Cristina Ileana Covaliu

Characterization and Application Results of Two Magnetic Nanomaterials

The toxicity of heavy metals for the environment can be solved by using the adsorption properties of magnetic nanomaterials. These types of nanomaterials can remove pollutants, especially from wastewaters. This study was conducted to determine whether two magnetic nanomaterials can be used as adsorbents for heavy metals (Cr, Cd, Cu, Zn, and Ni) from aqueous solutions under acidic conditions. Qualitative and quantitative elemental information and structural and surface characteristics before and after use as adsorbents were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The obtained data showed a good correlation with the Langmuir adsorption model using the two magnetic nanomaterials in aqueous solutions. The crystalline structure of the FeO powder was identified with XRD. The TEM images of FeO nanoparticles indicated a good dispersion of particles of 85.5 nm. The SEM analysis for FeO-PAA (magnetite covered with sodium alginate) showed spherical particles of magnetite wrapped into the polymer with dimension of ∼200 nm. According to the adsorption Langmuir model, the removal efficiency for uncoated FeO decreased in order: Cr(VI) > Cu(II) > Zn(II) > Ni(II) > Cd(II). For the FeO-PAA nanocomposite (45% w/w Fe in a mass of polymer), the adsorption phenomena appears as follows: Cr(VI) > Cd(II) > Cu(II) ∼ Zn(II) > Ni(II). Langmuir parameters indicated a favorable monolayer adsorption at pH 2.5. The nanocomposite FeO-PAA can be used as an adsorbent with the same performance as uncoated FeO but with the advantage of stability under conditions where industrial wastewaters have an acidic pH.

Method for preventing air pollution: Methane oxidation by two types of catalysts

Abstract Methane oxidation using different catalysts is an useful process for preventing air pollution. This study presents the methane oxidation by two types of catalysts: Pd-Sn/Al2O3 and spinel mixed oxide, CuFe2O4. The Pd-Sn/Al2O3 was successfully prepared by sol-gel method and CuFe2O4 by co-precipitation method. The catalysts obtained have been characterized structurally, morphologically and texturally by X-ray diffraction (XRD), scanning electron microscopy (SEM) and specific surface area (BET). The catalytic activity tests regarding methane oxidation were also performed.