A Laboratory Study for Alginate Hydrogel Extracted from the Brown Marine Algae (Sargassum vulgare) for the Simultaneous Removal of Lead (Pb²⁺), Cadmium (Cd²⁺), and Copper (Cu²⁺) Ions from Aqueous Solutions

Abstract

This study aims to evaluate the efficiency of alginate hydrogel extracted from the brown marine algae Sargassum vulgare for the simultaneous removal of lead (Pb²⁺), cadmium (Cd²⁺), and copper (Cu²⁺) ions from aqueous solutions using a biosorption approach. Alginate was extracted from the seaweed and subsequently converted into a hydrogel using a calcium chloride solution, which was then employed as a bio sorbent material. The concentrations of metal ions in standard solutions were measured before and after the adsorption process using a spectrophotometer following the formation of suitable colored complexes for each metal ion. The results demonstrated a significant reduction in metal ion concentrations, with removal efficiencies reaching 92.4% for lead, 87.6% for cadmium, and 81.3% for copper under optimal experimental conditions (pH 5–6, contact time 60 minutes, and an alginate hydrogel dose of 0.5 g per 100 mL solution). The study revealed that the hydrogel provides enough binding sites for heavy metal ions and can be regenerated through washing, making it an effective, low-cost, and environmentally friendly material for treating contaminated water. These findings highlight the potential of alginate hydrogel as a sustainable and practical solution for heavy metal removal in both laboratory and industrial applications.