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Fe@MWCNT-OH/SPEEK hybrid membranes for CO2 separation! Significant improvement of hybrid membrane's gas transport, magnetic, thermal, and mechanical parameters. Enhancement of interphase compatibility after CNT and polymer chemical modification.

The plasticizers used in this study were synthesized from renewable raw materials using succinic acid, oleic acid, and propylene glycol. Four environmentally friendly plasticizer samples were obtained; their chemical structures and compositions were confirmed by gas chromatography (GC) and infrared spectroscopy (FT–IR) analyses, and their physicochemical properties and thermal stability (TGA analysis) were investigated. The obtained ester mixtures were used as poly(vinyl chloride) (PVC) plasticizers and their plasticization efficiency was determined in comparison to traditional, commercially available phthalate plasticizers, such as DEHP (di(2-ethylhexyl phthalate) and DINP (diisononyl phthalate). Mechanical properties and migration resistance were determined for soft PVC with the use of three concentrations of plasticizers (40 PHR, 50 PHR, and 60 PHR). It was observed that the obtained plasticizers exhibited the same plasticization efficiency and were characterized with good mechanical and physical properties in comparison to commercial plasticizers. The tensile strength was approx. 19 MPa, while the elongation at break was approx. 250% for all tested plasticizers at a concentration of 50 PHR. Furthermore, plasticizer migration studies showed that the synthesized plasticizers had excellent resistance to plasticizer leaching. The best migration test result obtained was 70% lower than that for DEHP or DINP. The ester mixture that was found to be the most favorable plasticizer was characterized by good thermal and thermo-oxidative stability (5% weight loss temperature: 227.8 °C in air and 261.1 °C in nitrogen). The results of the research clearly indicate that the synthesized esters can provide a green alternative to toxic phthalate plasticizers.

The article presents the results of research on the impact of the transformation of Poland’s energy mix on the country’s energy security. Since energy security is a very complex problem, the impact of the transformation has been verified in three aspects, i.e., greenhouse gas emissions; energy availability in terms of its quantity, sufficient to meet the needs of citizens; and energy prices. The MANOVA model was used in the research. The model allowed us to examine the relationship between the share of coal in the energy mix and the above-mentioned factors. The MANOVA model allowed us to determine the influence of one explanatory variable on several response variables. The results obtained enabled the verification of the adequacy of the changes that have been made in the energy mix over the last 10 years. As is shown, the factor that is related to changes in the share of coal in the energy mix is the energy surplus, while a relationship between both prices and emission levels and the changes in the share of coal in the energy mix has not been established. Furthermore, a simulation was carried out, which showed that the correlation between price, emissions, and the share in the mix was obtained only by reducing 2017–2020 emissions by an average of 6% and prices by 17%.

Novel inorganic-organic hybrid membranes Fe@MWCNT/PPO or Fe@MWCNT-OH/SPPO (with a new type of CNTs characterized by increased iron content 5.80 wt%) were synthesized for CO

This article presents the results from research performed on the implementation of restructuring policies of Polish mining enterprises. The study sought to verify whether the changes planned in Poland since the 1990s have been successfully introduced. The main objective of the restructuring of the Polish mining industry was to transform it into a profitable, cost-effective sector, which would be able to survive in a competitive market. The study also allowed the determination of a ratio giving a clear and synthetic outcome&mdash, called the indicator of the ability to change (WZZ). This indicator included criteria for assessing the efficiency of a company during the process of change, the fundamental errors committed during the change process, and the reasons for a low level of ability to change. The WZZ indicator achieved only an average level of 30%. The main errors committed during the change process are the mining enterprises&rsquo, lack of experience in change management and a lack of executive conviction about the need not only for proper management of the process of change, but also for change in general. The problem is also a lack of adequate knowledge, competence in the field of change management, and communication with employees. Low level of ability to change is caused by the inflexible organizational structure, the organizational culture, a lack of motivation, and the limited flexibility of the human factor.

Magnetic inorganic-organic hybrid membranes based on metal (Na + and Fe 2+ ) substituted sulfonated poly(2,6-dimethyl-1,4-phenylene oxide) matrix and magnetic powders were prepared and characterized. It was stated that the magnetic membrane’s gas transport parameters ( D , P, S and α ) were improved with the rise of membrane’s saturation magnetization, remanence, magnetic particle content and type of polymer matrix. The modification of a polymer matrix by metal substitution and incorporation of magnetic powder had significantly changed membrane’s magnetic, mechanical (R m and E) and rheological (G′ and G″) properties. Especially the introduction of Fe 2+ ions (much higher magnetic susceptibility compared to Na + ), and their potential interaction with magnetic powder resulted in improved properties. The mechanical and rheological parameters of the tested membranes were improved by the increase of the magnetic filler addition and selection of appropriate type of polymer matrix. The best resistance to elastic deformation had the hybrid FeSPPO membrane with high filler addition.

This paper focuses on the preparation and characterization of a new type of polyimide magnetic inorganic-organic hybrid membranes and analysis of their potential application in synthetic air enrichment with oxygen. These hybrid membranes were based on linear (ODPA-MDA) and hyperbranched (ODPA-MTA) polyimide matrix and NdFeB magnetic microparticles. It was conducted the characteristics of their gas permeation, magnetic, thermal, mechanical and rheological properties. It was stated that the application of polyimides as polymer matrices and magnetic powders as fillers (especially with higher content and lower particle size) allowed to create unusual hybrid membranes with the improved gas transport and separation properties (coefficient’s P, D, S and α), mechanical and rheological parameters (E, G′, G″ and tan δ) and the excellent thermooxidative stability. All this will allow for their future potential application in the separation of air.

Various magnetic inorganic-organic hybrid membranes based on linear or hyperbranched polyimide matrix and magnetic microparticles were prepared and characterized. It was stated that the magnetic membrane's gas transport parameters ( D , P, S and α) were improved with the rise of membrane's saturation magnetization, remanence, magnetic particle content and coercivity, associated with the decrease in magnetic powder particle size. The hybrid membranes had much higher gas permeability and diffusivity, while their permselectivity and solubility coefficient values slightly increased. The mechanical and rheological parameters of the tested membranes were improved by the increase of the magnetic filler addition, decrease of its granulation and selection of appropriate type of polymer matrix. The best resistance to elastic deformation had the hybrid PI membranes with high filler addition and small granulation, while their resistance to viscous flow increased with filler particle size rise. The investigated membranes showed the excellent thermooxidative stability.

This paper contains an analysis of the hard coal production process in Poland with selected indicators such as productivity, marginal productivity and the substitution of production factors. Current organization of the hard coal mining process is mainly characterized by the decreasing economies of scale, the loss of the average and marginal productivity. Static model of the production function indicates a 50% decrease in the average productivity in the years 2005–2013. This indicates the incorrect use of available production factors and poses a threat to further existence of mining companies. The reduction of production costs will be inevitable in this situation. The obtained results of the analysis led to creation of two innovative strategies of: flexible and stable coal mining production.

The synthesis of magnetic hybrid inorganic-organic membranes consisting of EC and PPO as polymer matrices and various magnetic powder microparticles was successfully performed. The results showed that the separation (coefficient α ) and gas transport properties (coefficient's P , D , S ) of the magnetic hybrid membranes were enhanced with the increase of magnetic powder addition and decrease in powder particle size. The increase of the magnetic powder addition, decrease of its granulation and selection of appropriate type of polymer matrix improved mechanical ( R 0,2 , R , R m and E ) and rheological parameters ( G′ , G′′ , and tan δ ) of the tested membranes. The hybrid membrane's resistance to elastic deformation increased with the rise of magnetic powder content, while their resistance to viscous flow decreased. The obtained magnetic membranes are characterized by not only enhanced gas transport properties (the increase in not only permeability but also in selectivity) that allow better air separation, but also improved mechanical properties. That is extremely important in the separation processes of gas mixtures at high pressures.

Magnetic hybrid membranes based on ethylcellulose (EC), poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) and various magnetic praseodymium and neodymium powder microparticles as fillers were obtained. Permeability, diffusion and sorption coefficients of O 2 , N 2 and synthetic air components were estimated for homogeneous and heterogeneous membranes using the Time Lag method based on constant pressure permeation technique. The microstructure studies and the phase analysis of magnetic membranes were also performed using SEM and XRD. The influence of magnetic parameters, like coercivity, remanence and saturation magnetization of created membranes on the gas transport properties was studied. The results showed that their coercivity depended on composition and microstructure of the magnetic powder. On the other hand, remanence and saturation magnetization increased with the increase of the powder addition in the membrane. It was found that the magnetic membrane's gas transport properties were improved with the increase of membrane's remanence, saturation magnetization and magnetic particle filling. The decrease in powder particle size and associated increase of the membrane's coercivity also positively influenced the gas transport and separation properties of investigated membranes. It was observed that the magnetic ethylcellulose and poly(2,6-dimethyl-1,4-phenylene oxide) membranes had higher gas permeability, while their permselectivity and solubility coefficient values were rather maintained or slightly increased. The results also showed that the magnetic powder content enhanced significantly gas diffusivity in EC and PPO membranes. It was also analyzed the dependence of the drift coefficient w on the magnetic parameters of investigated membranes. The correlation between the membrane selectivity, permeability and magnetic properties with their XRD characteristics was stated.

An idea of using magnetic field to enhance oxygen transport, as an effective factor for the air enrichment, has already been successfully demonstrated. Direct consequence of this concept was to produce polymeric magnetic membranes by casting technique. An analysis of experimental data, obtained from transient and stationary states of mass transport, allowed to formulate a hypothesis of a “dead thickness” of magnetic membranes in question, i.e. the bulk polymer phase as a part of membrane with no magnetic channels but limiting the overall transport through it. It will be shown that removing this part increases the rate of transport and enhances the air separation. To complete the overall approach, the theory is provided both on phenomenological and molecular levels. The simulation by Monte Carlo and Brownian dynamics, to show some molecular properties of magnetic field and its activity during separation, was performed.

Sulfuric acid cross-linked chitosan membranes filled with a different amount of magnetite, were prepared. The permeation behavior of ethanol and water vapors in vapor permeation experiments were studied. Permeation rates were measured. Mass transport coefficients were evaluated. The study has been carried out to determine the influence of magnetic powder dispersed inside of the chitosan membrane on ethanol-water separation. The diffusion, fluxes, and permeation coefficients increased with greater amount of magnetite content. The separation factor increased with increasing flux and the best results were achieved for the membrane containing 15% w/w magnetite. The research allows optimizing the preparation procedure of chitosan magnetic membranes cross-linked by sulfuric acid with the best permeation properties.

Poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) and magnetic neodymium powder particles MQP-14-12 have been used for the preparation of magnetic mixed matrix membranes. Permeability diffusion and sorption coefficients of O2, N2, and synthetic air components were estimated for homogeneous and heterogeneous membranes using the Time Lag method based on dynamic experiments in a constant pressure system. The influence of magnetic field and magnetic powder particles on the gas transport properties of MMMs was studied. The results showed that the membrane permeation properties were improved with the magnetic neodymium particle filling. It was observed that the magnetic ethylcellulose and poly(2,6-dimethyl-1,4-phenylene oxide) membranes showed higher gas permeability, while their permselectivity and solubility were rather maintained or slightly increased. The results also showed that the magnetic powder addition enhanced gas diffusivity significantly in EC and PPO membranes.

Ethylcellulose (EC), linear polyimide (LPI) or hyperbranched polyimide (HBPI) and magnetic neodymium powder MQP-14-12 have been used for the preparation of magnetic mixed matrix membranes (MMMs). Permeability diffusion and sorption coefficients of O 2 , N 2 and synthetic air components were estimated for homogeneous and heterogeneous membranes using the time lag method based on dynamic experiments in a constant pressure system. The effect of magnetic powder particles on the gas transport properties of MMMs was studied. The results showed that the membrane permeation properties were improved with the magnetic neodymium particle filling. It was observed that the magnetic ethylcellulose and polyimide membranes showed higher gas permeability, while their permselectivity and solubility were rather maintained or slightly increased. The results also showed that the magnetic powder addition enhanced significantly gas diffusivity in EC and polyimide membranes.

Poly(2,6-dimethyl-1,4-phenylene oxide) composite membrane containing the different amount of nano-sized magnetic iron oxide (magnetite) was used in gas separation (N 2 /O 2 ) experiments and vapour permeation (ethanol/water) studies. Presence of the magnetic particles additive has an impact on the separation properties of the polymer matrix. Using this type of membranes in separation of gaseous mixtures restrains permeation of paramagnetic constituent and promotes diffusivity of the diamagnetic component. Diffusion coefficient of nitrogen increased from 8.66 × 10 −4 to 42.00 × 10 −4 cm 2 s −1 respectively for pure PPO membrane and loaded with 10 w/w% of Fe 3 O 4 . In case of the vapour permeation studies, increase both flux and diffusivity of less polar component (ethanol) is observed. Flux changed from 1.07 × 10 −12 to 53.2 × 10 −12 cm 3 (STP) cm −2 s −1 and diffusion coefficient raised from 2.01 × 10 −10 to 84.2 × 10 −10 cm 2 s −1 respectively for pure PPO membrane and loaded with 10 w/w% of Fe 3 O 4 .

A set of methods (D1–D8 transient sorption and permeation analysis system) previously used for the regular inhomogeneous membranes, that is, the membranes where the diffusive properties vary regula...

Structure and morphology of dense polymer membranes with dispersed magnetic powder (magnetic membranes) for air separation were investigated. Qualitative and quantitative description of membrane structures based on fractal analysis, is presented. Box counting method for calculating the generalized fractal dimension was used. Structures with the same value of fractal parameters as for real membranes were simulated, and random walk dimensions were evaluated. Study of transport processes in air separation using polymeric membranes with magnetic powder both experimentally and through the random walk, was performed. The experimental results were compared with theoretical predictions. Finally, the diffusion equation with a spatial dependent diffusion coefficient of self-similar type to describe diffusion processes in the aforementioned membranes, was proposed.

Polymer membranes filled with magnetic powder and magnetized, used for an air enrichment, are investigated. Various polymer matrix with different types and granulation of dispersed magnetic powder were used for the preparation of the membranes. All membranes were examined for N2, O2, and air permeability. Mass transport coefficients were evaluated basing on Time Lag methods and D1-D8 system. Structure and morphology of the obtained membranes were investigated using fractal analysis. Box counting method for calculating generalized fractal dimension was applied. Obtained results allowed to optimize the preparation procedure of magnetic membranes with the best permeation properties.

Composite membranes of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) or ethyl cellulose filled with magnetic nanoparticles, that is, ferroferric oxides (Fe3O4) were prepared. These membranes were examined for nitrogen and oxygen permeability. In the case of ethylcellulose membranes the gas flow was too high, since the macropore were formed. In further permeation measurements PPO membranes with 1 to 10 w/w% magnetic particles content were investigated. For the higher concentration of magnetite (more than 20%) in PPO polymer solution sedimentation phenomenon was observed. Mass transport coefficients (permeation and selectivity) were evaluated. Selectivity of the investigated membranes changed with the weight fraction of magnetic particles from oxygen (plain) towards nitrogen (2 and more w/w%).

A new concept of polymer membranes filled with neodymium powder and magnetized (“magnetic membranes”) for an air enrichment, was applied. Membranes (mostly EC) with dispersed metal powder were cast in an external magnetic field of a specially designed coil (magnetic induction up to 0.04 T). For final magnetization a strong field magnet of about 2 T, was used. Experimental setup with a gas chromatograph for comprehensive measurements of the air separation properties, was used.

Structure and transport properties of ethylcellulose membranes with dispersed magnetic powder were investigated. The study mainly focused on diffusion, which is one of the transport mechanisms. The transport properties depend on many parameters like: polymeric matrix used, type of powder, its amount and granulation. The structure of the pattern formed by magnetic particles in the membrane matrix was studied. Description of the system was based on the phenomenological and molecular (random walk on a fractal lattice) approaches. Two parameters were calculated: the fractal dimension of random walk d_{w}, and the fractal dimension of membrane structure d_{f}. The knowledge of both parameters made it possible to use the generalized equation of diffusion on the fractal structure obtained by Metzler et al. The research was carried out to determine the influence of magnetic powder granulation on the transport properties. The results showed that the random walk within the membranes of the smallest magnetic powder granulation was of the most subdiffusive character. Detailed investigation and quantitative description of gas transport through the membranes enables designing the membranes to be used in air oxygen enrichment.

In this paper results of the analysis of urine samples of healthy children and children with a congenital cyanotic heart defect and after heart transplantation are presented. The analysis of urine samples was carried out by X-ray fluorescence spectrometry with wavelength dispersion and using CRM urine Seronorm as a reference. It was found that for patients with a congenital cyanotic heart defect the loss of electrolytes like Na, Cl and K was increased. Moreover, urine samples of children from areas of different degree of environmental pollution were analysed. We observed (as expected) higher concentrations of heavy metals in the urine of children from ecological polluted areas.

Twenty herbs, showing medicinal benefits on human life, like Taraxacum officinale, Plantago lanceolata, Hypericum perforatum, Ocimum basilicum, Melissa officinalis, Mentha piperita, and others, were tested. The percentage content of pigments, i.e. chlorophylls, carotenoids, and flavonoids, in the chosen herbs was determined. The spectrophotometric method, which is quick and readily available, was used. Measurements required pigment extraction with a solvent. Ethanol was used for the determination of chlorophylls and carotenoids, and acetone for the determination of flavonoids. Hierarchical agglomerative cluster analysis was performed in order to confirm the experimental results. The study of flavonoids content showed an interesting regularity which can be used for the classification of herbs. Plants belonging to the Lamiaceae family showed the flavonoids content in the range from 0.18 % to 0.68 %, whereas those belonging to the Apiaceaehas family showed the flavonoids content in the 0.75–1.20 % range.

Ethylcellulose (EC) or linear polyimide (LPI) and magnetic neodymium powder particles MQP-14-12 were used for the preparation of inorganic-organic hybrid membranes. For all the membranes, N2, O2 and air permeability were examined. Mass transport coefficients were determined using the Time Lag System based on dynamic experiments in a constant pressure system. The results showed that the membrane permeation properties were improved by the addition of magnetic neodymium particles to the polymer matrix. The magnetic ethylcellulose and polyimide membranes exhibited higher gas permeability and diffusivity, while their permeability selectivity and solubility were either unchanged or slightly increased. Polyimide mixed matrix membranes were characterised by a higher thermal and mechanical stability, larger filler loading, better magnetic properties and reasonable selectivity in the air separation.

The concept of diffusion on fractal structure of polymeric membrane with magnetic powder is presented. The fractal characteristics, i.e. static fractal dimension df and fractal dimension of the trajectory of the random walk dw, were evaluated for qualitative and quantitative description of membrane structures. The way of introducing the fractal dimension and anomalous-diffusion exponent into the generalized diffusion equation on fractal geometries obtained by Metzler et al. has been shown. The results showed that the random walk within the membranes of the smallest granulation of magnetic powder was of the most subdiffusive character.

The idea of using magnetic membranes for enrichment of air by oxygen is based on the observation that oxygen and nitrogen have quite different magnetic properties, i.e., oxygen is paramagnetic whereas nitrogen diamagnetic. The oxygen molecule is paramagnetic with a magnetic moment of mO2 1⁄4 2:73 10 JT : Magnetic susceptibility of nitrogen is equal to w 1⁄4 150:8 10 6 mol 1 1⁄4 2:5 10 molecule 1 which corresponds only to m 1⁄4 2:5 10 JT 1 in a magnetic field of 1 T, a value five orders of magnitude smaller than the O2 magnetic moment (Morrish 1965; Borys et al. 2011). Magnetic membranes are polymeric membranes (ethyl cellulose (EC) or poly (2,6-dimethyl-1,4-phenylene oxide) (PPO)) with dispersed magnetic powder (ferrite, praseodymium, and neodymium). The membranes are made by casting of appropriate polymer solution with dispersed magnetic powder in an external magnetic field of a specially designed coil (stable magnetic field with range of induction 0–40 mT). Removed from Petri dish membranes are dried in 40 C for at least 2 days and then are stored in an exsiccator under the vacuum conditions (p = 3 mmHg). Collection of permeation quantities both for individual gases (O2, N2) and for their mixture (air 21 %O2/79 % N2) is measured in experimental setup (Fig. 1). The measurements are carried out in room temperature for membranes with dispersed magnetic powder before and after magnetization in a field magnet with magnetic induction about 2.5 T. The setup furnished with a gas chromatograph allows to measure the oxygen and the nitrogen concentration in permeate. The main part of the experimental setup is diffusive chamber, where the membrane is put in the form of disk. The setup is used for a low-pressure (from 0.1 to 1.0 MPa) analysis of gas permeation. Transport coefficients can be calculated using flow rate data and percentage of air enrichment. The flow rate of the permeate can be recorded using a flowmeter. Integration of flux with respect to time allows to sketch a downstream permeation curve. Typical plot of Q(l,t) versus time is presented in the Fig. 2. Time-lag method and D1-D8 system allow to get some insight into the nature of the considered transport process. In papers (Strzelewicz and Grzywna 2007, 2008; Rybak et al. 2009a, b, 2012; Grzywna et al. 2010) a concept of magnetic membranes for air enrichment is explained. The authors observed an increase in the oxygen flux with respect to the nitrogen flux and the enrichment in the oxygen content of the permeate up to