Preparation and characterization of biochar and activated carbon from marine macro-algal Sargassum ilicifolium and freshwater microalgal Scenedesmus quadricauda biomass have been examined as adsorbents for the removal of lead from aqueous solutions. Using a slow pyrolysis process biochars generated at 500°C under nitrogen atmosphere with the residence times of 60 min. The activated carbons have prepared by KOH activation under the same carbonization conditions of biochar. Pyrolysis characteristics of four carbonaceous adsorbents were studied by using the FTIR, BET and SEM analysis. The SEM images of BC and AC samples can be argued that all sorbents have a heterogeneous, well-developed structure. FTIR analysis results revealed the presence of –OH, COOH, C=O, and C-C functional groups in chars and activated carbons. Biochars and activated carbons prepared from (SI) and (Sq) showed surface area around 3.6, 54.6, 8.3 and 81.15 m 2 g ?1 , respectively. Adsorption Experiments of lead by batch study using Taguchi experimental design in five level, with four factors including lead (II) ions concentration, the adsorbent dose, contact time and pH have been carried out, that initial concentration and dose adsorbent had the most influence on the sorption, respectively for chars and activated carbons. Contact time in four sorbent had the less effect. The adsorption efficiency of lead for carbonaceous adsorbents in the optimal conditions were more than 90%. It was found that biochars removes lead ion from aqueous solution as well as the activated carbons. Results showed that the adsorption process was better described by the Langmuir model. It was found that the kinetics data fitted well to the pseudo second-order kinetics. It was shown that all sorbents can be regenerated and used as a sorbents of multi-use. 0.1 M HNO 3 was the best eluent for desorption of lead ion in the sorption/desorption studies in the third stage. It was proved that chars and activated carbons removes more efficiently lead ion from aqueous solutions than the commercial activated carbons. Keywords: Algae, Biochar, Activated carbon, Adsorption and Lead.
