Polyacrylate anion exchangers in sorption of heavy metal ions with non-biodegradable complexing agents

The polyacrylate anion exchangers are widely used in purification of heavy metal ions from wastewaters and different accompanying complexing agents. Such effluents containing the chelators (EDTA, NTA, HEDTA, DTPA, and IDA) are discharged from relevant industries such as printed circuits boards, plating on plastics, metal finishing and others. The sorption was studied as a function of phase contact time and pH by the batch technique. It was found that the removal of heavy metal ions in the presence of EDTA, NTA and IDA strictly depends on the phase contact time and pH values. Various kinetic models such as the pseudo first-order and the pseudo second-order as well as the intraparticle one were also tested to estimate the sorption rate. The equilibrium capacities of the studied anion exchangers for Cu(II), Zn(II), Co(II), Ni(II), Pb(II) and Cd(II) in the presence of EDTA were the highest for Pb(II) and Cd(II). The order of sorption for Amberlite IRA 458, Amberlite IRA 958 as well as Amberlite IRA 67 can be as follows: Pb(II) > Cd(II) > Zn(II) > Cu(II) > Ni(II) > Co(II). The stability of forming complexes was also compared. The estimation of the capacities of anion exchangers under investigation by the continuous column studies was also carried out.     

Calcium Ions Regulate K+ Uptake into Brain Mitochondria: The Evidence for a Novel Potassium Channel

The mitochondrial response to changes of cytosolic calcium concentration has a strong impact on neuronal cell metabolism and viability. We observed that Ca²⁺ additions to isolated rat brain mitochondria induced in potassium ion containing media a mitochondrial membrane potential depolarization and an accompanying increase of mitochondrial respiration. These Ca²⁺ effects can be blocked by iberiotoxin and charybdotoxin, well known inhibitors of large conductance potassium channel (BK_Ca channel). Furthermore, NS1619 – a BK_Ca channel opener – induced potassium ion–specific effects on brain mitochondria similar to those induced by Ca²⁺. These findings suggest the presence of a calcium-activated, large conductance potassium channel (sensitive to charybdotoxin and NS1619), which was confirmed by reconstitution of the mitochondrial inner membrane into planar lipid bilayers. The conductance of the reconstituted channel was 265 pS under gradient (50/450 mM KCl) conditions. Its reversal potential was equal to 50 mV, which proved that the examined channel was cation-selective. We also observed immunoreactivity of anti-β₄ subunit (of the BK_Ca channel) antibodies with ~26 kDa proteins of rat brain mitochondria. Immunohistochemical analysis confirmed the predominant occurrence of β₄ subunit in neuronal mitochondria. We hypothesize that the mitochondrial BK_Ca channel represents a calcium sensor, which can contribute to neuronal signal transduction and survival.     

Hydrogen permeation in Fe-40 at.% Al alloy at different temperatures

The electrochemical permeation technique for studying transport and trapping of hydrogen in Fe-40 at.% Al alloy at temperatures of 5, 25, 45 and 65 °C was used in the paper. The influence of temperature on the effective hydrogen diffusion coefficient, hydrogen permeation rate and hydrogen solubility was determined. The activation energy of hydrogen diffusion in iron aluminide in the studied temperature range was also determined.     

The impact of liberalisation of the electricity market on the hard coal mining sector in Poland

The liberalisation of the electricity market changed the conditions of operation not only for the power industry, but also for related sectors. One of the particularly sensitive industries in Poland is coal mining, which is the result of coal-based structure of electricity generation. As it is more difficult, in the liberalised market, to burden consumers with all the costs, electricity producers are eager to transfer the risk of operation to the suppliers. That increases uncertainty about the future of the hard coal industry. The aim of this paper was to quantitatively estimate the impact that liberalisation of the electricity markets may have on the coal mining sector in Poland. First of all, the possible areas of that impact were identified. Then the model, which involved detailed relations in the impact areas identified, was developed and employed to evaluate the performance of the mining sector. The comparison of scenarios of a monopolistic electricity sector with a liberalised one enabled an estimation of the scale of the impact on the mining sector to be made. The results showed that liberalisation causes decreased coal consumption and decreased operating profits in coal companies. However, some savings in electricity costs are possible for coal producers.     

Determination of thermal radiative properties of packed-bed media containing a mixture of polydispersed particles

Thermal radiative characteristics of packed beds containing a mixture of polydispersed SiO₂, ZnO, and C particles are determined numerically by employing the Monte Carlo technique, which is validated with the experimentally measured overall transmittance. A radiative heat transfer model is formulated for a pseudo-continuum multi-component medium of Mie-scattering particles. Good agreement is achieved by incorporating approximate phase functions that reproduce the experimentally observed preference for forward scattering.     

Anthocyanins,total polyphenols and antioxidant activity in amaranth and quinoa seeds and sprouts during their growth

Total antioxidant capacity, total phenolic contents (TP) and anthocyanins contents (ANT) were determined in Amaranthus cruentus and Chenopodium quinoa seeds and sprouts. Antioxidant activity of the investigated seeds decreased in the following order: quinoa, amaranth v. Rawa, amaranth v. Aztek for FRAP and quinoa, amaranth v. Aztek, amaranth v. Rawa for both ABTS and DPPH. Sprouts activity depended on the length of their growth, and the peak values were reached on the fourth day in the case of amaranth and on the sixth day in the case of quinoa. The data obtained by the three methods showed significant correlation between TP content in seeds and sprouts. In sprouts grown in the daylight and in the darkness we observed some significant changes of TP, ANT and antioxidant activity. Amaranth and quinoa seeds and sprouts can be used in food, because it is a good source of ANT and TP with high antioxidant activity.     

Raspberry seed extract effect on the ferroxidase activity of ceruloplasmin isolated from plasma

In this study, the effect of the raspberry seed extract (RSE) on the ferroxidase activity of ceruloplasmin (Cp) isolated from healthy male subject serum was analyzed. The ferroxidase activity of Cp was determined by spectrophotometry using Fe(II) – histidine complex and ferrozine as a chromogenic reagent. The ferroxidase activity of ceruloplasmin was demonstrated in dose-dependent way within the range 22–66 μg/ml. The effect of RSE on Fe(II) concentration, measured as the decrease of Fe(II) concentration in samples and expressed as ΔFe(II), was found to be a dose-dependent within the range 1.20–51.56 μg dm/ml. The ferroxidase activity of Cp was influenced by the RSE within its studied range. However, the addition of the highest concentration of RSE (51.56 μg dm/ml) to the sample containing the highest level of Cp (66 μg/ml) did not affect its ferroxidase activity. It may be suggested that the competition for Fe(II) as the substrate limits the effect of RSE on Cp activity and causes no further changes in Fe(II) elimination.     

Spin-glass-like behaviour in the ternary U3Fe4+xAl12−x uranium–iron aluminide

The U₃Fe_4+xAl_12?x (0 < x < 0.5) intermetallic was prepared by arc melting, followed by annealing at 850 °C. This compound crystallizes in the hexagonal Gd₃Ru₄Al₁₂-type structure (e.g. P6₃/mmc), with room temperature parameters a = 8.7516(3) Å and c = 9.2653(4) Å for x = 0. The structure is characterized by planar layers of M3Al4 (M = Gd, U), containing M atoms in a triangular arrangement and forming a distorted Kagomé net. Magnetic measurements revealed a spin-glass-type behaviour with a freezing temperature, T_f = 7.9 K. The magnitude of the frequency shift of the freezing temperature is ≈0.03 and a Vogel–Fulcher law is followed with values typical for a spin-glass. ⁵⁷Fe Mössbauer data show that there is no freezing of the iron magnetic moments directions below T_f, indicating that the origin of the spin-glass-like behaviour is related to topological frustration of the uranium moments.     

Iron-ruthenium catalyst for the water-gas shift reaction

Iron-ruthenium catalysts prepared by impregnation of calcination products of -, , -and -iron oxide-hydroxides with either ruthenium chloride or ruthenium red were tested for the activity for the water-gas shift reaction. The effect of support, ruthenium containing impregnation agent and thermal treatment on catalyst performance was discussed.     

PAN‐based fibers modified with two‐component ceramic nanoparticles

The authors determined conditions for manufacturing PAN precursor fibers containing a system of two nanoadditives, montmorillonite (MMT), and hydroxyapatite (HAp) in their structure. The PAN precursor fibers thus obtained are characterized by a tenacity of more than 30 cN/tex and a total volume of pores at the level of 0.29 cm³/g. Furthermore, it was found that the use of nanoadditives entails the remodeling of the paracrystalline structure of PAN fibers into a strictly crystalline one. This is accompanied by a decrease in spacing between MMT layers combined with their partial exfoliation. The fibers thus obtained, after being carbonized, will be used for medical applications. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009