A study of the process of desorption of hexavalent chromium

Abstract

In this work the process of desorption of hexavalent chromium, a toxic metal ion, from the marine algae Sargassum sp, following biosorption experiments 2³ factorial design was studied. A technique was applied to three eluents: HCl, H2SO4 and EDTA. Three factors of importance were evaluated: concentration of eluent, the ratio between mass of biosorbent and volume of eluent (S/L) and process time. A statistical analysis of the experimental results showed that the three variables evaluated are significant for all three eluents. The models for chromium desorption were validated, as the results agreed well with the observed values. Through use of the response surface methodology, a factorial design based optimization technique; it was possible to identify the most suitable eluent and the interval of values for the process variables that resulted in the most significant desorption of chromium, which is relevant information for work aiming at process optimization

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

“…After the alginate extraction procedure the presence of the two types of acids (i.e. guluronic acid (G) and mannuronic acid (M)), were determined using Solid state 13 C NMR Nuclear Magnetic Resonance spectroscopy, recorded with a Bruker Avance DRX 500 spectrometer (Bruker, Karlsruhe, Germany).…”

“…Solid state NMR of alginate samples (MAS 13 C NMR) is a technique that brings the advantage that sodium alginate powder can be examined directly, without need of partial hydrolysis. Normally this partial hydrolysis is used to decrease viscosity of high-molecularweight alginate solutions prior to recording their proton NMR spectra.…”

“…Many different kinds of biomass can effectively uptake heavy metals (algae, moss, fungi, bacteria, chitosan and zeolite) [2][3][4][5][6][7][8][9][10][11] , but recent research has shown that marine algae are very effective 8,12 for metal binding. Seaweed cells have a large superficial area with sites that are able to provide fast and reversible bonding with cations 13 . Sargassum sp.…”

“…This work presents the characterization of Sargassum filipendula algae by solid state 13 C NMR nuclear magnetic resonance spectroscopy, in order to determine the M/G ratio in the alginate extracted from algae matrix. This M/G ratio is important to choose a biosorbent for heavy metal treatment.…”

Adsorção de íons dicromato nos compósitos celulose/ZrO2.nH2O preparados pelos métodos da precipitação convencional e em solução homogênea

“…Lazarin e colaboradores 11 pesquisaram a preparação do híbri-do orgânico-inorgânico acetato de celulose/Al 2 O 3 modificando posteriormente este híbrido com grupos organofuncionais do tipo (RO) 3 13,14 . Esses materiais são compósitos à base de celulose modificada oriunda do bagaço de cana-de-açúcar, sendo a superfície recoberta com óxido de zircônio hidratado.…”