1,721,075 research outputs found
Sorption properties of an amorphous hydroxo titanate towards Pb2+, Ni2+, and Cu2+ ions in aqueous solution
No full textTitanates may be selectively used as inorganic adsorbents for heavy metal ions owing to their stability and fast adsorption kinetics. Nevertheless, the synthesis of such materials usually requires extreme reaction conditions. In this work, a new titanium-based material was rapidly synthesized under mild laboratory conditions. The obtained amorphous hydroxo titanate was tested for heavy metal sorption through kinetic and equilibrium batch tests, which indicated that the new material had high adsorption rates and adsorption capacities towards Cu2+, Ni2+ and Pb2 ions. Adsorption kinetics were pseudo-second order, and equilibrium data fitted the Langmuir isotherm model. The calculated maximum adsorption capacities of Cu2+, Ni2+ and Pb2+ in deionized water were around 1 mmol g−1, and they decreased for Cu2+ and Ni2+ in the presence of Na+, Ca2+ and Mg2+ ions, whereas the alkali metal ions did not influence Pb2+ uptake. The efficiency of adsorption and recovery of lead ions were evaluated through column dynamic tests, by feeding the column with groundwater and tap water spiked with Pb2+. The high performance of the hydroxo titanate over several cycles of retention and elution suggested that the product is potentially useful for the solid phase extraction of lead at trace levels in natural water samples, with potential use in metal pre-concentration for analytical applications
A one dimensional, self consistent model of charged particle transport and vibrational kinetics in weakly ionized hydrogen
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Plasma-surface interactions in the plasma deposition mechanism of structured Teflon-like coatings
No full textContinuous and modulated deposition of fluorocarbon films from c-C4F8 plasmas
No full textContinuous and modulated C-C4F8 (perfluorocyclobutane) plasmas were used to deposit thin Teflon-like films. Gas phase and film composition and structure were investigated and the results can be rationalized with the deposition mechanism developed in a previous work for C2F4-modulated plasmas. The effect of modulation on the morphology and the chemistry of the surface were studied
Functionalization of biomedical polymers by means of plasma processes: plasma treated polymers with limited hydrophobic recovery and PECVD of –COOH functional coatings
No full textThis short contribution is aimed to describe two plasma processes utilized at the group of the authors for biomedical applications, namely: the grafting process of polar groups intended to obtain stable hydrophilic surfaces on hydrophobic polymers, and the deposition of thin organic coatings highly functionalized with carboxylic groups. Both processes can develop cell-adhesive surfaces onto biomedical polymers. Combined with plasma deposition processes of non fouling coatings through a "physical mask", such methods can provide substrates patterned with diverse micrometric domains that can drive adhesion, spreading and growth of cells along predefined directions, an useful approach utilized in tissue engineering
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