Volume 18 (2016): Issue 1 (March 2016)

Seeking to obtain bulk (NPK – nitrogen, phosphorus, potassium), chlorine-free fertilizers, the influence of interaction between potassium chloride and ammonium dihydrogen phosphate in aqueous solutions at temperature of 20, 40, 60 and 80°C has been investigated. Components of the solid phase have been identified by methods of chemical and instrumental analysis: radiography (X – ray), infra – red molecular absorption spectroscopy (IR) and scanning electron microscopy (SEM). It has been observed that the largest amount of solid state potassium dihydrogen phosphate was obtained at 60–80°C, when the potassium chloride and ammonium dihydrogen phosphate molar ratio is equal 0.8:0.2. Changing the molar ratio of 0.5:0.5 to 0.8:0.2, and with increasing temperature, various shaped crystals have developed in the remaining aqueous solutions with a morphology shifting from sharp needles to tetragonal prism.

In this study, palm oil was the first time to convert into a novel polyester plasticizer for polyvinyl chloride (PVC). In the first stage, palm oil was converted into palm oil monoglyceride (POM) by alcoholysis with glycerol. Next, a novel palm oil monoglycerides based polyester plasticizer (POMP) was synthesized from POM and maleic anhydride through esterification and condensation reaction. The structure of POMP was characterized with FTIR, 1H NMR and GPC. Then PVC blends were prepared using POMP as a plasticizer, melting behavior, thermal property, compatibility, mechanical properties and mechanism of plasticization of PVC blends were systematically studied. Melting behavior indicated that POMP could decrease the torque and the melt viscosity of PVC blends that was conducive to process. With the content of POMP increasing from 5 g to 15 g in PVC blends, the plasticized PVC blends demonstrated better compatibility, the degradation temperature (T_d) increased from 252.6°C to 257.0°C, the glass transition temperature (T_g) decreased from 55°C to 49.5°C. Plasticization was put into effect by interaction of the electron cloud between the PVC chain and POMP molecule. This study may lead to the development of new type of PVC plasticizer based on vegetable oil.

Pd-Ni/Al₂O₃ systems were investigated in the reaction of hydrogen oxidation in terms of their possible application as catalysts used in passive autocatalytic recombiners (PARs) used in nuclear power plants. Testing experiments were carried out in a flowing system at different temperatures and humidity of the reaction mixture. The bimetallic catalysts exhibited higher response to the increase of temperature and higher resistance to inhibit water than the monometallic palladium catalyst. They showed excellent stability during a few tens of hours, similarly, like their monometallic counterpart. Our bimetallic catalysts of hydrogen oxidation can be used as cheaper alternatives to catalysts based on the precious metals in the hydrogen oxidation without loss of their activity over time.

The food industry produces large amounts of solid and also liquid wastes. Different waste materials and their mixtures were pyrolysed in the laboratory pyrolysis unit to a final temperature of 800°C with a 10 minute delay at the final temperature. After the pyrolysis process of the selected wastes a mass balance of the resulting products, off-line analysis of the pyrolysis gas and evaluation of solid and liquid products were carried out. The highest concentration of methane, hydrogen and carbon monoxide were analyzed during the 4th gas sampling at a temperature of approx. 720–780°C. The concentration of hydrogen was measured in the range from 22 to 40 vol.%. The resulting iodine numbers of samples CHFO, DS, DSFW reach values that indicate the possibility of using them to produce the so-called “disposable sorbents” in wastewater treatment. The WC condensate can be directed to further processing and upgrading for energy use.

A multiscale model for simulating the hydrodynamic behavior of catalytic bale packings has been proposed. This model combines computational fluid dynamics (CFD) and macroscopic calculation. At small scale calculation, the CFD model includes 3-D volume-of-fluid (VOF) simulation within representative elementary unit (REU) under unsteady-state conditions. The REU constitutes gauze and catalyst domain, and porous media model is applied. At large scale calculation, a new mechanistic model deduced from the unit network model is employed. Based on liquid split proportion from small scale calculation, liquid distribution of the entire bale packing can be predicted. To evaluate different packing design, three common bale arrangements, i.e. one-bale, nine-bales and seven-bales, are compared. The area-weighted Christiansen uniformity coefficient is introduced to assess the distribution performance. A comparison between simulation and experimental results is made to validate the multiscale model. The present methodology is proved to be effective to analysis and design of catalytic distillation columns.

In the B10 isotope enrichment industry, the purification of anisole mixture makes great sense. A dynamic-accumulative operation policy of continuous distillation (DACD) with repeated filling and dumping of the still is proposed for the separation of trace heavy impurities in the recycled anisole. To simulate and optimize the purification process of anisole, a mathematical model of DACD is derived, and the computer codes are developed in the MATLAB environment. Moreover, the experiment is performed in a pilot-scale distillation column. The results show that the experimental date agrees well with simulation results. DACD could solve the difficulty of flow rate control when the bottom flow rate is very small in continuous distillation. The size of the still in this operation mode is also smaller than that in batch distillation. And the yield of anisole is raised to 99.91%. In a word, DACD is especially suitable for separating trace heavy impurities from the recycled anisole.

Compounds emitted during thermo-oxidative decomposition of three commercial polyester fabrics for indoor outfit and decorations (upholstery, curtains) were studied. The experiments were carried out in a flow tubular furnace at 600°C in an air atmosphere. During decomposition process the complex mixtures of volatile and solid compounds were emitted. The main volatile products were carbon oxides, benzene, acetaldehyde, vinyl benzoate and acetophe-none. The emitted solid compounds consisted mainly of aromatic carboxylic acids and its derivatives, among which the greatest part took terephthalic acid, monovinyl terephthalate and benzoic acid. The small amounts of polycyclic aromatic hydrocarbons were also emitted. The emission profiles of the tested polyester fabrics were similar. The presence of toxic compounds indicates the possibility of serious hazard for people during fire.

Synthesis via ozone precipitation reaction was used to obtain manganese dioxide (OMD) and it was probed as an adsorbent for zinc ions. Adsorption was followed along shaking time and increasing ratio [NO₃⁻] / [Zn²⁺], and isotherms were obtained at different pH values and in the presence of several anions (chloride, nitrate, sulphate, and acetate). It was found that adsorption equilibrium is fast and follows the pseudo-second order model (q_e = 34 ±1 mg/g and K = 0.07 ±0.01 g/mg h). Isotherms were fitted to Langmuir, Freundlich, and Langmuir-Freundlich models, and the best fitting was found with the last one. The process is dependent on pH and the efficiency increases from pH 1 to 4. The ratio [NO₃⁻] / [Zn²⁺] up to 3 does not seem to change the behaviour of the process. Regarding the anions, the efficiency of Zn(II) adsorption occurs according to: acetate > nitrate and sulphate > chloride. Manganese oxide obtained via ozonization is an excellent adsorbent for zinc ions.

3-Mercaptopropyl-trimethoxysilane and [3-(2-aminoethylamino)propyl]trimethoxysilane were used to functionalize the surface of silica from Piotrowice in Poland to stabilize heavy metals (HMs) and arsenic in soil. The soil for the study was sampled from the impact zone of Głogów Copper Smelter and Refinery. The soil samples were exposed to five-step Tessier sequential extraction. The speciation studies were limited to five sequentially defined fractions in which metal content was determined. The addition of unmodified silica did not affect significantly the concentration of metals in individual fractions. Significant changes were noted upon introduction of functionalized silica in the soil. The hybrid formulations obtained significantly reduce the release of heavy metals and arsenic from soil sorption complex. The results indicate the potential use of functional formulations for reduction of metal migration in soil in the areas of exceeded concentration of heavy metals and arsenic in the soil, caused by industrial activity.

In batch fermentation of whey, selection of suitable species at desired conditions such as substrate, product concentrations, temperature and inoculum size were investigated. Four Lactobacillus species and one Lactococcus species were screened for lactic acid production. Among them L. bulgaricus ATCC 11842 were selected for further studies. The optimal growth of the selected organism for variable size of inocula was examined. The results indicated that inoculum size had insignificant effect on the cell and lactic acid concentration. The effect of temperature was also studied at 32, 37, 42 and 47°C. Results showed that the concentration of cell dry weight increased with increment of temperature from 32 to 42°C. The maximum cell and lactic acid concentration was obtained at 42°C. The effect of initial substrate concentration on lactic acid production was also examined. The optimum initial lactose concentration was found to be 90 g/l.

The aim of the work was to develop a mathematical model for computing the steady-state voltage – current characteristics of a planar Solid Oxide Fuel Cell and to determine the performance of a new SOFC design. The design involves cross-flow bipolar plates. Each of the bipolar plates has an air channel system on one side and a fuel channel system on the other side. The proposed model was developed using the ANSYS-Fluent commercial Computational Fluid Dynamics (CFD) software supported by additional Fuel Cell module. The results confirm that the model can well simulate the diagonal current path. The effects of temperature and gas flow through the channels and a Membrane Electrode Assembly (MEA) structure were taken into account. It was shown that a significant increase of the MEA temperature at high current density can lead to hot spots formation and hence electrode damage.

This paper presents the most important issues relating to the influence of mineral fertilizers on both the natural environment and human and animal health. The physiological, environmental and economic impact of fertilizer production and application, resulted from a low assimilation of mineral components by crops, has been described. The research on the development and production of a large and diverse group of materials with slow-release properties that can increase the effectiveness of nutrient uptake, alleviate the negative influence of fertilizers on the environment and reduce labor and energy consumption associated with the use of conventional fertilizers, has been reviewed.

In the present study, the fluid flow in a periodic, non-isotropic dual scale porous media consisting of permeable square rods in inline arrangement is analyzed to determine permeability, numerically. The continuity and Navier-Stokes equations are solved to obtain the velocity and pressure distributions in the unit structures of the dual scale porous media for flows within Darcy region. Based on the obtained results, the intrinsic inter and intraparticle permeabilities and the bulk permeability tensor of the dual scale porous media are obtained for different values of inter and intraparticle porosities. The study is performed for interparticle porosities between 0.4 and 0.75 and for intraparticle porosities from 0.2 to 0.8. A correlation based on Kozeny-Carman relationship in terms of inter and intraparticle porosities and permeabilities is proposed to determine the bulk permeability tensor of the dual scale porous media.

In this work, a modified random pore model was developed to study the kinetics of the carbonation reaction of CaO. Pore size distributions of the CaO pellets were measured by nitrogen adsorption and mercury porosimetry methods. The experiments were carried out in a thermogravimeter at different isothermal temperatures and CO₂ partial pressures. A fractional concentration dependency function showed the best accuracy for predicting the intrinsic rate of reaction. The activation energy was determined as 11 kcal/mole between 550–700°C. The effect of product layer formation was also taken into account by using the variable product layer diffusivity. Also, the model was successfully predicted the natural lime carbonation reaction data extracted from the literature.

In this present study, chemical coagulation process (CC) treatment process was investigated under different conditions such as pH, ferric chloride dose, agitation time and settling time to treat bagasse wastewater using response surface methodology (RSM). The outcomes were evaluated using Pareto analysis of variance (ANOVA) and second order polynomial models were created with the aim of being able to predict the responses. Ideal conditions were observed to be as per the following: agitation time of 25 min, pH of 7, ferric chloride dose of 6 g/L and settling time of 60 min. Under these conditions, turbidity removal of 62%, COD removal of 67%, TDS removal 53% and sludge production of 32 mL/L were obtained with operating cost of 3.50 Rupee/L. The mechanism of CC was analyzed using XRD spectrum and founds to be adsorption.

The paper proposes a novel process integration for biodiesel blend in the Membrane assisted Reactive Divided Wall Distillation (MRDW) column. Biodiesel is a green fuel and grade of biodiesel blend is B20 (%) which consist of 20% biodiesel and rest 80% commercial diesel. Instead of commercial diesel, Tertiary Amyl Ethyl Ether (TAEE) was used as an environment friendly fuel for blending biodiesel. Biodiesel and TAEE were synthesized in a pilot scale reactive distillation column. Dual reactive distillation and MRDW were simulated using aspen plus. B20 (%) limit calculation was performed using feed flow rates of both TAEE and biodiesel. MRDW was compared with dual reactive distillation column and it was observed that MRDW is comparatively cost effective and suitable in terms of improved heat integration and flow pattern.

Drawing up diagnostic relations between thermal characteristics determined in thermal imaging examinations and mechanical properties, allowing for forecasting the state of material during the use, was a purpose of the work. Research was performed on polyester – glass composites which were subjected to the ageing-fatigue degradation process in a device created specifically for that purpose. It was indicated how to assess the degree of the decline, taking into account the fall in material strength properties. The basis of a method was measurement of changes in temperature in activated thermal processes. Relations between changes of the speed of heating and cooling were related to the bending strength and the modulus of elasticity. Diagnoses were backed up with microscopic examinations.

A new method of preparation of multifunctional oligoetherols containing carbazole ring is presented. The oligoetherols were obtained in the reaction of 9-(2,3-epoxypropyl)carbazole with sorbitol and oxiranes like ethylene and propylene oxide. The structure of obtained oligoetherols was determined by IR, H-NMR and MALDI-ToF spectroscopies. Physical properties of the products render them good candidates for preparing polyurethane foams. The foams were obtained and their properties were examined. It has been found that the foams are rigid at room temperature and their apparent density was 50–70 kg/m³. The water uptake was low, maximum to 6.5 mass%. Obtained foams have high thermal resistance. Dynamic thermal analysis of these foams showed that 5% mass loss was initiated at 250–300°C, while temperature of 50% mass loss was 370–404°C. Concomitantly the increase of compression strength was observed.

The separation and purification of rebaudioside A from Stevia rebaudiana crude extracts (Steviosides) by macroporous resin were optimized by Taguchi orthogonal array (OA) experimental design methodology. This approach was applied to evaluate the influence of five factors (adsorption temperature, desorption time, elution solution ratio, adsorption volume and type of resin) on the rebaudioside A yield. The percentage contribution of each factor was also determined. The results showed that elution solution ratio and adsorption volume made the greatest (59.6%) and the lowest (1.3%) contribution, respectively. The results showed that the Taguchi method is able to model the purification of rebaudioside A process well (R² > 0.998) and can therefore be applied in future studies conducted in various fields. Adsorption temperature 35°C, desorption time 60min, elution solution ratio 3, adsorption volume 200ml and HPD-400 as resin were the best conditions determined by the Taguchi method.

Halloysite nanotubes (HNTs) reinforced epoxy composites with improved mechanical properties were prepared. The prepared HNTs reinforced epoxy composites demonstrated improved mechanical properties especially the fracture toughness and flexural strength. The flexural modulus of nanocomposite with 6% mHNTs loading was 11.8% higher than that of neat epoxy resin. In addition, the nanocomposites showed improved dimensional stability. The prepared halloysite reinforced epoxy composites were characterized by thermal gravimetric analysis (TGA). The improved properties are attributed to the unique characteristics of HNTs, uniform dispersion of reinforcement and interfacial coupling.