Use of Ni/Ni x B nanoparticles as a novel adsorbent for the preconcentration of mercury species prior to cold vapor-atomic fluorescence spectrometric determination

A selective matrix separation/enrichment method, utilizing a simple batch procedure with nickel/nickel boride (Ni/Ni x B) nanoparticles was proposed for the determination of inorganic mercury(II), Hg 2+ and methyl mercury(I), CH 3 Hg + in waters prior to cold vapor-atomic fluorescence spectrometry (CV-AFS). The Ni/Ni x B nanoparticles, were synthesized by the chemical reduction of Ni(II) to Ni/Ni x B. The novel adsorbent was selective to Hg 2+ and CH 3 Hg + species between pH values of 4 - 10. Both of the mercury species were recovered from the adsorbent using 1.0 mol L -1 hot HNO 3 with high efficiency. It was observed that the adsorbent selectively removed Hg 2+ and CH 3 Hg + from the bulk solution in the presence of several competitor ions (As 3+ , Sb 3+ , Pb 2+ , Zn 2+ , Cu 2+ , Cd 2+ and Fe 3+ ) with >96% adsorption. The limit of detection (3? above blank) was found to be 1.8 ng L -1 with a preconcentration factor of 20. The validation of the method was tested through spike recovery experiments with several water samples (tap and seawater) at µg L -1 concentration levels, and all recovery values were found to vary between 95 and 105%. 2016 © The Japan Society for Analytical Chemistry

PDMAEMA grafted microspheres as an efficient adsorbent for the removal of Sunset yellow from pharmaceutical preparations, beverages and waste water

Sunset yellow (SY) dye removal in the beverages, waters and pharmaceutical preparations is of great importance due to its negative side effects. In this context, a new and efficient adsorbent, PDMAEMA grafted PS-DVB-VBC microspheres were synthesized and applied for the adsorption of SY dye. The morphology, chemical and physical properties of the proposed adsorbent was fully characterized using scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), elemental and Brunauer–Emmett–Teller (BET) surface area analysis. The adsorption performance of the adsorbent was investigated systematically, including the influence of pH, contact time, adsorbent dose, adsorption isotherms, adsorption kinetics, and reusability. The optimized conditions of the SY towards the sorbent were as follows: pH of 2.0, contact time of 40.0 min, adsorbent dose of 0.4 g L?1 at 25 °C. The equilibrium adsorption process followed the Langmuir isotherm model with a maximum adsorption capacity of 312.5 mg g?1. Pseudo-second-order kinetic model was found to be most appropriate to define the adsorption of SY dye onto the adsorbent. The quantitative results (96.3–103%) obtained for the real samples (beverages, pharmaceutical preparation and synthetic waste water) confirmed the high performance, feasibility and efficacy of the novel method. The uptake of SY dye was high (>90%) even after recycling five times indicating that the adsorbent could be regenerated and reused in practical applications. © 202

A study of mechanism of nickel interferences in hydride generation atomic absorption spectrometric determination of arsenic and antimony

Studies have been carried out to clarify the mechanism of nickel interferences in the hydride generation atomic absorption spectrometric determination of arsenic and antimony. The most serious nickel interferences are observed when nickel/nickel boride nanoparticles are produced during NaBH 4 reduction. In this study these particles have been observed to have diameters of less than 40 nm and sorb As(III), As(V) and Sb(III) species rather than arsine and stibine generated as so far assumed. Bulk chemical composition and surface structure of these nanoparticles were studied and it was found that if the NaBH 4 reduction is carried out while passing nitrogen through the solution the black nanoparticles were composed of Ni 2B and, if the reduction is carried out under air the black nanoparticles were found to consist of Ni 3B or possibly a mixture of Ni(0) and Ni 2B. Surface analysis studies with scanning electron microscopy, energy dispersive X-ray spectrometry, X-ray photoelectron spectrometry and X-ray diffraction analysis have shown that the particles have amorphous structure consisting of Ni(0), Ni 2B, Ni 3B and Ni(OH) 2. However, sorption studies have shown that Ni(0) and Ni(OH) 2 do not sorb the analyte ions and arsine and stibine significantly. © 2011 Elsevier B.V. All rights reserved