Effect of Mg2+ ions on competitive metal ions adsorption/desorption on magnesium ferrite: Mechanism, reusability and stability studies.

The adsorption behavior of magnesium ferrite in single- and multicomponent metal ions solutions in the presence of Mg2+ ions were studied. A dramatic decrease in the adsorption capacity of magnesium ferrite towards Mn2+, Co2+, and Ni2+ ions for comparison study of single- and multicomponent solutions was established. The affinity of the sorbent in accordance with the maximum sorption capacities increases in the following order Cu2+ > Co2+ > Ni2+ > Mn2+. High efficiency of magnesium ferrite regeneration (~100%) with aqueous solutions of magnesium chloride in the concentration range of 0.001-0.1 M was shown. The low degree of toxic metal ions desorption combined with XRD, IR spectroscopy, and EDX analysis data indicate the key role of Mg2+ ion adsorption in the magnesium ferrite adsorbent regeneration. The positive effect of the introduction of Mg2+ ions into multicomponent solutions on metal ions adsorption was established, which is accompanied by an increase in the maximum sorption capacity for all metal ions and especially significant increase in the selectivity towards Cu2+ ions (2.41 mmol/g). The stability of the crystal structure of magnesium ferrite and a low degree of Mg2+ and Fe3+ ions leaching during multiple cycles of adsorption and regeneration of the adsorbent were observed.

Use of chicken feather and eggshell to synthesize a novel magnetized activated carbon for sorption of heavy metal ions.

Keeping environment and sustainability concept in view with preparation of new sorbents, two waste by-products from the poultry industry, i.e. feather and eggshell, were used for synthesis of a new magnetic activated carbon for sorption of heavy metal ions. Using response surface methodology based central composite design (RSM-CCD) technique, chicken feather and acid-digested eggshell were used as precursor and activation material, respectively, for the synthesis of the herein studied activated carbon (eggshell activated chicken feather carbon; ESCFC). The prepared activated carbon was magnetized for easy separation from water media, and iron oxide magnetized ESCFC (IOM-ESCFC) was comprehensively examined for removing some heavy metallic ions (Pb2+, Cd2+, Cu2+, Zn2+, and Ni2+) from water. The maximum mono-layer sorption capacities and the highness of sorption speed, along with thermodynamic studies, demonstrated that IOM-ESCFC can be regarded as a potential adsorbent against heavy metal ions from waters and wastewaters.

SnO2 Nanostructures: Effect of Processing Parameters on Their Structural and Functional Properties.

Zero- and 1D (one-dimensional) tin (IV) oxide nanostructures have been synthesized by thermal evaporation method, and a comparison of their morphology, crystal structure, sorption properties, specific surface area, as well as electrical characteristics has been performed. Synthesized SnO2 nanomaterials were studied by X-ray diffraction, scanning and transmission electron microscopy (SEM and TEM), N2 sorption/desorption technique, IR spectroscopy and, in addition, their current-voltage characteristics have also been measured. The single crystalline structures were obtained both in case of 0D (zero-dimensional) SnO2 powders and in case of 0D nanofibers, as confirmed by electron diffraction of TEM. It was found that SnO2 synthesis parameters significantly affect materials' properties by contributing to the difference in morphology, texture formation, changes in IR spectra of 1D structure as compared to 0D powders, increases in the specific surface area of nanofibers, and the alteration of current-voltage characteristics 0D and 1D SnO2 nanostructures. It was established that gas sensors utilizing of 1D nanofibers significantly outperform those based on 0D powders by providing higher specific surface area and ohmic I-V characteristics.

Magnetic Nanocomposites as Efficient Sorption Materials for Removing Dyes from Aqueous Solutions.

Magnetic composite sorbents based on saponite clays with different content of magnetite (2-7 wt%.) were synthesized. The samples were analyzed by X-ray diffraction methods, and it was found that the Fe3O4 in composites is in the nanorange. It has been shown that the magnetic nanocomposites have more developed microporosity and mesoporosity compared to saponite clay. The sorption properties of magnetic nanocomposite sorbents were determined, and the results evidenced that their efficiency is significantly higher than the individual phases of the composite. It was shown that all waste composite magnetic sorbents are successfully removed from the water environment by magnetic separation.