Hydroxyapatite derived from eggshell embedded on functionalized g-C₃N₄ for synergistic extraction of U(VI) from...

Area of Science:

• Materials Science
• Environmental Science
• Nanotechnology

Background:

• Graphitic carbon nitride (gCN) is a promising material for environmental applications.
• Eggshell waste is an abundant and underutilized biowaste resource.
• Developing efficient adsorbents for heavy metal removal is crucial for environmental protection.

Purpose of the Study:

• To synthesize and characterize a novel nanocomposite material (HAp@D-gCN) for Uranium(VI) removal.
• To investigate the sorption mechanism and capacity of HAp@D-gCN for U(VI) species.
• To evaluate the reusability and potential environmental remediation applications of the synthesized material.

Main Methods:

• Synthesis of hydroxyapatite (HAp) from eggshell waste and its functionalization onto diglycolamic acid modified graphitic carbon nitride (D-gCN).
• Characterization of HAp@D-gCN using SEM, XRD, BET, FTIR, and zeta potential measurements.
• Batch sorption studies to optimize U(VI) removal efficiency by varying parameters like pH, contact time, initial U(VI) concentration, adsorbent dosage, and ionic strength.

Main Results:

• The HAp@D-gCN nanocomposite was successfully synthesized and characterized, confirming the presence of HAp and D-gCN components.
• Adsorption kinetics followed a pseudo-second-order model, reaching equilibrium within 20 minutes.
• The Langmuir isotherm model best described the adsorption data, yielding a maximum sorption capacity of 993.6 mg U(VI)/g at 298K.
• U(VI) could be effectively desorbed using 0.01 M Na2CO3, with the adsorbent retaining its capacity after four adsorption-desorption cycles.

Conclusions:

• HAp@D-gCN is a highly efficient and recyclable adsorbent for Uranium(VI) removal from aqueous solutions.
• The use of eggshell biowaste for HAp synthesis aligns with circular economy principles.
• This nanocomposite shows significant potential for practical applications in environmental remediation of uranium-contaminated water.