, and selectivity of S-IIPs.
• To assess the performance of S-IIPs in real water samples and their reusability.

Main Methods:

• Grafting cysteamine onto epichlorohydrin crosslinked carboxylated carboxymethyl cellulose.
• Utilizing kinetic and isotherm models (pseudo-second-order, Langmuir) to study adsorption.
• Performing thermodynamic analysis and selectivity tests against other metal ions.
• Evaluating S-IIPs efficiency in real wastewater, groundwater, and tap water samples.

Main Results:

• S-IIPs exhibited a maximum adsorption capacity of 80 mg/g for Hg(II).
• Adsorption followed pseudo-second-order kinetics and Langmuir isotherm models.
• Thermodynamic studies indicated a spontaneous, endothermic adsorption process.
• High selectivity for Hg(II) was observed in the presence of other metal ions.
• Successful Hg(II) removal from real water samples (86-99% recovery).
• The adsorbent was regenerated for five cycles with minimal loss of adsorption capability.

Conclusions:

• S-IIPs are highly effective and selective adsorbents for Hg(II) removal from aqueous solutions.
• The developed S-IIPs show excellent potential for practical applications in water remediation.
• The reusability of S-IIPs enhances their economic viability for environmental cleanup.