Volume 16 (2014): Edizione 1 (March 2014)

This paper presents the results of studies which aim was to determine the pollution of the water environment for both methods of preparation for the utilization of sewage sludge in agriculture. The study was conducted in 2008-2012 in lysimeters filled with light sandy soil (clayey sand). During the study variants with equal doses of nitrogen in an amount of 20 g . m^-2 (15.7 g per one lysimeter) were supplied to the soil in sewage sludge and in the compost made from the same sludge. These variants were used three times for two species of perennial plants: Miscanthus gigantenus i Sida hermaphrodita Rusby. In a variant of sludge soil fertilizing, it was leached into water environment more than 12% of the applied nitrogen over 5 years of research. In case of compost nitrogen leaching was reduced to 8.1-10.0% of the quantity supplied to the soil.

In CNG station, the fuel is usually stored in the cascade storage bank to utilize the station more efficiently. The cascade storage bank is generally divided into three reservoirs, commonly termed low, medium and high-pressure storage bank. The pressures within these reservoirs have huge effects on the performance of the stations. In the current study, a theoretical simulation based on mass balance and thermodynamic laws has been developed to study the dynamic fast fi lling process of vehicle’s (NGV) cylinder from the cascade storage bank. The dynamic change of the parameters within the storage bank is also considered. Natural gas is assumed to contain only its major component, methane, and so thermodynamic properties table has been employed for finding the thermodynamics properties. Also the system is assumed as a lumped adiabatic system. The results show that the initial pressure of the cascade storage bank has a big effect on the storage bank volumes for bringing up the NGV cylinder to its target pressure (200 bar). The results also showed that ambient temperature has effect on the refueling process, chiefly the final NGV cylinder and the cascade storage bank conditions

In this work the selective transport of cobalt(II) and lithium(I) ions from aqueous chloride solutions through polymer inclusion membranes (PIMs) is presented. Triisooctylamine (TIOA) has been applied as the ion carrier in membrane. The effects of various parameters on the transport of Co(II) and Li(I) were studied. The obtained results show that Co(II) ions were effectively removed from source phase through PIM containing 32 wt.% TIOA, 22 wt.% CTA (cellulose triacetate) and 46 wt.% ONPOE (o-nitrophenyl octyl ether) or ONPPE (o-nitrophenyl pentyl ether) into deionized water as the receiving phase. The results indicate that there is a possibility of polymer inclusion membranes application to recover Co(II) and Li(I) from aqueous chloride solutions

The objective of the present study is to assess the efficiency of fly ash and fly ash agglomerates to remove arsenic(III) from aqueous solution. The maximum static uptakes were achieved to be 13.5 and 5.7 mgAs(III)/adsorbent for nonagglomerated material and agglomerated one, respectively. Isotherm studies showed good fit with the Langmuir (fly ash) and the Freundlich (fly ash agglomerates) isotherm models. Kinetic studies indicated that the sorption of arsenic on fly ash and its agglomerates follows the pseudo-second-order (PSO) chemisorption model (R2 = 0.999). Thermodynamic parameters revealed an endothermic nature of As(III) adsorption on such adsorbents. The adsorption results confirmed that fly ash and its agglomerates can be used for As(III) removal from aqueous solutions. Fly ash can adsorb more arsenic(III) than agglomerates, which are easier to use, because this material is less dusty and easier to separate from solution.

This study deals with experimental thermodynamic and rheological characterization of kaolin. Water sorption isotherms of kaolin were determined for three temperatures (30, 50 and 70°C). Desorption isotherms were fitted by using five models (GAB, BET, Henderson modified, Adam and Shove, Peleg) among the most used ones in literature. The GAB model was found to be the most suitable for describing the relationship between equilibrium moisture content and water activity for the whole range of temperature (30-70°C) and relative humidity(0-100%). Desorption enthalpy and entropy were determined. The desorption enthalpy decreases with increasing moisture content. The density and the shrinkage of the material and the Young’s modulus variations as a function of moisture content were determined experimentally. The Young modulus varies between 0.1 MPa and 14 MPa. The viscoelastic parameters of kaolin were also determined by using a series of Prony.

In the study, sodium tripolyphosphate (STPP) was obtained according to the one-stage method. Batch mixes with varied degrees of soda ash neutralization were produced using thermal or wet processing phosphoric acid and/ or recycled STPP calcined in a laboratory rotary kiln. Chromatographic analysis of the phosphate forms showed that products containing as much as 94.73% of a single component were produced. At STPP recycling rates of 2.5 and 5, products with a low bulk density ranging between 0.437-0.547 kg/dm3 were obtained. The recycling of STPP reduces the insoluble substance content, which affects the properties of the product. The phase composition of the products largely depends on the type of recycled phase of sodium tripolyphosphate (phase I and/or phase II) and the calcining temperature.

The study presents a technology of sodium tripolyphosphate (STPP) production with the use of a dry, single-stage method. The reacting substrates (concentrated wet-process phosphoric acid - WPPA and solid Na2CO3 ) are mixed with a recycled final product (STPP) in a mixer, then a „quasi-dry” mixture is calcined in a rotary kiln. Thanks to that, some stages of a classic method of STPP production are eliminated: one of the two-stage neutralization of the phosphoric acid with sodium carbonate at temperature ~80°C, filtration of the neutralised solution and its evaporation, as well as the stage of drying a solution of mono- and di-sodium orthophosphate in a spray dryer. According to the presented technical and economical analysis, the costs of STPP production using a single-stage dry method can be 10% lower compared to the classic method.

The results of the study regarding utilization of the waste gypsum formed as a by-product during the production of the magnesium sulphate from dolomite have been presented. The use of this waste have been proposed for the production of granulated multi-component fertilizers containing 25% N; 8% S; 14% CaO and 3.5% MgO. In the process of fertilizer production, the urea which will be bounded with the calcium and magnesium sulphate from the waste in the form of adducts of CaSO4 . 4CO(NH2)2 and MgSO4 . CO(NH2)2 . 3H2O will be the source of nitrogen in the fertilizer. It has been stated on the basis of the laboratory tests that the fertilizer with the assumed composition can be obtained by means of granulation of the raw material pulp, along with the dried and ground product return. The possibility of the production of the fertilizer with good physical properties according to the assumed concept has been confirmed in the pilot scale

The objective of this study was to find major PAHs produced in ambient air from the automobile exhaust as a function of fuels (diesel, petrol, and biodiesel) and engine type qualitatively and quantitatively. The recovery range was found between 30% and 70%. The study was carried out on two, three, and four wheelers. Biodiesel samples tested in the study were synthesized indigenously from different starting raw materials and analyzed for PAHs concentration in the exhaust on a Honda genset (EBK 2000AC Model). Biodiesel samples were blended with diesel in different ratio (25:75, 35:65 and 45:55) to investigate the exhaust behavior. Biodiesel was blended with Diesel the concentration of almost all PAHs reduces in comparison to pure Diesel exhaust. B(a)A and B(a) P was the common PAH found in higher concentration in almost all fuels. FTIR results indicate esterification of vegetable oil and NMR results indicate a complete conversion of oils into biodiesel.

The effect of time, temperature, the catalyst particle size and the ratio of the catalyst weight to the leaching solution volume (S:L) on the treatment of spent vanadium catalyst components was determined using citric acid solutions at atmospheric pressure. The optimal parameters of catalyst leaching in 10% acid solutions at atmospheric pressure are: T = 323 K, t = 4 h, the particle size of less than 0.160 mm, the S:L ratio below 0.1. Under these conditions it was possible to dissolve about 90% of vanadium and potassium compounds and more than 60% of iron compounds contained in the catalyst. These results fall within the scope of research on a comprehensive method for recovering spent vanadium catalyst components.

Anodic aluminum oxide (AAO) has been fabricated in the 0.3 M oxalic acid at voltage range 20-60 V and temperature range of 35-50oC. The resulting nanoporous alumina surfaces were characterized by high resolution scanning electron microscopy, and the images were quantitatively analysed by means of an innovative approach based on fast Fourier transform. The influence of operating anodization voltage and electrolyte temperature on nanopores geometry (pore diameter, interpore distance, porosity, pores density) and arrangement has been studied in details and compared to literature data and theoretical calculations. It was found that independently from the temperature, the best arrangement of the nanopores is for anodic aluminum oxide formed at voltages ranging from 40 to 50 V. Moreover, it was found that pore diameter and interpore distance increase linearly with voltage, what is in line with the literature data.

In recent years, the processing order during the synthesis of new chemical compounds has been redefined. Until now a chemist considered primarily receiving a new compound and only then searched for its potential application. The new philosophy of proceedings forces chemists to answer the question: what physical and chemical properties a new chemical compound must have, and what should be structured. After that it has to be planned how to get the compound including the defined budget. The compounds obtained by conventional chemical synthesis are then used to create new functional materials having the properties as scheduled. The paper presents the way of the proceedings from a molecular receptor to a new nanomaterial containing this receptor, so in other words from individual molecules to new material with specific and previously planned properties.

The performance of 1-(9-ethylcarbazol-3-yl)-4,4,4-trifluorobutane-1,3-dione (1) as a fluorescent probe for the monitoring of cationic photopolymerization processes by Fluorescence Probe Technique (FPT) has been evaluated in comparison with the response of 7-diethylamino-4-methylcoumarin (Coumarin 1) (2). Triethylene glycol divinyl ether and diphenyliodonium hexafluorophosphate were used as an example monomer and a cationic photoinitiator respectively. It has been found that the probe 1 withstands the cationic polymerization conditions and provides correct probe response. 1-(9-ethylcarbazol-3-yl)-4,4,4-trifluorobutane-1,3-dione shifts its fluorescence spectrum with progress of cationic photopolymerization of the monomer, which enables the monitoring of the polymerization progress using the fluorescence intensity ratio measured at two different wavelengths as the progress indicator. By comparing the behavior of 1 and 2, it has been documented that the fluorescence spectrum of probe 1 shows a spectacular hypsochromic shift (Δλ = 33 nm) upon the monomer polymerization, while the shift of 2 is three times smaller (Δλ = 11 nm). Moreover, the sensitivity of probe 1 is more than 2.5-times higher than that of any other probes suitable for monitoring cationic polymerization processes, reported previously. Therefore, application of the carbazole derivative (1) as a new probe for the monitoring of the crosslinking process of coatings cured by cationic photopolymerization has been proposed.

For ground phosphate rock (GPR) to be applied as phosphorus fertilizer, the availability of phosphorus to plants needs to be improved. One possible way to achieve this is by adding sulphur, which will accelerate decomposition of phosphate in soil owing to the activation of microbiological processes. This study involved granulation of fertilizers composed of phosphate and sulphur mixed at 38:1 and 10:1 ratios and two analogous fertilizer variants but with added molasses as a source of organic carbon for sulphur bacteria. A small-scale industrial installation for production of multi-component fertilizers was used to make granular fertilizer by the compaction method. The granular fertilizers were then tested in an agricultural experiment. The fertilizer in which the phosphate to sulphur ratio was 10:1 produced better effects. Addition of molasses to the fertilizers did not improve their fertilizing capacity

This paper describes the influence of the chain length and the functional group steric accessibility of thiols modifiers on the phase transfer process efficiency of water synthesized gold nanoparticles (AuNPs) to toluene. The following thiols were tested: 1-decanethiol, 1,1-dimethyldecanethiol, 1-dodecanethiol, 1-tetradecanethiol and 1-oktadecanethiol. Nanoparticles (NPs) synthesized in water were precisely characterized before the phase transfer process using Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM). The optical properties of AuNPs before and after the phase transfer were studied by the UV-Vis spectroscopy. Additionally, the particle size and size distribution before and after the phase transfer of nanoparticles were investigated using Dynamic Light Scattering (DLS). It turned out that the modification of NPs surface was not effective in the case of 1,1-dimethyldecanethiol, probably because of the difficult steric accessibility of the thiol functional group to NPs surface. Consequently, the effective phase transfer of AuNPs from water to toluene did not occur. In toluene the most stable were nanoparticles modified with 1-decanethiol, 1-dodecanethiol and 1-tetradecanethiol.

The results of dehydrochlorination of 1,3-dichloropropan-2-ol to epichlorohydrin are reported. The process ran in the reaction-stripping column system with a continuous removal of epichlorohydrin in a steam stream. The influence of 10 wt% alkali solution (NaOH, Ca(OH)2) and the method of distillate collection on the 1,3-dichloropropan-2-ol conversion, selectivity of transformation to epichlorohydrin and by-products, and the composition of wastewater have been analysed.

The purpose of this study was to investigate the natural gas hydrate promotion capabilities of the hydrotrope Toluene Sulfonic Acid (TSA) isomers as an additive. The capabilities of TSA isomers were measured with different concentrations. The optimum additive concentration for hydrate formation was determined for the given pressure, temperature, mixing condition, and cooling time. The natural gas hydrate promotability of para-TSA was found to be 20% and 35% more than meta-TSA and ortho-TSA respectively at the optimum concentration. Beyond the optimum TSA concentration, the hydrate formation declined as the ice formation reduced the overall gas-to-water volume ratio in the hydrates

This paper presents the results of nonlinear statistical modeling of the bauxite leaching process, as part of Bayer technology for alumina production. Based on the data, collected during the year 2011 from the industrial production in the alumina factory Birač, Zvornik (Bosnia and Herzegovina), nonlinear statistical modeling of the industrial process was performed. The model was developed as an attempt to define the dependence of the Al2O3 degree of recovery as a function of input parameters of the leaching process: content of Al2O3, SiO2 and Fe2O3 in the bauxite, as well as content of Na2Ocaustic and Al2O3 in the starting sodium aluminate solution. As the statistical modeling tool, Adaptive Network Based Fuzzy Inference System (ANFIS) was used. The model, defined by the ANFIS methodology, expressed a high fitting level and accordingly can be used for the efficient prediction of the Al2O3 degree of recovery, as a function of the process inputs under the industrial conditions.

Pulp and paper industries have provided great research opportunities to control systems. The objective of this study was to investigate the relationships between 80 process variables of CMP tower and stock preparation, and 17 newsprint quality properties in Mazandaran Wood and Paper Industries (MWPI). After the preparation of two suitable data series considering the time needed for pulp to paper, the relations between process dependent and newsprint independent variables were determined using partial least squares (PLS) regression. As a result, two PLS models were developed. The first model with 4 latent vectors categorized and related CMP tower variables and the second one, through 8 latent vectors connected stock preparation variables with paper properties. PLS regression coefficients determined how much the most influencing process variables impact each paper properties

Transition metal catalysts (mainly: iron, cobalt and nickel) on various supports are successfully used in a largescale production of carbon nanotubes (CNTs), but after the synthesis it is necessary to perform very aggressive purification treatments that cause damages of CNTs and are not always effective. In this work a preparation of unsupported catalysts and their application to the multi-walled carbon nanotubes synthesis is presented. Iron, cobalt and bimetallic iron-cobalt catalysts were obtained by co-precipitation of iron and cobalt ions followed by solid state reactions. Although metal particles were not supported on the hard-to-reduce oxides, these catalysts showed nanometric dimensions. The catalysts were used for the growth of multi-walled carbon nanotubes by the chemical vapor deposition method. The syntheses were conducted under ethylene - argon atmosphere at 700°C. The obtained catalysts and carbon materials after the synthesis were characterized using transmission electron microscopy (TEM), X-ray diffraction method (XRD), Raman spectroscopy and thermogravimetric analysis (TG). The effect of the kind of catalyst on the properties of the obtained carbon material has been described.