Sirlei Jaiana Kleinübing

Equilibrium of Cu(II) and Ni(II) biosorption by marine alga Sargassum filipendula in a dynamic system: Competitiveness and selectivity

The study focuses on the equilibrium of dynamic biosorption in single and binary systems containing Cu(II) and Ni(II) ions using Sargassum filipendula (a marine alga). The experiments were performed in fixed-bed columns with both single-component and bi-component metal solutions (using different molar concentrations). Experimental data were fitted with different equilibrium models such as Langmuir, Langmuir with inhibition, Jain and Snowyink and Langmuir-Freundlich equations. The biosorption of pure metal ions in solution presented adequate capacities both for Cu(II) and Ni(II). In binary solutions the preferential sorption of Cu(II) over Ni(II) was demonstrated by the displacement of Ni(II) (marked overshoot on the breakthrough curves).

Characterization and evaluation of copper and nickel biosorption on acidic algae Sargassum Filipendula

The marine algae Sargassum filipendula was collected from Sao Paulo seashore (Brazil) and submitted to treatment with acid. The biosorption mechanisms of Cu2+ and Ni2+ ions onto acidic algae Sargassum filipendula were examined using various analytical techniques: Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and potentiometric titration (pHZPC). The effect of acidic treatment on algae by hydrochloric acid (pH 2.0, 3.0, 4.0 and 5.0) was evaluated for Cu2+ and Ni2+ adsorption. Alginate was extracted from raw algae and the two types of acids present in the biomass (β-D-mannuronic (M) and α-L-guluronic (G) acid) were characterized by 13C NMR. The M/G ratio was found to be 0.50. According to the pHZPC analysis, at a pH higher than 5.5 the acidified algae surface presents a negative charge. The FT-IR analyses showed that the main chemical groups involved in the biosorption were carboxylic, alcoholic, sulfonate and amino groups.

Sargassum filipendula alginate from Brazil: Seasonal influence and characteristics

The aim of this work is focused on the extraction and characterization of the Brazilian seaweed Sargassum filipendula alginate. Alginates obtained at different seasons were characterized by liquid state nuclear magnetic resonance spectroscopy and scanning electron microscopy. The alginate extraction efficiency was about 20%. Different seasons of the year and different stages in the life cycle of Sargassum sp. in southeastern Brazil influenced the M/G and, consequently, the technological properties of extracted alginates.

Extraction of alginate biopolymer present in marine alga sargassum filipendula and bioadsorption of metallic ions

This paper studies the bioadsorption of Pb2+, Cu2+, Cd2+ and Zn2+ ions by marine alga Sargassum filipendula and by the alginate biopolymer extracted from this alga. The objective is to evaluate the importance of this biopolymer in removing different metallic ions by the marine alga S. filipendula. In the equilibrium study, the same affinity order was observed for both bioadsorbents: Pb2+ > Cu2+ > Zn2+ > Cd2+. For Pb2+ and Cu2+ ions when the alginate is isolated and acting as bioadsorbents, adsorption capacities greater than those found for the alga were observed, indicating that it is the main component responsible for the removal of metallic ions. For Zn2+ and Cd2+ ions, greater bioadsorption capacities were observed for the alga, indicating that other functional groups of the alga, such as sulfates and amino, are also important in the bioadsorption of these ions.

Characterization of Sargassum sp. from Brazil and Evaluation of Cu2+ and Ni2+ Biosorption

Fundamental investigation on adsorption of Cu2+ and Ni2+ ions on Sargassum sp. was performed in fixed-bed column. The Langmuir isotherm fitted well the biosorption equilibrium and the maximum Cu2+ and Ni2+ uptake capacities were 1.35 and 1.06 mmolg- 1, respectively. Mappings of copper and nickel in the algae surface using energy dispersive X-ray spectroscopy indicated a homogeneous distribution of Cu- and Niadsorbent sites. Fourier-transform infrared analysis revealed that the main chemical groups involved in the copper and nickel biosorption were carboxyl, ether, alcoholic, amino, and sulphonic groups.

ESTUDO DO EQUILÍBRIO DE BIOSSORÇÃO DOS ÍONS CU2+ E NI2+ EM SISTEMA BATELADA PELO RESÍDUO DA EXTRAÇÃO DO ALGINATO DA ALGA SARGASSUM FILIPENDULA

Neste trabalho investigou-se a bioadsorção e dessorção dos íons Cu 2+ , Ni 2+ e Pb 2+ em soluções monocomponentes pelo resíduo da extração do alginato da alga marinha Sargassum filipendula. O material bioadsorvente foi caracterizado empregando a técnica de espectroscopia na região do infravermelho (FT-IR) para a identificação dos grupos funcionais envolvidos no processo de remoção dos íons. Os principais grupos funcionais encontrados no bioadsorvente foram os grupos carboxílicos e sulfônicos. Ensaios cinéticos e de equilíbrio de bioadsorção monocomponente foram realizados em reator batelada, pH 4 e agitação constante. Os modelos cinéticos de pseudo primeira ordem e pseudo segunda ordem foram utilizados para representar a cinética, sendo que o modelo de pseudo primeira ordem melhor descreveu o comportamento de todos os sistemas investigados. Os modelos de Langmuir e Freundlich foram utilizados para descrever os dados experimentais de equilíbrio de bioadsorção. O ajuste pelo modelo de Langmuir indicou uma capacidade máxima de adsorção de 0,652 mmol g -1 para o Cu 2+ , 0,569 mmol g -1 para o Ni 2+ e 0,714 mmol g -1 para o íon Pb 2+ . Os ensaios de dessorção foram realizados utilizando o CaCl2 (0,5 mol L -1 ) como eluente. As eluições atingiram valores superiores a 91% e com perdas de massa do adsorvente inferiores a 14%. Os resultados mostraram que mesmo após a extração do alginato, o resíduo ainda apresenta potencial de aplicação no tratamento de efluentes contaminados com metais pesados pelo processo de adsorção.