Evaluation of the Marine Algae Sargassum latifolium and Sargassum crassifolium for the Biosorption of Heavy Metal Ions from Aqueous Solutions

A batch experimental study was conducted using biomass of two algal species, Sargassum latifolium, and Sargassum crassifolium, collected from the Gulf of Suezto investigate their ability to remove cadmium (Cd), copper (Cu), cobalt (Co), and nickel (Ni) ions from aqueous solutions. Those solutions were prepared in the laboratory by dissolving (CH₃COO)₂Pb.3H₂O, Ni(NO₃)₂.6H₂O, CdCl₂H₂O, and CuSO₄.5H₂O (analytical grade) in double distilled water. Biomass of both algal species was grounded and then sieved to three different sizes (0.63, 0.125, and 0.250μm). Some experimental conditions (pH, biomass dosage, particle size, agitation speed, contact time, and initial concentrations of metal ions) were optimized to test and define the best conditions for the maximum heavy metals removal attainment. In addition, the tested conditions were also gathered with various factors to determine the most effective combination. Results showed that the algal biomass of both species was significantly efficient in removing the tested metal ions as both Sargassum species performed a percentage of  99, 88, 99, and 99% for the biosorption of Pb, Cd, Ni, and Cu, respectively. Experimental conditions results determined that the maximum metal uptake for both sargassum species was attained at 8 pH during a contact time of 60 minutes, considering these levels as the optimum conditions for the best absorption efficiency. Such results showed the potential use of macroalgae for biosorption functions. Results confirmed that both brown seaweed species were promising, highly competent, and biodegradable biosorbents. These results enabled new methodologies to remove heavy metal pollutants from industrial wastewater while being economically valuable and environmentally safe.