Science topic

Carbonates - Science topic

Carbonates are in chemistry, a carbonate is a salt of carbonic acid, characterized by the presence of the carbonate ion, CO2− 3. The name may also means an ester of carbonic acid, an organic compound containing the carbonate group C(=O)(O–)2.
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In my lab, we measure clumped isotope on bioapatite carbonates. Our acid reaction is at 70deg.C. We are wondering if anyone knows the acid fractionation value that we need to use or can give me a ref? I only found for 90 and 110deg.C. Thank you!
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Decreased carbonate ions with increased bicarbonate ions reduce pH. But while measuring water quality, we estimate carbonate and bicarbonate ions as one of the parameters and a higher concentration of these ions indicates alkalinity. But how ocean acidification happens when bicarbonate concentration increases.
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I'd say it's just the opposite. The activity ratios of CO3-2, HCO3- and H2CO3* are controlled by the pH value and also by the partial pressure of CO2. It is carbonate equilibria.
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The HR ESIMS of a compound we obtained from natural source seems to exhibit a carbonate adduct. If this has already been reported, please kindly send me the paper.
Best regards,
Remy
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Thank you very much
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I am looking for an alternate method to measure percentage of carbonate impurity from sodium bicarbonate. The specification is <0.23% carbonate. There is a titration method using barium chloride to precipitate the carbonate and back titration for the bicarbonate. This will measure total carbonate/ bicarbonate and also bicarbonate only, in order to calculate the carbonate. I am not sure if this will be sensitive enough for small amount of carbonate, which is less than 0.23%. I try find other ideas or separation with different techniques, for example using ion chromatography, but it seemed that carbonate and bicarbonate not separable by IC by many articles. Any comment and suggested techniques or method for this quantitation. This was originally a project to find alternate method from the USP method using the carbonate apparatus (for sodium bicarbonate) since we have difficulty with the method.
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This is now an old question. What did you do? How satisfactory was it? Vogel's Quantitative Inorganic analysis also has a titration method
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I am looking for a lab methodology that would be suitable to arsenic sequential extraction in carbonates. Many of the papers I find are applied to siliciclastics and the strong acid reagents used can dissolve carbonates, hence yielding erroneous results.
Thanks
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Use an alkaline system with sodium hydroxide and sodium sulfide. Thank you.
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Am making carbonized biomass value chain analysis and for such work, I am calculating carbon footprint.
I would therefore appreciate if anyone can share one (carbon footprint calculator e.g., spreadsheet) with me or direct me to a link/website where I can access one.
Thank you!
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Recently there were published many “comment papers” in valid journals such as Palaeoworld, Geological Journal, Carbonates and Evaporites and ... regarding the larger benthic foraminifera where accurate identifications require a high level of experience and knowledge of their taxonomy, this is the main question who are really the cause of these mistakes and problems?
1- Authors
2- Reviewers
3- Editors
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Hello Mehdi Hadi
I return to your original question/heading/topic of "What makes bad articles". I think that bad articles are ones that do not adequately address the topic/aim/title of their study. That happens in many fields, unfortunately, and it is often quite a good thing that letters and comments are sent in response. If people stay silent, that is because people are lazy but should make an effort to point out the problem(s) with the study/paper. I support this approach and definitely do it myself. To answer your original question - the author(s) should be held responsible for this situation.
That, though, might still mean that it is a good paper and may be thought-provoking and draws responses from readers who have different points of view so I totally support what some - such as Suman Sarkar - have said that comments might actually mean it is a thought-provoking article.
As for transparent reviews, as mentioned by Suman Sarkar ,
Mike Simmons
and Lorenzo Consorti most recently - I can only think that as a reviewer, I like to remain anonymous for most times. I wonder if that would make potential reviewers less likely to accept the task when invited...?
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These specimens were found in carbonate sediments in Tunisia. Kasserine area
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If by ‘contiguous’ you mean as the original ‘paired shells‘, the answer is yes. However, this is most common for burrowing species. For surface dwelling species it is the exception that the two valves stay together upon death. For burrowing species it is quite common.
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In anticline structure carbonate Reservoir of areal extension 31x10 km with 24 to26 degrees. no compartments. And no faces alteration (hydraulic continuty exist) multiple Downhole samples, MDT, and well testing samples were taken the bubble point ranging from 2140 psi in one flank to 2746 psi as average.
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If rock samples from core or cuttings are available, it might be possible to see if the source rock interval is more complex than assumed. Taking samples throughout the interval for geochemical analysis might help. Comparing extracted hydrocarbons to pyrolysis results might be enlightening with regard to fluid prediction.
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Can the inorganic carbon isotopes measured in a sequence of deep-water profiles dominated by black shale be used as a stratigraphic correlation? If the absolute values are affected (possibly more negatively than shallow-water carbonates), can the isotopic trends be correlated?
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I am a bit skeptical. We studied the Early Paleozoic Graptolite Shales which have almost worldwide extension on different continents and which are also of interest as "hot shales" (U) and deposits of a variegated "bunch" of rare metals. Even there facies the changes in this rather homogeneous argillaceous facies did not provide a good platform for a isotope stratigraphy. Chemical elements used as ratios such as V/Cr or NI/Co are in some cases much more enlightening than C isotopes, only.
HGD
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Dear colleagues,
I'm looking for a laboratory that measures clumped isotopes - Δ47. My research interests are carbonate minerals occurring in ultramafic rocks. I plan to reconstruct the formation conditions of various carbonates from ultramafic massifs from the north-east part of the Bohemian Massif. The carbonates were probably formed in both supergene and hydrothermal conditions and I aim to distinguish how these conditions had changed in terms of time and space. I would like to reconstruct magnesite precipitation conditions using clumped Isotope palaeothermometry.
Please let me know if you are open to collaboration and what are possible costs involved. Long-time scientific cooperation is possible :)
Contact me on Researchgate or blazej.cieslik2@uwr.edu.pl
Thanks!
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Hi! There is a clumped lab in ATOMKI, Debrecen, Hungary. Check it out.
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What type of marine carbonate factory is more predictable to be present in here ? what animals were responsible for the formation of the carbonates?
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If we take the facies diagram literally with actual slope deposits downdip from the platform, I will offer some alternative interpretations. In my experience, these are not large platforms and I suspect the stratal geometry is not purely depositional or the basin to shelf correlations are incorrect. Assuming, the correlations are correct, one could argue that the top of cycle 3 would have been flat at the time of deposition and that some uplift and subsidence occurred during the earlier cycles. The variation in facies patterns also argues for episodic changes in subsidence. Looking at the distribution of slope facies one can conclude that all the cycles are aggradational except cycle 2 which shows progradation due to slower subsidence. The overall stacking pattern of the cycles is also consistent with long-term creation of accommodation presumably driven by tectonics. This pattern is similar to the Pennsylvanian-Early Permian subsurface succession of the Midland Basin of Texas. During Ancestral Rockies deformation, middle Pennsylvanian shallow carbonate platforms evolved into the late Pennsylvanian/Early Permian Horseshoe Atoll capped by "pinnacle reefs" surrounded by organic-rich basinal sediments just like cycle 3. Within the Midland basin, direct indications of the adjacent basement tectonics are subtle except adjacent to uplifts. The huge volume of basinal deposits is also a clue that somewhere outside this basin there was an abundant sediment source terrain probably the result of tectonics.
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Dear, I need to prepare carbonate buffer for my ELISA work. It requires the pH of 9.6 to be used. In the ref. method, it is stated that bicarbonate/carbonate buffer is used. However, I ever done ELISA before this time, using just only bicarbonate dissolved in water and it has pH around 8.5. My advisor told me it is the same thinig between the two buffer system but somehow Im eager to know how the two is the same (or different). I already have tried to look for explanation anywhere but im not quite good at chemistry much.
Another question is that I see from "https://www.sigmaaldrich.com/TH/en/technical-documents/protocol/protein-biology/protein-concentration-and-buffer-exchange/buffer-reference-center" and I understand that 0.1 M of bicarbonate/carboante buffer has concentration of bicarbonate and carbonate both equal to 0.1 M. However, when I look into "https://www.aatbio.com/resources/buffer-preparations-and-recipes/carbonate-bicarbonate-buffer-ph-9-2-to-10-6" at pH 9.6 (which can be adjust), it shows that the concentration of those 2 chemicals are not equal but somehow give the summation into 0.1. I wonder which I am misunderstanding the concept. Thank you in advance for the reply ^^"
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The purpose of the alkaline bicarbonate/carbonate buffer is for binding the antigen to the ELISA plate. My understanding is that the alkaline pH is mildly denaturing to proteins, causing exposure of the hydrophobic interior of the protein, which enhances protein binding to the hydrophobic surface of the plate. I don't think the precise recipe is important. The moderately alkaline pH is the important thing.
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I am doing the synthesis of tert-butyl 6-(3-hydroxy-propyl-methy-lamino)quinoline-4-carboxylate, using Cesium carbonate, BINAP, and Pd2(dba)3 and N-methyl-1,3-propanolamine in Toulene.
TLC using different solvents and ratios didn't work out even using column chromatography, so does anyone know how to purify my compound ?
to get rid of Cesium Carbonate, BINAP and Pd2dba3 ?
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Thanks a lot @Vladimir Khlebnikov
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I want to use orbitolinids for the biostratigraphy of a Barremiam/Aptian carbonate platform, to support my chemostratigraphy data. I have used related publications for descriptions and pictures trying to identify the different species, but I would like to have the opinion of an expert to confirm my classification.
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try this new published open access work:
Özcan, E., Yücel, A.O., Erkızan, L.S. et al. Atlas of the Tethyan orthophragmines. Med. Geosc. Rev. 4, 3–213 (2022). https://doi.org/10.1007/s42990-022-00072-1
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I want to know about the carbonization process related to electrospun fiber.
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I need to carbonize the NBR rubber sample. Can anyone explain the formation of graphitic structure from the carbonization of NBR? Is there any mechanism relevant for this formation?
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The yield of carbon will depend on the acrylonitrile (ACN) content of the polymer and is generally quite low (~12% for a 50% ACN NBR). The mechanism is very broadly as described for the manufacture of carbon fibre from polyacrylonitrile. If the Nitrile rubber is carbon black filled, then this will also contribute to the Carbon yield, as might polymeric plasticisers.
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Which method and which function is suitable to be used to get the target?
1. Productivity of single well at a different location in fractured cave carbonate reservoir
2. Productivity of multiple wells at a favorable location in fractured cave carbonate reservoir
Your help will be highly appreciated
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Mass balance calculations require that carbonates with δ13-C < -5 (per mil) contain some carbon derived from the oxidation of organic matter. Given that several negative isotopic anomalies much smaller than that (< -10) are recorded, notably in the Neoproterozoic, is it possible that there is another source for depletion in 13C?
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Carbonate isotopic compositions are largely a reflection of the environment in which they form. Methane oxidation by methanotropic bacteria at the anoxic interface of a stratified water column can contribute isotopically depleted CO2 to the environment where there is an active methane e.g., the Ancient lakes that deposited the Green River Formation or the Lacustrine oils in many Basins in China.
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What kind of carbonate minerals depression is preferrable for Au-bearing sulfides flotation (may be reverse flotation?) for such an ore:
  • quartz - 10-30%
  • feldspar (orthoclase) - 5-40%
  • clay&mica - 20-30%
  • Fe-dolomite&ankerite - 5-60% (!)
  • FeS2 - 1-8%
  • FeAsS - 0,5-3%
  • AsS - 0,2-2%
  • ZnS - 0,1-4%
  • PbS - 0,1-1%
Gold is mainly assotiated with Py and AsPy. There are also 0,5-5,0 mkm particles of electrum. Any advice for effective modern reagents?
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Maria, danke dir für deine Überlegungen! Ich kenne Lev Odysseyevich seit 20. Jahrhundert, noch von der Universität. Es scheint, muss ich ihn wirklich zu diesem Thema beiziehen.
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Hi,
I'm working on Late Cretaceous carbonates in central southern atlas of Tunisia. I think that these are longitidunal sections of Rudists but I need confirmation and a more detailed description.
Thank's
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As previously stated by Stevens and El Hassi, they are rudists. With those sections is not easy to precise genus or species, but in the first picture at the right side, one of the specimens shows a typical reticulate structure of the wall that copuld be usefulo to identify them.
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I have noticed that often bedding planes are not included in discrete fracture network (DFN) for carbonate rocks. Personally I believe that bedding can be an important anisotropy for fluid flow, and theoretically should be added together with the different fracture sets in a DFN. What's the general opinion in the DFN modeling world?
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Ty this link if you don't read it before, please:
Dershowitz, W.S., and P.R. La Pointe. "Discrete Fracture Network Modeling For Carbonate Rock." Paper presented at the 1st Canada - U.S. Rock Mechanics Symposium, Vancouver, Canada, May 2007
In the past, I observed papers using fracture network (DFN) models of anisotropic models (mainly shales), but for carbonates, I did not see any, even the Orinoco Basin is totally covered by carbonates.
Best Regards.
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I have got following answer but bit confused
The total phenolic contents in all samples was calculated the using the formula:
C = c V/m
where, C = total phenolic content mg GAE/g dry extract, c = concentration of gallic acid obtained from calibration curve in mg/mL, V = volume of extract in ml, m = mass of extract in gram.
we have used following procedure
  • 500 μl of the sample was taken in 25 ml volumetric flask. To this, 10 ml of water and 1.5 ml of Folin ciocalteu reagent were added.
 The above mixture was kept for 5 min. and then 4 ml of 20 %sodium carbonate solution was added and the volume was made up to 25 ml with distilled water.
 The mixture was kept for 30 min. and the absorbance of the blue color developed was recorded at 765nm. than graph ploted and we got y=mx+c, from that we got C now
wt of crude drug = 50 g
wt of dried extract = 100 mg
sample is dissolved in 100ml methanol
sample used for assay is 0.5ml
so my question is what is V in our case and what is m in our case.
some time i also find to C = c V DF/m where DF is dilution factor so what is it in our case
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The total phenolic contents in all samples was calculated the using the formula: C = c V/m where, C = total phenolic content mg GAE/g dry extract, c = concentration of gallic acid obtained from calibration curve in mg/mL, V = volume of extract in ml, m = mass of extract in gram.
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I am doing description of the Triassic carbonate description in terms of Diagenesis and facies analysis. where can I find the related paper or book? thanks for your recommendation
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May I recommend the following book: ISBN: 978-3-642-68423-4
Microfacies Analysis of Limestones
Author: Erik Flügel (1982)
Institut für Paläontologie Universität Erlangen-Nürnberg, Erlangen, Germany
Abstract
With the aid of sedimentological as well as paleoecological data, the microfacies types of limestone of various ages can be combined into major types which reflect the depositional and ecological conditions in a certain sedimentary environment. This concept, which was developed on Upper Triassic reef carbonates in the Alpine Mediterranean region (E. Flügel, 1972), was expanded by Wilson (1975) and made more specific for numerous Paleozoic and Mesozoic examples. These Standard Microfacies Types (SMF Types) should, however, not be overrated, although they often prove useful as a basis for discussing depositional environments.
Keywords
Patch Reef Planktonic Foraminifera Microfacies Type Facies Belt Facies Zone
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To Know the Trace elements concentration in carbonate and phosphorite minerals separately.
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Dear Rajeev,
an interesting question, indeed.
There are classical approaches using sequential extractions to separate calcite from FAP. Dolomite, unfortunately, behaves in acidic media more similar to FAP than calcite.
To avoid any contamiantion issues for the TEs (sequential extraction is seldom quantitative), and depending on the number of samples you have, you may think about the application of simple mixing model: Analyse the total TE content of Do-FAP mixtures (formed under the same conditions at one site) with different relative mixing mineral proportions (based phase analysis via XRD or total geochemistry) and estimate the composition of the end-members by extrapolation. Another approach would be La-ICPMS based.
Good luck, interesting topic indeed. Best Michael
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How can carbon quantum dots(CQDs) be distinguished from carbonized polymer dots (CPDs)?
What Characterization techniques help to indicate the type of CDs?
Any guidance is really appreciated.
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The main difference between the two types of nanoparticles you are talking about is the order of the carbon atoms. This order should be able to be distinguished in either XRD or TEM experiments. CQDs will exhibit a multilayer graphitic structure, whereas the CPDs will often resemble more of a crosslinked pattern. The CPDs may also not be fully carbonized, in which case you could exploit their hydrophilic surface properties to separate them and then perform optical analysis.
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I would like to know the toxic effects of Ammonium bi carbonate as a food additives in bakery items especially in biscuits
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When evaluating the toxicological significance of ammonium carbonate and bicarbonate, the thermal decomposition temperatures of both salts are absolutely decisive (for both of them it is stated at about 30-60oC, for ammonium carbonate probably 58oC). In the pastry, some E503 can hardly survive. If a large amount were used, there would be a problem with NH3 emissions, but there is no need to address that trace amount. Using urea to reduce NOx emissions will result in incomparably higher NH3 emissions.
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Hi,
I wonder if it is possible to find natural soil carbonates (calcite, dolomite, etc.), not coming from liming, in soils naturally having a low pH (4-5.5).
Is it possible to find these mineral forms of C in acidic tropical soils?
I am asking because while measuring both total C and inorganic C (after acid dissolution) of tropical soil samples from Indonesia with an Elementar, I sometimes get a gap between the two measurements.
Sometimes the gap is positive (total C > organic C), and other times the gap is negative (organic C > total C !?). Generally, total C is equal to organic C, meaning most samples do not show these confusing 2-way gaps, and suggest the absence of inorganic forms of C.
In both cases, I wonder if discrepancies are just technical (noise), or if the gaps between samples are due to the natural variability of my samples, or in some cases, there could be some carbonates present in those soils (which have a relatively low pH of 4-5).
Best,
Thomas
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Thomas Fungenzi Tough question but i dont think that the carbonates can be found in the acidic soils as it is found or in fact present in the alkaline soils
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Is there any effective way to reconstruct the thermal history of deep carbonate formations?
I know that there is a Δ47/(U-Pb) method, but is this method too harsh for the selection of carbonate samples?
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Hi, very nice question!
If you want to test different scenarios, depending on the scale you work on, vitrine reflectance in OM rich layers combined with a basin modelling analysis can help you to reconstruct the thermal history of a sedimentary unit.
Best,
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I am trying to prepare a bicarbonate buffer for TNBS analysis which requires a 0.1 M bicarbonate buffer of pH 8.5. Most of the chemical suppliers have a reagent of 1 M and of different pH. I have been told that I can use carbonate and bicarbonate to make the buffer using the Henderson-hasselbalch equation, but I am not sure how to calculate exactly how much concentration or volume must be added in order to obtain a specific pH buffer of the same. Can anyone point out the exact process to make the same? Thanks.
[I have also attached the protocol steps for reference.]
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Yes, that seems manageable Dalibor Matýsek. I will go with the titration process. Thankyou.
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What is the effect of increasing carbonate minerals (calcium and magnesium carbonates) on the value of the cationic exchange capacity (CEC) of the soil ?
If calcium carbonate was coated soil particles and its percentage is not less than 25%.
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If the formation of carbonates is of pedogenic origin due to rise in temperature and decline in rainfall then the soils will be moderately to highly alkaline and would lose the productivity even when their CEC is remarkably high.
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Is it permissible to use a soil sample (Bulk Sample) without removing carbonate minerals, organic matter and iron oxides in the mineral examination with a diffracted X-ray device, or by examination with a polarizing light microscope or a scanning electron microscope ?
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No.
Soil scientists follow a specific analytical protocol to get knowledge of the presence of primary and secondary minerals in soil samples. You may refer to Jackson, M. L., Soil Chemical Analysis – Advanced Course, University
of Wisconsin, Madison, USA (Published by the author),
1979, 2nd edn.
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Is it permissible to use a soil sample (Bulk Sample) without removing carbonate minerals, organic matter and iron oxides in the mineral examination with a diffracted X-ray device, or by examination with a polarizing light microscope or a scanning electron microscope ?
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For primary and other minerals petrographic microscope can help but not the scanning electron microscope (SEM). SEM only provides the morphology of minerals not the nature and composition of minerals. For clay minerals XRD can be very useful but it has a altogether a much different analytical protocol with regard to separation of soil particles, saturation with cations and laying on glass slides. Please refer to Jackson, M.L. (1979) Soil Chemical Analysis - Advanced Course. Published by the author, University of Wisconsin, Madison, USA.
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Hello
Is there a modern method to remove carbonate minerals from a soil sample for the purpose of conducting an X-ray examination?
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Hi Layth,
a common way to remove carbonates from a soil sample is a treatment with dilute HCl or H3PO4. You can find other useful information in the attached papers.
My best regards
Michele
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I'm planning to run GC analysis but having difficulties on:
1. whether to use internal standard or not and which one will be best for cyclic carbonates detection
2. How to chose the best capillary column
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it depends, for me i use Propanol as internal standard on quantitative determination of ethanol in biological matrices,
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I don't know much about sedimentology. Two question about carbonate sediment were bothering me in recent studies. Hope you can give me some suggestions or references. Thank you in advance!
Two questions about precambrian carbonates:
Q1: Did Precambrian carbonate sediments often undergo dolomitization after deposition?
Q2: Did Precambrian carbonate sediments (especially dolostone?) usually with high Mn/Sr ratio, and this diagenesis criteria whether or not perfectly fir for the Precambrian carbonate sediments?
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Yes I am gona say that the limestone with older geologic age its probbability to converted to dolomite increases.
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Actually I want to make activated carbon and I have soaked carbonized carbon in NaOH...now if I use filter paper for filtration this powdery mass will stick to it.IS filter paper is right way to do filtration of carbonized carbon?
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At first you have to dilute NaOH by large amount of water. Diluted part have to kept aside for 24 h with out any disturbace. Then activated carbon will settled down now you can decant the supernant from the mixture. Finally activated carbon will seperated from sludge by centrifugation and oven dried
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I've synthesized hyroxyapatite and carbonated apatite and I need these cards ( PDF card #9-432 and PDF card #35-180) to analyze my XRD results. Does anyone know how I can get them?
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Respected Sir,
Kindly find the attachment of JCPDS Card #9-432
For more details refer https://www.icdd.com/ (International Centre for Diffraction Data)
Hope this information is useful.
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why folin–ciocalteu's reagent forms a green color and precipitate from the addition of sodium carbonate
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Dear Sarawut Chanthinok, the following document and the references therin deals with the case of the influence of carbonates concentration. My Regards
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I have a body of water with about pH: 6.8 and alkalinity of about 30 mg/L CaCO3. And I am looking to increase the alkalinity as much at as least to 100 mg/L CaCO3 but without increasing pH level.
I have used sodium carbonate and has increase alkalinity but pH levels as wells, while I need to keep pH at a maximium of 7.
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I wonder how alkalinity can be increased without raising pH. It is the general understanding that adding sodium carbonate would cause an increase in pH.
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Analysis of a carbonate (calcite vein) sample yielded d18O of 6.09 (V-SMOW) and d13C of -4.23 (V-PDB), and only 47 ppm Sr. Stable isotopic data indicate 'mantle signature', while Sr abundance is very low (Sr isotopic ratio is not available yet). Can the sample be of a carbonatite vein? If carbonatite, what could be the reason of its extremely low Sr content? Please suggest me some relevant literature on petrogenesis of such type of carbonatite.
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Carbonatites are rarely only calcite. Is there something else in the vein? What is the host rock? Are there any reaction rims or selvages between the vein and the host rock? Do you have the full composition of calcite?
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Since 1850 59% of atmospheric CO2 emissions have been taken up by terrestrial and marine sinks according to AR6 (see attached image). This amounts to 1430 Gt of CO2. Unlike the terrestrial sink, which is largely permanent (soil organic matter and living biomass), some of the marine sink is transitory. For example, a portion of dissolved CO2 (and the carbonate and bicarbonate is equilibrates with) will offgas when atmospheric partial pressure of CO2 drops, after accounting for the time lags in oceanic circulation.
Do any of you have references to studies that estimate what portion of the marine sink is permanent? This is important when calculating how much excess CO2 (atmospheric plus transitory marine) we need to draw down to solve climate change and ocean acidification. Thank you!
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Dear Colleagues,
I want to synthesize different composite materials by adding different components with desired percentage.
What type of furnace is required for this purpose?
For example, I want to prepare YBCO by adding Yttrium Oxide, Barium carbonate and Copper Oxide.
Please help by discussion.
Thanks and Regards
N Das
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For the synthesis of complex oxides in an air atmosphere, muffle furnaces with high-temperature heaters, for example, silicon carbide (temperature about 1700 C), are usually used. If the synthesis of a complex oxide is to be performed in a protective atmosphere or in hydrogen, a tubular furnace must be used.
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How to reconstruct the history of fluid pressure evolution in carbonate formations in the absence of fluid inclusion data?
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I think these papers could help you;
  1. The Fluid Evolution of Ancient Carbonate Reservoirs in Sichuan Basin and Its Implication for Shale Gas Exploration, August 2021,
  2. Reconstruction of fluid (over-)pressure evolution from sub-seismic fractures in folds and foreland basins, May 2013,
They're available on the ResearchGate Server for download.
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I want to test the phenol content in my plant sample and I have chosen this method:
"One ml of 20% sodium carbonate solution
was added to 1 ml of the phenolic extract and incubated
for 5 min. at room temperature. Then 0.5 ml of Folin
Ciocalteo phenol reagent (1:1 diluted with distilled water)
was added and incubated for 10 min. at room temperature.
Absorbance of the colored solution was read at 735 nm
using a spectrophotometer".
But I noticed later that most protocols call for an FCR ratio of 1:10 or 10%. Why is that? Is my method reliable or should I change it?
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I have come across FCR ratio of 1:10 in some methodologies and I do not think your method is wrong. In my professional opinion, diluting the FCR is merely to have lower absorbance reading. Thus, if you use the same method, but different FCR ratio, you will definitely get different absorbance readings at 735 nm since the FCR are of different concentrations.
What should be of importance to you is expressing the final answer in whatever method you wish to (mg GAE/100 g, etc). So you need to use the same FCR concentration you used on your samples for preparing the calibration curve. If you do this, the results should be statistically close no matter the FCR ratio you have used. The main point is: Maintain the same FCR concentration/ratio for your samples and the calibration curve preparation.
Regards,
Jay
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I am a new researcher in the field of Carbonatite. I have samples from northeastern India I thought it is carbonatite but geochemically it does not show any characteristics of Carbonatite like LREE enrichment and total REE content or (trace element like Ba, Sr).
I didn't get any apatite in petrography but I found spinel, olivine, and tremolite so I think that it might be marble or meta carbonate.
So I need tools to resolve this problem. whether it is carbonatite or not
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I think these papers could help you;
  1. Metacarbonatite or marble? - The case of the carbonate, pyroxenite, calcite-apatite rock complex at Borra, Eastern Ghats, India, January 2002,
  2. The carbonatite-marble dykes of Abyan Province, Yemen Republic: The mixing of mantle and crustal carbonate materials revealed by isotope and trace element analysis, September 2004,
They're available on the ResearchGate Server for download.
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Hi everyone. i am currently conduct an investigation on the flexural properties of the polylactic acid/polypropylene carbonate with the incorporation of 2,4, and 6 wt. % halloysite nanotubes. From my observation, the flexural modulus of the blends reduced when the blends incorporated with 2 wt.% of HNT. however, it increased back when the amount of HNT increased to 4 and 6 wt.%. My question is, why there is inconsistency in term of the patterns of flexural modulus?
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However, in clay composites, the heterogenicity is more and likely less compatibility with the matrix materials. This causes agglomerations which act as impurity and thus cause failure.
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I am interested in the minerals particles suspended in seawater. What are the minerals? Carbonates, silicates, what more? Which clays are the most common? Could someone provide articles related to the study of mineralogical composition in sea water suspension, that is derived from shallow water bottom sediments and from river detritus?
Thanks in advance!
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What the books told us about this subject are out of date. Today, suspended particles includes plastics and denim material from old decayed jeans.
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I am trying to introduce the Folin-Ciocalteu method in the extraction of phenolic contents with NADES. The problem is that when I trying to measure TPC, Folin precipitates, specifically using solvents that contain Choline Chloride, generating a yellow precipitate when the Folin reagent is added (without adding Sodium Carbonate). When I add the Sodium Carbonate, the precipitate is blue. Can this be fixed? Do I have to find another method? Has someone else precipitated the sample by adding Folin-Ciocalteu?
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Hi,
It seems to be the precipitate you get include phosphomolybdate which gives the yellow color to Folin-Ciocalteou’s (FC) reagent. In this case, there are some possibilities. Phosphomolybdate has an affinity to compose coordination complex with ammonium salts. Ionic liquids prepared as DES/NADES with choline chloride as proton acceptor can serve as a quaternary ammonium salt functionality to observe bulky ammonium phosphomolybdate precipitate which is typically insoluble in DI water. This is a possibility since the DES/NADES is formed by quaternary amine salts in this query. You are altering the molecular interactions (primarily H bonding) between the DES components by forming a type of octahedral or tetrahedral coordination complex. You can also break DES structures by diluting them using water or organic solvents.
As another assumption, disrupting the molecular web of DES may cause the loss of solubility for phenolics thus hydrophobic ones can precipitate if they are abundant in your matrix. Folin C reagent conjugated phenolics may form a precipitate and your total phenolic assay may be occurring at the solid phase. Adding Na₂CO₃ and increasing the pH will catalyze the reduction of bound metals thereby color changes could be seen at the precipitate. It would be clarifying to know which constituents and ratio you have in DES formulation, did you directly mix the sample with FC reagent, or did you apply any dilution prior to assay and which matrices are you working on. Another co-eluent from your matrix or DES subunits may also induce this reaction.
By implementing some modification to the technique, accurate results may be acquired. I would try to add organic (EtOH/MeOH) or water dilution steps to experiment to improve the solubility and reducing the amount of choline. Optimize your sample prep for TPC as follow and give a try; 0.1 mL of extract, 7.9 mL DI water, and 0.5 mL of Folin-Ciocalteu reagent. Always use Folin R. considering its expiry date. Confirmatory results could be obtained by performing alternative approaches such as radical introducing (e.g. DPPH, ABTS) or non-redox-based assays such as chromatographic elution and UV monitoring.
Good luck,
Emir
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Standardization of tiamulin was tried using HPLC, mobile phase consisting of acetonitrile and 1 percent ammonium carbonate... The rt was detected at 8.3 based on the gradience, however rt kept changing on subsequent attempts... Could it be due to deterioration of the drug being used?
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variation in the second decimal place of the retention time, such as ±0.02–0.05 min is normal. Can you specify the range in rt change. Furthermore, following article can help you understand the reasons.
Good luck.
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GOR Variation in Fractured Carbonate Reservoir: Different from a sandstone reservoir?
Whether the following statements associated with a sandstone reservoir – will also remain true for a fractured carbonate reservoir?
(A) The gas expels oil from the reservoir formation by means of (a) gas carrying oil with it due to its velocity; and (b) gas driving the oil ahead of an expanding volume of gas.
(B) Since the reservoir pressure gets reduced by the earlier completions, the amount of gas required to expel the same quantity of oil would remain greater; and in turn, the enhanced initial GOR for later completions would result only from the drainage of pressure by the earlier wells.
(C) When the gas acts as the only force that expels the oil from the reservoir-formation, then, the rate of decline of oil production would remain faster than the rate of decline of gas production. Also, an enhanced rate of increase of GOR will always have the greatest decline of oil production.
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I think these papers could help you;
  1. Brine-Dependent Recovery Processes in Carbonate and Sandstone Petroleum Reservoirs: Review of Laboratory-Field Studies, Interfacial Mechanisms and Modeling Attempts, Adedapo Awolayo, Hemanta Sarma, Long Nghiem, November 2018, Energies.
  2. The Geological Characteristics of Reservoirs and Major Controlling Factors of Hydrocarbon Accumulation in the Ordovician of Tazhong Area, Tarim Basin, Haijun Yang, Guangyou Zhu, Yu Wang, Jin Su and Baotao Zhang, June 2014, Energy Exploration & Exploitation.
  3. Major influencing factors of water flooding in abnormally high-pressure carbonate reservoir, Hou Qingying, Chen Kaiyuan, Fan Zifei, Fu Libing, Chen Yefei, January 2017, IOP Conference Series Earth and Environmental Science.
They're available on the ResearchGate Server for download.
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I am making a polymer and using hydrogen peroxide(H2O2) as a catalyst in a reaction. I am also using Sodium Carbonate(Na2CO3) to balance the pH to 7 at the end of the reaction. I am afraid either the hydrogen peroxide or the Sodium Carbonate is causing gas bubbles in my polymer. Maybe both. Would anyone recommend a way to get rid of air bubbles that is cheap and easy? A purifying step? My polymer seems to separate into a watery and oily layer. Even after I centrifuge the watery layer still separates over time. If you have any more questions or suggestions I would love to hear it. Thank you!
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Hi,
If you are sure the reaction stopped and there is no further possibility to continue, then you can try to heat your polymer solution with gentle stirring at 60°C during all nigth. This allows solution viscosity to decrease and bubbles can diffuse from inside to outside.
Another approach is close to the one described by Amit before. Place your solution in a glass filtering vessel and connect it directly to a vacuum pump. Cover the top of the vessel with a rubber stopper (cap) to get a vacuum inside. Be careful with the solution volume that you add to the glass container to avoid the solution goes out during the process.
best wishes,
Gustavo
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I need UCS data conducted on carbonate rocks can anyone refer me to any published and unpublished source. I need the formation and location as well. Of course, I'm searching everywhere but would like to know from expert researchers on this platform. I will be thankful, as I need a lot of Carbonate UCS data for my research.
Thank You all!!
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CO2 is normally isotopically depleted compared to carbonate rocks (e.g. limestone). However, CO2 liberated during decarbonation of carbonate rocks are enriched in both O18 and C13. Why?
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Thank you Dr. Ashraf for directing me to the paper. Actually before putting up the question I have referred to it. But I did not find a suitable explanation to my question. If you can explain, it will be nice.
Regards,
Himadri Basu
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Field emission scanning electron microscopy a powerful diagnostic tool for kidney stone disease ?
Such a diagnostic tool would represent a significant benefit to the clinician.In view of the increase in infection-related stones over the past two decades, Urinary Track Infection must always be considered a significant possible cause of urolithogenesis. In a recent publication, We note the presence of bacterial imprints for kidney stones with a high, but sometimes a low content, of Wk. Thus, we propose FE-SEM as a diagnostic tool for stone patients who have a negative urine culture associated with kidney stones containing less than 20% by weight Wk, a low level of carbonate in apatite, and no struvite.
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I agree with you for the interest of diffraction. In fact, we have used PND in the case of cystine stones to evaluate the role of drugs. There is some limitation regarding XRD like the measurment of the level of carbonate in apatite which may indicate infection. That's why FTIR spectroscopy constitutes the golden standard which is use at the hospital routinely
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Hi. I am looking for ethyl methyl carbonate Hansen solubility parameters.
There is no data in Google.
How can I know the value?
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Thank U! In fact, I already found that software, but I can not afford it. Anyway have a good day :-)
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What's the easy way to separate these compounds? I would be glad if you help
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The results obtained from the variation process of Na2CO3 and K2CO3 indicate that both as bases provide a high yield. The use of K2CO3, which is because Na2CO3 was harder or stronger than K2CO3.
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I have some strange phenomena, usually it well known that ethylene carbonate will be freeze in room temperature, because it melting point is 34 degree celcius. But Why my ethylene carbonate does not freeze in the nearest room temperature?
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Organic liquids are often prone to supercooling (by the way, the melting point of pure ethylene carbonate, according to my data, is about 38.5 C). Very often ethylene carbonate freezes poorly due to poor purity (water impurities, for example). Such a significant deviation of the freezing point of the substance from the table one indicates its bad quality ...
In the overwhelming majority of cases (if we are not talking about very expensive or rare reagents), finding out the reasons for the deviation of the properties of the reagent is unproductive - it is better to find a source of a quality product, otherwise there is a danger of making a series of experiments that have a place in the trash can.
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Hi everyone, I'm looking for a method to obtain max carbonation yield (95 wt.% and more) after gas-solid reaction between CO2 and dense bulk CaO. I can run the reaction up to T=800°C and PCO2=50-60 bar (inside pressurized reactor). But the reaction at 800°C, 60 bar CO2, for 24 hours is not complete (max yield is 80-85 wt.%).
Any suggestion? Add water to CaO (what concentration?), light acidic treatment of CaO (or other chemical treatments), etc...
Thanks
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Please I need a material that clearly explain the quantitative inorganic analysis of a mixture of carbonate and bicarbonate with HCl.
Also the quantitative inorganic analysis of a mixture of sodium carbonate and sodium hydroxide with HCl.
I'm getting negative values for my Mml and Pml respectively.
I need help.
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Generally when the dilute HCL acid reacts with sodium carbonate then sodium chloride, carbon dioxide and water are formed. A brisk effervescence is seen in the release of carbon dioxide.
and as far as the reaction is considered then The excess NaOH is immediately titrated with standard HCl to determine how much HCO3 - was present. From the total alkalinity and bicarbonate concentration, you can calculate the original carbonate concentration.
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Molarity o HCl is 0.1M. Is it possible to have a negative value for Mml ?
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Dear Gideon Ibekwute I think this is a technical question which can be easily answered by searching the general internet. As typical examples please have a look at the following useful links:
1. Experiment on the analysis of a mixture of carbonate and bicarbonate
and
2. Analysis of a Mixture of Carbonate and Bicarbonate
(see attached pdf file)
In any case the procedure involves two titrations.
Moreover I strongly suggest that you should go to your university library and get hold of a textbook on quantitative chemical analysis.
Good luck! 👍
P.S. What is Mml ? According to the link cited below, "Mml" can mean anything from "Michigan Municipal League" to "Mobile Man Lift":
I think you will get more qualified answers to your technical question when you avoid such lab jargon as already indicated by Paul Milham. 😊
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How quickly oil wells reach their ‘maximum daily output’ following their completion - associated with a carbonate reservoir?
How different - the rapidity of decline - will be in a carbonate reservoir - from that of a sandstone reservoir?
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This paper could be of great help, especially, to differentiate between
oilfield decline rates and depletion rates:
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So, I have been doing reactions using both P4S10 and Lawesson's Reagent (LR) as of lately. I have been using a secondary amide, Boc-protected Phenylalanine N-methyl amide. Two literature papers I have been reading, one using LR, K2CO3, and diglyme solvent at 120oC ( ), the other using P4S10, K2CO3, & DCM at 40-50oC ( ), showed rather obviously that the base does not inhibit the reactivity of either thionating agent.
Yet when using my substrate, the base appears to severely depress reactivity. LR in THF at r.t. gave 65% conversion on NMR after 2h. P4S10 did the same in refluxing DCM after 2h. Adding potassium carbonate to both reduced conversion to trace amounts.
The K2CO3 our lab uses has been stored inside a cabinet for several months, flushed with nitrogen, tightly closed, and sealed with parafilm. Are we storing it incorrectly to where it's absorbing too much moisture & thus quenching the thionation agent?
What is more puzzling is that Cs2CO3, which has been stored in a desiccator for longer than I've been in the lab, also totally suppressed LR reactivity. That too has been flushed with nitrogen and wrapped in parafilm.
I also have not been terribly strict about oven-drying my glassware before use, given a plethora of literature using both thionation agents not using solvents that were perfectly dry and still getting acceptable yields. If this was to blame then I would have seen little to no yields w/ no carbonate added.
So, what do I do about this?
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What to do 🤔 hmmmmm.......
I might try climbing up top of the 5th floor of Hunter. ( Yes there are 5 floors.) then get right up to the tallest edge of the building and then go back downstairs while thinking that If you could fly you wouldn't have this problem.
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Dear colleagues,
I am a researcher working with bovine hydroxyapatite. I want to reduce the percentage of carbonate on the sample. Is there any suggested techniques for this? I am measured the carbonate from EDX (SEM-EDX). Thank you
Thank you.
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Dear Maria Apriliani Gani,
These may be addition of impurities, high temperature and environmental conditions can reduce the formation of carbonates.
Bone mineral is not pure hydroxyapatite. The small, plate-shaped (20–50 nm long, 15 nm wide, and 2–5 nm thick) apatite crystals contain impurities, most notably carbonate in place of the phosphate groups. The concentration of carbonate (4–6%) makes bone mineral similar to a carbonate apatite known as dahllite. Other substitutions are potassium, magnesium, strontium, and sodium in place of the calcium ions, and chloride and fluoride in place of the hydroxyl groups.These impurities can reduce the crystallinity of the apatite , and, in doing so, may alter certain properties such as solubility. The solubility of bone mineral is critical for mineral homeostasis and bone adaptation.
Carbonate substitution in apatite each control the crystal’s perfection and crystallite domain size, affecting material properties, in different environmental conditions. High temperature substitution methods indicating a higher energy barrier for the formation of carbonate.
Ashish
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Hello everyone,
We recently adquired a Digiprep block digestion system in our lab and I wonder if it can be used for highly-carbonated soils decarbonization. I have been looking for similar protocols but I had no results.
Thanks in advance and kind regards.
Layla M. San Emeterio
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Just trying this exact same method on our Digi-Prep to remove carbonates from sediment samples for 13C analysis: 100 mg dried sediments, 60 Celsius, 15 hours of reflux, 30 ml HCL in a glass vial with watch glass. Repeat heating cycle with distilled water 3 times to remove acid traces.
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If I have an excess of sodium carbonate and add sulfuric acid to it, which of the following reaction takes place having in count that there is an excess of sodium carbonate?:
1. 2Na2CO3 + H2SO4 --> 2NaHCO3- + Na2SO4 (before the firts equivalente point)
and 2NaHCO3- + H2SO4 --> 2H2CO3 + Na2SO4 (after the firts equivalente point)
2. Na2CO3 + H2SO4 ---> Na2SO4 + H2CO3
This is without having in count that the final products are Na2SO4 + CO2 + H2O because of the descomposition of the carbonic acid.
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It seems advisable to purge (stripping) the titrated solution from dissolved CO2 by sparging N2. The endpoint for the titration of a Na2CO3 aq. with H2SO4 aq. is not expected to be perfectly neutral. For purged titrated solution, is the pH of (pure) Na2SO4 aq. solution.
About predicting the pH of (pure) H2SO4 aq. solutions. ― cf. my posts at: https://www.researchgate.net/post/Do-you-know-a-method-for-titration-of-HNO3-H2SO4-mixtures
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The diagram shows Raman spectra (measured with a blue diode laser at 473 nm) of carbonized polyacrylonitrile (PAN) nanofibers. The fibers were in contact with different metal surfaces during carbonization in nitrogen atmosphere. I wanted to analyze the D and G band intensities but noticed these sharp double peaks at 1000/1040 cm-1 and 1580/1600 cm-1. Can anyone tell me where these peaks are coming from?
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It may be lines from the products of decomposition of PAN nanofibers. PAN fibers have sharp bands at 1456 cm-1 and 2243 cm-1. If you send me spectra, I’ll take a look. The band close to 1000 cm-1 may be aromatic compounds as polystyrene has a strong and sharp Raman band at 1004 cm-1. The easy way is to remove background and D/G bands and run a search over the Raman library.
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It is a general view that carbonation of OPC-based concrete can improve the compressive strength in comparison to reference non-carbonated concrete; carbonation parameters (relative humidity, CO2 exposure time, CO2 concentration/pressure, temperature), concrete porosity, microstructure, and amount of portlandite can affect the results.
There are studies that show improved mechanical behavior after carbonation
Are there studies available that tried to correlate the compressive strength of carbonated and reference non-carbonated concrete, analytical or empirical? So we can assume how much strength would increase after carbonation with certain parameters.
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Can you explain your question in more detail?
Do you look for an analytical relationship or an empirical one?
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What is the best way to wash residual potassium carbonate out of chemically activated carbon? In the literature, washing is mentioned, yet most don't explain how.
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Dear Ayushi Jaiswal thank you for your interesting technical question. According to the research article cited below, hot water is best to remove residual K2CO3 from your activated carbon. In this paper it is stated: "After carbonization, the sample was cooled down under nitrogen (N2) flow and was washed sequentially several times with hot water, and finally with cold distilled water to remove residual chemicals. Thenthe sample was dried at 110°C."
Preparation and characterization of activated carbon from palm shellby chemical activation with K2CO3
Also please have a look at the following relevant article:
Chars from gasification of coal and pine activated with K2CO3: Acetaminophen and caffeine adsorption from aqueous solutions
In this paper "After cooling, under N2 flow, the samples were washed with distilled water up to pH 7 and dried at 100 °C."
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Hello Professors and colleagues
I am trying to draw a detailed Tectonic schematic cross section for a subducting slab focusing mainly on the transformation of shales and carbonates into greenschist facies schist and Thermal skarn overlying this slab .. ... i know that less is known about the 3D imagination of subduction zones and specially what happens to the sediments !
But what is the best schematic model i can follow from your opinion ?
Suggest references or attach your own images would enrich our discussion :)
Thanks in advance
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Dear Ahmed Morad: I understand perfectly what is your proposal. The best way to show how marine sediments get into a subduction zone is to draw a detail of the hinge zone where the oceanic plate bends when foundering inside the mantle. In this hinge zone stretching occurs, and some expansive graben structures are formed (normal faults parallel to the trench), which trap sediments and lead them to subduction. Then those sediments are metamorphosed under high P/T conditions and become phyllites and schists, usually white schists, and even metacherts and fine grained marbles. There is a quite accesible outcrop in a main freeway near the city of Puerto Cabello (north-central Venezuela) of eclogite knockers inside a relatively monotonous micaschist. A close look at thin sections of this schist shows the presence of kyanite, garnet, white mica, and Mg-glaucophane, these are usually called white schists, since the glaucophane is almost colorless and retrogradly altered to talc! Some have carbonate too, and in nearby localities of this same high P terrane there are also metacherts and marbles. So, there's no doubt that some marine sediments are indeed subducted and transformed to high P metamorphic rocks in the subduction complex. Regards, Sebastian.
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I am modelling an extractive distillation of Dimethyl carbonate and methanol using phenol as entrainer on Aspen Hysys V10 but I can’t find dimethyl carbonate amongst the component list
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Hello
Reald Tashi
Rick Manner !
I am simulating the corn stover (Lignocellulosic biomass) for the production of biochemical. My simulation goes very well without any error, but the issue is I am getting a very very higher value of Duty (Q-cal/sec) say 7.89 x 10 ^24, which is something unreasonable, would like to get some pointers on this issue.
Also, I am simulating the process with a mixed stream class in which solids (I,e cellulose, xylan, lignin took as a CIPSD stream).
Do you think I have to do the simulation in a solid template (when we start the aspen plus....we also have a separate category for the solid stream with the metric unit ) ??
Sincerely,
Nirav
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Chemical index of alteration (CIA) is widely used in fine detrital sedimentary rocks for reflecting intension of continental weathering. But, I am wondering that whether carbonate insoluble residues can be used for CIA analysis!?
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Dear Dr. Biao,
these are the common rock-forming minerals in calcareous sediments (main constituents in bold print):
Øcalcite
ØMg calcite (MgCO3= 0 to 6 %; > 11 % at T values > 15°C and higher- up 40 %)
Øferroan calcite (reducing environment)
Ødolomite
Øferroan dolomite/ ankerite (reducing environment, late diagenetic)
Øsiderite (reducing environment, late diagenetic)
Øcollophanite/ hydroxyl-apatite
Øclay minerals (e.g,. illite, smectite, sepiolite, glauconite...)
Øalkaline feldspar
Øsiliceous compounds (derived from spicules, radiolarian tests, diatoms
Øsulfate (gypsum, celestite)
Øhalogenide (halite, fluorite)
Irrespective of the mode of formation, be it detrital or diagenetic you can use the CIA index. But why should you make a step backwards. Minerals like those separated from limestones tell you much more about the weathering regime than a bunch of chemical elements. It needs experience, kowledge and skilfulness, that is true, but you obtain much more information. Those who want to achieve a reliable and detailed information of calcareouus sediments conduct mineralogical and chemical analyses. I myself would sideline studies which try and collect data by chemistry only.
H.G.Dill
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I am preparing a practical course on carbonate petrography so I need CT image datasets or 3d objects (e.g. *.stl) of fossils or fossiliferous limestone, for educational purposes. All efforts are, of course, to be acknowledged. Thanks in advance.
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You can find downloadable 3D models produced with microCT there:
Rugosa coral: https://skfb.ly/6ooZ8
Brachiopod shell: https://skfb.ly/6nnDz
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I am performing a Boc-deprotection with HCl in organic solvent (dioxane or Ethylacetate) but would like to isolate the free amine.
Several problems:
- Neutralizing with inorganic base as NEt3 involves too large amounts as I am using 25 eq of HCl (reaction is too long with less eq)
- Washings with carbonate solution leads to product degradation
Has someone experience of such situation ? Could ion-exchange resins help ? Which one ?
The process has moreover to be upscalable ...
Thanks in advance
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Thank you all for your answer.
Madhukar Baburao Deshmukh : I am currently going this way but massive foaming is difficult to manage.
James E Hanson I will have a look on Nafion. Thanks
Kamil Makowski Product is readily soluble in almost all organic solvents. Problem with this procedure is that I produce impurity both by evaporation (acidic hydrolysis upon heating) and by washing with carbonate (basic hydrolysis)