Biosorption of lead from aqueous solutions by marine algae Ecklonia radiata

Experimental studies showed that brown marine algae, Ecklonia radiata, can be used for the development of an efficient biosorbent material for heavy metal removal from wastewater. E. radiata exhibited high uptake capacities for lead, cadmium and copper. In particular, lead sorption was very marked. The equlibrium data fitted well to the Langmuir isotherm model. Within a pH range of 4.5 to 5.5, the uptake capacity of E. radiata for lead is 1.36 mM/g (282 mg/g), which is much higher than those of powdered activated carbon and natural zeolite. Studies indicated that sorption of lead increases as pH increases and reaches a plateau at pH 5. The lead uptake process was rapid, with 60% of the sorption completed within 10 minutes. Presence of light metal ions in solution did not affect lead sorption significantly. Breakthrough curves of fixed bed operations were obtained to illustrate the process of lead removal in a continuous flow system.