Formation of saponite by hydrothermal alteration of metal oxides: Implication for the rarity of hydrotalcite

2019 ◽  
Vol 104 (8) ◽  
pp. 1156-1164
Author(s):  
Qi Tao ◽  
Qingjin Zeng ◽  
Manyou Chen ◽  
Hongping He ◽  
Sridhar Komarneni
Keyword(s):  
Metal Oxides ◽  
Carbon Cycling ◽  
Hydrothermal Alteration ◽  
Chemical Stability ◽  
Negative Charge ◽  
Solid Phase ◽  
Isomorphous Substitution ◽  
Metal Availability ◽  
The Earth ◽  
High Concentrations

AbstractConversion of hydrotalcite (Ht) to saponite was observed by hydrothermal alkaline alteration of metal oxides. The conversion was through a pathway of hydration-dissolution-precipitation. It involved several critical steps, including the construction of Ht from metal oxides, dissolution of Al3+ from Ht, condensation of metasilicate anions with Ht, and finally crystallization of saponite. The condensation was favored by relatively low Mg/Al ratios of Ht, along with high concentrations of Al3+ and silicate oligomers in the environment, resulting in highly crystalline saponite. The latter conversion was greatly accelerated by the isomorphous substitution of Al3+ for Si4+ in silicate oligomers. The substitution generated the extra negative charge and led to the aforementioned condensation with Ht surface, thereby promoting the formation of saponite TOT layers. During the process, CO2 is an indispensable component. Initially intercalated as CO32− to form Ht, CO2 was subsequently eliminated from the solid phase, and saponite formed when the layer charge was reversed. Thus, this study presents a novel formation mechanism of saponite from metal oxides via hydrotalcite and contributes to a better understanding of the crystallization, chemical stability, and transformation of Ht to saponite. The results are also relevant to evaluating metal availability and carbon cycling on the surface of the Earth.

scholarly journals High and specific diversity of protists in the deep-sea basins dominated by diplonemids, kinetoplastids, ciliates and foraminiferans

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Alexandra Schoenle ◽  
Manon Hohlfeld ◽  
Karoline Hermanns ◽  
Frédéric Mahé ◽  
Colomban de Vargas ◽  
...  
Keyword(s):  
Carbon Cycling ◽  
Deep Sea ◽  
Trophic Levels ◽  
Earth System ◽  
Parasitic Species ◽  
Unicellular Eukaryotes ◽  
The Earth ◽  
Dna Metabarcoding ◽  
Global Carbon ◽  
Pelagic Communities

AbstractHeterotrophic protists (unicellular eukaryotes) form a major link from bacteria and algae to higher trophic levels in the sunlit ocean. Their role on the deep seafloor, however, is only fragmentarily understood, despite their potential key function for global carbon cycling. Using the approach of combined DNA metabarcoding and cultivation-based surveys of 11 deep-sea regions, we show that protist communities, mostly overlooked in current deep-sea foodweb models, are highly specific, locally diverse and have little overlap to pelagic communities. Besides traditionally considered foraminiferans, tiny protists including diplonemids, kinetoplastids and ciliates were genetically highly diverse considerably exceeding the diversity of metazoans. Deep-sea protists, including many parasitic species, represent thus one of the most diverse biodiversity compartments of the Earth system, forming an essential link to metazoans.

scholarly journals Fe3O4@C Nanoparticles Synthesized by In Situ Solid-Phase Method for Removal of Methylene Blue

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 330
Author(s):  
Hengli Xiang ◽  
Genkuan Ren ◽  
Yanjun Zhong ◽  
Dehua Xu ◽  
Zhiye Zhang ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Solid Phase ◽  
Raw Materials ◽  
Phase Method ◽  
Maximum Adsorption Capacity ◽  
High Catalytic Activity ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
High Concentrations

Fe3O4@C nanoparticles were prepared by an in situ, solid-phase reaction, without any precursor, using FeSO4, FeS2, and PVP K30 as raw materials. The nanoparticles were utilized to decolorize high concentrations methylene blue (MB). The results indicated that the maximum adsorption capacity of the Fe3O4@C nanoparticles was 18.52 mg/g, and that the adsorption process was exothermic. Additionally, by employing H2O2 as the initiator of a Fenton-like reaction, the removal efficiency of 100 mg/L MB reached ~99% with Fe3O4@C nanoparticles, while that of MB was only ~34% using pure Fe3O4 nanoparticles. The mechanism of H2O2 activated on the Fe3O4@C nanoparticles and the possible degradation pathways of MB are discussed. The Fe3O4@C nanoparticles retained high catalytic activity after five usage cycles. This work describes a facile method for producing Fe3O4@C nanoparticles with excellent catalytic reactivity, and therefore, represents a promising approach for the industrial production of Fe3O4@C nanoparticles for the treatment of high concentrations of dyes in wastewater.

Measurement of Plasma 1,25 Dihydroxyvitamin D Using a Novel Immunoextraction Technique and Immunoassay with Iodine Labelled Vitamin D Tracer

1997 ◽  
Vol 34 (6) ◽  
pp. 632-637 ◽  
Author(s):  
W D Fraser ◽  
B H Durham ◽  
J L Berry ◽  
E B Mawer
Keyword(s):  
Vitamin D ◽  
Solid Phase ◽  
Plasma Concentrations ◽  
Sample Volume ◽  
Cross Reactivity ◽  
Regression Equations ◽  
Vitamin D Metabolites ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
High Concentrations

We evaluated a novel assay for the measurement of 1,25 dihydroxyvitamin D (1,25 (OH)2D). Immunoextraction of 1,25 (OH)2D is performed using a mini column containing a solid-phase monoclonal antibody followed by radioimmunoassay (RIA) using an 125I-labelled 1,25 (OH)2D derivative tracer and Sac-cell separation. The mean recovery of 1,25(OH)2D3 was 101%, linearity was excellent, inter- and intra-assay coefficients of variation were 9, 8 and 13% and 11, 10 and 14% at low, medium and high concentrations of 1,25(OH)2D3, respectively. The cross-reactivity of vitamin D metabolites was <0·0015% for 25-hydroxyvitamin D3, 24, 25 dihydroxyvitamin D3 and dihydrotachysterol and 0·54% for lα calcidol. 1,25 dihydroxyvitamin D2 cross-reactivity was 79%. The detection limit of the assay was 5pmol/L. Comparison with a commercial radio receptor assay (RRA) and an in-house RIA gave regression equations of y = 0·94x+11·8 ( r = 0·98) and y = 0·91x-1·7 ( r = 0.95), respectively, with no major discrepancies between the methods in all patient groups studied. Plasma concentrations of 1,25 (OH)2D obtained with the assay were as follows: normal, unsupplemented subjects: mean 88, range 48–155 pmol/L, n = 68, patients with chronic renal failure: mean 11, range 3–36 pmol/L, n = 27, primary hyperparathyroidism: mean 198, range 130–299 pmol/L, n = 23, Paget's disease: mean 92, range 42–149 pmol/L, n = 24, osteomalacia: mean 43, range 27–61 pmol/L, n = 9. A minimum sample volume of 300 μL is required, the hands-on time is significantly less than other commercial assays and the measuring procedure is gamma counting rather than scintillation counting. The assay offers several advantages over previous methods and should allow more laboratories to offer measurement of 1,25 (OH)2D as part of their repertoire.

Effects of Soybean Pectin Gel on Flavor Compounds Variation of Cheddar Cheeses during Ripening

2014 ◽  
Vol 881-883 ◽  
pp. 797-800
Author(s):  
He Liu ◽  
Jun Li ◽  
Ping Geng ◽  
Yu Tang He ◽  
Tao Ma
Keyword(s):  
Volatile Compounds ◽  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Cheddar Cheese ◽  
Flavor Compounds ◽  
Volatile Substances ◽  
Pectin Gel ◽  
High Concentrations

In this manuscript, flavor compounds development of Cheddar Cheese with addition of soybean pectin gel was investigated during ripening. A rapid and simple Solid-Phase Microextraction (SPME) procedure was used for identifying and classifying the volatile compounds. The result showed that addition of soybean pectin gel to cheese had similar flavor profiles with full-fat cheeses. Higher levels of acid volatile compounds and aldehydes were obtained in comparison with experimental cheese. Results simultaneously indicated that experimental cheeses contained high concentrations of volatile amine as soybean pectin gel promoting the volatile substances.

The Use of Edible Plants for Rhizofiltration under Different Hydroponic Conditions

2021 ◽  
Author(s):  
juyeon Lee ◽  
minjune Yang
Keyword(s):  
Raphanus Sativus ◽  
Brassica Campestris ◽  
Solid Phase ◽  
Root Surface ◽  
Edible Plants ◽  
Groundwater Samples ◽  
Ph Conditions ◽  
Uranium Accumulation ◽  
High Concentrations ◽  
Hydroponic Conditions

&lt;p&gt;This study conducted a rhizofiltration experiment for uranium-removal with the edible plants (&lt;em&gt;Lactuca sativa, Brassica campestris &lt;/em&gt;L., &lt;em&gt;Raphanus sativus &lt;/em&gt;L., and &lt;em&gt;Oenanthe javanica&lt;/em&gt;) which generally consumed in South Korea. Various batch experiments were performed with different initial uranium concentrations, pH conditions, and genuine groundwater. The results showed the uranium accumulation and bioconcentration factor (BCF) of plant roots increase with an increase in initial uranium concentrations in the solution. Of the four plants, the amount of uranium accumulated in &lt;em&gt;Raphanus sativus &lt;/em&gt;L. roots was 1215.8 &amp;#956;g/g DW with the maximum BCF value of 2692.7. The BCF value based on various pH conditions (pHs 3, 5, 7 and 9) of artificial solutions was highest at pH 3 for all four plants, and the BCF value of &lt;em&gt;Brassica campestris &lt;/em&gt;L. was the maximum of 11580.3 at pH 3. As a result of rhizofiltration experiments with genuine groundwater contaminated with uranium, the BCF values of &lt;em&gt;Raphanus sativus &lt;/em&gt;L. were 1684.7 and 1700.1, the highest among the four species, in Oesam-dong and Bugokdong groundwater samples with uranium concentration of 83 and 173 &amp;#956;g/L. From SEM/EDS analysis, it was confirmed that uranium in contaminated groundwater was adsorbed as a solid phase on the root surface. These results demonstrate that &lt;em&gt;Raphanus sativus &lt;/em&gt;L. not only has a high tolerance to high concentrations of uranium and low pH conditions but also has a remarkable potential for uranium accumulation capacity.&lt;/p&gt;

Highly sensitive assays of autoantibodies to thyroglobulin and to thyroid peroxidase.

1989 ◽  
Vol 35 (9) ◽  
pp. 1949-1954 ◽  
Author(s):  
K Beever ◽  
J Bradbury ◽  
D Phillips ◽  
S M McLachlan ◽  
C Pegg ◽  
...  
Keyword(s):  
Solid Phase ◽  
Protein A ◽  
Cross Reactivity ◽  
Thyroid Peroxidase ◽  
Scatchard Analysis ◽  
Thyroid Autoantibodies ◽  
Serum Samples ◽  
Highly Sensitive ◽  
Phase Protein ◽  
High Concentrations

Abstract These highly sensitive assays are based on the interaction between thyroid autoantibodies and 125I-labeled autoantigens. Serum samples are incubated with labeled thyroid peroxidase (TPO) or thyroglobulin (Tg) to allow the formation of antibody-labeled antigen complexes. The complexes are then precipitated by addition of solid-phase Protein A. In the presence of high concentrations of TPO antibody or Tg antibody, more than 50% of the respective labeled antigen was precipitated, whereas only 1-2% was precipitated in the absence of autoantibody. Interassay CVs were 3.2% and 5.7%, respectively, for the anti-TPO and anti-Tg assays. There was no cross-reactivity between Tg antibody and TPO antibody. Results correlated highly significantly with results from other assay systems based on antigen-coated cells or plastic supports, but the assays described here were considerably more sensitive. Scatchard analysis of the assay data provided information on the affinity and serum concentration of TPO autoantibodies (ka approximately 10(9) L/mol and concentrations up to 1 g/L) and Tg autoantibodies (ka approximately 4 x 10(10) L/mol and concentrations up to 1 g/L). Overall, these assays provide a sensitive, precise, and convenient system for measuring and investigating the properties of thyroid autoantibodies.

Organic acid mediated nutrient extraction efficiency in three calcareous soils

Soil Research ◽  
2009 ◽  
Vol 47 (2) ◽  
pp. 213 ◽  
Author(s):  
Z. Khademi ◽  
D. L. Jones ◽  
M. J. Malakouti ◽  
F. Asadi ◽  
M. Ardebili
Keyword(s):  
Organic Acids ◽  
Organic Acid ◽  
Acid Concentration ◽  
Extraction Efficiency ◽  
Solid Phase ◽  
Calcareous Soils ◽  
Ionic Form ◽  
High Concentrations ◽  
Extractant Solution ◽  
Nutrient Extraction

This study was conducted to evaluate the effects of organic acids on the concentrations of metals and anions in soil solution. Three soils with contrasting CaCO3 contents were extracted with organic acid solutions (citrate and oxalate) of different concentrations for different time periods and analysed for Fe, Mn, Zn, Cu, P, and Ca. The soils showed a significant change after the addition of the organic acids to the soil. The mobilisation of metals from the solid phase was dependent on concentration and ionic form of organic acid. High concentrations of citric acid were more effective than oxalate in mobilising Ca, Fe, Mn, and Zn. Overall; oxalate was slightly more effective than citrate in mobilising P. Generally, the higher the organic acid concentration of the extractant solution, the greater was the amount of elements extracted from the soil. Citrate tended to be more effective than oxalate at mobilising elements from the soil. All pH changes were dependent on organic acid concentration.

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