Biosorption of toxic heavy metals from aqueous solution by Ulva lactuca activated carbon

• Algal dosage, pH, metal concentration and contact time influence the biosorption efficiency.
• The marine Ulva lactuca has high capacity for biosorption.
• The highest biosorption efficiency was 84.6 mg/g.

Pollution with heavy metals is one of the most severe environmental problems in the world. In this study, the batch adsorption of toxic Cu+2, Cr+3, Cd+2 and Pb+2 ions using marine macroalga Ulva lactuca (AP) and its activated carbon (AAC) were examined. The adsorption mechanism of heavy metal ions on AP and AAC was studied using various analytical techniques. The effect of several parameters such as contact time, algal dose, effect of pH, and initial concentration of metal ions on the adsorption process was estimated. The optimum adsorption was found to occur at pH 5.0, contact time 60 min, adsorbent dose 0.8 g/L, and initial concentration 60 mg/L. The maximum removal efficiency values of AP and AAC for heavy metal ions were 64.5 and 84.7 mg/g for Cu+2, 62.5 and 84.6 mg/g for Cd+2, 60.9 and 82 mg/g for Cr+3, and 68.9 and 83.3 mg/g for Pb+2. This work confirms the potential use of green macroalga U. lactuca and its activated carbon for the removal of heavy metals from contaminated water.