In vitro evaluation of anti-pathogenic surface coating nanofluid,obtained by combining Fe3O4/C12 nanostructures and 2-((4-ethylphenoxy)methyl)-N-(substituted-phenylcarbamothioyl)-benzamides

In this paper, we report the design of a new nanofluid for anti-pathogenic surface coating. For this purpose, new 2-((4-ethylphenoxy)methyl)-N-(substituted-phenylcarbamothioyl)-benzamides were synthesized and used as an adsorption shell for Fe₃O₄/C₁₂ core/shell nanosized material. The functionalized specimens were tested by in vitro assays for their anti-biofilm properties and biocompatibility. The optimized catheter sections showed an improved resistance to Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853 in vitro biofilm development, as demonstrated by the viable cell counts of biofilm-embedded bacterial cells and by scanning electron microscopy examination of the colonized surfaces. The nanofluid proved to be not cytotoxic and did not influence the eukaryotic cell cycle. These results could be of a great interest for the biomedical field, opening new directions for the design of film-coated surfaces with improved anti-biofilm properties.     

Adsorption and Thermal Desorption of Volatile Organic Compounds in a Fixed Bed – Experimental and Modeling

Adsorption and thermal desorption dynamics of acetone in fixed-bed silica gel were studied experimentally and theoretically. The effect of process factors on adsorption and desorption performances was established. Acetone adsorption from air stream was performed by the dynamic (flowing gas) method in a laboratory setup at two levels of air superficial velocity (0.7 and 1.7 cm s^?1), temperature (30 and 40°C), and adsorbent particle diameter (0.21 and 0.54 cm). The values of saturation adsorption capacity (0.147–0.270 g g^?1) increased up to 78% and 36%, respectively, with a decrease in air velocity and adsorption temperature. Acetone thermal desorption from spent silica gel was studied in a thermobalance at three levels of process temperature (60, 70, and 80°C) and two values of particle size (0.21 and 0.54 cm). Equilibrium desorption efficiency (63–81%) was up to 14% larger for finer particles and increased with the desorption temperature. Kinetic models with relevant parameters adjusted based on experimental data were adopted to predict the dynamics of acetone adsorption and thermal desorption. The models simulated well the real conditions and could be applied to scale up and operate the adsorption columns used for air remediation.     

Thermal stability of additivated isotactic polypropylene

Summary Isotactic polypropylene stabilised with fullerene [C60], its adduct with methyl levopimarate, carbon black, p-t-butylcalix[4]arene, p-t-butylcalix[6]arene, Irganox 1076 or Topanol OC was investigated by means of oxygen uptake method under isothermal (165^°C) and isobaric (normal pressure) conditions. Oxidation investigations were performed in air as degradation environment. Additive concentration was 0.25 % (w/w). Kinetic parameters, oxidation induction and oxidation rate are compared with similar characteristics of additive-free i-PP. Effect of γ-irradiation on thermal oxidation is also presented. Three γ-exposure doses (50, 100 and 150 kGy) were selected. The influence of radiation treatment on the efficiency of studied compounds and some mechanistic aspects are also presented. Received: 5 June 2002/Revised version: 10 August 2002/ Accepted: 12 September 2002 Correspondence to Traian Zaharescu     

Ozone Dissolution vs. Aqueous Methylene Blue Degradation in Semi-Batch Reactors with Dielectric Barrier Discharge over the Water Surface

Ozone accumulation in water was compared with aqueous methylene blue (MB) degradation in a stirred semi-batch reactor. Comparable concentrations of gas-phase ozone, generated by parallel-plate dielectric-barrier AC discharge in high-purity oxygen, were allowed to contact the tested liquid using one of three regimens of ozone generation: (1) dry ex-situ; (2) humid ex-situ; and (3) humid in-situ ( “electroozonation” ). Results from (1) and (2) were similar, whereas in case (3) a slower ozone accumulation rate was contrasted by a three times faster MB degradation. A faster decomposition of aqueous ozone due to an assumed prevalence of free-radical induced MB degradation over direct ozonation in case (3) are indicative of a process similar to glow-discharge electrolysis.     

Acrylic weak‐base anion exchangers and their behaviors in the retention process of some heavy‐metal cations

Two macroporous acrylonitrile/10% vinyl acetate/10% divinylbenzene copolymers as beads were obtained by the aqueous suspension copolymerization of the three comonomers in the presence of toluene as a diluent, which was used in two different amounts. These copolymers were chemically modified by their reactions with ethylenediamine, diethylenetriamine, and triethylenetetramine in the presence of water when the aminolysis–hydrolysis reaction of the nitrile groups and the hydrolysis reaction of the acetate groups occurred. From these reactions, weak‐base anion exchangers with high ion‐exchange capacities, between 1.6 and 2.2 mequiv/mL and 6.5 and 10.5 mequiv/g, were obtained. For these anion exchangers, the behaviors in the retention processes of the Ni(II), Cd(II), and Pb(II) cations were evaluated with the bath method. All the resins exhibited retention properties, but the retained amounts of the metal cations differed as a function of the resin and cation nature. Thus, the resin from the reaction with triethylenetetramine of the copolymer obtained in the presence of a larger amount of toluene could be considered the most suitable sorbent for the three metal cations, especially for Ni(II). Its maximum retention capacity for this cation was 2.67 mequiv/g of dried resin. From the noncompetitive and competitive retentions was observed the following selectivity order: Ni(II) > Cd(II) > Pb(II). The retention took place by the chelating processes between the functional groups with the ligand role, especially free amine groups, and metal cations. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 930–938, 2005