Wyniki wyszukiwania - BazTech

1

Thermal Impact on Heavy Metal Bioavailability in Burnt Rocks of Waste Heap of Chervonohradska Coal-preparation Plant (Lviv Region, Ukraine)

Kochmar Iryna, Karabyn Vasyl, Stepova Kateryna, Stadnik Vitalii, Sozanskyi Martyn

Geomatics and Environmental Engineering

|

2024

|

Vol. 18, no. 1

117--133

EN

For effective waste management of mining industries is important to investigate their physical and mineralogical changes. For this purpose, X-raydiffraction (XRD), thermogravimetry (TG), derivative thermogravimetry (DTG), and differential thermal analysis (DTA) methods were used. Changes in the contents of mobile forms of heavy metals in rocks were investigated using an acetate-ammonium buffer solution with a pH of 4.8 after burning rocks at a temperature of 800–850°C. The obtained data indicated the significant role of the mineral composition in the thermal behavior of the rock samples and the subsequent influence of the thermal processes on the changes in the bioavailability of heavy metals.

2

Preliminary studies on electrodeposition of Zn-Fe-W alloy coatings from citrate-sulphate baths

Shoaib Hafiz Muhammad, Winiarska Katarzyna, Winiarski Juliusz

Ochrona przed Korozją

|

2023

|

nr 2

44--47

EN

Exploratory studies of the electrodeposition process of zinc coatings containing iron and tungsten were carried out using SEM/EDS and XRD techniques. It was shown that from a citrate-sulphate plating bath composed of (mol dm−3): ZnSO4 – 0.2, FeSO4 – 0.2, Na3Cit (tri-sodium citrate salt) – 0.4, (NH4)2SO4 – 0.1 and Na2WO4 – 0.01 Zn-Fe-W alloys can be obtained on a rotating disc electrode. It was noted that the induced co-deposition of tungsten with iron only occurred at pH > 6.0. Below this value, a Zn-Fe alloy coating was obtained. In the pH range from 5.0 to 9.0, the maximum contents of tungsten (15.96 wt. %) and iron (29.36 wt. %) were shown by the coatings deposited at pH 7.0. The increase in the bath pH from 5.0 to 9.0 resulted in clear changes in the phase composition of the deposited coatings. According to the results of XRD analyzes, the following can be indicated as probable: Fe22Zn78 and Fe7W6. However, the recorded diffractograms are difficult to interpret and it was very difficult to clearly define the type of phases present in the coating without additional tests.

PL

Stosując techniki SEM/EDS i XRD, przeprowadzono rozpoznawcze badania procesu elektroosadzania powłok cynkowych zawierających żelazo i wolfram. Wykazano, że z cytrynianowo-siarczanowej kąpieli galwanicznej o składzie (mol dm−3): ZnSO4 – 0,2, FeSO4 – 0,2, Na3Cit (cytrynian tri-sodu) – 0,4, (NH4)2SO4 – 0,1 i Na2WO4 – 0,01 można otrzymać na wirującej elektrodzie dyskowej powłoki stopowe Zn-Fe-W. Zauważono, że indukowane współosadzanie wolframu z żelazem zachodziło dopiero przy pH > 6,0. Poniżej tej wartości otrzymywało się powłokę stopową Zn-Fe. W zakresie pH od 5,0 do 9,0 maksymalną zawartość wolframu (15,96% mas.) i żelaza (29,36% mas.) wykazały powłoki osadzone przy pH 7,0. Wzrost pH kąpieli od 4,5 do 9,0 powodował wyraźne zmiany w składzie fazowym osadzanych powłok. Zgodnie z wynikami analiz XRD można wskazać jako prawdopodobne występowanie: Fe22Zn78 oraz Fe7W6. Zarejestrowane dyfraktogramy są jednak trudne w interpretacji i jednoznaczne określenie rodzaju faz obecnych w powłoce bez wykonania dodatkowych badań było mocno utrudnione.

3

The characterization study of inhibited silica/silicate scale using vinyl sulfonated copolymer (VS-Co)

Sazali R.A.b., Sorbie K. S., Boak L. S., Azman A. Z., Mohd Saaid I.b., Dollah A.b., Kassim Shaari N.Z.b., Ismail K.N.b.

Journal of Achievements in Materials and Manufacturing Engineering

|

2023

|

Vol. 117, nr 2

57--70

EN

Purpose Silica/silicate scale is a significant problem, especially in oilfield production during Alkaline Surfactant Polymer (ASP) flooding, where chemical inhibitors are the preferred method to prevent them. In this study, the effect of inhibitor vinyl sulfonated copolymer (VS-Co) on silica/silicate scale formation was analysed using X-Ray Diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). Design/methodology/approach The functional group type of VS-Co are sulfonate ions, SO3-, and these interact in the scaling process. Bulk-inhibited scaling brine tests were conducted at 60°C and pH 8.5. During these tests, the silicon brine (with VS-Co) representing the inhibited ASP leachate was mixed with a magnesium brine representing the connate water to replicate reservoir conditions during ASP flooding. The samples tested in this study were non-inhibited Si/Mg mixed brine of 60 ppm Mg2+ and 940 ppm Si4+ (60Mg:940Si) as a blank, and inhibited 60Mg:940Si mixture with various VS-Co concentrations of 20 ppm, 50 ppm, and 100 ppm. The inhibition efficiency of the VS-Co was determined, followed by the characterisation study of the silica/silicate scale deposited from both test conditions. Findings The IR spectra of all 60Mg:940Si samples show a similar peak at 1050 cm-1 to 1080 cm-1, attributed to a Si-O covalent bond and a band at 790 cm-1 to 800 cm-1 showing the presence of Si-O-Si stretching. XRD patterns produced a broad scattering peak for all samples at 2θ of 24° showing that the samples are amorphous silica. For tests of high Mg2+ in the brine mix, 900Mg:940Si, a mix of crystalline silica and crystalline magnesium silicate was produced. Based on these results, it can be concluded that the scale formed even with 100 ppm of VS-Co present. Further studies are required to address how to mitigate scale formation effectively in the future. Research limitations/implications Based on the research conducted, we can conclude that the VS-Co alone could not significantly inhibit the formation of silica/silicate scale even at the highest concentration (100 ppm) of VS-Co. However, having VS-Co present caused an alteration in IR spectra frequency which requires further investigation to assess how best to develop the inhibiting properties of the VS-Co product. The application of nanoparticles and their successful stories spark the interest of authors in searching for an efficient method of managing the silica/silicate scale where the modification of potential scale inhibitor (SI) with nanoparticles may be able to improve the inhibition efficiency towards the silicate/silicate scale. Practical implications The presence of VS-Co in the scaling brine only slightly inhibits the Mg2+ ion (initially comes from connate water) from reacting. It is worth further investigation on how this VS-Co can make it happen. Hence, the functional groups responsible for this may be altered by adding other functional groups to provide a synergistic effect in preventing this silica/silicate scale; or by modifying the VS-Co with nanoparticles to improve their adsorption/desorption capacity. Originality/value The newly developed technique in analysing the inhibition mechanism of a chemical inhibitor using various spectroscopic analysis is promising where an alteration in the spectra may provide proof of the chemical’s inhibition efficiency.

4

Effect of MHA on tribo-behaviour of Al-MHA-Si3N4 hybrid composites

Faris Mohammad, Suhaib Mohd, Ahmed Mumtaz

Composites Theory and Practice

|

2023

|

R. 23, nr 1

37--43

EN

In the contemporary research community, hybrid composites with improved performance are emerging as a trend, overcoming the drawbacks of conventional composites and satisfying needs in tribological applications. In this work, Al-MHA-Si3N4 hybrid composites reinforced with various weight percentages of mustard husk ash (MHA), 0, 2.5, 5, 7.5% and 10%, produced by powder metallurgy techniques at 300, 400, 500, 600 and 700 MPa compaction pressure were analysed. The microstructural characterization of the metal matrix hybrid composites, followed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) investigations show the homogeneous distribution of the reinforcement in the metal matrix. A sliding wear study without lubrication was performed on a pin-on-disc wear testing machine under the following sliding conditions: sliding velocity (SV) of 1.5 m/s, sliding distance (SD) of 300 m and applied loads of 25 N and 35 N. The deformation of the worn surfaces was also investigated. It was found that the tribological characteristics of the composites were enhanced by increasing the weight percentage of MHA and the compaction pressure.

5

XRD and STA Characterization of Phosphate Layers Deposited on the Carbon Steel Surface

Burduhos-Nergis Diana Petronela, Bejinariu Costica, Cazac Alin Marian, Sandu Andrei Victor, Vizureanu Petrica

Archives of Metallurgy and Materials

|

2023

|

Vol. 68, iss. 3

955--960

EN

Carbon steel is one of the most widely used alloys in many industries, however, its use is limited by its low corrosion resistance. Depositing a layer of phosphate on its surface improves the corrosion resistance as well as other properties, such as wear resistance, adhesion etc. Accordingly, preliminary studies demonstrated that carbon steel coated with phosphate layers can be used in the manufacture of carabiners for various fields: civil engineering, oil industry etc. Whereas, to demonstrate their capacity to operate in severe conditions related to fire rescue and extinguishing operations, it is necessary to evaluate the thermal behaviour of these materials. Thus, the main goal of this paper is to study the behaviour at high temperatures of three different types of phosphate layers deposited on carbon steel surface, by STA analysis. Also, the paper aims to study the formation of different phosphate layers by determining the types of compounds formed after the completion of the phosphating process, by XRD analysis.

6

Eco friendly synthesis of silver oxide nanoparticles from borassus flabellifer fiber and its antibacterial activity against representative micro organisms

Vanitha R., Kavitha C., Ananda Kumar S.

Advances in Materials Science

|

2023

|

Vol. 23, nr 4(78)

27--36

EN

The present study reports an easy eco-friendly, cost efficient, and rapid method for the synthesis of silver nanoparticles (Ag NPs) using palm sprouts as reducing cum capping agent. Green synthesis of silver nanoparticles was successfully performed using palm sprouts plant extract via a simple and cheaper eco-friendly method. Palm sprouts extract reduces silver nitrate to silver nanoparticles. The resulting materials were analyzed by Fourier-transform infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and X-ray Diffraction (XRD) analysis. FT-IR spectrum confirms the presence of various functional groups in the active biomolecules, it acts as a capping agent for the nanoparticles. The morphology of this sample was analyzed through SEM and the presence of silver was confirmed accordingly. The green synthesized Ag NPs exhibited an excellent antibacterial activity against E. coli and P. aeruginosa and B. subtilis and S. aureus besides imparting efficient antimicrobial activity against pathogenic bacteria as well.

7

Material investigations of components used in the production of composites for the electronics and electrotechnical industries

Makówka Marcin, Jakubas Adam, Łada-Tondyra Ewa, Suchecki Łukasz

Przegląd Elektrotechniczny

|

2022

|

R. 98, nr 2

164--167

EN

One of the great achievements of the last 50 years is the development of high-quality composite materials. By definition, classic composites are materials that are a combination of at least two components (phases), e.g. embedded particles, fibers, fabrics in a polymer, metal or ceramic matrix. Composites exhibit many unique properties if compared with solid metal and ceramic materials, as well as pure polymers and copolymers. This is typical to their stiffness and strength to weight ratios (strength and relative stiffness). The properties of composites depend to a large extent on the size, shape and form of the filling fibers and particles, in particular with their large share in the volume of the composite. This also applies to composite materials manufactured for the electronics and electrotechnical industries, where apart from appropriate mechanical properties, appropriate electrical properties are required, e.g. high ability to shielding of electromagnetic field in a wide frequency range.

PL

Znaczącym osiągnięciem ostatnich 50 lat jest rozwój badań nad wytwarzaniem wysokiej jakości materiałów kompozytowych. Z definicji klasyczne kompozyty to materiały będące kombinacją co najmniej dwóch składników (faz), np. cząstki, włókna, tkaniny w matrycy polimerowej, metalowej lub ceramicznej. Kompozyty wykazują wiele unikatowych właściwości w porównaniu z litymi materiałami metalowymi i ceramicznymi, a także czystymi polimerami i kopolimerami. Dotyczy to zwłaszcza stosunku ich sztywności i wytrzymałości do masy (wytrzymałość i sztywność właściwa). Właściwości kompozytów zależą w dużej mierze od wielkości, kształtu i postaci włókien i cząstek je wypełniających, w szczególności w przypadku ich dużego udziału w objętości kompozytu. Dotyczy to również materiałów kompozytowych wytwarzanych dla przemysłu elektronicznego i elektrotechnicznego, gdzie oprócz odpowiednich właściwości mechanicznych wymagane są odpowiednie właściwości elektryczne, m.in. wysoka zdolność ekranowania pola elektromagnetycznego w szerokim zakresie częstotliwości.

8

Biosynthetic of Titanium Dioxide Nanoparticles Using Zizyphus Spina-Christi Leaves Extract: Properties

Alobaidi Tuqa B., Alwared Abeer I.

Journal of Ecological Engineering

|

2022

|

Vol. 23, nr 1

315--324

EN

The present project utilizes a straightforward, inexpensive, and environmentally friendly approach to produce Titanium dioxide nanoparticles utilizing Zizyphus Spina-Christi leaves (Z-TiO2). Ultra-Spectrophotometry (UV-Vis) was used to characterize the synthesized nanoparticles, which showed the production of nanoparticles at 320 nm absorbance. To investigate functional groups, Fourier Transform Infrared Spectroscopy (FTIR) has been used. The presence of Titanium Dioxide was verified using Energy Distribution X-ray Spectroscopy (EDS). Surface area is calculated using the Brunauer Emmett Teller (BET) formula. Images from Field Emission Electron Microscopy (FE-SEM) verified the nanoparticles' spherical shape and relatively homogenous size distribution. These findings demonstrated that the production of Z-TiO2 nanoparticles was successful.

9

Biological synthesis and characterization of titanium dioxide nanoparticle from Cynodon dactylon

Renitta R. E., Jebaseeli T. J., Dhanaraj A., Paul S.

Journal of Achievements in Materials and Manufacturing Engineering

|

2022

|

Vol. 113, nr 1

31--41

EN

Purpose: There are several advantages of using a biological technique to produce nanoparticles versus a chemical method. The primary goal of this work is to characterize and biologically synthesize titanium dioxide (TiO2) nanoparticles from Cynodon dactylon. The characterization has experimented with UV-Vis Spectroscopy, EDX analysis, SEM, XRD, and FTIR. Design/methodology/approach: The suggested study uses a simple biological technique to accomplish the systematic biological synthesis of TiO2 nanoparticles utilizing Cynodon dactylon plant extract and titanium tetra isopropoxide as a precursor. UV-Vis spectroscopy, Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and X-Ray Diffraction (XRD) are used to confirm the fabrication of the TiO2 nanoparticles. The plant extract as well as titanium-based nanoparticles of the herb, Cynodon dactylon will be tested for its antibacterial activity against human pathogens. This eco-friendly technique for nanoparticle synthesis is straightforward and adaptable to major commercial manufacturing and technological applications. Findings: Cynodon dactylon biosynthesis of TiO2 nanoparticles is efficient, nutrition dependent, does not employ hazardous compounds, and happens at neutral pH levels. The antibacterial study results show that TiO2 nanoparticles synthesized using Cynodon dactylon have good antibacterial properties. TiO2 nanoparticle method of action against bacteria is unknown. This is an alternative process for synthesising TiO2 nanoparticles, apart from other chemical protocols, since this is quick and non-toxic. The antimicrobial property of biologically synthesized TiO2 nanoparticles against Escherichia coli, Staphylococcus aureus, and Acinetobacter baumannii was tested at four different doses of 15 μl/mg, 25 μl/mg, 50 μl/mg, and 75 μl/mg. The present results revealed the 75 μl/mg concentration got the highest zone of inhibition (15, 13, 15 mm) for Acinetobacter baumannii, Staphylococcus aureus, and Escherichia coli. Research limitations/implications: Many nanoparticles smaller than 100 nm are firmly agglomerated with each other in the study. TiO2 nanoparticles absorb in the UV region of 200 to 400 nm. XRD measurements confirmed the presence of TiO2 nanoparticles in the biologically produced sample. In our work, EDX was used to confirm the existence of Ti after its synthesis by Cynodon dactylon. Practical implications: The biosynthesized TiO2 nanoparticles utilizing Cynodon dactylon plant extracts exhibit a good potent antibacterial activity. The proposed results showed that the TiO2 nanoparticles are well suited for biomedical applications. Originality/value: The suggested research identifies several eco-friendly, biological, and cost-effective procedures for manufacturing nano-coated herbal products. The agar well diffusion technique was used to assess antibacterial activities toward test pathogens such as Acinetobacter baumannii, Staphylococcus aureus, and Escherichia coli.

10

Hardness and dry sliding wear behaviour of Al7050 hybrid composites produced by stir casting

Srivallirani Katepalli, Venkateswara Rao M

Composites Theory and Practice

|

2022

|

R. 22, nr 3

150--159

EN

Hardness and dry sliding wear behaviour of Al7050 hybrid composites produced by stir casting The current study aims to investigate at the tribological properties of Al7050 reinforced with TiO2 and BN particles utilising a pin-on-disc apparatus. By means of the stir-casting process, MMCs were fabricated with three different weight percentages of TiO2 particles: 1, 3, and 5%, as well as various weight percentages of h-BN particles: 2, 4, and 6%. The volumetric wear rates and coefficients of friction were continuously recorded under normal loads of 20-40 N, sliding speeds of 2-4 m/s and for sliding distances of 1000, 1500 and 2000 m. Microstructural analysis revealed that the TiO2 and BN particles were uniformly dispersed throughout the Al7050 matrix with minimal agglomeration. The experimental data reveals that the tensile strength and Vickers hardness of the cast hybrid composites gradually improved by increasing the weight percentages of the TiO2 and h-BN reinforcing particles. The worn micrographs reveal that abrasion and delamination are the dominant wear mechanisms in the case of the hybrid composites. The composite containing 6 wt.% h-BN particles had the lowest coefficient of friction and wear rate at a normal load of 40 N, sliding speed of 4 m/s and for the sliding distance of 2000 m when compared to other composites. On the other hand, the composites with 2 wt.% h-BN particles had the highest coefficient of friction and wear rate. The XRD analysis showed the generation of strong interfacial reactions, which contributed to the hardness of the hybrid composites.

11

Ocena wpływu aktywacji bentonitu na jego właściwości sorpcyjne

Niziurska Natalia, Skokoń Magdalena, Ściślak Szymon, Wieczorek Wojciech, Fendrych Katarzyna

Analit

|

2022

|

Nr 12

23--35

PL

W pracy przedstawiono wyniki badań dotyczące oceny wpływu aktywacji bentonitu na jego zdolności sorpcyjne. W tym celu analizie poddano betonit surowy pochodzący ze słowackiego złoża Jelśovy Potok oraz betonit poddany procesowi aktywacji z wykorzystaniem Na2CO3. Materiał do badań stanowiły próbki bentonitu pobrane podczas wyjazdu technologicznego na terenie firmy CERTECH w Niedomicach. Proces aktywacji skutkuje wzrostem ilości wyługowanych z bentonitu rozpuszczalnych w wodzie składników oraz wzrostem pHPZC, tj. wartości pH przy którym powierzchnia zawiesiny bentonitu wykazuje w wodzie elektryczny ładunek zerowy. Ponadto proces aktywacji sodowej bentonitu skutkuje niemal 4-krotnym wzrostem wartości pojemności kationowymiennej CEC, która kształtuje się na poziomie 353.3 meq/100 g bentonitu aktywowanego. Analiza składu ilościowego oraz fazowego, dokonana w oparciu o wyniki uzyskane za pomocą odpowiednio spektroskopii fluorescencji rentgenowskiej XRF oraz dyfraktometrii rentgenowskiej XRD, potwierdziła skuteczność zastosowanej procedury aktywacji bentonitu. Pomiary z wykorzystaniem spektroskopii FT-IR ujawniły pozostałość węglanu w strukturze materiału po procesie aktywacji. Badania mikrostrukturalne z wykorzystaniem skaningowej mikroskopii elektronowej SEM wskazuje, iż proces aktywacji wpływa na różnice w rozmiarze ziaren bentonitu aktywowanego (126 μm) w stosunku do bentonitu surowego (512 μm). Wzrost rozwinięcia powierzchni swobodnej bentonitu aktywowanego wpływa korzystnie na jego zdolności sorpcyjne.

EN

This work presents results of research related to assessment of activation of bentonite on its sorption properties. Samples originated from Slovak deposit Jelśovy Potok, and bentonite activated with Na2CO3. Bentonite was aquired during field trip to CERTECH located in Niedomice, Poland. Process of activation leads to increase of amount of water soluble substances leached from bentonite and an increase in pHPZC. A specific value of pH in which surface of the bentonite displays zero electrical charge. Additionally, activation of bentonite results in almost 4 times increase of Cation Exchange Capacity (CEC), which is around 35.3 [meq/100g] of activated bentonite. Quantitive and phase analysis was conducted through results of XRF and XRD methods, and they showed clear effectiveness of bentonite activation. FT-IR analysis revealed residues of carbonates inside structures of bentonite, a byproduct of activation. SEM microscopy showed visible change to particulate size due to activation of bentonite. Activated bentonite had praticles sized 126 [μm] whilst raw bentonite had particles 512 [μm] in size. Siginificant increase in bentonite free surface is beneficial to its sorption abilities.

12

Rotunda św. Mikołaja w Przemyślu - badanie struktur materiału budowli.

Gosztyła Marek, Sikorski Krystian

Teka Komisji Urbanistyki i Architektury Oddział PAN w Krakowie

|

2021

|

T. 49

405--417

PL

W artykule, który można potraktować jako kontynuację badań mających na celu określenie lat budowy rotundy pw. św. Mikołaja w Przemyślu, podjęto kolejną próbę wskazania okresu wzniesienia świątyni w oparciu o aktualny stan badań oraz z wykorzystaniem precyzyjnej aparatury badawczej. Badania ukierunkowane zostały na określenie struktur materiału budowli na drodze analiz składu chemicznego i krystalicznego pobranych próbek zapraw. Podjęto również próbę określenia miejsca kamieniołomu, z którego pozyskiwano materiał do budowy świątyni, wykorzystując narzędzia do oceny ich składu chemicznego i krystalicznego. Rozpoznanie składu próbek przeprowadzono w oparciu o badania in situ oraz laboratoryjne (analizy instrumentalne). Wyniki badań pozwoliły określić skład chemiczny i krystaliczny zapraw, skład chemiczny i krystaliczny kamieni oraz porównać z innymi datowanymi obiektami.

EN

In the paper, which can be treated as a continuation of research intended to identify the time period when the Rotunda of St. Nicholas in Przemyśl had been built, we made another attempt to define the period of the church’s construction based on the current state of the art and with the use of precise research equipment. Our study was aimed at defining the structures of the building’s material obtained via chemical and crystalline composition analysis of collected mortar samples. We also attempted to define the site of the quarry from where the material used to build the church had been procured from, using tools to assess their chemical and crystalline compositions. We identified the composition of the samples via in situ and laboratory testing (instrumental analyses). The findings allowed us to determine the chemical and crystalline composition of mortars and the chemical and crystalline composition of stone and to compare it with other dated buildings.

13

Zróżnicowanie procesów deterioracji elewacji piaskowcowej XIX-wiecznego budynku Archiwum Państwowego w Poznaniu

Szczepaniak Małgorzata

Przegląd Geologiczny

|

2021

|

Vol. 69, nr 2

127--134

EN

Stone has been used in architecture since Antiquity. The processes of its deterioration in different buildings have always been associated with natural processes of its weathering (physical, chemical, biological). However, this situation has changed over centuries. Currently, air pollution (mainly in urbanised areas) has a significant impact on the accelerated weathering of stone monuments. The research presented in this paper concerns the deterioration of stone facade of the 19th century building of the National Archive in Poznań, where the latest factor (contemporary air pollution) plays the greatest role. Based on the ICOMOS glossary, selected forms of deterioration were described and classified in macro and micro scales. For this purpose, optical and scanning microscopy and X-ray diffraction were used. As a result of the research, lichen species composition and secondary mineralisation in the black crust were identified. Elements, such as: barium, zinc, lead, and iron, which were detected on the black crust, were directly related to anthropogenic pollution caused mainly by combustion and low emissions.

14

Reinvestigations of the Li2O–Al2O3 system. Part I: LiAlO2 and Li3AlO3

Tabero Piotr, Frąckowiak Piotr, Dąbrowska Grażyna

Polish Journal of Chemical Technology

|

2021

|

Vol. 23, nr 3

30--36

EN

Reinvestigations of the Li2O–Al2O3 system focused on the synthesis and properties of LiAlO2 and Li3AlO3 phases have been performed with the help of XRD and IR measuring techniques and Li2CO3, LiOH.H2O, Al2O3-sl., α-Al2O3, Al(NO3)3.9H2O and boehmite as reactants. Results of investigations have shown the formation of α-, β-, and γ- polymorphs of LiAlO2. It was found that only the use of LiOH.H2O as a reactant yields to β-LiAlO2 as a reaction product. On the other hand, it was proved that Li3AlO3 does not form in the Li2O–Al2O3 system. A new method for the synthesis of α-LiAlO2 was developed, consisting in grinding the mixture of Li2CO3 and Al(NO3)3.9H2O and heating the obtained paste at the temperature range of 400–600°C. The IR spectroscopy was used to characterize obtained phases.

15

In situ thermal decomposition route: Preparation and characterization of nano nickel, cobalt, and copper oxides using an aromatic amine complexes as a low-cost simple precursor

Refat Moamen S., Mohamed Soha F., Altalhi Tariq A., Bakare Safyah B., Al-Hazmi Ghaferah H.

Polish Journal of Chemical Technology

|

2021

|

Vol. 23, nr 2

47--53

EN

The main interest now is the development of metallic or inorganic-organic compounds to prepare nanoparticle materials. The use of new compounds could be beneficial and open a new method for preparing nanomaterials to control the size, shape, and size of the nanocrystals. In this article, the thermal decomposition of [M2(o-tol)2(H2O)8]Cl4 (where o-tol is ortho-tolidine compound, M = Ni2+, Co2+, Cu2+) new precursor complex was discussed in solid-state conditions. The thermal decomposition route showed that the synthesized three complexes were easily decomposed into NiO, Co3O4 and CuO nanoparticles. This decomposition was performed at low temperatures (~600°C) in atmospheric air without using any expensive and toxic solvent or complicated equipment. The obtained product was identified by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX). FT-IR, XRD and EDX analyses revealed that the NiO nanoparticles exhibit a face-centered-cubic lattice structure with a crystallite size of 9–12 nm. The formation of a highly pure spinel-type Co3O4 phase with cubic structure showed that the Co3O4 nanoparticles have a sphere-like morphology with an average size of 8–10 nm. The XRD patterns of the CuO confirmed that the monoclinic phase with the average diameter of the spherical nanoparticles was approximately 9–15 nm.

16

Formation and characterization of furfuryl mercaptan-β-cyclodextrin inclusion complex and its thermal release characteristics

Zhu Guangyong, Xiao Zuobing, Yu Gengfa, Zhu Guangxu, Niu Yunwei, Liu Junhua

Polish Journal of Chemical Technology

|

2021

|

Vol. 23, nr 4

35--40

EN

Furfuryl mercaptan has the aroma characteristics of coffee. However, it is unstable during storage of coffee brew and roasted coffee. In order to enhance the stability of furfuryl mercaptan, furfuryl mercaptan-β-cyclodextrin inclusion complex was synthesized using the precipitation method in this work. Fourier transform infrared spectroscopy, x-ray diffraction, and thermogravimetric analysis (TG) were used to characterize the resulting products. The interaction of furfuryl mercaptan with β-cyclodextrin was inve-stigated by the molecular mechanics (MM) method. These changes in FTIR and XRD gave supporting evidence for the successful formation of furfuryl mercaptan-β-cyclodextrin inclusion complex. The TG results showed that the formation of furfuryl mercaptan-β-cyclodextrin inclusion complex could improve the thermal stability of furfuryl mercaptan and provide a long-lasting effect. The structure of furfuryl mercaptan-β-cyclodextrin inclusion complex with the minimum energy was obtained by MM2 calculation, and the minimum binding energy was –77.0 kJ mol–1 at –1.96 × 10–10 m.

17

Mineralogical studies of the Maastrichtian Gerinya Claystone of the Patti Formation, southern Bida Basin, Nigeria: Implication for industrial application

Oyetade Oluwaseye P., Konwea Charles I., Ojo Olusola J., Odesanmi Tayelolu M.

Mineralogia

|

2021

|

Vol. 52, iss. 1

10--18

EN

The mineralogical compositions of the Gerinya claystone, Patti Formation, Southern Bida Basin, Nigeria, were investigated to infer their sedimentological process and industrial application. Mineralogical analysis of the claystone was carried out using the X-ray diffraction (XRD) method. The diffractogram peaks aided the identification of the clay and non-clay minerals in the study area. The XRD showed kaolinite as the major clay mineral with compositions ranging from 10.8 - 67.6 wt%. The non-clay minerals were quartz, anatase, diopside, goethite, hematite, rutile, muscovite and microcline. Among the non-clay minerals, quartz had the highest percentage mineralogical composition of 21.2 to 83.4 wt%. The mineral assemblage is typical of a hot and humid climate where chemical alteration and hydrolysis of silicate minerals are severe. The sediments are of mafic and felsic crystalline rocks origin. The sediments are of low energy floodplain/interchannel depositional environment. The Gerinya claystone vary from low to high porosity and very low to low permeability. The claystone can be used as clay liners and as raw material for ceramic production. The application of the claystones in fertiliser production will require some processing. The claystone can be used for haemorrhage control in the pharmacological/medical sector. Although, the ingestion of the claystones could lead to dental damage and possible perforation of the sigmoid colon in the gastrointestinal tract.

18

Assessment of the properties of HAp micropowders after ion exchange process in silver nitrate solution

Głuszek Marta, Świrska Zuzanna, Kaczorowski Witold, Januszewicz Bartłomiej, Wrotniak Maciej

Engineering of Biomaterials

|

2021

|

Vol. 24, no. 161

15--20

EN

Bioceramic materials, such as hydroxyapatite (HAp), are characterized by high biocompatibility in the presence of tissues and body fluids without causing toxic or allergic reactions. Hydroxyapatite, due to its similarity to structures found in bones, is used both in the form of powders, e.g. as additives to bone cements, and implants coatings. However, this material is not characterized by antimicrobial properties, therefore attempts are made to improve its properties by introducing additional elements into the hydroxyapatite structure. Thanks to HAp’s high ion-exchange ability, silver can be introduced into its structure. The calcium ions present in the HAp structure can be easily replaced by silver ions to create a material endowed with high biocompatibility and antibacterial properties. The presented study is based on the analysis of the morphology of the modified powders via scanning electron microscopy (SEM), their chemical composition via X-ray energy dispersive spectroscopy (EDS) and chemical structure via X-ray diffraction (XRD) and Raman spectroscopy. The powders obtained through the ion exchange were mixtures of silver phosphates Ag3PO4 and HAp. The highest silver content was found in the sample modified with a 1M concentration of AgNO3 in the aqueous solution. It was also determined that the annealing of the obtained powders under vacuum at 800°C resulted in the formation of metallic silver and a change in the structure of HAp to β-TCP.

19

Review of Methods for Testing the Compatibility of High Energy Mixed Components

Gołofit Tomasz, Zakościelny Bartosz, Maksimowski Paweł, Chmielarek Michał, Cieślak Katarzyna, Sałaciński Tomasz

Central European Journal of Energetic Materials

|

2021

|

Vol. 18, no. 4

512--528

EN

A review of methods for testing the compatibility of high energy mixed components is presented. The advantages, deficiencies as well as the limitations of particular research methods are described based on selected applications reported in the literature. The most frequently used techniques for testing compatibility are thermal methods, such as DSC, TG, VST, and HFC, in which the processes of decomposition of samples conditioned at elevated temperatures are analyzed. Examples of non-thermal methods for testing compatibility, such as DFT, FTIR or XRD are reported in the literature as well. Incompatibility may lead to thermal detonation, which can occur even at low degrees of conversion. For this reason, the authors focused specifically on the limitations of methods for determining compatibility at high degrees of conversion. The methods allowing testing of compatibility based on an analysis for the initial decomposition stage are recommended.

20

Badanie betonu geopolimerowego z kruszywem z żużla żelazochromowego na działanie podwyższonej temperatury

Indu P., Greeshma S.

Cement Wapno Beton

|

2021

|

R. 26, nr 4

340--351

PL

Niniejszy artykuł dotyczy wytrzymałości i ubytku masy betonu geopolimerowego w porównaniu z konwencjonalnym betonem cementowym, po ekspozycji w podwyższonej temperaturze. W niniejszej pracy kruszywo grube konwencjonalnego betonu geopolimerowego zostało częściowo (40%) zastąpione kruszywem z żużla żelazochromowego w celu uzyskania mieszanki zastępczej betonu geopolimerowego. Omówiono również mikrostrukturę betonu geopolimerowego na podstawie badań XRD, SEM i tomografi i rentgenowskiej. W wyniku badań stwierdzono, że po ekspozycji w podwyższonej temperaturze, konwencjonalny beton cementowy wykazuje spadek wytrzymałości większy o 17,65% od konwencjonalnego betonu geopolimerowego. Zauważono również, że zastępcza mieszanka geopolimerowa wykazuje utratę wytrzymałości o 24,4% większą i utratę masy o 1,35% większą niż konwencjonalna mieszanka geopolimerowa. Jednak w większości zakresów temperatur miała ona większą wytrzymałość od konwencjonalnej mieszanki geopolimerowej. Tak więc mieszanka zastępcza betonu geopolimerowego zachowuje się lepiej niż konwencjonalny beton geopolimerowy i konwencjonalny beton cementowy zarówno w warunkach otoczenia, jak i w podwyższonej temperaturze.

EN

This paper deals with the strength and mass loss of geopolymer concrete in comparison with conventional cement concrete after elevated temperature exposure. In this study, the coarse aggregates of the conventional geopolymer concrete are replaced partially (40%) with ferrochrome slag aggregates, to obtain the replacement mix of geopolymer concrete. The microstructure of geopolymer concrete was examined by XRD, X-ray tomography, and SEM and also discussed in this paper. The results concluded that after exposure at elevated temperature, the conventional cement concrete has a strength loss of about 18% higher than the geopolymer concrete. It was also noted that though replacement geopolymer mix exhibited the strength loss of 24.4% and mass loss of 1.35% higher than the conventional geopolymer mix, it had greater strength than conventional geopolymer mix, for most of the temperature ranges. Thus the replacement mix of geopolymer concrete behaves better than conventional geopolymer concrete, both at ambient and elevated temperature conditions.