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Mixed Al, Fe pillared clay (AlFePILC) was synthesized from Na-exchanged Wyoming clay (Na-Wy) rich in montmorillonite. In the pillaring process Na-Wy was modified with a mixed intercalating (Al, Fe) solution with molar ratio of Fe3+/(Al3++Fe3+) = 10%. The obtained AlFePILC was impregnated with cobalt using the incipient wetness impregnation method, dried at 110 ºC and calcined at 450 ºC (Co-AlFePILC). Co-AlFePILC was tested as a catalyst in catalytic oxidation of tartrazine in the presence of Oxone®. Decolorization was monitored at wavelength =426 nm, while degradation of aryl groups was followed at =257 nm using UV-Vis spectroscopy. The influence of the mass of the catalyst on degradation process was followed in the mass range from 10 mg to 50 mg at 30 °C. It was found that mass increase was beneficial for the decolorization rate. The effect of temperature was investigated from 30 ºC to 60 ºC. The decolorization was over 90% after only 10 minutes for the temperature of 60 ºC, while with the temperature decrease, the decolorization rate decreased. Co-AlFePILC was found to be an efficient catalyst in degradation of tartrazine in the presence of Oxone®.

In recent years, mineral oxides (i.e. zeolite, alumina and clay minerals)-supported non-precious transition metals have extensively studied as highly promising sustainable and green glucose-sensing materials (Mudrinić, 2019). The reason for that is their low cost, easiness of synthesis, low negative environmental impact, and desirable electrochemical properties toward glucose oxidation. It is widely accepted that the catalytic activity of the mineral oxides-supported cobalt is strongly influenced by cobalt-mineral oxide interaction. As a consequence of this interaction different cobalt oxides (Wang, 1991) could be formed: Co3O4-contains both cobalt ions in tetrahedral (Co2+Td) and octahedral (Co3+Oh) coordination and CoAl2O4-contains only Co2+Td. However, little is known about the catalytic activity of these cobalt oxides (i.e. cobalt ions) in the reaction of the electro-oxidation of glucose. In this work, cobalt oxides in both tetrahedral (Co2+Td) and octahedral (Co3+Oh) coordination and with only Co2+Td were synthesized on aluminum pillared clay (AP) and alumina (A). The obtained materials were characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and temperature-programmed reduction (TPR). Electrochemical measurements were performed in alkaline solution with and without glucose using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometry (CA). TPR and XPS along with the results of electrochemical measurements in alkaline solutions without glucose confirmed the successful synthesis of the different cobalt oxides on both AP and A. The electrochemical measurements in glucose-containing solutions showed the enhanced electrocatalytic activity of AP and A with Co2+Td in comparison to their counterparts with both Co2+Td and Co3+Oh. This result suggested that the Co2+Td acted as the main active site for the glucose oxidation.

This work investigated the kinetics of the glucose oxidation reaction on the carbon paste electrode modified with aluminum pillared clay-supported cobalt (CP-CoAP) in alkaline solution. Cyclic voltammetry and double-step chronoamperometry methods were employed for determining the kinetic parameters such as the charge transfer coefficient, the catalytic rate constant, and the diffusion coefficient. The obtained results confirm that the CP-CoAP can be considered as a competitive electrode material for glucose oxidation.

Our previous study demonstrated that cobalt content strongly affected the electro-activity of aluminum pillared clay-supported cobalt (CoAP) toward glucose oxidation. It was found that the electro-activity of CoAP increased with the increase of cobalt loading. However, at the 10 wt.% of cobalt content, the electro-activity significantly decreased. In the present study, the focus is on the investigation of the nature of the surface sites that might cause the difference in the electro-activity of CoAP. For this purpose, CoAP with 3 wt.% and 10 wt.% cobalt contents (x%CoAP, x=3 and 10) were characterized using FE-SEM and HR-TEM with EDX techniques, and XPS. The microscopic techniques coupled with EDX have shown that cobalt oxide nanoparticles were evenly distributed in both samples. However, the higher cobalt loading resulted in cobalt oxide agglomeration that led to larger particle sizes. The results of XPS confirmed the presence of Co (II) in the 3%CoAP. On the other hand, the presence of Co3O4 which contains both Co (II) and Co (III) was confirmed in 10%CoAP. It is clear from this study that the electro-activity of CoAP strongly depends on the oxidation state of cobalt. However, the effect of agglomeration and cobalt oxide particle sizes cannot be ruled out.

Catalytic degradation of Tartrazine in the presence of Oxone® activated by Co-supported chitosan derived carbon-montmorillonite as catalyst was investigated. The catalyst was synthetized using impregnation-carbonization method. The carbonization temperature was 500 °C. The catalytic experiments were performed at different temperatures in range from 25 °C to 40 °C in order to determinate kinetics parameters. The kinetics data showed best fit with the first-order kinetics model. The activation energy of the investigated degradation process was calculated according to the Arrhenius equation.

Aluminum pillared montmorillonite-supported cobalt (Co/AP) has proven to be a suitable non-enzymatic sensing material (Mudrinić, 2019). Beside low cost, Co/AP exhibited adequate electrocatalytic performance toward glucose. However, further improvements of electrocatalytic performances are needed, especially regarding increasing sensitivity and widening the linear range of glucose detection. In this regard, in addition to the monometallic cobalt oxide catalyst, a series of bimetallic catalysts supported on AP (Co+Cu/AP, Co+Zn/AP, Co+Fe/AP, and Co+Ni/AP) have been synthesized by the incipient wetness impregnation method (Pinna, 1998). The total amount of supported metal was fixed at 4 mass%, while cobalt:dopant molar ratio was 9:1 for all samples. The synthesized materials were prepared in the form of carbon paste electrode (Co+dopant/AP-CPE) with the same mass ratio of Co+dopant/AP to carbon black (CB) and applied as a working electrode. All the electrochemical measurements of each Co+dopant/AP-CPE were conducted using an Autolab PGSTAT302N potentiostat with Nova 2.1 software. The experiments were carried out in a three-electrode cell with prepared electrodes as working, Ag/AgCl (3 M KCl) as a reference electrode, and platinum rod as a counter electrode. Electrochemical behavior of the working electrodes for glucose detection was studied by the cyclic voltammetry and chronoamperometry in alkaline solution, with and without glucose. Among investigated electrodes for glucose electrooxidation, the Co+Fe/AP-CPE exhibited the highest current response with the best sensitivity. These very first results indicated a vital role of Fe in enhancing the glucose-sensing performance of aluminum pillared montmorillonite-supported cobalt. The physical chemical characterization of all Co+dopant/AP materials is ongoing.

Recently the focus of electrochemical glucose sensing is on the fabrication of enzyme-free electrodes based on non-precious transition metal oxides, especially cobalt oxide [1]. To our best knowledge, these materials were primarily prepared by conventional methods using solutions, while the solvent-free mechanochemical approach was scarcely reported. Therefore, in this work Co3O4 supported on alumina (Co3O4/Al2O3) were prepared by ball milling using different milling times (0.5, 1, and 2 h) and Co3O4 contents (4, 8, and 16 wt. %). Ball to powder ratio was 30:1 and the rotation speed was 300 rpm. The electrodes based on the synthesized material were prepared in the form of a carbon paste electrodes (CP-Co3O4/Al2O3). The particle size distribution, phase, and chemical composition of the obtained materials were determined using LDPSA, XRPD, and XRF, respectively. The electrochemical performance of the CP-Co3O4/A12O3 electrode was tested in an alkaline solution containing glucose using cyclovoltammetry (CV) and chronoamperometry (ChA). CV revealed that milling time affected the electrochemical response. The highest current response was obtained with material milled for 1 h. Both ChA and CV confirmed that the electrochemical performance was further improved by increasing cobalt content. The CP electrode-based mechanochemically prepared samples showed enhanced performance in comparison to hand mixed Co3O4 and alumina. The beneficial effect of ball milling was attributed to the high dispersion of cobalt oxides over alumina even for large cobalt loadings without agglomeration. The obtained experimental results proved that the solvent-free mechanochemical approach is a promising synthetic route for obtaining green and sustainable glucose-sensing material for the fourth generation.

Alumina oxyhydrates have different structural and textural properties, as well as different density of surface functional groups. Three alumina oxyhydrates with different water content, 3mol H2O/ mol Al2O3 (gibbsite), 1mol H2O/ mol Al2O3 (boehmite) and 0.6 mol H2O/ mol Al2O3 (α,γ-alumina phase), were used in this study. The samples were used as modifiers of carbon paste electrode. Their electrochemical behavior toward ferricyanide/ferrocyanide redox probe was evaluated by electrochemical impedance spectroscopy and cyclic voltammetry. Ferricyanide/ferrocyanide redox system has a well-known electrochemical behavior and is sensitive to the changes occurring at the electrode surface. The lowest charge transfer resistance was obtained for α,γ-alumina phase. The redox process of ferri/ferro redox probe on investigated electrodes exhibited a quasi-reversible behavior, since the obtained values of peak-to-peak separation are greater than 59 mV value expected for a reversible process. The response toward quinone/hydroquinone redox probe was evaluated by cyclic voltammetry in buffered solutions at various pH. Gibbsite and boehmite showed expected response, while the surface groups of α,γ-alumina phase enabled quinone oxidation to proceed through two pathways simultaneously. The surface chemistry of investigated samples influenced their electrochemical properties.

In this work cobalt supported on chitosan-derived carbon-smectite composite catalyst was synthetized using impregnation-carbonization method (Co/cCh-S). The carbonization temperature was 400 °C. The obtained catalyst was tested as peroxymonosulfate (in form of Oxone®) activator for the food dye tartrazine degradation. The textural properties were obtained using low temperature N2 physisorption. The calculated textural parameters of the Co/cCh-S catalyst were compared with properties of the carbonized chitosane-smectite composite (cCh-S). The catalytic tests confirmed that neither Oxone® without catalyst nor cCh-S were unable to activate Oxone®. The catalyst Co/cCh-S was found to be effective for tartrazine degradation in presence of Oxone®.

Modified highly active CaO catalyst (ESCHC-600) derived from waste chicken eggshells were prepared and used in the transesterification of sunflower oil. Eggshells were subjected to calcination-hydration-calcination (CHC) cycles described in detail previously [1]. After CHC treatments, highly active CaO was obtained, which indicates its great potential for biodiesel synthesis. The transesterification reaction was carried out in a batch reactor at 60 ºC, methanol to oil molar ratio of 12:1, and different catalyst concentrations ranging from 2 to 8 wt%. Fatty acid methyl esters (FAMEs) content was determined by the HPLC analytical technique. The highest triacylglycerols (TAGs) conversion to FAMEs was achieved at a catalyst loading of 4 wt% (Fig. 1a). A further increase in catalyst loading (> 4 wt%) led to a decrease in TAGs conversion. The higher catalyst loadings (6 and 8 wt%) limited mass transfer of the TAGs and reaction products (FAMEs, DAGs and MAGs) due to the higher reaction mixture density and viscosity of the complex multiphase system. Compared to raw eggshell calcined at 900 ºC (ES-900) (Fig. 1b), the synthesized ESCHC-600 catalyst showed a higher activity, which could be attributed to a more favourable pore structure of CHC treated catalyst and better availability of the active sites.

This paper presents new data and reviews the available evidence pointing to the existence of three main ingredients of militant extremist mindset (MEM). Three different methods of item development identified factors that we have labeled Nastiness, Grudge, and Excuse. In other words, there are in our midst nasty people who are more prepared than others to accept, approve, or even advocate the use of violence. When such people feel a grudge, in that they see somebody as threatening to themselves (or to members of the group they belong to) or think that the world is not a hospitable place in which to live, they may resort to violence. This violence is often accompanied by an excuse or justification that refers to a higher authority or a "noble" principle such as religiosity or utopianism. Although all three ingredients may be open to intervention, Grudge might be the most amenable. Social policies related to immigration and procedures for dealing with protest counterculture may be effective in reducing MEM. The most important, however, is the need to espouse principles of diversity and tolerance.

For more than three decades 4A zeolite has been an irreplaceable ingredient of powder detergents, but there is still striving to it’s improvement in order to meet the ever more stringent market and environmental demands.Alumina d.o.o., as one of the world-renowned producers of this zeolite, tends to meet these requirements, and one of the latest examples is the work on the production of zeolite 4A with increased adsorption of surface active substances, and the testing of parameters for the synthesis of such a zeolite as well as its characterization is the subject of this paper. The zeolite synthesis were performed to examine the effect of the Na2O concentration in the reaction system, as well as the crystallization time on thecharacteristics of detergent zeolite, namely:the adsorption of dibutylphthalate (DBP), the mean particle diameter, and the ion exchange capacity. The additional characterization of the samples was performed by XRD and FTIR instrumental methods. It’s shown that the conditions examined have a significant effect on the characteristics of the synthesized powders. In general, at all crystallization times, adsorption of DBP, as well as the mean diameter, increases with the increase in Na2O concentration, while the ion exchange capacity decreases,and it is very important to find the right conditions in which all the parameters will be satisfactory.The influence of the crystallization time is not significantly pronounced when adsorption is concerned, but it is on the other characteristics of zeolite.XRD diffractograms and FT-IR spectroscopy showed the effect of reaction conditions on the crystallinity of the synthesized powders, and the relationship between the crystallinity and other characteristics of 4A zeolite., Zeolit 4A sada već više od tri decenije nezamenljiv je sastojak praškastih deterdženata, ali se i dalje teži njegovom usavršavanju kako bi se što uspešnije ispunili sve strožiji tržišni i ekološki zahtevi. Kompanija Alumina d.o.o. kao jedan od svetski priznatih proizvođača ovog zeolita teži ispunjavanju tih zahteva. Predmet ovog rada je upravo ispitivanje parametara za sintezu takvog zeolita kao i njegova karakterizacija. Sinteze zeolita izvođene su tako da se ispita uticaj koncentracije Na2O u reakcionom sistemu, kao i vremena kristalizacije na karakteristike deterdžentskog zeolita, i to adsorpciju dibutilftalata (DBP), srednji prečnik čestice (Ds50) i jonoizmenjivački kappacitet (JIK).Dodatna karakterizacija uzoraka izvršena je XRD i FTIR instrumentalnim metodama. Pokazalo se da ispitivani uslovi imaju značajan uticaj na karakteristike sintetisanih prahova. Generalno, pri svim vremenima kristalizacije, adsorpcija DBP raste sa porastom koncentracije Na2O, kao i srednji prečnik, dok JIK opada, te je jako bitno pronaći uslove u kojima će svi parametri biti zadovoljavajući. Uticaj vremena nije značajno izražen kada je adsorpcija u pitanju, ali jeste na ostale karakteristike zeolita. XRD difraktogramii FT-IR spektroskopija pokazali su uticaj reakcionih uslova na kristaliničnost, te vezu između kristaliničnosti i drugih karakteristika 4A zeolita.

The analysis and sizing of the distillation column for the separation of n-heptane-n-octane mixture were conducted using a traditional method for modeling and describing distillation systems, combined with modern software systems. Basic parameters were obtained by using rigorous separation and calculation procedures for the separation of the mixture used. These parameters describe distillation process, as well as basic dimensions and physical and hydro-dynamic parameters of the distillation column. Analytical and numerical methods were used for the analysis, modeling, sizing and operation control of the system. The previously used calculation methods were verified by developing the program for the case of the binary mixture. The values, obtained in this program were used for further description of the system, as well as sizing and determining basic physical and hydro-dynamic properties such as column diameter, and pressure drop. The key parameters describing this system are optimal reflux, minimum reflux, number of theoretical stages and minimum number of theoretical stages. Changes of the number of stages, reflux and column diameter were monitored as a function of mixture composition, as well as flow of the mixture at entrance of the column. Key words: distillation of binary mixture, rigorous calculation procedures, design methods, distillation columns, Tradicionalne metode modelovanja i opisivanja destilacionih sistema, u kombinovanju sa savremenim softverskim paketima, poslužile su za analizu rada i dimenzionisanje destilacione kolone za razdvajanje binarne smješe nheptan-n-oktan. Primjenom rigoroznih postupaka razdvajanja i proračuna za razdvajanje smješe, praćeni su osnovni parametri, koji opisuju tok destilacije, kao i osnovne dimenzije destilacione kolone sa ventilskim podovima i osnovne fizičke i hidro-dinamičke parametre (dijametar kolone i pad pritiska). Za analizu, modelovanje, dimenzionisanje i kontrolu rada ovog sistema korišćene su grafičke, analitičke i numeričke metode. Razvijanjem programa verifikovane su ranije korišćene metode proračuna, a vrijednosti dobijene proračunom su poslužile za dimenzionisanje kolone. Ključni parametri koji opisuju ovaj destilacioni sistem su radni refluksni odnos i minimalni refluksni odnos, broj teorijskih podova i minimalni broj teorijskih podova. Promjene navedenih veličina praćene su u funkciji sastava smješe, kao i protoka smješe na ulazu u destilacionu kolonu.

Solvent base oils of group API I contain larger quantities of aromatic compounds and sulfur, as compared to base oils of higher quality groups. Processing of base oils by commercial clays is performed in order to reduce the content of undesirable compounds, improving the color and oxidation stability. Commercial clays are based on aluminosilicates with a large specific surface area and developed porosity. Bentonite has good adsorption characteristics, which can be further improved by various methods of modification. In this paper, adsorption processing of solvent base oils is derived by acid-activated bentonite and commercial clay. The structural composition of starting oil and refined solvent oil (content of aromatics, paraffins, naphtenes and sulfur) is determined by following methods: IEC 590, UV, IP 346 and BAS ISO 20846. The results showed that processing of a solvent oil by activated bentonite leads to change of structural composition, similar to a change achived by processing with commercial clay.