Simultaneous Removal of Some Heavy Metal Ions From Aqueous Solutions by Magnetic Mg-Al Layered Double Hydroxide...

Area of Science:

• Materials Science
• Environmental Science
• Biotechnology

Background:

• Conventional adsorbents for heavy metal removal face limitations in selectivity and reusability.
• Biomass-based adsorbents offer potential but often lack sufficient capacity and stability.
• Developing efficient, sustainable, and magnetically separable adsorbents is crucial for water remediation.

Purpose of the Study:

• To fabricate a magnetic Mg-Al layered double hydroxide (LDH) nano-bio-composite functionalized with Dunaliella salina (D. salina).
• To evaluate the enhanced heavy metal removal efficiency and selectivity of the nano-bio-composite in aqueous systems.
• To investigate the adsorption mechanism, thermodynamics, kinetics, and reusability of the developed material.

Main Methods:

• Fabrication of a magnetic Mg-Al LDH nano-bio-composite using D. salina.
• Batch adsorption experiments for heavy metal removal (Pb(II), Cu(II), Cd(II), Ni(II), Co(II)).
• Thermodynamic, kinetic, and isotherm modeling (Langmuir, pseudo-first-order, pseudo-second-order).
• Regeneration studies over five cycles.

Main Results:

• The nano-bio-composite demonstrated superior uptake for Pb(II) and Cu(II) compared to conventional adsorbents.
• Adsorption processes were endothermic and entropy-driven, fitting the Langmuir isotherm model.
• Kinetic studies indicated pseudo-first-order for Cu(II), Cd(II), Ni(II), Co(II) and pseudo-second-order for Pb(II).
• The material maintained high efficiency for Pb(II) and Cu(II) over five regeneration cycles.

Conclusions:

• The microalga-LDH nano-bio-composite offers a synergistic enhancement in adsorption capacity and selectivity for heavy metals.
• The material is sustainable, magnetically separable, and highly reusable, addressing limitations of current remediation technologies.
• This novel platform presents a promising solution for efficient and eco-friendly heavy metal removal from water.