Influence of the Drying Conditions ofSargassumsp. Alga on the Bioadsorption of Hexavalent Chromium

Abstract

Industrial wastes containing synthetic organic compounds and heavy metals are among the most dangerous residues, whose growth has followed the increase in industrial activity. Heavy metals are readily assimilated into the food chain and therefore easily accumulated in the ecosystem. To remove heavy metals from aqueous solutions, marine algae may be used as adsorbents either in their natural form or after treatments by a cross-linking process to improve their mechanical resistance. Drying of biosorbents, such as marine algae, is mentioned in many previous works as a step preceding the adsorption/dessorption cycle. Concerning algae, drying of its fresh biomass allows for proper storage and enhances performance in the sorption of heavy metals. In this work, physical and morphological analyses of fresh and dried Sargassum sp. marine algae, harvested offshore São Sebastião, São Paulo state, Brazil, were performed in order to assess the influence of drying conditions on the biosorption process. Chromium concentrations were also determined in different parts of the algal structure before and after the biosorption process. The drying promoted structural changes in the algae, like shrinkage and porosity reduction. It was also observed that the chromium retention was dependent on the structural arrangement of the alga parts, in which the leaf was the major biosorbent.

Adsorption mechanism of rare earth elements in Laminaria ochroleuca and Porphyra haitanensis

“…The biosorption capability of algae has been attributed mainly to the cell wall, which is composed of reticular apparatus by polysaccharides, protein, and lipids. There are several chemical groups can attract and sequester the metals: carbonyl, hydroxyl, carboxyl, amino, amido, sulfhydryl, and phosphate, of which the carboxyl and sulfhydryl groups are considered to play an important role in binding (Rocha, De Assis, Da Silva, & Gonçalves, ).The sorption capacity of different kinds of algae is distinct, which can be attributed to the chemical composition of the corresponding cell walls.…”

Pulverized Banana Peel as an Economical Sorbent for the Preconcentration of Metals

“…Various authors have reported increases in the metal sorption capacity in the case of heat-inactivated biomass samples (Kacar et al 2002;Bayramoglu, Bektas, and Arica 2003;Gurisik et al 2004;Arica et al 2005;Tunali, Kiran, and Akar 2005). Drying of biomass also has been reported by many researchers as having a positive effect on metal uptake (Rocha et al 2006). On the other side, it seems likely that saponification of various ester groups may be involved, increasing the number of carboxylate groups on the treated surfaces (Reddad et al 2002;Xuan et al 2006;Li et al 2007;.…”

Adsorptive Removal of Chromium by Dried Brown Alga Sargassum Hornschuchii

“…Moreover, drying and grinding biomasses reveal the sites where metal ions could be sequestered and so increase the probability of encountering metal ions. Besides, the metal removal system using dried biomass is not subject to toxicity limitations (Rocha et al, 2006, Parameswari et al, 2009and Mane et al, 2010.…”