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STUDY OF THERMALLY TREATED ZEOLITIC TUFFS OF SERBIA , DEPOSITS "ZLATOKOP" AND "OPĆIŠTE"-BEOČIN
No full textZeolites are a group of natural and synthetic inorganic compounds. They have specific physicochemical properties suitable for industrial application [1,2]. According to their origin, variety of chemical composition, structural characteristics and application, zeolites form a specific group of minerals within the tectosilicates. In sedimentary formations rich in zeolites, the most characteristic minerals that are present are: clinoptilolite/hailandite, chabazite, mordenite, erionite, phillipsite and analcime. The most widespread zeolite of sedimentary origin is represented by the HEU series (clinoptilolite-heylandite). Its general crystal chemical formula is (Na,K,Ca)6Al6Si30O72nH2O.. Based on chemical and X-ray powder diffraction analysis, it is not possible to separate clinoptilolite and hoylandite . This is due to their isostructural nature. To identify these two isostructural minerals, even today, the simplest so-called Mampton's test [3]. Mumpton [4]. The results of X-ray diffraction analysis of thermally treated clinoptilolitic tuffs from the Zlatokop and Beočin deposits will be presented in this paper. The interplane distance values will be shown in the characteristic temperature range from 400oC to 500oC (when the first polymorphic transition occurs). These values characterize the zeolitic tuffs of our deposits in a certain way
Mechanochemical synthesis of strontium titanate
No full textIn this work, SrO and TiO2 were mechanochemically activated for 520 minutes. The X-Ray Diffraction Analysis determined that strontium titanate was obtained. The starting components reacted in an amount of 99.1%. Phase changes during the reaction were analyzed and the dynamics of mechanochemical synthesis were defined. The occurrence of an intermediate compound (activated complex) on the reaction path from the reactant to the stable product of the reaction was assumed and experimentally proven. The rate constant of the mechanochemical neutralization reaction between strontium oxide and titanium oxide is defined. A mathematical relation with the basic thermodynamic and other physicochemical parameters of the process was established
Impact of agro-ecological conditions and fertilization on yield a ecological conditions and fertilization on yield and quality of triticale on pseudogley soil
No full textThe results of the study of the influence of fertilization and calcification on the yield and yield components of winter triticale grown on low pH soil are presented in this paper. Five variants of fertilization were tested during three growing seasons. Trial treatments included different fertilization variants: V1-control, V2-N120, V3-N120P80K60, V4-N120P80K60 + 5 t ha- 1 of lime and V5-N120P80K60 + 5 t ha-1 of lime + 30 t ha-1 of manure. The results of the research showed that all yield components responded positively to the application of mineral nutrition by changing the production characteristics and grain quality. The variant with the combined application of NPK, lime and manure had the greatest positive effect on all tested parameters affecting triticale productivity. During the study, the highest yield of triticale 5.826 t ha-1 was obtained on the fertilization variant with the combined application of lime, manure and NPK fertilizers. The achieved increase in the grain yield of triticale was significant compared to the control and the NPK variant of fertilization. Highly significant positive dependencies were found between the grain yield with 1000-grain weight, and test weight and significant positive dependencies were found between 1000-grain weight and test weight. Theresearch highlighted the impact of different fertilizer treatments on the yield and grain quality traits of winter triticale
Evaluation of parameters for the production of Al–WO3 composites
No full textThe paper presents the results of the analysis of the influence of the synthesis parameters on obtaining the composite
system (WAl12 + Al2O3)/Al with improved mechanical properties. The starting powders of Al and WO3 were
homogenized until reaching the required composition with 1%, 2%, 5% and 7% WO3. After homogenization,
the obtained samples were pressed under a pressure of 10 MPa. The sintering of the obtained samples was performed
in an argon atmosphere at temperatures of 550 oC, 585 oC, 615 oC and 650 oC for 20, 40 and 60 minutes. As a result
of the test, it was concluded that the sintering temperature, as well as the sintering time, do not have a significant effect
on the increase in hardness of these composites. The main parameter that affects the increase in strength of these
composites is the WO3 content. With an increase in the WO3 content, there is an increase in the hardness of
the composite
Prečišćavanje otpadnih voda primenom MBBR sistema
No full textProcesi prečišćavanja otpadnih voda, koji su do sada korišćeni, pokazuju ograničenu mogućnost
efikasnog uklanjanja nutrijenata. Ispuštanje netretiranih ili nedovoljno tretiranih otpadnih voda
u recipijente, kao što su reke, jezera i mora, može ugroziti akvatične ekosisteme izazivanjem
procesa eutrofikacije. Stoga je neophodno tretirati otpadne vode, kako sanitarne tako i
industrijske, i ukloniti iz njih štetne materije. U ovom radu je prikazano biološko uklanjanje
azota kao nutrijenta iz otpadnih voda primenom nekonvencionalnih metoda tretmana otpadnih
voda – MBBR (eng. Moving bed biofilm reactor). Biće prikazane njihove modifikacije i prednosti
koje ovakvi procesi nude u odnosu na standardni tretman aktivnim muljem, koji se najčešće
koristi. Prednosti korišćenja MBBR reaktorskih sistema se ogleda u mogućnosti njihove primene
u tretmanu različitih tipova industrijskih otpadnih voda, mogućnosti upotrebe nosača u
konsekutivnim reakcijama prečišćavanja što uzrokuje niže operativne troškove procesa i time ih
čini veoma pogodnim za denitrifikaciju otpadnih voda. Unapređeni procesi biološkog uklanjanja
azota pomoću različitih tipova mikroorganizama biće praćeni sa stanovišta efikasnosti samog
procesa. Cilj ovog rada jeste predstavljanje inženjerskih osnova u primeni ovih procesa u daljim
eksperimentalnim istraživanjima
Application of organominerals for the removal of the emerging contaminant diclofenac
No full textПриродни минерали, зеолит и бентонит, модификовани са различитим
количинама катјонског сурфактанта, хексадецилтриметиламонијум-бромида су испи-
тивани као адсорбенти за уклањање диклофенака из водених раствора. Адсорбоване
количине диклофенака су расле са порастом количине сурфактанта код органозеолита
као и код органобентонита. Разлике у структури полазних минерала су условиле и
разлике у адсорпцији диклофенака на органозеолиту и органобентониту. Највећа
адсорпција диклофенака је постигнута на органобентониту код кога су сви неоргански
катјони измењени са сурфактантом. Резултати су показали да се органоминерали могу
разматрати као ефикасни адсорбенти за уклањање диклофенака из воде.Natural minerals, zeolite and bentonite, modified with different amounts of
cationic surfactant, hexadecyltrimethylammonium bromide, were investigated as adsorbents
for the removal of diclofenac from aqueous solutions. The adsorbed amount of diclofenac
increased with the increasing the amount of surfactant in organozeolite as well as in
organobentonite. Differences in the structure of the starting minerals caused differences in
the adsorption of diclofenac on organozeolite and organobentonite. The highest adsorption
of diclofenac was achieved on organobentonite where all inorganic cations were exchanged
with surfactant. The results showed that organominerals can be considered as effective asorbents for the removal of diclofenac from water
The process of obtaining biochar and the development of the products thus obtained
No full textBiochar continues to strengthen its presence in many new industries with its new applications, which are full of scientific and business news. A flurry of activity has sprung up around this carbon-based material, produced from biomass, following its use in water treatment, energy production and animal husbandry. In any new industry, process and product development, as well as feasibility studies, are very important for the product to come to market. This is especially true when it comes to biochar. Besides being in its infancy as an industry, biochar itself presents a number of challenges that make various tests necessary. Many properties affect the quality and performance of biochar products (pore size, cation exchange, electro- conductivity...) and will most likely vary depending on the starting material and the method of obtaining. Biochar can be made from a very long list of biomass materials. Although the above creates opportunities for industries that abound with highly adaptable products, it can still make biochar unpredictable, given that each starting material affects the characteristics of the final products differently
Postupak dobijanja hidrofobne smese za višenamensko gašenje požara primenom magnezijum stearata u cilju sprečavanja kondenzacije i aglomeracije
No full textPrema prikazanom pronalasku obezbeđen je postupak za dobijanje smese za gašenje požara na bazi domaćih sirovina koja je primenom magnezijum stearata dobila hidrofobna svojstva, čime je spečena mogućnost kondenzacije i aglomeracije smese bilo u aparatu za gašenje požara ili u skadištenom prostoru. Suština ovog pronalaska je da se na jednostavan i efikasan način pripremi odgovarajuća smesa za gašenje požara na bazi domaćih sirovina, da se time izbegnu troškovi uvoza inostranih smesa za gašenje požara. Pripremljena smesa je suvi hidrofobni prah koji može da se koristi za gašenje svih klasa požara. Zahvaljujući magnezijum stearatu koji je dodat pripremljenoj smesi, dobijena je hidrofobna smesa koja se ne kondenzuje, ne zgušnjava se i ne menja svoja fizička i hemijsja svojstva sa vremenom stajanja
Postupak dobijanja regranulata PVC-a sa dodatkom modifikovanog etilenvinilacetata (EVA) za meke proizvode
No full textSphalerite leaching in acid media: a review
No full textThe reserves of rich ores, from which the production of zinc by the existing conventional roasting-leaching-electrowinning process is technologically possible and economically justified, are decreasing year by year. For this reason, increasing attention has been directed towards researching the possibility of obtaining zinc from complex polymetallic ores with a low metal content, adhering to sustainable development goals following strict environmental regulations. Leaching procedures are commonly utilized for the processing of such mineral raw materials.As sphalerite is the widespread and most significant mineral of zinc sulfide, a large part of the research focuses on studying the behavior of sphalerite in the leaching process. This paper reviews the existing knowledge about the leaching of sphalerite in acidic solutions as well as the phenomena accompanying the dissolution process. Special attention is given to research related to the kinetics and mechanism of sphalerite oxidation in an acidic medium influenced by various oxidants, such as hydrogen peroxide, oxygen, dichromate ions, nitrate and nitrite ions, ferric and cupric ions, and others. All these results enable the development of new technological procedures to produce zinc from low-grade and complex ores while meeting increasingly rigorous environmental requirements