X-ray Diffractometry Analysis Research Articles

Effective degradation of dyes using silver nanoparticles synthesized from Thunbergia grandiflora leaf extract

Motivated by the urgent need to address dye-related environmental pollution, this study explores the green synthesis of silver nanoparticles (SNPs) using Thunbergia grandiflora leaf extract for its simplicity, affordability, and eco-friendliness. UV–Vis spectroscopy reveals a distinctive signal at 441 nm, while Dynamic Light Scattering shows a zeta potential charge of −18.2 mV, indicating nanoparticle stability. The study demonstrates the catalytic activity of SNPs in degrading industrial dyes Acid Red 88 and Methylene Blue, showcasing first-order kinetics with kinetic constants of 0.18 min−1 and 0.14 min−1, respectively. Moreover, Scanning Electron Microscopic images reveal predominantly spherical nanostructures, while X-ray diffractometry analysis portrays a face-centered crystalline structure. These findings underscore the potential of SNPs synthesized from T. grandiflora leaf extract in nanoremediation efforts, offering a sustainable solution to the pressing challenge of dye-contaminated wastewater, thereby contributing to environmental protection.

Corrosion Behavior of Al-Containing CoNiV Medium Entropy Alloy Coating Fabricated by Laser Cladding.

CoNiV medium entropy alloys (MEAs) have been widely recognized for their superior corrosion resistance. Nonetheless, their extensive application has been hindered by high production costs and complex fabrication processes. In this study, CoNiVAlx MEA coatings were synthesized on AISI 304 stainless steel substrates via laser cladding technology. The microstructure, phase composition, corrosion resistance, and corrosion mechanisms of the coatings were systematically investigated by using advanced characterization techniques, including optical microscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffractometry, and electrochemical workstation analysis. The ratio of O2-/OH- in the passivation film of the coated surface exhibited a gradual increase with the addition of Al. The formation of the Al-containing precipitated phase L21 was observed at x = 0.3 and 0.4. The results demonstrated that moderate Al doping (x ≤ 0.2) enhanced corrosion resistance by improving the stability of the passivation film and reducing the thermodynamic tendency toward corrosion. In contrast, excessive Al doping (x > 0.2) led to the formation of the L21 phase, which increased the susceptibility to localized corrosion, thus compromising the overall corrosion resistance.

Effect of Mineral Admixtures on Physical, Mechanical, and Microstructural Properties of Flue Gas Desulfurization Gypsum-Based Self-Leveling Mortar.

The production of flue gas desulfurization gypsum poses a serious threat to the environment. Thus, utilizing gypsum-based self-leveling mortar (GSLM) stands out as a promising and effective approach to address the issue. β-hemihydrate gypsum, cement, polycarboxylate superplasticizer, hydroxypropyl methyl cellulose ether (HPMC), retarder, and defoamer were used to prepare GSLM. The impact of mineral admixtures (steel slag (SS), silica fume (SF), and fly ash (FA)) on the physical, mechanical, and microstructural properties of GSLM was examined through hydration heat, X-ray diffractometry (XRD), Raman spectroscopy, and scanning electron microscopy (SEM) analyses. The GSLM benchmark mix ratio was determined as follows: 94% of desulfurization building gypsum, 6% of cement, 0.638% each of water reducer and retarder, 0.085% each of HPMC and defoamer (calculated additive ratio relative to gypsum), and 0.54 water-to-cement ratio. Although the initial fluidity decreased in the GSLM slurry with silica fume, there was minimal change in 30 min fluidity. Notably, at an SS content of 16%, the GSLM exhibited optimal flexural strength (6.6 MPa) and compressive strength (20.4 MPa). Hydration heat, XRD, and Raman analyses revealed that a small portion of SS actively participated in the hydration reaction, while the remaining SS served as a filler.

Influence of Stacking Order on the Structural and Optical Properties of Cu2ZnSnS4 Absorber Layer Prepared from DC-Sputtered Oxygenated Precursors

Several studies have attempted to overcome the sudden volume expansion of the precursor during sulfurization by the use of oxygen-containing precursors when growing the CZTS absorber. This work demonstrates the influence of precursor stacking orders on the properties of the CZTS thin film absorber layer from DC-sputtered oxygenated precursors for solar cell applications. CZTS absorber layers were prepared from three types of DC-sputtered stacks, namely, Zn-O/Sn/Cu, Sn/Zn-O/Cu, and Sn/Cu/Zn-O. The precursors were sequentially deposited on a soda lime glass (SLG) using DC-magnetron sputtering and annealed in a sulfur and nitrogen ambient. X-ray diffractometry (XRD) and Raman spectroscopy analyses reveal the formation of crystalline kesterite CZTS structure regardless of the precursor stacking order. Atomic force microscope (AFM) analysis showed that CZTS thin films grown from precursor stacks SLG/Zn-O/Sn/Cu and SLG/Sn/Zn-O/Cu had improved morphological properties with densely packed large grains compared to that with stack SLG/Sn/Cu/Zn-O. SLG/Zn-O/Sn/Cu is the best stack among the studied stacking orders since it exhibits large grains in the absorber layer, which is preferential for high-efficiency thin film solar cells. The use of oxygenated precursor with order Sn/Zn-O/Cu promises improved CZTS absorber properties as it exhibits better morphological properties.

β-Cyclodextrin metal-organic framework as a green carrier to improve the dissolution, bioavailability, and liver protective effect of luteolin

The incidence of acetaminophen-induced liver injury has increased, but effective prevention methods are limited. Although luteolin has hepatoprotective activity, its low solubility and bioavailability limit its applications. Cyclodextrin metal-organic frameworks (CD-MOFs) possess 3D-network structures and large inner cavities, which make them excellent carriers of poorly soluble drugs. In this study, we used CD-MOFs as carriers to improve the dissolution of luteolin and assessed their antioxidant activity, bioavailability, and hepatoprotective effects. Luteolin was loaded into β-CD-MOF, γ-CD-MOF, β-CD, and γ-CD, and characterized by powder X-ray diffractometry (PXRD) and thermogravimetric analysis (TGA). Our results showed that luteolin-β-CD-MOF was the most stable. The main driving forces were hydrogen bonds and van der Waals forces, as determined by molecular simulation. The loading capacity of luteolin-β-CD-MOF was 14.67 wt%. Compared to raw luteolin, luteolin-β-CD-MOF exhibited a 4.50-fold increase in dissolution and increased antioxidant activity in vitro. Luteolin-β-CD-MOF increased the bioavailability of luteolin by approximately 4.04- and 11.07-fold in healthy rats and liver injured rats induced by acetaminophen in vivo, respectively. As determined by biochemical analysis, luteolin-β-CD-MOF exhibited a better hepatoprotective effect than raw luteolin in rats with acetaminophen-induced liver injury. This study provides a new approach for preventing acetaminophen-mediated liver damage.

Structural, Optical and Dielectric Properties of Some Nanocomposites Derived from Copper Oxide Nanoparticles Embedded in Poly(vinylpyrrolidone) Matrix.

Polymer nanocomposite films based on poly(vinyl pyrrolidone) incorporated with different amounts of copper oxide (CuO) nanoparticles were prepared by the solution casting technique. The PVP/CuO nanocomposites were analyzed by X-ray diffractometry (XRD), scanning electron microscopy, UV-Visible absorption spectroscopy and dielectric spectroscopy. The XRD analysis showed that the monoclinic structure of cupric oxide was maintained in the PVP host matrix. The key optical parameters, such as optical energy gap Eg, Urbach energy EU, absorption coefficient and refractive index, were estimated based on the UV-Vis data. The optical characteristics of the nanocomposite films revealed that their transmittance and absorption were influenced by the addition of CuO nanoparticles in the PVP matrix. Incorporation of CuO nanoparticles into the PVP matrix led to a significant decrease in band gap energy and an increase in the refractive index. The dielectric and electrical behaviors of the PVP/CuO nanocomposites were analyzed over a frequency range between 10 Hz and 1 MHz. The effect of CuO loading on the dielectric parameters (dielectric constant and dielectric loss) of the metal oxide nanocomposites was also discussed.

Green synthesis of gold nanoparticles via Artocarpus odoratissimus peel extract for potential applications of optical filter and catalytic degradation

Gold nanoparticles (Au NPs) were synthesized via a green synthesis method, utilizing the peel extract of Artocarpus odoratissimus as both the reducing and capping agent. This study investigates the impact of peel extract concentration (ranging from 0.002 to 0.012 g/mL) and reaction temperature (including room temperature, 45 °C, and 75 °C) on the properties of the synthesized Au NPs. Various characterization techniques, such as UV–Visible spectrophotometry, transmission electron microscopy (TEM), Fourier Transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD), and zeta potential analysis, were employed to analyze the synthesized samples. UV–Visible spectroscopy revealed absorption peaks of the Au NPs around 533–537 nm, varying with synthesis parameters, while TEM analysis indicated particle sizes ranging from 12 to 25 nm. XRD analysis confirmed the formation of Au NPs, with diffraction peaks aligning well with the standard. FTIR analysis suggested interactions between phytochemicals and Au NPs, contributing to their reduction and size control. The synthesized Au NPs exhibited remarkable optical filtering capability, with up to 87 % transmittance in the 751–1126 nm spectral range and significant absorbance in the lower wavelength region (300–751 nm). Additionally, catalytic studies revealed that Au NPs accelerated the degradation of rhodamine B dye, 0.0795 min−1, compared to 0.0445 min−1 without Au NPs. These findings underscore the potential of Au NPs for use in hybrid photovoltaic-thermal systems as filters, where transmitted light can be harvested for photovoltaic energy generation while absorbed light can be utilized for the thermal aspect. Moreover, Au NPs offer promise for improving wastewater quality by enhancing pollutant degradation.

Engineering 5-flourouracil and leucovorin-loaded vesicular systems for possible colon specific delivery: In vitro evaluation and real time cell assay against HCT-116 colon cell lines

5-flourouracil (5-FU) is typically modulated with leucovorin (LEU) in clinical practice to improve clinical efficacy and patient survival rates. However, this combination has undesirable side effects and makes 5-FU more toxic. Hence, integrating a vesicular system (proniosomes) with another delivery vehicle may improve drug targeting, while resolving the aforementioned drawbacks. This study aimed to engineer 5-FU/LEU proniosomes for possible delivery to the colon. The modified slurry approach was used to create drug-loaded proniosomes (150 mg/9 g of carrier) using both water-soluble (dextrin (DEX) and lactose (LAC)) and insoluble (Neusilin FH2 (NEU)) carriers. The powdered formulations were filled into Eudragit S100 (10 %)-coated capsules or Eudragit FS 30D capsules for enteric- or colon-specific delivery. In vitro evaluations (flow properties, powder X-ray diffractometry (XRD) analysis, particle size analysis, entrapment efficiency, drug release, scanning electron microscopy (SEM), polydispersity index, Fourier transform infrared spectroscopy (FTIR), and stability studies) were performed on the formulations. An in vitro cytotoxicity test [real-time cell assay (RTCA)] against HCT-116 colon cancer cell lines was performed using the optimized formulation. In vitro evaluations showed that the nanoparticles had good physicochemical properties. RTCA studies showed sustained cell death with the formulations compared to the pure drug and placebo. The sequential drug release of the colon-targeted capsules containing 5-FU and LEU- loaded proniosomes showed negligible drug release in SGF (pH 1.2) and phosphate buffer solution (pH 6.8) (approximately 11 %) but profound drug release (>80 %) at pH 7.4. Drug-loaded proniosomes engineered for colon targeting (Eudragit S100 (10 %) capsules or Eudragit FS 30D capsules) showed good colon-specific targeting and favorable in vitro cytotoxicity profiles.

Photocatalytic Degradation of Methylene Blue Dye by Using Different Nanoparticles

Zinc sulfide nanoparticles (NPs) were produced through a straightforward and cost-efficient chemical co-precipitation technique, intended for use in the photocatalytic decomposition of methylene blue (MB) dye, both under ultraviolet and visible light exposure. To evaluate the synthesized nanoparticles, various analytical tools including ultraviolet-visible (UV-Vis) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffractometry (XRD) were employed. The XRD analysis confirmed the cubic symmetry of the synthesized NPs. SEM analysis revealed that the nanoparticles tend to aggregate, forming clusters of nanoparticles. TEM analysis illustrated that the ZnS nanoparticles exhibit a spherical morphology with uniform size distribution. Additionally, Fourier-transform infrared (FTIR) analysis exhibited a vibrational peak at 616 cm-1. The degradation of methyl blue was investigated using a UV-Vis spectrophotometer as part of the study.

Mineralogical compositions of soils under three geological formations in some parts of Ogun state, Nigeria and their agricultural potentials

Investigating the mineralogical compositions of soils under different geological formations becomes imperative for maximizing agricultural productivity and ensuring the long-term viability of agricultural practices. Therefore, studies were carried out on mineral compositions and diversities of soils developed over the Basement complex rock, Coastal plain sands and Ewekoro formations in Ogun state Nigeria. A total of nine profile pits (three per location) of 2 m × 1 m × 2 m size were dug in all the three locations. Soil samples were collected from the pedogenic horizons of each profile pits in replicates into a well labeled polyethylene bag. Using X-ray diffractometry (XRD) and scanning electron microscopy (SEM) the mineral contents and their relative abundance, elemental compositions and morphologies of the fine sand, coarse silt and clay fractions of the soils at different topographic positions were identified, described and compared. Results obtained from XRD and SEM analyses exhibited similarities. The most abundant elements in the basement complex and Ewekoro pedon were oxygen, carbon and silicon whereas in the coastal plain sand pedon, oxygen, carbon and aluminum were the most abundant element. The presence of mixed-layer illite, mica, kaolinite, quartz, hematite, anatase, goethite, and chlorite at varying degrees was observed in the pedons developed on these geological formations, although kaolinite and quartz dominated the soil matrix. The mineralogical complexity of the pedons followed the order of basement complex > coastal plain sand > Ewekoro formation. Profiles developed on the Ewekoro formation exhibited the highest degree of weathering, as evidenced by their chemical properties and mineralogical compositions. The petrographic evaluation of the three geological formations revealed that all pedons were rich in quartz and exhibited varying degrees of mineral complexity and maturation. The overlapping and distinct characteristics among the geologies indicated different stages of weathering. By using the mineral maturity index, profiles developed over the basement complex rock and the coastal plain sand could be regarded as sub-matured and this could have contributed significantly to the native fertility of these soils and profiles from the Ewekoro formation were the most weathered. The use of Ewekoro formation for agriculture would necessitate significant investments in agro-inputs and sound principles of soil management through integrated soil fertility management.

A comparison of microstructure and mechanical characteristics correlation of the joint specimens for duplex stainless steel UNS S32304 and super-duplex stainless steel UNS S32750: The role of post-weld heat treatment

The present investigation studies the impact of post-weld heat treatment (PWHT) on the microstructure and mechanical characteristics of joints made by gas tungsten arc welding between duplex stainless steel and super-duplex stainless steel specimens. The PWHT process was considered at 1100 °C for 10 minutes followed by water quenching on UNS S32304 and UNS S32750 materials. Scanning electron microscopy, optical microscopy, X-ray diffractometry (XRD), and energy dispersive X-ray analyses have been applied in microstructure evolution, including recognizing local chemical contents and elemental distribution. To analyze the mechanical characteristics of samples, tensile and hardness tests were performed. It was shown that after applying PWHT, the morphology of the austenite varied becoming mostly intergranular/spheroidal in shape, accompanied by an improvement in the percentages of austenite. This investigation indicates the PWHT results in restoring an equal percentage of both phases. The phase percentages, based on both ASTM E1245 and ASTM E562, show a good agreement between the austenite and ferrite phases of weld materials. According to XRD, the phases are mainly ferrite and austenite with different lattice parameters with no evidence of unwanted intermetallic phases. It was concluded that the PWHT process plays a crucial role in the ductility of joint specimens due to the phase balance between austenite and ferrite.

Exploring the Potential of Sr2+ for Improving the Post-Hardening Strength and Durability Characteristics of Cement Paste Composites

This study investigates the effects of strontium ions on enhancing the post-hardening strength and durability characteristics of hydrated cement composites, exploring their potential use as a rehabilitation method for aging concrete structures. A 30% strontium nitrate solution served as the source of strontium ions. Cement paste specimens with a water-to-cement ratio of 0.5, cured for 28 days, were submerged in the 30% strontium nitrate solution to facilitate strontium ion penetration. Compressive and flexural strength tests were conducted on the specimens and compared to those cured in deionized water. Moreover, the durability performance, including surface abrasion resistance, water sorptivity, and porosity, was examined. Scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and X-ray diffractometry (XRD) analyses were also carried out to investigate the microscopic morphology and chemical characteristics of the specimens. Results indicated that the strontium-treated specimens exhibited notable enhancements in both compressive and flexural strengths, especially in flexural strength. The specimens also demonstrated improved surface abrasion resistance, decreased water absorption, and a marked reduction in porosity. SEM analysis revealed a densified microstructure in the strontium-treated cement paste specimens, and EDS and XRD analyses showed changes in their morphology and chemical compositions and structures, indicating the formation of new types of hydrates. Accordingly, this study suggests that the strontium ion treatment method has significant potential for the maintenance and restoration of aging cementitious materials.

A Linear Two-Coordinate Cr(II) Complex: Synthesis, Characterization, and Reactivity.

The synthesis and characterization of a linear two-coordinate Cr(II) amido complex, Cr{N(t Bu)Dipp}2 (Dipp=2,6-diisopropylphenyl), from the reaction of 1 molar equivalent (equiv) of CrCl2 and 2 equiv. of LiN(t Bu)Dipp is reported. Single-crystal X-ray diffractometry (SC-XRD) analysis revealed that it has a short Cr-N bond distance of 1.8878(9) Å, which could be attributed to the relatively less bulky nature of the amido ligand compared with reported systems. Furthermore, the oxidation reaction of the two-coordinate Cr(II) complex was explored. The oxidation reaction of Cr{N(t Bu)Dipp}2 with the one-electron oxidants AgOTf and [FeCp2 ][BArF 4 ] (BArF 4 - =[B{C6 H3 -3,5-(CF3 )2 }4 ]- ) afforded the trigonal planar three- and bent two-coordinate Cr(III) complexes Cr{N(t Bu)Dipp}2 (OTf) and [Cr{N(t Bu)Dipp}2 ][BArF 4 ], respectively. The reaction of Cr{N(t Bu)Dipp}2 with 1 equiv. of the organic azides AdN3 (Ad=1-adamantyl) and PhN3 afforded the three-coordinate Cr(IV) imido complexes Cr{N(t Bu)Dipp}2 (NAd) and Cr{N(t Bu)Dipp}2 (NPh), respectively. The reaction of Cr{N(t Bu)Dipp}2 and two equiv. of Me3 NO afforded the Cr(VI) dioxo complex Cr{N(t Bu)Dipp}2 (O)2 . The reaction of Cr{N(t Bu)Dipp}2 with 1 equiv. of CyN=C=NCy resulted in the insertion of the carbodiimide into the Cr-N bond, with the formation of a three-coordinate Cr(II) complex. Finally, density functional theory (DFT) calculations were used to elucidate the electronic structure of these complexes.

Preparation of 2D Tungsten Diselenide (WSe2) thin films by selenization of DC-sputtered W precursors

Two-dimensional layered transition metal dichalcogenides based on WSe2 films demonstrated promising properties for nano-electronics and photovoltaic applications. In this work, WSe2 films were prepared by selenization of DC-sputtered W precursors. The influence of the selenization temperature on the structural, morphology, and optical properties of the WSe2 films was investigated. The selenization temperature was varied from 350 °C to 450 °C at the interval of 50 °C. Structural, morphology and optical properties of the WSe2 were investigated using X-ray diffractometry (XRD), Atomic Force Microscope (AFM), and UV-VIS-NIR spectrophotometer, respectively. XRD analysis revealed that all WSe2 were polycrystalline and exhibited the co-existence of c-axis perpendicular and parallel substrate texture. Samples selenized at 400 °C demonstrated strong - types of crystal orientations – perpendicular c-axis substrate texture – dominated crystal growth. The AFM images further revealed the co-existence of parallel and perpendicular crystal orientations for samples selenized at 350 °C and 450 °C. Optical measurement showed that all WSe2 samples were transparent and consisted of an excitonic peak at the wavelength of around 620 nm. The estimated bandgap values were in the range of 1.22 eV to 1.37 eV which is somchat lower than expected – the presence of W5O14 phases is suggested to be the main cause.

Facies analysis and paleoenvironment of the Poti Formation in the Itaueira and Floriano region: Contribution to the Carboniferous depositional history of the Parnaíba basin

The Parnaíba intracratonic basin exhibits sedimentation that reflects the different evolutionary stages of climate and paleogeography in the West Gondwana supercontinent. In this regard, we conducted a study comprising the Poti Formation in the southeast of Itaueira and Floriano regions in Piauí State, within the Parnaíba Basin. The facies analysis enabled the establishment of the depositional model for the study area, comprising ten sedimentary facies separated into two facies associations (FA) deposited in a shallow platform environment dominated by storm waves: Upper Shoreface (FA-1) and Lower Shoreface/Offshore transition (FA-2). It was possible to determine that the wave base line constantly varied, and a high-energy event provided the deposition of sediments with fine-to coarse-grained sandstone from FA-1 over those of FA-2, creating a first-order erosive surface (surf diastema) with a gradient varying from 40 to 45° that limits the two distinct facies association. This sedimentary event resulted in the excavation of the muddy offshore sediments by the lower shoreface, resulting in coarsening- and thickening-upward sandstones lying mostly under fine-grained sandstone with hummocky cross-stratifications. In the paleogeographic context, the cross-stratification paleocurrent indicates a direction towards the NW and, to a lesser extent, the SW. This direction suggests a connection between the epicontinental sea formed in the Parnaíba Basin and the paleosea of Tethys in the Late Carboniferous. Petrographic analysis classified the sandstones as subarkose and quartzarenite. This study employed petrography, X-ray diffractometry, architectural elements, and facies analysis to make inferences about the depositional system, climate, and geomorphology of the storm and wave-dominated deposits of the Poti Formation. The occurrence of kaolinite and illite in the studied deposits are typical clay minerals of humid and hot (dry) climatic conditions, respectively. Therefore, the overall data indicates a shift from retrogradational to progradational deposits that records changes in facies association and climate conditions in the Late Carboniferous.

Study on the mechanical properties, microstructure and hydration mechanism of phosphogypsum-based geopolymer cement with added micron-sized silica particles

Phosphogypsum (PG) is a solid waste product that is generated during the manufacture of phosphoric acid. In this study, beta-hemihydrate phosphogypsum (β-HPG), slag, sodium metasilicate (SM), citric acid (CA) and micron-sized silica particles (MSSP) were mixed to form a phosphogypsum-based geopolymer (PBG) cement. The results revealed that by adding 3 % MSSP, the 28-day unconfined compressive strength (UCS) reached its highest level of 59.2 MPa. Furthermore, adding 2 % MSSP resulted in the greatest water resistance, with a softening coefficient of 0.92. Additionally, X-ray diffractometry (XRD) Rietveld analysis, scanning electron microscopy-energy dispersive spectrometry (SEM-EDS) imaging, thermogravimetry-differential scanning calorimetry (TG-DSC) analysis, high-temperature XRD analysis, and mercury intrusion porosimetry (MIP) testing were employed to analyse the PBG cement. Results indicated that dihydrate gypsum (CaSO4·2H2O), ettringite (Ca6(Al(OH)6)2(SO4)3(H2O)26), and polymers (Nan{−(SiO2)zAlO2}n·ωH2O) were the principal hydration products in the PBG cement system. Also, the addition of MSSP led to reduced porosity, lower pore-specific surface area, and fewer cracks in the cement structure. After exceeding temperatures of 990.9 °C, these polymers gradually decomposed into Na6(AlSiO4)6, Al2O3, and SiO2. PBG cement is characterized by its easy processing, high strength, eco-friendly nature, and high PG incorporation. It shows promise as a potential substitute for traditional Portland cement in certain sectors, thereby facilitating the consumption of waste gypsum.

Assessing biogeochemical controls on porewater dissolved inorganic carbon cycling in the gas hydrate-bearing sediments of the Makran accretionary wedge, Northeastern Arabian Sea off Pakistan

Quantitatively assessing the porewater dissolved inorganic carbon (DIC) cycling in methane-enriched marine sediments is crucial to understanding the contributions of different carbon sources to the global marine carbon pool. In this study, Makran accretionary wedge was divided into Zone 1 (high methane flux area) and Zone 2 (background area). Porewater geochemical compositions (Cl–, SO42–, NH4+, Mg2+, Ca2+, Ba2+, DIC and δ13C-DIC) and a reaction-transport model were used to determine the DIC source and calculate the DIC flux through carbonate precipitation and releasing into overlying seawater in sediments. Zone 1 is characterized by the shallower depth of sulfate-methane transition (SMT), where most of porewater sulfate was consumed by anaerobic oxidation of methane (AOM). In contrast, a relatively low flux of methane diffusion in Zone 2 results in a deeper SMT depth and shallow sulfate is predominantly consumed by organoclastic sulfate reduction (OSR). Based on the porewater geochemical profiles and δ13C mass balance, the proportions of porewater DIC originating from methane were calculated as 51% in Zone 1 and nearly 0% in Zone 2. An increase of porewater DIC concentration leads to authigenic carbonate precipitation. Solid total inorganic carbon (TIC), X-ray diffractometry (XRD) and scanning electron microscopy (SEM) analysis display that carbonate content increases with depth and aragonite appears at or below the depths of SMT. Meanwhile, the flux of DIC released from sediments calculated by the reaction-transport model is 51.3 ~ 90.4 mmol/m2·yr in Zone 1, which is significantly higher than that in Zone 2 (22.4 mmol/m2·yr). This study demonstrates that AOM serves as the dominant biogeochemical process regulating the porewater DIC cycle, which has an important impact on the authigenic carbonate burial and the seawater carbonate chemistry.

Heterometallic Co–Sr −2,3-pyridinedicarboxylate complex and its related perovskite oxide: Synthesis, structural characterization and magnetic properties

A new heterometallic complex {[CoSr(2,3-pdc)2(H2O)5]3H2O}n (1), where 2,3-H2pdc stands for 2,3-pyridinedicarboxylic acid, has been synthesized and investigated by single crystal X-Ray diffractometry, IR spectroscopy and thermal analysis. The compound is self-organized in a polymeric structure forming a 2D framework. The 2,3-pyridinedicarboxylic acid is fully deprotonated performing several types of coordination: monodentate, bridging chelating, bidentate bridging. Thermal decomposition of the heterometallic 2,3-pyridinedicarboxylate 1 leads to the formation of a perovskite type oxide of brownmillerite series, 2, with 20.8 % yield. Magnetic studies of 1 show the paramagnetic behavior of Co(II) ions with a significant influence of a ground state zero-field splitting at low temperatures. Variable field and temperature magnetic studies of the oxide product 2 (obtained by the controlled heating of 1) indicate the presence of the Sr6Co5O15, detected by the diffraction method. Also, trace amounts of SrCoO2.75 and SrCoO2.5 were revealed by magnetic and DSC methods, respectively.

Parameter Influence, Characterization and Adsorption Mechanism Studies of Alkaline-Hydrolyzed Garcinia kola Hull Particles for Cr(VI) Sequestration.

Despite the regulations by The World Health Organization (WHO) on the permissible limit of chromium, many industries still discharge wastewater polluted with chromium into the environment irrationally. This poses a lot of risk to aquatic lives and humans because of its carcinogenic and toxic attributes. Thus, treatment of industrial wastewater polluted with chromium is highly imperative before its disposal. Nonetheless, the hulls generated from Garcinia kola in our various farmlands also causes environmental pollution when dumped unknowingly. In this present study, Garcinia kola hull particles (GK-HP) was hydrolyzed using NaOH and applied as adsorbent for Cr(VI) sequestration. The raw Garcinia kola hull particles (rGK-HP) and modified Garcinia kola hull particles (cMGK-HP) were characterized using Brunauer-Emmett-Teller (BET) method, scanning electron microscopy (SEM), powder X-ray diffractometry (XRD), Fourier-Transform-Infrared (FTIR), thermogravimetric analysis (TGA), energy dispersive spectroscopy (EDS) and point of zero charge (pHpzc). The influence of pH, adsorbent dose, contact time, temperature and adsorbate initial concentration on Cr(VI) sequestration were examined. The cMGK-HP was able to remove 96.25% of Cr(VI) from solution and proved to be effective than rGK-HP. The amount of Cr(VI) removed from solution decreased as the pH and adsorbate initial concentration were increased. However, the amount increased as the adsorbent dose, contact time and temperature were increased. Change in morphological structure, textural property, spectral peak, phase composition and adsorbents chemical composition before and after Cr(VI) sequestration from solution were proved by SEM, BET, FTIR, XRD, and EDS analyses respectively. The isotherm and kinetic studies suggest Cr(VI) adsorption on adsorbents' surface to be monolayer in nature and adsorption data to be well-fitted into pseudo second order model respectively. The cMGK-HP possessed excellent reusability attribute and high thermal stability as shown by TGA. In conclusion, cMGK-HP could effectively be used as an adsorbent for Cr(VI) sequestration from solution.

Investigating the anticancer potential of 4-phenylthiazole derived Ru(II) and Os(II) metalacycles.

In this contribution we report the synthesis, characterization and in vitro anticancer activity of novel cyclometalated 4-phenylthiazole-derived ruthenium(II) (2a-e) and osmium(II) (3a-e) complexes. Formation and sufficient purity of the complexes were unambigiously confirmed by 1H-, 13C- and 2D-NMR techniques, X-ray diffractometry, HRMS and elemental analysis. The binding preferences of these cyclometalates to selected amino acids and to DNA models including G-quadruplex structures were analyzed. Additionally, their stability and behaviour in aqueous solutions was determined by UV-Vis spectroscopy. Their cellular accumulation, their ability of inducing apoptosis, as well as their interference in the cell cycle were studied in SW480 colon cancer cells. The anticancer potencies were investigated in three human cancer cell lines and revealed IC50 values in the low micromolar range, in contrast to the biologically inactive ligands.