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Origin of oils and source rocks characterization of the Turija-Sever oil field (SE Pannonian Basin, Serbia)
No full textPerformance of aquatic weed - Waste Myriophyllum spicatum immobilized in alginate beads for the removal of Pb(II)
No full textA new biosorbent - alginate encapsulated with Myriophyllum spicatum - MsA was investigated for lead ions removal. This biosorbent was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), zeta potential, X ray Diffraction (XRD) and size distribution analysis. FT-IR analysis demonstrated that the lead ions sequestration mechanism included ion exchange and lead complexation with the carboxyl, carbonyl and hydroxyl groups in MsA. In order to better understand the mechanisms of the binding of Pb(II) on immobilized M. spicatum beads, 3 reaction and one diffusion based kinetic models were applied on kinetic data removal lead ions on three materials: M. spicatum, Ca-alginate and MsA. Myriophyllum spicatum encapsulated with alginate - MsA have higher adsorption capacity than M. spicatum. Among examined six isotherms Redlich-Peterson and the Langmuir isotherm model exhibited the best fit to the experimental data, with capacities ranging from 230 to 268.7 mg/g. Among the various tested desorption agents, nitric acid has proven to be the best. The obtained results suggest that the immobilized M. spicatum biosorbent holds great potential for lead wastewater treatment applications
the non-linear regression - the levenberg-marquardt algorithm for assumption the energy losses of hydraulic transport in a case of the mine "trepca"
No full textThe main problem of hydraulic transport is the resistance generated during the mixture transport through the pipe-line. Testing the flow characteristics of mixtures, shown in this paper, are based on the principles of determining the unit energy losses by a mathematical calculation using the non-linear regression - the Levenberg-Marquardt algorithm. Such obtained results allow determining a transport rate in the horizontal pipe-line, depending on the mixture bulk density and pipe-line diameter. The flotation tailings is mainly used as a filling material in the mine "Trepca" - Stari Trg. According to the grain size distribution, it is a fine-grained material of a size of 0.074 mm to 1.2 mm. It is a multicomponent material containing pyrite, pyrrhotine and other heavy metals, and therefore, has a high bulk mass. The average rate of the hydromixture, in which the energy losses reach the minimum value, depends on the pipe-line diameter and kinetic bulk density of the mixture. For the test interval of change in the pipe-line diameter, shown in this paper (0.168 mm, 0.176 mm, 0.193 mm, and 0.225 mm), and kinetic bulk density of the hydraulic mixture (1-1.6 kg/m(3)), this rate ranges from 3-5.5 m/s. The increase of the energy losses in the hydraulic mixture transport increases proportionality with the increase of its kinetic bulk density. The results, presented in this paper, show that the required bulk density of 1.6 kg/m(3) should be accepted as a limit from a point of view of the hydraulic transport cost-efficiency
The applicability of asphaltene treatment (mild oxidation and pyrolysis) in the investigation of crude oils
No full textAdsorption of Cu(II) ions from synthetic solution by sunflower seed husks
No full textAnnual production of the sunflower seed in Serbia is between 650,000-720,000 tons. Most of this amount is used in vegetable oil industry. Abundant by-products from this processing are sunflower seed husks. Husks are usually incinerated by vegetable oil producers in order to obtain energy, used as an animal feed, or, unfortunately, landed up at some landfills. In order to promote new, added value for this abundant, renewable resource, the investigation presented in this paper was conducted. For that purpose, adsorption of Cu(II) ions from synthetic solution by unmodified sunflower seed husks was examined. ATR-FTIR was used to identify functional groups as potential active sites for Cu(II) sorption. Zeta potential values were determined to reveal the surface charge, while the cation exchange capacity (CEC) was determined to reveal the amount of exchangeable ions on its surface. ATR-FTIR analysis revealed the presence of specific functional groups (hydroxyl, carboxyl, carbonyl, and amine) responsible for removal of Cu(II) ions. The total CEC of sunflower husk is 47.74 meq/100g and Ca(II) and Mg(II) ions are in dominant exchangeable positions. The study of ion-exchange mechanism involvement was done and results confirmed that this mechanism is not the only mechanism which is involved in copper sorption. Also, the results show that the Cu(II) ions have preference for Mg(II) ions substitution. Sorption experiments were conducted in batch system. The effect of operating parameters (pH, contact time, initial concentration of Cu(II) ions and adsorbent dosage) on the adsorption capacity were investigated. The obtained experimental data were fitted by Langmuir and Freundlich isotherm models. The maximum adsorption capacity for Cu(II) ions calculated from Langmuir adsorption isotherm was 34.89 mg/g which is 15 to 35% higher than the capacity that other researchers reported previously for the same material and pollutant. These results are suggesting that sunflower seed husks have a potential to be applied as an effective adsorbent of copper ions from contaminated waters
Fenton process in dispersed systems for industrial wastewater treatment
No full textIndustrial wastewater contains recalcitrant organic compounds with a very complex chemical structure, built of molecules with long chains of carbon atoms and attached different functional groups. Chemical or biological treatments used for removal of these compounds are being replaced with more efficient non-commercial wastewater treatments. Advanced oxidation processes overcome limitations of conventional methods regarding formation of by-products during degradation of recalcitrant organic compounds. The Fenton process, or use of the Fenton's reagent, has became one of the most utilized processes due to simplicity, economy and accessible amounts of ferrous iron and hydrogen-peroxide, which are used in the process. In specific, the Fenton's reagent is a catalytic-oxidative mixture of these two components. The ferrous iron Fe2+ initiates and catalyzes decomposition of H2O2, resulting in generation of hydroxyl radicals, which are the main radical species in the process able to detoxify several organic pollutants by oxidation. In addition, other mechanisms besides formation of hydroxyl radicals may occur during the Fenton process and participate in degradation of target pollutants. Generally, the treatment efficiency relies upon the physical and chemical properties of target pollutants and the process operating conditions. The main disadvantage of the Fenton process is production of sludge formed by iron hydroxide at certain pH values. An alternative solution for this problem is application of this process in fluidized bed reactors. This paper presents an overview of Fenton and photo-Fenton processes in dispersed systems for removal of different industrial wastewater pollutants. The most important process parameters, required for efficient degradation of recalcitrant organic compounds are also described, such as the catalyst type, pH value, temperature, H2O2 concentration and retention time. Strict control of Fenton process parameters in fluidized bed reactors at desired values can bring these systems to the commercial use
Adsorption of zearalenone by organokaolins
No full textMycotoxins are secondary metabolites produced by fungal species [1]. Zearalenone (ZEN) is estrogenic mycotoxin, produced by Fusarium species, commonly found on different cereal crops [2]. This mycotoxin causes reproductive disorders in animals. Addition of adsorbents is the most economical approach to decontaminate animal feed contaminated with mycotoxins. Commonly used mineral adsorbents for this purpose are zeolites and bentonite. In their natural forms, they can bind only aflatoxins [3]. For adsorption of other mycotoxins, chemical modification is needed. In this study, the kaolin from a plant for production of quartz sand in Rgotina is investigated as potential adsorbent for ZEN. Preliminary experiments confirmed that the natural kaolin has no affinity to adsorb this toxin. Thus, organokaolins were prepared by treatment of the natural mineral with three different levels of octadecyldimethylbenzyl ammonium (ODMBA) ions equivalent to 25, 50 and 90% of kaolin cation exchange capacity (CEC). Adsorption of ZEN on organokaolins was followed at pH 3 under in vitro conditions by using high performance liquid chromatography (HPLC). The effects of amounts of surfactant used to prepare organokaolins and adsorbent mass (5.0 - 0.5 mg/mL) on adsorption of ZEN was investigated with the initial concentration of ZEN at 2 mg/L. Results indicated that ZEN adsorption increased with increasing amounts of surfactant on the kaolin and with increasing the amount adsorbent in suspension. Based on the obtained results, adsorption of ZEN is related to the increasing number and availability of adsorption sites at organokaolinic surface
Novel zeolite`s nanocomposites with a two-tailed cationic surfactant – Arquad ® 2HT-75 with increased stability
No full textFunctionalization of natural zeolites (NZ) with cationic surfactants drastically alters the surface chemistry of zeolite and opens new applications possibilities for water treatment: adsorption of pharmaceuticals, pesticides, dyes, etc. The use of surface modified natural zeolites (SMNZs) could be a reliable approach for water treatment, as they can simultaneously remove cations, anions, and/or non-ionized molecules. The main advantages of the NZs, as starting materials, are their abundance in nature, low-cost and good stability. However, the main drawback is a potential instability of surfactant at the zeolite surface. Literature data showed that a certain amount of surfactant can be removed from the zeolite surface depending on experimental conditions, which could have a negative impact on water quality. To increase SMNZs stability and abate possible negative effects on the environment, it is suggested to use different novel types of surfactants (Reeve et al., 2018 and references therein). For these reasons, a zeolite-rich tuff IZ CLI (Turkey) with clinoptilolite as the main component (79%) has been modified using two cationic surfactants such as Cetylpyridinium chloride (CPyCl) and Arquad®2HT-75 (ARQ), the latter with two hydrocarbon chains. The bilayer composites (B), CPyCl-B and ARQ-B, were prepared using the method of fast functionalization (de Gennaro et al., 2016). To test the stability of composites, 1 g of CPyCl-B or ARQ-B was washed with 2 l of distilled water. Z-potential (Zetasizer Nano ZS90, Malvern Instruments) was measured for unmodified tuff as well as for composites before and after washing. Z-potential for IZ CLI has shown a negative value (-37.9 mV). The formation of a bilayer was confirmed by the inversion of Z - potential values which turned to positive for both composites CPyCl-B and ARQ-B (+37.7mV and +36.1mV, respectively). After extensive washing of composites, Z - potential of CPyCl-B has dropped to -7.9 mV indicating a significant loss of surfactant molecules. On the other hand, washing of ARQ-B almost did not affect Z-potential indicating great stability of bilayer at the zeolite surface when a two tailed surfactant was used. These results could open new possibilities for SMNZs applications in fields where surfactant stability is crucial, such as water treatment, thus promoting further research on the use of different
novel cationic surfactants
Production of glass-ceramics from coal fly ash and limestone
No full textThe results of laboratory scale experiments of vitrification of fly ash collected from the coal fired power plant are presented. The final glassy material was obtained by melting a mixture of ash and limestone at T= 1450 oC and quenching the melt in air. To convert the waste into useful and environmentally acceptable material the crystallization of fly ash glass was performed by powder route processing. The properties of the resultant glass-ceramic indicate a potential various application such as building materials, ceramics tiles, etc
Fuel potential and properties of grape pomace hydrochar
No full textIncreasing fossil fuel depletion that leads to air pollution and global warming have become
serious environmental problem. For this reason, a numerous of alternative biofuels have been developed
and investigated as potential energy sources to substitute them. One of promising and
highly effective technology for conversion of wet and waste biomass into multi-functional materials
is a hydrothermal carbonization. In this study grape pomace was hydrothermally carbonized at different
temperatures (180, 200 and 220 °C). Produced hydrochars were characterized in order to
investigate its potential application as an alternative and energy-efficient renewable fuels. The carbon,
fixed carbon, sulphur and volatile matter contents were determined in all hydrochar samples.
Obtained results showed that temperatures play significant role on the structural characteristics of
produced materials. As expected, the carbon content and fixed carbon content in hydrochars were
increased with temperature increasing. Higher yields of carbon and fixed carbon observed in hydrochars
indicated that intensive carbonization of biomass occurred. On the contrary, sulphur and
volatile matter content were decreased. Observed reduction may be a result of dehydration and
decarboxylation of grape pomace during hydrothermal treatment. These reductions are highly beneficial
and improve the efficiency of solids’ direct combustion. Decreased volatile matter content
can potentially reduce the release of inorganic vapours and pollutant emission during combustion,
while decreased sulphur content preventing generation and emission of harmful sulphur oxides,
SOx, compared to the parent biomass. The present study showed that hydrothermal carbonization
mproved fuel qualities and potential of grape pomace hydrochars among different reaction temperatures