Kinetics of palygorskite hydrolysis in dilute salt solutions

Clay Minerals ◽  
2000 ◽  
Vol 35 (2) ◽  
pp. 433-441 ◽  
Author(s):  
A. Neaman ◽  
A. Singer
Keyword(s):  
Chemical Composition ◽  
Chemical Compositions ◽  
Salt Solutions ◽  
Initial Amount ◽  
Al Content ◽  
Surface Areas ◽  
Soils And Sediments ◽  
High Al Content ◽  
Neutral Conditions ◽  
Kinetics Of

AbstractFive palygorskite samples with different chemical compositions and specific surface areas (SSA) were used for this study. Batch experiments in dilute salt solutions under neutral conditions were conducted to study the kinetics of clay hydrolysis. The rates of release of Mg and Si differ significantly among the palygorskite samples. It was found that differences in release rate of Mg among the palygorskite samples are due to differences in both surface area and chemical composition. The rate of release of Mg was greater in palygorskites with high SSA and high Mg and Fe contents than that in palygorskites with low SSA and high Al content. The rate of release of Si depends on the SSA of the mineral and is not related to chemical composition. The initial amount of Si released increases with SSA, while the Si rate of release decreases with increasing SSA. These data suggest that the decomposition of palygorskite in soils and sediments also takes place under neutral conditions.

Influence of the Chemical Composition on the Ausferritic Transformation in Carbide-Free Bainitic Cast Steel

2014 ◽  
Vol 793 ◽  
pp. 85-91
Author(s):  
Alejandro D. Basso ◽  
Nicolás E. Tenaglia ◽  
Roberto Enrique Boeri ◽  
Juan M. Massone
Keyword(s):  
Chemical Composition ◽  
Cast Steel ◽  
Isothermal Transformation ◽  
The Other ◽  
Chemical Compositions ◽  
Transformation Kinetics ◽  
Continuous Cooling ◽  
Cast Steels ◽  
High Silicon ◽  
Kinetics Of

This work focuses on the study of the solid state transformations that take place during the austempering of high silicon carbide-free bainitic cast steels with different chemical composition. In order to get this objective three cast steel melts with different chemical compositions were produced, evaluating the influence of Cr, Mn, Ni, Al and Co. For each of these steels, samples were subjected to an austempering heat treatment at 340 oC varying the austempering time from 5 sec to 120 sec. The results show that small regions of free ferrite were obtained during continuous cooling from the austenitising to the austempering temperatures in unalloyed high silicon cast steels. At short austempering time (5 sec), the presence of a small fraction of ausferrite was observed. Austempering for 60 sec showed a larger amount of ausferrite. However, the ausferritic reaction is incomplete, and some martensite also was present, mainly located in last to freeze (LTF) zones. After an austempering of 120 sec, a fully ausferritic matrix was obtained. The addition of Cr and Mo avoided the initial precipitation of free ferrite, and lowered the isothermal transformation kinetics. On the other hand the use of Al and Co increase the presence of ferrite formed during continuous cooling and accelerates the kinetics of the ausferritic reaction.

Coarsening kinetics of γ′ phase in isothermal aged high Al content Ni–17 at.% Al alloy

2021 ◽  
pp. 124902
Author(s):  
Shujing Shi ◽  
Chengwei Liu ◽  
Yongsheng Li ◽  
Shahid Maqbool ◽  
Xiaoyuan Zhang ◽  
...  
Keyword(s):  
Al Alloy ◽  
Al Content ◽  
Coarsening Kinetics ◽  
High Al Content ◽  
Kinetics Of

High-throughput screening of the chemical composition distribution of random styrene-butyl acrylate copolymers

e-Polymers ◽  
2005 ◽  
Vol 5 (1) ◽  
Author(s):  
Iván García Romero ◽  
Harald Pasch
Keyword(s):  
Chemical Composition ◽  
High Throughput ◽  
Butyl Acrylate ◽  
High Throughput Screening ◽  
Size Exclusion ◽  
Chemical Compositions ◽  
Composition Distribution ◽  
Chemical Composition Distribution ◽  
Exclusion Chromatography ◽  
Liquid Chromatographic

AbstractThe development of high-throughput liquid chromatographic techniques for the analysis of styrene-butyl acrylate (SBA) copolymers is discussed. The analysis time in size-exclusion chromatography (SEC) can be reduced to about 3 min per sample when high-throughput SEC columns and high flow rates are used. In gradient HPLC, small columns with improved separation efficiencies can be applied. The time requirements can be decreased to less than 2 min per sample. Using the high-throughput HPLC technique, the chemical composition distribution of high-conversion SBA copolymers can be analyzed in a fast and efficient way. The calibration of HPLC separation is conducted by coupling the HPLC system with FTIR through the LC-transform interface. A comparison of the chemical compositions of the copolymers obtained by 1H NMR, off-line FTIR and coupled HPLCFTIR verifies the accuracy of the high-throughput copolymer analysis approach.

scholarly journals Mixing state and compositional effects on CCN activity and droplet growth kinetics of size-resolved CCN in an urban environment

2012 ◽  
Vol 12 (21) ◽  
pp. 10239-10255 ◽  
Author(s):  
L. T. Padró ◽  
R. H. Moore ◽  
X. Zhang ◽  
N. Rastogi ◽  
R. J. Weber ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Water Soluble ◽  
Anthropogenic Sources ◽  
Droplet Growth ◽  
Mixing State ◽  
Aerosol Composition ◽  
Activation Kinetics ◽  
Aerosol Mixing State ◽  
Kinetics Of ◽  
Ccn Activity

Abstract. Aerosol composition and mixing state near anthropogenic sources can be highly variable and can challenge predictions of cloud condensation nuclei (CCN). The impacts of chemical composition on CCN activation kinetics is also an important, but largely unknown, aspect of cloud droplet formation. Towards this, we present in-situ size-resolved CCN measurements carried out during the 2008 summertime August Mini Intensive Gas and Aerosol Study (AMIGAS) campaign in Atlanta, GA. Aerosol chemical composition was measured by two particle-into-liquid samplers measuring water-soluble inorganic ions and total water-soluble organic carbon. Size-resolved CCN data were collected using the Scanning Mobility CCN Analysis (SMCA) method and were used to obtain characteristic aerosol hygroscopicity distributions, whose breadth reflects the aerosol compositional variability and mixing state. Knowledge of aerosol mixing state is important for accurate predictions of CCN concentrations and that the influence of an externally-mixed, CCN-active aerosol fraction varies with size from 31% for particle diameters less than 40 nm to 93% for accumulation mode aerosol during the day. Assuming size-dependent aerosol mixing state and size-invariant chemical composition decreases the average CCN concentration overprediction (for all but one mixing state and chemical composition scenario considered) from over 190–240% to less than 20%. CCN activity is parameterized using a single hygroscopicity parameter, κ, which averages to 0.16 ± 0.07 for 80 nm particles and exhibits considerable variability (from 0.03 to 0.48) throughout the study period. Particles in the 60–100 nm range exhibited similar hygroscopicity, with a κ range for 60 nm between 0.06–0.076 (mean of 0.18 ± 0.09). Smaller particles (40 nm) had on average greater κ, with a range of 0.20–0.92 (mean of 0.3 ± 0.12). Analysis of the droplet activation kinetics of the aerosol sampled suggests that most of the CCN activate as rapidly as calibration aerosol, suggesting that aerosol composition exhibits a minor (if any) impact on CCN activation kinetics.

Relationship between Chemical Composition and the Amount of Phosphorus Adsorbed

2011 ◽  
Vol 695 ◽  
pp. 141-144
Author(s):  
Eiji Watanabe ◽  
Kaori Nishizawa ◽  
Masaki Maeda
Keyword(s):  
Chemical Composition ◽  
Chemical Compositions ◽  
Natural Materials ◽  
Adsorption Behaviors ◽  
Relationship Of

Relationship of the adsorption behaviors of phosphorus with several natural materials and artificial HAS-clay with various chemical compositions was investigated. The amounts of phosphorus adsorbed by them were closely related with the contents of aluminum in the material. It was found that the higher the aluminum contents of material, larger the amount of phosphorus were adsorbed.

scholarly journals Soil and Leaf Nutrients Drivers on the Chemical Composition of the Essential Oil of Siparuna muricata (Ruiz & Pav.) A. DC. from Ecuador

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2949
Author(s):  
Juan I. Burneo ◽  
Ángel Benítez ◽  
James Calva ◽  
Pablo Velastegui ◽  
Vladimir Morocho
Keyword(s):  
Gas Chromatography ◽  
Chemical Composition ◽  
Secondary Metabolites ◽  
Essential Oil ◽  
Chemical Elements ◽  
Climatic Conditions ◽  
Gas Chromatography Mass Spectrometry ◽  
Chemical Compositions ◽  
Leaf Nutrients ◽  
First Time

Chemical compositions of plants are affected by the initial nutrient contents in the soil and climatic conditions; thus, we analyzed for the first time the effects of soil and leaf nutrients on the compositions of the essential oils (EOs) of Siparuna muricata in four different localities in Ecuador. EOs were obtained by hydrodistillation and analyzed by gas chromatography/mass spectrometry (GC/MS) and a gas chromatography/flame ionization detector (GC/FID). Enantiomeric distribution by GC/MS was determined, modifying the enantiomeric separation of β-pinene, limonene, δ-elemene, β-bourbonene, cis-cadina-1 (6), 4-diene and atractylone. A total of 44 compounds were identified. The most representative for L1 were guaiol, atractylone and 4-diene; for L2, cis-cadina-1(6),4-diene and myrcene; for L3, atractylone, myrcene and germacrene B; and finally, L4 germacrene B, myrcene and cis-cadina-1(6),4-diene. Correlations between soil- leaf chemical elements such as Al, Ca, Fe, Mg, Mn, N and Si in the different localities were significant with chemical composition of the essential oil of Siparuna muricata; however, correlations between soil and leaf K, P, and Na were not significant. Cluster and NMDS analysis showed high dissimilarity values of secondary metabolites between four localities related with changes in soil- leaf nutrients. Thus, the SIMPER routine revealed that not all secondary metabolites contribute equally to establishing the differences in the four localities, and the largest contributions are due to differences in guaiol, cis-cadina-1(6),4-diene, atractylone and germacrene. Our investigation showed for the first time the influences of altitude and soil- leaf chemical elements in the chemical composition of the EOs of S. muricata.

Influence of High-Calcium Ash Composition on the Composite Binders’ Properties

2021 ◽  
Vol 316 ◽  
pp. 1019-1024
Author(s):  
O. A. Ignatova ◽  
A. A. Dyatchina
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Cement Stone ◽  
Normal Density ◽  
Fine Aggregate ◽  
Equivalent Amount ◽  
High Calcium ◽  
Composition Structure ◽  
Kinetics Of ◽  
Positive Effect

The paper presents the studies’ results of chemical composition, structure, and physico-mechanical properties of high-calcium ashes from the Kansk-Achinsk coals (2017-2019 selection). It was found that ash has a complex poly-mineral composition and contains hydraulically active minerals and oxides of СаОfr, β-C2S, CA, C3A, C4AF, C2F, CaSO4. According to the content of CaOfr, MgO does not meet standards’ requirements. The uniformity of the volume change is maintained by the composition with 50% of cement. The structure and hardening kinetics of ash and ash-cement stone compositions, obtained from the test of normal density, were analyzed. It was established that the hardening of compositions with ash from the Kansk-Achinsk coals was largely influenced by ash minerals. An equivalent amount of cement in composite binders cannot be replaced. In order to obtain a positive effect, compositions with ash instead cement of no more than 30% and a part of fine aggregate, without exceeding the ratio of ash: cement = 1: 1, should be used.

scholarly journals Relationship between the Optical Properties and Chemical Composition of Urban Aerosol Particles in Lithuania

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Julija Pauraite ◽  
Kristina Plauškaitė ◽  
Vadimas Dudoitis ◽  
Vidmantas Ulevicius
Keyword(s):  
Optical Properties ◽  
Chemical Composition ◽  
Organic Aerosol ◽  
Single Scattering ◽  
Chemical Compositions ◽  
Spectra Analysis ◽  
Average Value ◽  
Aerosol Mass ◽  
In Situ Investigation

In situ investigation results of aerosol optical properties (absorption and scattering) and chemical composition at an urban background site in Lithuania (Vilnius) are presented. Investigation was performed in May-June 2017 using an aerosol chemical speciation monitor (ACSM), a 7-wavelength Aethalometer and a 3-wavelength integrating Nephelometer. A positive matrix factorisation (PMF) was used for the organic aerosol mass spectra analysis to characterise the sources of ambient organic aerosol (OA). Five OA factors were identified: hydrocarbon-like OA (HOA), biomass-burning OA (BBOA), more and less oxygenated OA (LVOOA and SVOOA, respectively), and local hydrocarbon-like OA (LOA). The average absorption (at 470 nm) and scattering (at 450 nm) coefficients during the entire measurement campaign were 16.59 Mm−1 (standard deviation (SD) = 17.23 Mm−1) and 29.83 Mm−1 (SD = 20.45 Mm−1), respectively. Furthermore, the absorption and scattering Angström exponents (AAE and SAE, respectively) and single-scattering albedo (SSA) were calculated. The average AAE value at 470/660 nm was 0.97 (SD = 0.16) indicating traffic-related black carbon (BCtr) dominance. The average value of SAE (at 450/700 nm) was 1.93 (SD = 0.32) and could be determined by the submicron particle (PM1) dominance versus the supermicron ones (PM > 1 µm). The average value of SSA was 0.62 (SD = 0.13). Several aerosol types showed specific segregation in the SAE versus SSA plot, which underlines different optical properties due to various chemical compositions.

scholarly journals Thermokarst lake waters across the permafrost zones of western Siberia

2014 ◽  
Vol 8 (4) ◽  
pp. 1177-1193 ◽  
Author(s):  
R. M. Manasypov ◽  
O. S. Pokrovsky ◽  
S. N. Kirpotin ◽  
L. S. Shirokova
Keyword(s):  
Western Siberia ◽  
Chemical Elements ◽  
Chemical Compositions ◽  
Thermokarst Lakes ◽  
Thermokarst Lake ◽  
Surface Areas ◽  
Discontinuous Permafrost ◽  
Latitudinal Position ◽  
Hydrochemical Composition ◽  
Lake Waters

Abstract. This work describes the hydrochemical composition of thermokarst lake and pond ecosystems, which are observed in various sizes with different degrees of permafrost influence and are located in the northern part of western Siberia within the continuous and discontinuous permafrost zones. We analysed the elemental chemical composition of the lake waters relative to their surface areas (from 10 to 106 m2) and described the elemental composition of the thermokarst water body ecosystems in detail. We revealed significant correlations between the Fe, Al, dissolved organic carbon (DOC) and various chemical elements across a latitude gradient covering approximately 900 km. Several groups of chemical elements that reflect the evolution of the studied water bodies were distinguished. Combining the data for the studied latitude profile with the information available in the current literature demonstrated that the average dissolved elemental concentrations in lakes with different areas depend specifically on the latitudinal position, which is presumably linked to (1) the elements leached from frozen peat, which is the main source of the solutes in thermokarst lakes, (2) marine atmospheric aerosol depositions, particularly near the sea border and (3) short-range industrial pollution by certain metals from the largest Russian Arctic smelter. We discuss the evolution of the chemical compositions observed in thermokarst lakes during their formation and drainage and predict the effect that changing the permafrost regime in western Siberia has on the hydrochemistry of the lakes.

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