Polish Journal of Chemical Technology (v.13, #1)
Equilibrium and rate of iron(III) extraction from chloride solutions by individual hydrophobic extractants and their mixtures
by Katarzyna Staszak; Ryszard Cierpiszewski; Krystyna Prochaska; (pp. 1-5).
The main goal of this work was to study and compare the rate of iron(III) extraction from chloride solutions by commercial extractants: Alamine 336, TOPO and LIX 54 and their mixtures. Using the interfacial tension data, obtained for mixed systems, the values of surface mole fraction and molecular interaction parameter of extractants were estimated. Determination of the extraction rates was performed by using the Lewis-type stirred transfer cell. It was found that the extraction efficiency of extractants are changed in the following order: Alamine 336>TOPO>β-diketone. The addition of a chelating extractant to the system decreases the extraction efficiency, for example the addition of β-diketone to TOPO decreases the extraction efficiency by about 50%.
Keywords: extraction; iron(III); Alamine 336; TOPO; β-diketone
Analysis of a Detailed Kinetic Model of Natural Gas Combustion in IC Engine
by M. Mansha; A. R. Saleemi; S. H. Javed; Feroz Nadeem; (pp. 6-15).
Detailed kinetic models are important to describe the oxidation of hydrocarbon fuels. In the present study, a detailed kinetic models has been developed to simulate the combustion of natural gas in IC engine. The proposed models consists of 208 elementary reactions and 72 species. The rate of the production and sensitivity analysis of the proposed reaction models were carried out to visualize the effect of reactions on the formation of various pollutants. In the rate of production analysis, an absolute rate of production coefficients and the normalized rate of production coefficients were calculated for the reactions involved in the formation of pollutant species (CO, NO, NO2, & NH3). In sensitivity analysis, normalized logarithmic sensitivity coefficients were determined the reactions of rates affects the output concentrations of the pollutant species. These two analysis were carried out for two temperatures ranges i.e. 1500 °C and 4000 °C under stoichiometric conditions (when φ=1.0).
Keywords: Sensitivity Analysis; models; Rate of Production Analysis
The effect of thermal treatments on the mechanical and electrical properties of nickel-coated carbon fibre composites
by Boguslaw Pierozynski; (pp. 16-19).
Nickel-coated carbon fibre (NiCCF) composites may find technological applications within many industrial sectors, including: laptop computers, automotive and military industries. Typically, these applications require that NiCCF be subjected to extensive material processing; thus, optimization of mechanical (and electrical) properties for this material at the stage of its production is of significant importance. The present paper reports the application of specific, high-temperature heat treatments to laboratory-produced 12K50 NiCCF material, carried-out in order to improve the ductility and interfacial adhesion of electrodeposited Ni coating to the surface of carbon fibre substrate.
Keywords: nickel-coated carbon fibre; NiCCF; interfacial adhesion; electrical resistivity
Utilization of agricultural and industrial wastes for metal removal from aqueous solutions
by Marta Biegańska; Ryszard Cierpiszewski; (pp. 20-22).
In this study a possibility of obtaining sorbents from basketry wastes has been investigated. Therefore, adsorption of cadmium ions on wicker bark of Salix americana has been studied. The obtained experimental results were described by the Freundlich equation and adsorption kinetics by the pseudo-second order equation. The effect of pH on cadmium ions adsorption by S. americana was also investigated. It has been found that for the pH values ranging from 2 to 7 cadmium removal from the solution was held at almost constant level.
Keywords: waste; adsorption; heavy metals; toxicity; wicker bark; Freundlich isotherm; kinetic
New thermoplastic poly(carbonate-urethane) elastomers
by Anna Kultys; Magdalena Rogulska; (pp. 23-30).
Two series of novel thermoplastic poly(carbonate-urethane) elastomers, with different hard-segment content (30 - 60 wt %), were synthesized by melt polymerization from poly(hexane-1,6-diyl carbonate) diol of Mn = 2000 as a soft segment, 4,4'-diphenylmethane diisocyanate (MDI) or hexane-1,6-diyl diisocyanate (HDI) and 6,6'-[methylenebis(1,4-phenylenemethylenethio)]dihexan-1-ol as a chain extender. The structure and basic properties of the polymers were examined by Fourier transform infrared spectroscopy, X-ray diffraction analysis, atomic force microscopy, differential scanning calorimetry, thermogravimetric analysis, Shore hardness and tensile tests. The resulting TPUs were colorless polymers, showing almost amorphous structures. The MDI-based TPUs showed higher tensile strengths (up to 21.3 MPa vs. 15.8 MPa) and elongations at break (up to 550% vs. 425%), but poorer low-temperature properties than the HDI-based analogs.
Keywords: thermoplastic polyurethane elastomers; poly(hexane-1,6-diyl carbonate) diol; 4,4'-diphenylmethane diisocyanate; hexane-1,6-diyl diisocyanate; thermal and mechanical properties; atomic force microscopy
Investigation of applying calcium oxide for the removal of bitter substances from hop wastes
by Krystyna Hoffmann; Józef Hoffmann; Marta Huculak-Mączka; Jakub Skut; (pp. 35-40).
Utilization of brewery wastes is one of the solutions for the production of the fodder supplements containing biogenic nutrients. The condition of such application is to meet the requirements included in the regulations regarding animal feeding, particularly removing a bitter taste. The aim of the performed investigations was the removal of bitter acids from the post-extraction hop waste using the calcium oxide addition. For the examination hop wastes obtained as a by-product from the CO2 plant extraction in supercritical conditions, were applied. Physicochemical properties of the waste samples collected for the investigations were determined by applying the available standard analytical techniques. The analyses of the determination of bitter acids were carried out by the high performance liquid chromatography method. During the experiments very good effects of bitter acids removal from hop wastes, were obtained by using CaO suspensions in water. The investigations on the influence of the CaO concentration in suspension on the efficiency of bitter acids removal indicate the possibility of applying suspensions by 2 wt% for this purpose.
Keywords: hop wastes; bitter acids; calcium oxide
Obtaining protein hydrolysates with chemical and enzymatic methods
by Zygmunt Kowalski; Agnieszka Makara; Marcin Banach; (pp. 41-46).
The goal of our research was to work up a method of hydrolisates protein production using as raw material fresh pork meat-bone tissue after dismantling the process of half carcasses. Actually this raw material was practically all utilized as waste. The results of laboratory research and an industrial test allowed to state that is possible to produce hydrolysates containing 8 - 10% of proteins, and the most advantageous parameters of the chemical process are: the reaction time ~105 min., temperature 120°C, pressure 3.0 bars. With the use of enzymes (Protamex and Flavourzyme), it is possible to obtain a non-gelling protein hydrolysate with a high degree of clarity and light cream colour. The best results were achieved with the following parameters: the meat-bone feedstock to the water ratio from 1:1 to 1:2, the temperature of 40 - 45°C, the time of the process 3 h, pH ~6.
Keywords: meat waste; protein hydrolysate; chemical method; enzymatic method
Polyurethane pressure-sensitive adhesives as raw materials for the manufacturing of protective films
by Monika Łągiewczyk; Zbigniew Czech; (pp. 47-50).
The present paper relates to water-borne polyurethane pressure-sensitive adhesives (PU-PSA) systems for self-adhesive protective films, and methods of their preparation. The typical protective films are self-adhesive films with excellent removability. Their manufacture is a film conversion process using common materials developed for the packaging industry (PVC and polyolefins). The most often used carrier for the constructions of protective films is PE. Polyurethane PSA layers are characterized by constant low peel adhesion between 3 and 5 N/2,5 cm.
Keywords: polyurethane; self-adhesive; protective films; peel adhesion
Preparation of sorbents from selected polymers
by Wiesława Ciesińska; Grzegorz Makomaski; Janusz Zieliński; Tatiana Brzozowska; (pp. 51-54).
In this work, the results of studies on the preparation of sorbents from selected polymers were presented. The polymers were carbonized and subsequently physically activated by steam or carbon dioxide, or alternatively, chemically activated with potassium hydroxide. For the obtained materials, a specific area was evaluated by means of low-temperature nitrogen adsorption and benzene adsorption, iodine number was also determined. The obtained results indicated a possibility to procure hydrophobic sorbents of microporous structure. Sorbents having the best properties, i.e. the specific area of above 2000 m2/g were produced from poly(ethylene terephthalate) and phenol-formaldehyde resin.
Keywords: polymers; carbonization; physical activation; chemical activation; carbon sorbents
A preliminary study of the degradation of selected commercial packaging materials in compost and aqueous environments
by Marta T. Musioł; Joanna Rydz; Wanda J. Sikorska; Piotr R. Rychter; Marek M. Kowalczuk; (pp. 55-57).
The paper presents the results of the degradation of two commercial packaging materials CONS-PET and BioPlaneta in the compost and distilled water at 70°C. The materials containing polylactide (PLA), CONS-PET 13% and BioPlaneta 20%, aliphatic-aromatic copolyester terephthalic acid/adipic acid/1,4-butanediol (BTA) and commercial additives degraded under the industrial composting conditions (composting pile or container) and in distilled water at 70°C in the laboratory holding oven. Distilled water provided the conditions for the hydrolytic (abiotic) degradation of the materials. Weight loss, changes of molecular weight, dispersity monitored via the GPC technique and the macroscopic surface changes of the tested materials were monitored during the experiments. The investigated systems show similar trends of degradation, however on the last day of the incubation the decrease of the molecular weight was higher in water than under the industrial composting conditions. The results indicate that commercial packaging materials can be degraded both while composting ((bio)degradation) and during the incubation in distilled water at 70°C (abiotic hydrolysis).
Keywords: Polylactide; PLA; aliphatic-aromatic copolyester; BTA; (bio)degradation; industrial composting pile; container system; hydrolytic degradation
Possibilities of utilizing the solid by-products of biodiesel production - a review
by Elżbieta Gąsiorek; Marta Wilk; (pp. 58-62).
As a consequence of the intended rise in the volume of the biodiesel produced by the member states of the European Union, predominantly from rapeseeds and sunflower seeds, the quantity of the by-products being generated, e.g. glycerol, rapeseed/sunflower seed straw and rapeseed/sunflower seed meal, will increase dramatically. It is therefore recommendable to find effective methods for their processing or utilization in order to reduce the costs of biodiesel production without polluting the environment by excessive wastes. As the utilization of glycerol has often been addressed in the literature1, the aim of our study is to describe the potentiality for utilizing the solid by-products of biodiesel production, namely rapeseed/sunflower straw and rapeseed/ sunflower seed meal.
Keywords: renewable energy; biodiesel; rapeseed straw; rapeseed meal; sunflower seed meal; white biotechnology
Epoxy adhesive formulations using latent imidazole metal cation complexes
by Ryszard Pilawka; Honorata Maka; (pp. 63-66).
Complexes of 2-methylimidazole with cations from several metal sulfates were prepared and investigated as curing agents for epoxy resins. The reactivity of one-part formulations of these complexes with a bisphenol A type epoxy resin was determined by the differential scanning calorimetry and the pot life observed by viscosity measurements. Tensile lap shear tests at room temperature and at 120°C were used to evaluate the adhesive strength of the formulations directly after preparation as well as after one and three months of storage at room temperature.
The DSC measurements showed much lower reactivity (7 - 32%) and higher reaction temperatures of the complex formulations in comparison to the mixtures with pure 2-methylimidazole. The viscosity of most formulations remained almost unchanged over the observed period of three months. The adhesive strength of the freshly prepared complex formulations is comparable to a formulation with pure 2-methylimidazole and decreases over time, depending on the type of metal cation and the cation-to-imidazole molar ratio. The obtained results indicate that complexes of 2-methylimidazole with cations are suitable as latent curing agents for epoxy resins.
Keywords: epoxy adhesives; latent curing agent; imidazole complexes; pot life; shear strength
Corrosion inhibition of mild steel in HCl solution by Tinidazole
by Imran Reza; A. R. Saleemi; S. Naveed; (pp. 67-71).
Tinidazole, a pharmaceutical compound has been investigated with reference to the inhibition of mild steel acidic corrosion in 1 molar HCl by means of weight loss and electrochemical measurements. The outcomes attained at 30°C revealed that the Tinidazole had obtained 90% inhibition efficiency at 400 ppm concentration. These results explain that the inhibition process occurs by means of adsorption. The inhibitor molecules adsorb on the surface of the metal, following Langmuir's adsorption isotherm. Potentiodynamic polarization measurements established that Tinidazole is an inhibitor of a mixed type. An appropriate equivalent electric circuit for modeling and the analysis of impedance data to give a better explanation of the process of corrosion inhibition have been proposed.
Keywords: Acid corrosion; mild steel; Polarization; EIS; Tinidazole