Elemental Chemical Composition Research Articles

Crystalline Phase Segregation of Quantum-Dots-Passivated CH3NH3PbI3 Film via Argon Plasma Treatment

In this study, a composite perovskite film composed of lead cesium triiodide (CsPbI3) quantum dots (QDs) and methylammonium lead iodide (CH3NH3PbI3; MAPbI3) was proposed. The CsPbI3 QDs prepared by hot-injecting were used as an anti-solvent in precursors to passivate the surface of this composite perovskite film. The further argon (Ar) plasma treatment improves the surface of the film. The effects of the powers from 100 to 200 W on the composite perovskite film structure, chemical element composition, and optical properties were studied. The experimental results demonstrate that the CsPbI3 QDs passivation boosts the ultraviolet light absorption (350–450 nm) and inhibits the formation of the PbI2 phase. Furthermore, Ar plasma treatment effectively improved CsPbI3 QDs passivation on MAPbI3 film. The powers lower than 140 W cause C=O bonds to dissolve and coordination bonds to form between OA carboxyl moieties and undercoordinated Pb2+ ions. At 160 and 140 W, the obvious crystal phase segregation and a decrease in light absorption are observed, respectively. Meanwhile, the strong bombardment of Ar ions at higher than 160 W causes the severe degradation of MAPbI3 film.

Mechanical behavior of ion-irradiated ODS RAF steels strengthened with different types of refractory oxides

One of the most promising candidates for constructing IV generation nuclear reactors is Oxide Dispersed Strengthening (ODS) Reduced Activation Ferritic (RAF) steel. It is known that introducing refractory oxides to the ferritic matrix makes it possible to obtain a brand-new kind of materials with an excellent set of properties. In the present work, the authors focused on verifying materials' structural and mechanical properties strengthened by three different types of refractory oxides submitted to ion-irradiation. Three materials with an elemental chemical composition of 12 %Cr, 2 %W, 0.3 %Ti, and strengthened with 0.3% Y2O3 or Al2O3 or ZrO2 were produced by mechanical alloying and subsequently consolidated by Spark Plasma Sintering technique. Manufactured materials have been submitted to high energy (500 keV) Ar-ion irradiation at room temperature with three fluences (up to 5x1015 ions/cm2). This procedure allowed to generate a thin, strongly damaged zone with approximate thickness of 230 nm. SEM/EBSD and TEM bservations, Grazing Incidence X-ray Diffraction analysis, and nanoindentation tests have been included in examination of modified layers. Implementation of these techniques allowed to reveal alteration of structural and mechanical features between unmodified material and radiation-affected layer. Obtained results showed a strong correlation between the strengthening oxide and materials' microstructural and mechanical behavior under radiation damage. It has been proved that below 1x1015 ions/cm2 mechanical properties in the modified layer of all materials are very similar. Reported behavior may be related to the efficient annealing of the radiation defect process. Above this limit, significant differences between the materials are visible. It is believed that described phenomenon is directly related to the presence of the structural features and their capacity to act as defect sinks. Consequently, type of dominant mechanisms occurring in modified layer is proposed.

Laboratory investigation of cup lump modified bitumen emulsion

In recent years, bitumen emulsion in cold mix asphalt (CMA) has gained much attention because of its economic and environmental benefits. However, cold mix asphalt faces some major concerns related to its performance. Bitumen modification with polymer is considered to be an effective way to enhance its performance. In the present study, cup lump rubber (CLR) was used as a new modifier for the preparation of new cup lump modified bitumen emulsions (CMBE) to improve its performance. In addition, to further understand the modification mechanism, we discussed the effect of CLR and emulsification on basic engineering properties, chemical composition compatibility, elemental compositions, thermal properties, phase microstructures, surface morphology, and micromechanical features of CMB and its evaporation residues. The results indicate that the basic properties of modified bitumen with CLR were improved, emulsification affects the basic performance to some extent. The inclusion of CLR did not show any significant change in the functional groups of CMB. Moreover, the CLR was dispersed homogeneously and resulted in a stable multi-phase structure of CMB, resulting in satisfactory compatibility. Whereas the emulsification did not affect the elemental composition of evaporation residues of CMB. Furthermore, the thermal stability was enhanced by CLR addition, and the emulsification further improved the thermal properties of all types of bitumen. In addition, the CLR modification and emulsification did not significantly affect the crystalline structure of bitumen and their evaporation residues. Finally, atomic force microscopy results exhibited that the addition of CLR increased the size of bee-structures, which prevented the oxidization of chemical components and enhanced the diffusion ability of bitumen molecules, but the emulsification decreased the size and increased the formation of bee structures, thus improving the physical properties of the evaporation residue of modified bitumen.

Rapid co-deposition of dopamine and polyethyleneimine triggered by CuSO4/H2O2 oxidation to fabricate nanofiltration membranes with high selectivity and antifouling ability

Membrane surface properties play important roles in the separation performance and fouling behavior during the membrane-based water treatment processes. Mussel-inspired polydopamine (PDA) layer with abundant functional groups can endow the membrane surface with increased hydrophilicity as well as extraordinary versatility and creative potential for further functionalization toward specific applications. However, the slow deposition rate still limits its application in membrane modification. In this study, rapid deposition of the PDA layer on the surface of the polysulfone membrane was realized by catalytic oxidation using CuSO4/H2O2. Meanwhile, polyethyleneimine (PEI) was introduced to co-deposit with PDA to obtain a hydrophilic, uniform, and electroneutral separation layer for the nanofiltration membrane. An optimized stoichiometry of modifiers and oxidants was obtained by UV–vis absorbance measurement. The membrane surface properties including surface morphology, roughness, chemical element compositions, wettability, and charge behavior before and after modification were characterized through various techniques. The optimized PDA/PEI modified membrane (a-Cu(15)-PDA/PEI) possessed higher MgCl2/NaCl and dye/salt selectivities as well as improved anti-fouling performance compared to the commercial NF-270 membrane. Furthermore, the Gaussian simulation combined with XPS analysis illustrated that the introduction of Cu2+/H2O2 accelerated the dopamine oxidation and facilitated the formation of CO quinoid structures, thus providing more reactive sites for the Schiff base reaction in the PDA/PEI co-deposition process. The results from this study provide theoretical foundations for improving nanofiltration membrane performances by PDA/PEI modification.

Discriminating Geographical Origin of Cashew Nuts Based on the Combination of Multi-elements and Chemical Component Analysis

This study aims to distinguish Indonesian cashew nuts’ geographical origin based on their elemental profiles and chemical composition. Nine elements and five chemical components of cashew nut samples were analyzed. The profiles of four micro-elements, Zn, Cu, Mn, Cr, and five macro elements, K, Ca, Mg, Fe, Na, of Indonesian cashew nuts were determined using Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). Simultaneously, the chemical components of moisture, ash, total protein, total fat, and carbohydrate contents were measured using the AOAC standard. The combination of elemental profiles was then analyzed with a scatterplot matrix diagram and a multivariate statistical technique, Canonical Discriminant Analysis (CDA). Inter-region discrimination among four major Indonesian cashew nuts producers was achieved by applying CDA. Sodium (Na), calcium (Ca), potassium (K), manganese (Mn), zinc (Zn), and total protein were the best descriptors for cashew nuts origin. According to the findings, the most abundant element in cashew nuts is potassium (K), followed by magnesium (Mg), and calcium (Ca) (Ca). Fat is the most abundant chemical composition in cashew nuts at the same time. Potassium (K), magnesium (Mg), and calcium (Ca) concentrations showed major regional variations. On the other hand, zinc (Zn) and manganese (Mn) are two micro-elements that may help identify the origin of cashew nut samples. The use of a Canonical Discriminant Analysis scatters plot to visualize the origin of Indonesian cashew nut samples was less successful based on micro-element concentrations. The CDA scatter plot application based on macroelements, and the CDA scatter plot application based on a mixture of micro- and macro-elements produced better results than the CDA scatter plot application based on micro-elements. Furthermore, the best visual separation was achieved using a CDA scatter plot based on a combination of elemental profiles and protein concentration. For a complete characterization of cashew nuts, further research with a large number of samples is needed.

Magneto-chemical characterisation of Saharan dust deposited on snow in Poland

Recent research has convincingly shown the advantages of combining environmental magnetism and geochemical analyses for the proxy estimation of anthropogenic pollution due to their atmospheric deposition in local environments. Few studies have also focused on anthropogenic particles deposited on snow. However, papers reporting on Sahara dust particles deposited on snow in central Europe and which involve magnetic methods are missing. To the best of our knowledge, this is the first study investigating the magnetic features of the SDE recorded in snowfall in this part of Europe (i.e. Poland). Our aim was to provide the magnetic characteristics and chemical elemental compositions of a snow horizon containing Saharan dust deposited near the Polish Jakuszyce meteorological station during a snowfall event that occurred from the 1st to the February 7, 2021. Samples of snow with and without Saharan dust were analysed with respect to iron oxide contents (magnetic susceptibility, hysteresis loop, magnetic remanence acquisition) and compared with chemical compositions. Our results revealed the presence of both ferrimagnetic magnetite and antiferromagnetic hematite in the dust-enriched horizon, and the diamagnetic behaviour of the reference layer consisting of ‘pure’ snow. The samples recorded the presence of geogenic elements such as Al, Fe, Mn, and Ti, anthropogenic elements such as As, Co, Cr, Cu, Ni, Pb, and Zn, and nutrients including Ca and K. The total concentrations of geogenic elements, nutrients, and anthropogenic elements in the snow samples with deposited Saharan dust were, respectively, >3700, >320, and >110 times greater than in the samples without Saharan dust. These findings may serve as reference data for a variety of environmental magnetic studies.

Efficient and stable heterostructured Co9S8/Cu7S4 composite counter electrodes derived from Prussian blue analogs for quantum dot-sensitized solar cells

The challenge of boosting the efficiency of QDSSCs lies in the rational development and design of economical, stable and efficient counter electrode (CE) catalysts for fast and efficient electron transport at the CE/electrolyte interface. Here, we creatively construct Co9S8/Cu7S4 heterostructure composite CEs using CuCo-Prussian blue analogs (PBA) as precursor by one-step in-situ solvothermal vulcanization method. Work function analysis and systematic electrochemical characterizations reveal that the presence of heterojunctions in the Co9S8/Cu7S4 can increase the interfacial electric field driving force inside the material, thereby reducing the Rct at CE/electrolyte interface, promoting the efficient transfer of electrons. Correspondingly, the Co9S8/Cu7S4 composite CE can improve the stability and compensate for the deficiency of the single component CE through a decent synergistic catalytic effect. Remarkably, the Mn-CdS/CdSe/ZnS co-sensitized QDSSC equipped with Co9S8/Cu7S4 heterostructure composite CE delivers an optimal conversion efficiency of 8.43% with Jsc = 23.42 mA/cm2, Voc = 0.672 V; FF = 0.54, which was significantly superior to physically mixed CE (PM-Co9S8/Cu7S4, 6.55%), single-component CE (Cu7S4, 5.60%; Co9S8, 5.13%) and conventional Brass/Cu2S CE (4.96%). In briefly, the advanced heterostructure engineering and the abundant, tunable chemical elemental composition of PBA provide new views for the purposeful design of economical and outstanding heterostructured composite CEs.

CHEMICAL COMPOSITION OF GERANIUM WLASSOVIANUM (GERANIACEAE)

The article presents the results of experimental findings concerning the study of the chemical composition of above-ground and underground parts of Geranium wlassovianum. The amount of number of tannins into the plant matter gathered during the blooming period is 19.45±0.04% in the root system and 20.93±0.03% in the above-ground part of a plant. Tannins are referred to phenolic compounds. For qualitative determination of peculiar phenolic compounds the HELC (high-efficiency liquid chromatography) method was used. This method allowed to determine 21 compounds from the aqueous extract of the above-ground parts and 11 compounds from the aqueous extract of the underground parts of the Geranium wlassovianum. 8 compounds were found both in the shoot system and in the root one, 13 substances are contained only in the grass, 3 substances were found only in the underground plant parts. During the study, the elemental composition of a plant was identified, as a result 22 chemical elements were found out. For 6 elements the root barrier index is lower than one that points at barrier-free transition of elements from a root system to an above-ground parts of a plant. The rest 16 elements meet the barrier during transition (in the range from 1 to 10), that is the concentration of these 16 elements is higher in the underground part than in the grass part. The variety of the chemical composition and quantitative content of the chemical elements in the plant matter of the species that is under the research depend on different natural factors.

Interactions between ZnO Nanoparticles and Polyphenols Affect Biological Responses.

Zinc oxide (ZnO) nanoparticles (NPs) are used as a food additive Zn supplement due to the role of Zn in biological functions. They are directly added to complex processed foods or Zn-fortified functional foods. Hence, the interactions between ZnO NPs and nutritional or functional components can occur. In this study, the effects of ZnO NP interactions with two polyphenols (quercetin and rutin) on cytotoxicity, antioxidant activity, ex vivo intestinal absorption, and solubility were evaluated. Moreover, the characterization on the interactions was carried out by analyzing crystallinity, surface chemical bonding, chemical composition, and surface chemistry. The results demonstrate that the interactions caused higher cytotoxicity, ex vivo intestinal transport, and solubility of ZnO NPs than pristine ZnO NPs but did not affect antioxidant activity nor intestinal absorption of the polyphenols. The interaction effects were more evident by ZnO NPs interacted with quercetin than with rutin. The crystallinity of ZnO NPs was not influenced, but the degree of exposure of the chemical bondings, elemental compositions, and chemical group intensities on the surface of ZnO NPs, quercetin, or rutin were quenched or decreased to some extent by the interactions, especially by ZnO NPs interacted with quercetin. It is, therefore, concluded that the interactions affect chemical characteristics and surface chemical sates of ZnO NPs, quercetin, or rutin, which can cause high cytotoxicity, intestinal absorption, and solubility of ZnO NPs. Further study is required to elucidate the mechanism of action of the interactions.

Titanium oxide coatings formed by plasma spraying followed by induction heat treatment

Porous titanium-containing coatings were formed on titanium samples by atmospheric plasma spraying. The resulting samples were subjected to induction heat treatment in an oxygen-containing (air) atmosphere at normal pressure and treatment temperature of 650–1250 °C. As a result of experimental studies, it was established that thermal modification allowed an increase in the oxygen content in the coatings from 49.6 ± 9.2 to 71.7 ± 1.1 at.%. The change in the elemental chemical composition was accompanied by the formation of titanium oxide coatings, the surface of which was distinguished by the presence of acicular crystals of titanium oxide (TiO), anatase, and rutile (TiO2) with an average length of 150–200 nm and a width of about 50–100 nm. Induction heat treatment also led to an increase in the microhardness of titanium oxide coatings from 1530 ± 55 to 1825 ± 191 HV0.98 and an increase in adhesive strength.

Influence of silver content on microstructural, bactericidal, and cytotoxic behavior of TiAlVN (Ag) composite coatings deposited by magnetron sputtering

Titanium alloys are attractive for the manufacture of bone implants, due to their high biocompatibility, chemical stability, and adequate resistance/specific weight ratio. However, its ability to reject the adhesion of bacteria and the formation of biofilms is very limited. Further, their low hardness and tribological resistance limits the scope of their application, so it is common to apply surface treatments to improve this property. In this work, the deposition of TiAlVN(Ag)x nanocomposite coatings using the direct current magnetron sputtering technique was proposed, with the aim of giving the coated substrates a significant bactericidal effect without significantly affecting their hardness and cell viability. The coatings were deposited from two independent targets of Ti6Al4V alloy and silver faced at 180° to each other. The atomic percent contents of silver in the compound were 8.1%; 10.6%; 12.6% and 14%, which was adjusted by varying the power applied to the silver target between 0 and 100W while maintaining the power supplied to the titanium alloy target constant at 2000W. The microstructural properties, elemental chemical composition, phase composition and surface topography of the deposited coatings were evaluated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), and atomic force microscopy (AFM), respectively. The bactericidal effect of the composite coatings was assessed by evaluating the inhibition (JIS Z-2801 standard) and adhesion of the Pseudomonas aeruginosa bacteria, while the cell viability was assessed using human osteoblasts of the Saos-2 cell line, following the MTT method (colorimetric assay for assessing cell metabolic activity). All the deposited coatings showed a high bactericidal effect against P. aeruginosa, exhibiting inhibition greater than 99.99% and avoiding surface adherence by 100%. The TiAlVN(Ag) samples with 8.1 at% and 10.6 at% silver, and which presented the best ratio of mechanical and tribological properties (not shown here), exhibited high biocompatibility and adherence of the osteoblasts to the coated substrates.

Polymerization of chondroitin sulfate and its stimulatory effect on cartilage regeneration; a bioactive material for cartilage regeneration

Chondroitin sulfate (CS) is one of the major glycosaminoglycans (GAGs). GAGs are linear polymers comprising disaccharide residues and are found as the side chains of proteoglycans. CS has significant stimulatory effects on cell behavior and is widely used in tissue-engineered and drug delivery devices. However, it is difficult to incorporate a sufficient amount of CS into biopolymer-based scaffolds such as collagen to take full advantage of its benefit. In this study, CS has been polymerized to an 11 times higher molecular weight polymer (PCS) in an attempt to overcome this deficiency. We have previously shown that PCS was significantly more effective than CS in chondrogenesis. This study aimed to characterize the physicochemical properties of the manufactured PCS. PCS was characterized by Fourier transform infra-red (FTIR) spectroscopy together with X-ray photoelectron spectroscopy (XPS) to obtain information about its chemical structure and elemental composition. Its molecular size was measured using dynamic light scattering (DLS) and its viscoelastic properties were determined by rheology measurements. The average PCS diameter increased 5 times by polymerization and PCS has significantly enhanced viscoelastic properties compared to CS. The molecular weight of PCS was calculated from the rheological experiment to give more than an order of magnitude increase over CS molecular weight. Based on these results, we believe there is a great potential for using PCS in regenerative medicine devices.

Temperature Changes in Oral All-Ceramic Materials with Different Optical Properties under Er:YAG Laser Irradiation.

Objectives This in vitro study is aimed at assessing the oral all-ceramic materials energy transmission and temperature changes after Er:YAG laser irradiation of monolithic zirconia all-ceramic materials with varying optical properties. Materials and Methods Two monolithic zirconia materials, Zenostar T and X-CERA TT (monolithic Zirconia), were studied. Specimens were divided into four groups, with a thickness of 1.0, 1.5, 2.0, and 2.5 mm, respectively. The chemical elemental composition of the two materials was determined using X-ray spectroscopy and Fourier transform infrared spectroscopy. The light transmittance of specimens with different thicknesses was measured using a spectrophotometer at three wavelength ranges: 200–380, 380–780, and 780–2500 nm. Irradiation with Er:YAG laser was performed, and the resultant temperature changes were measured using a thermocouple thermometer. Results Compositional analysis indicated that Si content in X-CERA TT was higher than that in Zenostar T. The light transmittance of both materials decreased as specimen thickness increased. Er:YAG laser irradiation led to temperature increase at both Zenostar T (26.4°C–81.7°C) and X-CERA TT (23.9°C–53.5°C) specimens. Both optical transmittance and temperature changes after Er:YAG laser irradiation were consistent with exponential distribution against different thickness levels. Conclusion Er:YAG laser penetration energy and resultant temperature changes were mainly determined by the thickness and composition of the examined monolithic zirconia materials.

Biogas production from the landfilled easily degradable fraction of municipal solid waste: mining strategy for energy recovery.

The growing demand for space and financial resources to manage current and new municipal solid waste (MSW) landfills has become a massive challenge for several countries. Additionally, landfills contribute to adverse environmental impacts such as pollution and CO2 (carbon dioxide) and CH4 (methane) emissions. This paper has analyzed the possibility of producing biogas from landfilled MSW. An easily degradable fraction of landfilled MSW with 8 years of landfilling was mined and subjected to chemical characterization and elemental composition analysis. The abbreviation for the study sample was called ED8 – Mined. The low values of lignin (24.5%) and nitrogen content (0.7%) and high values of holocellulose (75.9%) and C/N (46.1%) on dry basis were obtained resulting in materials with the potential to be used for biogas generation. Recalcitrant materials were found in greater amounts than easily biodegradable fresh MSW fractions. The reuse of energy from landfilled MSW can contribute positively to the country’s environment and economy, reducing environmental liabilities and generating energy in a controlled way. In Delta A Sanitary Landfill, Southeastern Brazil, the recovery of the ED8 – Mined would reflect a significant recovery of about 100,000 tonnes of landfilled materials for annual MSW cells of about 450,000 tonnes, allowing recovery of materials and space expansion for rejects.Graphical abstractfx1

Natural Resources Exploitation in Sulfate-Resisting Portland Cement Manufacturing: Towards Quality Improvement and Reduction of Environmental Impact.

Sulfate-resisting (SR) Portland cement is commonly used in building works to improve concrete’s durability against external sulfate attack. This attack is considered a very serious chemical aggression that causes damage and cracking of concrete structures. These special cements have a very particular mineralogical composition, C3A ≤ 3% and (2C3A + C4AF) ≤ 20%, which makes the cementitious matrix resistant to sulfate attack. This kind of product is very difficult to manufacture since low alumina (C3A) necessitates the use of a high kiln temperature in order to keep a sufficient liquid phase necessary to maintain the stability of the cement manufacturing process. In this context, this study aims to optimize SR Portland cement raw meals using natural materials collected from different regions in Tunisia, mainly ordinary limestone, siliceous limestone, black marl, grey marl, iron ore, and natural fluorapatite. The collected specimens were characterized by an X-ray fluorescence spectrometer in order to determine its elemental chemical composition. The optimization of the SR Portland cement raw meal combinations was done by means of a calculation tool based on the chemical composition of each used raw material and the variation of burning modules (LSF, SIM, and ALM). It has been found that natural fluorapatite integration (0%–15%) in raw mix preparation leads to the raw meals required for the SR Portland cement standard (C3A ≤ 3% et 2 C3A + C4AF ≤ 20%). Moreover, it was shown that the estimated SR raw meals ensure the cement manufacturing process stability (acceptable burning modules “LSF = 100; SIM = 3; ALM = 0.91 and sufficient liquid phase) and decrease the CO2 emissions in cement production.

Mechanical and Acoustic Properties of Alloys Used for Musical Instruments.

Music should be integrated into our daily activities due to its great effects on human holistic health, through its characteristics of melody, rhythm and harmony. Music orchestras use different instruments, with strings, bow, percussion, wind, keyboards, etc. Musical triangles, although not so well known by the general public, are appreciated for their crystalline and percussive sound. Even if it is a seemingly simple instrument being made of a bent metal bar, the problem of the dynamics of the musical triangle is complex. The novelty of the paper consists in the ways of investigating the elastic and dynamic properties of the two types of materials used for musical triangles. Thus, to determine the mechanical properties, samples of material from the two types of triangles were obtained and tested by the tensile test. The validation of the results was carried out by means of another method, based on the modal analysis of a ternary system; by applying the intrinsic transfer matrix, the difference between the obtained values was less than 5%. As the two materials behaved differently at rupture, one having a ductile character and the other brittle, the morphology of the fracture surface and the elementary chemical composition were investigated by scanning electron microscopy (SEM) and analysis by X-ray spectroscopy with dispersion energy (EDX). The results were further transferred to the finite element modal analysis in order to obtain the frequency spectrum and vibration modes of the musical triangles. The modal analysis indicated that the first eigenfrequency differs by about 5.17% from one material to another. The first mode of vibration takes place in the plane of the triangle (transverse mode), at a frequency of 156 Hz and the second mode at 162 Hz, which occurs due to vibrations of the free sides of the triangle outside the plane, called the torsion mode. The highest dominant frequency of 1876 Hz and the sound speed of 5089 m/s were recorded for the aluminum sample with the ductile fracture in comparison with the dominant frequency of 1637 Hz and the sound speed of 4889 m/s in the case of the stainless steel sample, characterized by brittle fracture.

Physicochemical parameters of a hydrochemical technology employing sodium chloride to obtain cryolite used in aluminium production

The paper aims to study the physicochemical parameters of a hydrochemical technology employing hydrofluoric acid and local mineral resources (sodium chloride) to obtain cryolite used in the electrolysis of cryolite-alumina melts. In order to determine the elemental chemical and phase compositions of initial, intermediate, and final products, titration and X-ray diffraction analysis (using an upgraded Dron-2 unit) were employed. The conducted studies indicate that the proposed process of cryolite production from hydrofluoric acid at 28–30 % concentration using aluminium hydroxide and a concentrated sodium chloride solution occurs at 25 °С for 10–15 min. The yield of cryolite reaches 87.6 %, while ~12 % of cryolite remains dissolved in the hydrochloric acid solution. With the temperature rising from 25°С to 95°С, the cryolite yield is shown to decrease from 87.6 % to 69.3 % due to its higher solubility in the formed hydrochloric acid. The cryolite production process was validated via X-ray diffraction analysis. The analysed sample was found to be consistent with the cryolite reference, i. e., indicating an interaction between sodium chloride and fluoroaluminic acid. The conducted studies served as a basis for developing a process flow diagram of hydrochemical cryolite production using hydrofluoric acid, aluminium hydroxide, and sodium chloride. The conducted studies revealed that the technology of cryolite production employing sodium chloride is easy to implement and cost-effective due to the use of local mineral resources and low energy consumption.

Proficient route in synthesis of glucose stabilized Ag modified ZnS nanospheres for mechanistic understandings of commercially used dyes degradation

• A facile, one step hydrothermal synthesis method was applied. • Glucose, a bio-molecule was used as a capping agent. • Enhanced sunlight driven photocatalytic dye degradation activity of Ag-ZnS nanospheres than that of ZnS nanospheres. • Charge transfer behavior of ZnS and Ag-ZnS photocatalysts at a low faradic process. • Environmental toxic dyes degradation using photo catalytic process without thermal hazards. The work reported here is based on the one-step facile hydrothermal synthesis of glucose stabilized pristine zinc sulfide (ZnS) nanospheres and silver (Ag) modified ZnS nanospheres. The cubic crystal structure with spherical morphology of as-synthesized nanospheres was confirmed from X-ray diffraction spectroscopy and Field emission scanning electron microscopy, respectively. Blue-shift of optical absorption maxima was studied through UV–Visible absorbance spectroscopy while defect-related emission properties were deduced from the photoluminescence spectroscopy. Energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopic method were employed for elemental analysis and chemical composition study. Incorporation of Ag into ZnS to form Ag-ZnS nanospheres led to superior photocatalytic efficacy to the photocatalytic mineralization of both rhodamine-B (RhB) and methylene blue (MB) dyes after 120 min of solar irradiation. The respective pseudo-first-order degradation rate constants were 0.0163/min and 0.0225/min for the degradation of RhB and MB dyes, respectively.

Analisis Bahan Gerabah Pada Temuan Hasil Ekskavasi di Kawasan Lembah Behoa

The Behoa Valley Area is one of megalithic cultural heritage from the early metal era (paleometallic) and the supporting communities was already familiar with technology of pottery creation. The discovery of pottery fragments dominates each research carried out in this site. This paper aims to understand the source of the pottery materials by comparing modern pottery materials used by the current community around the site. Total of 26 samples were used, consist of 24 pottery fragments sampled from sites in The Behoa Valley area, one pottery fragment sampled from Pangawumbu, and one pottery fragment sampled from craftsman in Doda village. Method of analysis used in this research is chemical element analysis, conducted towards the clay matrix and carried out microscopically using Scanning Electron Microscope (SEM). Chemical element analysis of the clay matrix are used to understand the pottery clusters based on chemical element composition contained in the clay matrix. Pottery clusters then discovered from statistical analysis using Principal Component Analysis and Hierarchical Clustering Analysis methods. Based on the result of the chemical elements analysis, it is revealed that pottery material from the sites in The Behoa Valley area has similarity with pottery material from craftsman around the site.

Adsorption Capacity and Mechanism of Biochar Derived from Typical Agricultural Wastes for Cadmium in Aqueous Solutions

Twelve biochar types were derived from animal manure (cow manure, chicken manure, and pig manure) and crop straw (wheat straw, rice straw, and corn straw) at different temperatures (300℃/700℃ and 300℃/500℃) for Cd2+ in a solution system in the present study. A scanning electron microscope, Fourier infrared spectrometer, X-ray diffraction, and CHN analyzer were applied to analyze the physical and chemical properties, surface structure, and elemental composition of the biochar. The adsorption capacity and related mechanism of biochar for Cd2+ in an aqueous solution was studied. The results showed that the maximum adsorption capacity of cow manure, chicken manure, and pig manure biochar for Cd2+ increased from 83.40, 19.65, and 96.74 mg·g-1 to 106.54, 268.89, and 164.53 mg·g-1, respectively, with the increase in pyrolysis temperature. With the increase in pyrolysis temperature, the pore structure of biochar became more abundant, oxygen-containing functional groups increased, and the aromatic structure appeared. Quantitative analyses revealed that ion exchange accounted for 12%-52%, chemical precipitation accounted for 27%-79%, complexation accounted for 1%-8%, and cation-π accounted for 1%-28% of the total adsorption capacity of Cd2+. With the increase in pyrolysis temperature, the proportion of cation-π interaction increased from 1%-13% to 8%-30%, but the proportion of chemical precipitation and ion exchange were still very high (70%-93%). Therefore, ion exchange and chemical precipitation could be the main mechanisms of agricultural waste biochar adsorption for Cd2+.