Hydride generation using a metallic atomizer after microwave-assisted extraction for inorganic arsenic speciation in biological samples.

The present speciation method reports the determination of inorganic arsenic forms, using metallic furnace hydride generation atomic absorption spectrometry. The inorganic As speciation is carried out using mild conditions for hydride formation, such as slightly acid pH media (4.50) and low tetrahydridoborate(1-) concentration (0.1% (w/v)). Limits of detection and quantification of 2.0 and 6.6 µg L(-1) of iAs(III) are obtained using optimized conditions. Additionally, microwave-assisted extraction using water as solvent is carried out to provide the appropriate environment for As species extraction as well as impeding inter-conversion between species. With these analytical strategies, As was accurately determined (at 99.9% confidence level) in water and plankton samples.

Grape bagasse as an alternative natural adsorbent of cadmium and lead for effluent treatment.

This work investigated the utilization of grape bagasse as an alternative natural adsorbent to remove Cd(II) and Pb(II) ions from laboratory effluent. X-ray diffractometry, Fourier transform infrared spectroscopy, scanning electron microscopy, nuclear magnetic resonance, thermogravimetric analyses, surface analysis, porosity and porous size were used for characterization of the material. Batch experiments were carried out to evaluate the adsorption capacity of the material. Parameters such as adsorption pH and contact time were optimized for the maximum accumulation onto the solid surface. The pH values found were 7 and 3 for Cd(II) and Pb(II), respectively, and contact time was 5 min for both metals. Adsorption capacity for metals were calculated from adsorption isotherms by applying the Langmüir model and found to be 0.774 and 0.428 mmol g(-1) for Cd(II) and Pb(II), respectively. The competition between metals for the same adsorption sites on grape bagasse was also evaluated, showing an increasing affinity for Pb(II) over Cd(II) when only these metals are present. The potential of this material was demonstrated by efficient metal removal from laboratory effluent using a glass column. The results indicate that the referred material could be employed as adsorbent for effluent treatment, especially due to its easy acquisition and low cost as well as the fast adsorption involved.