engleski

Nanoscale zero-valent iron – Characterization and analytical application

Nanomaterials have gained the greatest interest over other materials as the adsorbents of analytes such as transition metals and semimetals from complex environmental samples. [1] Utilization of zero-valent iron nanoparticles (nZVI) is widely adopted in analytical preconcentration and extraction procedures due to large surface area, chemical stability, durability, corrosion resistance, and cost effectiveness. Reductive immobilization of trace quantities of potentiallly toxic metal species on iron nanoparticles is in focus of many studies directed toward environmental and health effects. Removal efficiency is often determined by imaging of solid particles by scanning emission microscopy, or by X-ray diffraction. The studies which concern the changes of solution, especially aqueous solution are rarely described in literature. [2] Therefore, in this work we have developed the ICP- OES method for quantitative analysis of chromium (VI) removal from water by nanoscale iron. Zero valent iron nanoparticles (nZVI) were synthesized in ethanolic medium by the method of ferric iron reduction using sodium borohydride as a reducing agent. A systematic characterization of nZVI was performed using XRD and SEM studies. The extraction capabilities of synthesized particles were tested and optimized to mass fraction used in the experiments on model aqueous solutions containing hexavalent chromium species. The efficiency of Cr(VI) removal from aqueous solutions was measured by ICP-OES analysis on selected chromium emission lines. Reductive immobilization of hexavalent chromium on bare nanoparticles and nanoparticles which were modified by addition of 1, 5- diphenylcarbazide was performed. [3] Separation of particles from solution was achieved using solid phase extraction (SPE). The sensitive plasma spectrometry measurements of starting and residual chromium content showed that better removal efficiency (96 %) was obtained in lower concentration range (1-5 mg L-1) of Cr(VI) and with the addition of 1, 5- diphenylcarbazide reagent.

ICP-AES

nije evidentirano