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The Iguape-Cananéia estuary-lagoon complex (CELIC) has different environment conditions between the northern and Southern sections, with different anthropic pressures. Current study evaluates the space and time variation of bioavailability of metals Fe, Zn, Mn, Co, Cu, Cr, Cd, Pb and Ni in sediments at 8 sites of CELIC during two periods in 2013. Metal bio-availability was assessed by the method of simultaneous extractions of metal ions and sulfates volatized by acidification (SEM/SVA). There was a broad space and time variability in the parameters under analysis where mean availability of metals followed the sequence Fe>Mn>Zn>Pb>Cu. All sites provided ratio SEM/SVA > 1 for metal ions Pb, Cd, Ni, Cu and Zn, with greater toxicity in the northern sediments. The above suggests bio-availability of the metals and highlighted the potential of the sediments, adversely affecting local biota. Results underscore the influence of numerous urban, agricultural and mining activities on the system, mainly derived from the river Ribeira de Iguape. [ABSTRACT FROM AUTHOR]

This article describes an analytical procedure for the determination of copper in fuel samples using the modified graphite electrode basal pyrolysis (BPPGME) by tetrazolium salts: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2Htetrazolium (MTT) Br]. The determination of metals in fuel is an issue of environmental relevance because it believes that these elements can be released into the atmosphere causing damage to the environment and health. Fuel samples (ethanol, biodiesel and gasoline) were previously digested in a microwave oven using nitric acid and peroxides (biodiesel) and only nitric acid (alcohol and gasoline). The metal ion studied reacted on the surface of the chemically modified electrode to produce marked changes in the corresponding voltammograms. In order to determine the species of interest the best results were at pH 5.0 for copper and pH 6.0 for other species. The concentration scale for copper was 2.0x10-6 at 1.25 X 10-5 mol L-1. The limit of detection in fuels of samples (ethanol, biodiesel or gasoline), by ARV was 2.5x10-6 mol L-1. The accuracy of the proposed technique was compared by providing similar results, ie the copper concentration in the samples analyzed by both techniques at a non-statistically different 95% certainty level. [ABSTRACT FROM AUTHOR]

Natural clays containing kaolinite (AC) and montmorillonite (AM), obtained from State of Sergipe, Northeast of Brazil, were used as adsorbents for metal ions in aqueous solution. The adsorption equilibrium was reached in the first minutes and the contact time of 60 min was selected for the rest of the study. Adsorption increased with pH for AC and did not change significantly for AM. Montmorillonite showed a higher adsorption capacity for the metal ions with the Langmuir monolayer capacity (Qo) of 1.48 to 6.98 mg g-1 compared to that of 0.42 to 1.51 mg g-1 for kaolinite. [ABSTRACT FROM AUTHOR]

This study aims to evaluate metal biosorption in an acid mine drainage (AMD) synthetic sample by determining the equilibrium time, the amount of metal captured and removed, and also the biomass changes. For this, tests were performed with parameter constants: 25°C temperature, 2.6 pH, lg.L ' biomass concentration, and at 175rpm shake. The gram-positive bacterium Rhodococcus opacus was used as biosorbent, after having been grown in YMA (yeast mannitol agar) for 24h at 28°C and shaken at 150rpm. After the biosorptive process, samples were centrifuged: the supernatant was analyzed by atomic absorption and the biomass was characterized by analysis of scanning electron microscopy (SEM). The results showed that maximum uptake time occurs in about 1 minute, when the maximum uptake was 48.2mg.g', which corresponds to approximately to 11.7% of the total removal. The changes observed in the SEM indicate that there are interactions between metal ions and biomass. [ABSTRACT FROM AUTHOR]

Removal of metal ions present in aqueous solutions from wastewater through biosorption has an important role for pollution control. Metals such as cadmium, chromium (III), chromium (VI), zinc, nickel and arsenic are hazardous and present risks to human health Application of traditional treatments requires high costs and continuous input of chemicals which affect environment. However, regulatory standards are not always achieved. Hence, eco-friendly techniques are required for fine tuning of effluent wastewater treatment, so biosorption technology seems to be a promising process. In the last decades different types of biomass have been investigated for heavy metals removal. This work presents the results for studies of biosorption using coconut shell powder as biosorbent for the removal of heavy metals (As(V), Cr(III), Cr(VI), Ni(II), Zn(II) and Cd(II)). The removal capacity in batch tests was evaluated, and the the influence of pH, particle size, and initial metal concentration were also studied. The results are evaluated using Langmuir and Freundlich isotherms. [ABSTRACT FROM AUTHOR]