Biosorption of cadmium with brown macroalgae.

Area of Science:

• Environmental Science
• Marine Biology
• Biotechnology

Background:

• Cadmium is a toxic heavy metal posing significant environmental and health risks.
• Effective and sustainable methods for cadmium removal from contaminated water are crucial.
• Brown macroalgae are increasingly recognized for their biosorption potential.

Purpose of the Study:

• To evaluate the efficacy of Lessonia nigrescens and Durvillaea antarctica for cadmium removal.
• To determine optimal conditions and kinetic models for cadmium sorption by these macroalgae.
• To compare the cadmium uptake capacity and kinetics of the two selected brown macroalgae.

Main Methods:

• Batch sorption experiments were conducted using Lessonia nigrescens and Durvillaea antarctica.
• Optimum pH, contact time, and equilibrium were investigated for cadmium sorption.
• Sorption isotherms and kinetics were analyzed using Langmuir, Lagergren pseudo-first-order, and Ho and McKay pseudo-second-order models.

Main Results:

• Both macroalgae demonstrated significant cadmium removal capabilities.
• Optimal sorption occurred at pH 3.7±0.2, requiring 5 days for equilibrium.
• Maximum experimental uptake was 109.5 mg Cd g⁻¹ for L. nigrescens and 95.3 mg Cd g⁻¹ for D. antarctica.
• Langmuir model accurately described equilibrium, while kinetic models varied between species; D. antarctica showed faster uptake.

Conclusions:

• Lessonia nigrescens and Durvillaea antarctica are effective biosorbents for cadmium removal.
• L. nigrescens exhibited a higher sorption capacity than D. antarctica.
• The study provides valuable data for developing algal-based cadmium remediation strategies.