Volume 18 (2016): Issue 3 (September 2016)

The supported co-catalyst (Co, Ni)₃O₄/Al₂O₃ was prepared via using a co-precipitation method. Three sets of these materials were prepared by calcination at three different temperatures 500, 600, and 700°C. Crystal structure of the prepared materials was investigated using powder X-rays diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), Atomic force microscope (AFM), and specific surface area (BET). The activity of the prepared catalysts was investigated by following both of photocatalytic and adsorption removal of Reactive yellow 145 dye (RY 145) from simulated industrial wastewaters. In this study, different reaction conditions were performed such as effect of pH of the reaction mixture, mass dosage of the used catalyst, and effect of temperature. In addition to that adsorption isotherms and reaction kinetics were investigated. Also the activity of these catalysts were investigated after cyclization of the used catalysts.

The aim of this study was experimental and modelling analysis of the nanofiltration process used for the removal of chromium(III) ions from salt solution characterized by low pH. The experimental results were interpreted with Donnan and Steric Partitioning Pore (DSP) model based on the extended Nernst-Planck equation. In this model, one of the main parameters, describing retention of ions by the membrane, is pore dielectric constant. In this work, it was identified for various process pressures and feed compositions. The obtained results showed the satisfactory agreement between the experimental and modelling data. It means that the DSP model may be helpful for the monitoring of nanofiltration process applied for treatment of chromium tannery wastewater.

The efficiency of lactic acid solutions nanofiltration with dynamically formed zirconium (IV) hydrous oxide polyacrylate (ZrIV/PAA) membranes application were considered in this paper. The results of investigations on flux decline in nanofiltration of lactic acid solutions under conditions resulting in low and high lactic acid rejection are reported. In the long term experimental research on pressure driven membrane processes the main reason of permeate flux reduction is an accumulation of concentration polarization and fouling effects. The experimental permeate flux versus time curves were analyzed in the frame of resistance-in-series model with the aim to develop the characteristic fouling and concentration polarization resistances. The analysis of experimental data and results of calculations showed that both: concentration polarization and fouling phenomena in investigated system depend on hydrodynamic conditions and properties of filtered solutions and (ZrIV/PAA) membrane.

Two types of composite imprinted membranes, i.e., composite membrane comprised of D-Phe imprinted beads and D-Phe imprinted membrane or DCM and composite membrane comprised of L-Phe imprinted beads and L-Phe imprinted membranes or LCM, were synthesized by phase inversion technique after a uniform dispersion of beads within the polymeric solutions using simple physico-mechanical process. The assemblies of the prepared DCM, LCM and control membranes were employed in ultrafiltration for chiral separation of D, L-Phenylalanine racemate solution. DCM and LCM showed an improved adsorption capacity (0.334 mg g^-1 and 0.365 mg g^-1 respectively), and adsorption selectivity (2.72 and 2.98 respectively). However, the percent rejection of the template and counter enantiomer were lower than that of control membranes. Compared to control membrane, the DCM and LCM showed inverse permselectivity. These composite membranes having better adsorption and separation ability for Phenylalanine racemate solution will be suitable in the future for various other applications.

Ordered SBA-15 mesoporous silica supports have been synthesized and used for incorporation of titanium with different Ti/Si weight ratio via incipient wetness impregnation. Titanium tetraisopropoxide (TTIP) was used as a source of Ti. Obtained catalysts were characterized to investigate the chemical framework and morphology by nitrogen sorption measurements, powder X-ray diffraction (XRD), X-ray fluorescence elemental analysis (XRF), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS) and Fourier transform infrared photoacoustic spectroscopy (FT-IR/PAS). The photocatalytic degradation of phenol and methylene blue water solutions were selected as a probe reactions to the photoactivity test of prepared samples and to verify the potential application of these materials for water purification. Experimental results indicate that the photocatalytic activity of Ti/Si mixed materials depends on the adsorption ability of composites and the photocatalytic activity of the titanium oxide.

In this work, some parameters during the partial acidulation by phosphoric acid of phosphate 53.75% BPL (bone phosphate of lime) having different particle sizes are determined. P₂O₅ recovery is obtained by performing a series of reactions using phosphoric acid diluted from 10 to 40 wt.% and with reaction times ranging from 10 to 50 minutes. The best conversion rates are obtained with the following reaction parameters: phosphates size: 88-177 μm, reaction time: 50 minutes and phosphoric acid concentration: 40 wt.%. In the second part, the water-soluble P₂O₅ of PAPRs (Partially Acidulated Phosphate Rocks) obtained with phosphoric acid 30% and 40 wt.% is measured. The results of experiments showed that the water-soluble P₂O₅ has reached 15.2% for PAPRs obtained by reacting phosphate 88 μm with phosphoric acid 40 wt%.

Cyclopentane carboxylic acid (CPCA) is a model compound of Naphthenic acids (NAs). This objective of this paper is to discover total acid number (TAN) reduction kinetics and pathways of the reaction between CAPA and subcritical methanol (SubC-MeOH). The experiments were carried out in an autoclave reactor at temperatures of 180-220°C, a methanol partial pressure (MPP) of 3 MPa, reaction times of 0-30 min and CPCA initial gas phase concentrations of 0.016-0.04 g/mL. TAN content of the samples were analyzed using ASTM D 974 techniques. The reaction products were identified and quantified with the help of GC/MS and GC-FID respectively. Experimental results reveal that TAN removal kinetics followed first order kinetics with an activation energy of 13.97 kcal/mol and a pre-exponential factor of 174.21 s^-1. Subcritical methanol is able to reduce TAN of CPCA decomposing CPCA into new compounds such as cyclopentane, formaldehyde, methyl acetate and 3-pentanol.

The aim of this study was to test the usefulness of magnetron sputtering technology to produce coatings on selected elements of a firefighter’s helmet to protect against infrared radiation (PN-EN 171 standard). The scope of research includes testing the deposition produced via magnetron sputtering of metallic and ceramic coatings on plastics, which are used to manufacture the components comprising the personal protection equipment used by firefighters. The UV-VIS, NIR used to research the permeation coefficients and reflections for light and infrared light and the emission spectrometry with ICP-AES used for the quantitative analysis of elements in metallic and ceramic coatings. Microstructural and micro-analytical testing of the coatings were performed using scanning electron microscopy (SEM). Measurements of the chemical compositions were conducted using energy-dispersive X-ray spectroscopy (EDS). The hardnesss of the coatings were tested using a indentation method, and the coating thicknesses were tested using a ellipsometry method.

In this paper, Co,Ce/Ca₁₀(PO₄)₆(OH)₂ catalysts with various cobalt loadings for steam reforming of ethanol (SRE) were prepared by microwave-assisted hydrothermal and sol-gel methods, and characterized by XRD, TEM, TPR-H₂, N₂ adsorption-desorption measurements and cyclohexanol (CHOL) decomposition tests. High ethanol conversion (close to 100%) was obtained for the catalysts prepared by both methods but these ones prepared under hydrothermal conditions (HAp-H) ensured higher hydrogen yield (3.49 mol H₂/mol C₂H₅OH) as well as higher amount of hydrogen formed (up to 70%) under reaction conditions. The superior performance of 5Co,10Ce/HAp-H catalyst is thought to be due to a combination of factors, including increased reducibility and oxygen mobility, higher density of basic sites on its surface, and improved textural properties. The results also show a significant effect of cobalt loading on catalysts efficiency in hydrogen production: the higher H₂ yield exhibit catalysts with lower cobalt content, regardless of the used synthesis method.

The paper presents a simple way to improve the photocatalytic properties of titanium dioxide using mechanochemical method. The TiO₂ (Anatase) powders was subjected to high-energy ball milling in dry environment and in methanol. It has been shown that it is possible to induce the phase transformation from Anatase to Rutile and produce a material with a higher photocatalytic activity in the UV light. Physicochemical characteristics of the products were based on the following methods and techniques: X-ray powder diffraction (XRD), IR and UV-Vis (DR) spectroscopy, measurements of specific surface area (BET). The photocatalytic activity of the powders was measured in the decomposition reaction of methyl orange in water.

Optimized methods for simultaneous removal of nitrate, nitrite and ammonium are important features of nutrient removal. Nitrogen removal efficiency in an intermittently aerated sequencing batch reactor (IA-SBR) with multiple filling events was studied. No external carbon source was added and three filling events were considered. Oxidationreduction potential (ORP) and pH curve at solids retention time (SRT) of 20 d were analyzed. Effects of three organic loading rates (OLR), 0.67, 1.0 and 1.5 kgCOD/m³d, and three nitrogen loading rates (NLR), 0.054, 0.1 and 0.15 kgN/m³d, on nitrogen removal were studied. Nitrate Apex in pH curve and Nitrate Knee in ORP profile indicated that the end of denitrification would be achieved sooner. The kinetic coefficients of endogenous decay (kd) and yield (Y) were identified to evaluate heterotrophic specific denitrification rate (SDNRb). In period 2 at NLR of 0.054 kgN/m³d and considering 2 anoxic and 3 aerobic phases, nitrogen removal efficiency was 91.43%.

The biosorption process of three divalent metal ions – nickel, lead and zinc- from on calcium alginate from aqueous solution was studied, in single component systems. The biosorbent were investigated by Fourier Transform Infrared Spectroscopy. The batch mode experiments of the adsorption process were carried out as a function of pH, initial metal ions concentration, sorbent dosage and contact time. The adsorption influencing parameters for the maximum removal of metal ions were optimized. The experimental data were analyzed using the Langmuir, Freundlich, Langmuir-Freundlich, Koble-Corrigan and Redlich-Peterson models. The kinetic data of biosorption process were evaluated using pseudo-first and pseudo-second order equations. The Weber and Morris model was employed to interpret the metal ions diffusion in biosorption process.

The yield and composition of pyrolysis products depend on the characteristics of feed stock and process operating parameters. Effect of particle size, reaction temperature and carrier gas flow rate on the yield of bio-oil from fast pyrolysis of Pakistani maize stalk was investigated. Pyrolysis experiments were performed at temperature range of 360-540°C, feed particle size of 1-2 mm and carrier gas fl ow rate of 7.0-13.0 m³/h (0.61.1 m/s superficial velocity). Bio-oil yield increased with the increase of temperature followed by a decreasing trend. The maximum yield of bio-oil obtained was 42 wt% at a temperature of 490°C with the particle size of around 1.0 mm and carrier gas flow rate of 11.0 m³/h (0.9 m/s superficial velocity). High temperatures resulted in the higher ratios of char and non-condensable gas.

One of the promising processes, belonging to the so-called clean coal technologies, is catalytic coal gasification. The addition of a catalyst results in an increased process rate, in which synthesis gas is obtained. Therefore, the subject of this research was catalytic gasification of low-ranking coal which, due to a high reactivity, meets the requirements for fuels used in the gasification process. Potassium and calcium cations in an amount of 0.85, 1.7 and 3.4% by weight were used as catalytically active substances. Isothermal measurements were performed at 900°C under a pressure of 2 MPa using steam as a gasifying agent. On the basis of kinetic curves, the performance of main gasification products as well as carbon conversion degree were determined. The performed measurements allowed the determination of the type and amount of catalyst that ensure the most efficient gasification process of the coal ‘Piast’ in an atmosphere of steam.

Use of bran oil in various edible and nonedible industries is very common. In this research work, efficient and optimized methodology for the recovery of rice bran oil has been investigated. The present statistical study includes parametric optimization, based on experimental results of rice bran oil extraction. In this study, three solvents, acetone, ethanol and solvent mixture (SM) [acetone: ethanol (1:1 v/v)] were employed in extraction investigations. Response surface methodology (RSM), an optimization technique, was exploited for this purpose. A five level central composite design (CCD) consisting four operating parameter, like temperature, stirring rate, solvent-bran ratio and contact time were examined to optimize rice bran oil extraction. Experimental results showed that oil recovery can be enhanced from 71% to 82% when temperature, solvent-bran ratio, stirring rate and contact time were kept at 55°C, 6:1, 180 rpm and 45 minutes, respectively while fixing the pH of the mixture at 7.1.

l-menthol has been widely used in flavour, food and pharmaceuticals. Because of its high volatility and whisker growth, l-menthol-hydroxypropyl-β-cyclodextrin inclusion complex was produced to improve shelf-life, provide protection, and enhance the stability of l-menthol. The inclusion complex was characterized by Fourier transform infrared spectroscopy, X-ray diffraction. The results show that l-menthol was successfully encapsulated in hydroxypropyl-β-cyclodextrin. l-menthol loading capacity is about 8.44%. Geometries and binding energies of l-menthol-hydroxypropyl-β-cyclodextrin inclusion complexes were investigated using molecular mechanics calculations. The shape and orientation of the most stable complex, and the minimum binding energy were determined. L-menthol release from complex was determined by thermogravimetric analysis. Two l-menthol release rate peaks were observed at 69.3 and 279.1°C. The l-menthol release reaction order, release activation energy and the preexponential factor were obtained.

Energy generation from biomass presents some serious problems like slagging, fouling and corrosion of boilers. To address these problems, demineralization of biomass is performed using different leaching agents. This study is focused on determining the influence of leaching agents and leaching time on the physiochemical structure of rice husk during demineralization. Dilute (5% wt) solutions of HCl and H₂SO₄ were used for the demineralization of rice husk separately with leaching time of 15, 60 and 120 minutes. It is shown that H₂SO₄ exhibited higher removal of alkali and alkaline earth metals (AAEM) comparatively as depicted by the 34.2% decrease in ash content along with an increase of 7.10% in the heating value. The acid has been seen to induce more notable changes in physiochemical structure as depicted by the FTIR spectra and SEM micrographs. The thermal degradation behavior of the demineralized rice husk has also been reported.

Stress-strain mechanical properties of polystyrene foam plastic material were tested under different loading conditions. An empirical constitutive model for describing metal materials was proposed for the polystyrene plastic foam. The static and dynamic tests results show that the ductility and watertightness of the polystyrene plastic foam are significantly improved. At the same time, in order to check its seismic-isolation property, the high-performance foam concrete as filling materials of Galongla tunnel in Tibet was simulated by FEM. The simulated results show that the polystyrene plastic foam can remarkably decrease the stress and the plastic zone in final lining, so it can effectively reduce the seismic damage of the tunnel. Considering the seismic-isolation property and low price of polystyrene plastic foam, it is a good reference for the anti-seismic design of tunnels in high intensity zones.

A review paper of the technology basics of vegetable oils epoxidation by means of peracetic or performic acid in the presence of acidic ion exchange resins has been presented. The influence of the following parameters: temperature, molar ratio of acetic acid and hydrogen peroxide to ethylenic unsaturation, catalyst loading, stirring intensity and the reaction time on a conversion of ethylenic unsaturation, the relative percentage conversion to oxirane and the iodine number was discussed. Optimal technological parameters, mechanism of epoxidation by carboxylic peracids and the possibilities of catalyst recycling have been also discussed. This review paper shows the application of epoxidized oils.

In the present study, rice husk ash, which is a renewable and abundant material, was utilized as a carrier for lipase immobilization for the first time. Poly (ε-caprolactone) synthesis was successfully achieved by the new enzymatic catalyst: Candida antarctica lipase B immobilized onto surface-modified rice husk ashes by covalent binding. It was aimed to obtain optimum polymerization conditions at which highest molecular weight was reached and characterize the polymer produced. Moreover, thermal stability and effectiveness of the new biocatalyst in non-aqueous media were also shown with successful polymerization reactions. In addition, by using the new enzyme preparation, ε-caprolactone was able to be polymerized even at 30°C, which was promising for an energy saving process. Consequently, this work provides a new alternative route for poly (ε-caprolactone) synthesis.