Carbonates - Science topic

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.

Thank you very much

This is now an old question. What did you do? How satisfactory was it? Vogel's Quantitative Inorganic analysis also has a titration method

Use an alkaline system with sodium hydroxide and sodium sulfide. Thank you.

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 , 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...?

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.

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.

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

Hi! There is a clumped lab in ATOMKI, Debrecen, Hungary. Check it out.

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.

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.

Thanks a lot @Vladimir Khlebnikov

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

thank you Hayder Ibrahim Mohammed

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.

Emmanuel Etim Okon Abdulhussien Alattabi Arezoo Agharezaei

Thank you so much for your help

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.

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.

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.

Dr. Alessandro Verdecchia

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.

Vaibhavi Savalia

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.

May I recommend the following book: ISBN: 978-3-642-68423-4

Author: Erik Flügel (1982)

Institut für Paläontologie Universität Erlangen-Nürnberg, Erlangen, Germany

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.

Patch Reef Planktonic Foraminifera Microfacies Type Facies Belt Facies Zone

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

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.

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.

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

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,

Yes, that seems manageable Dalibor Matýsek. I will go with the titration process. Thankyou.

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.

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.

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.

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

it depends, for me i use Propanol as internal standard on quantitative determination of ethanol in biological matrices,

Yes I am gona say that the limestone with older geologic age its probbability to converted to dolomite increases.

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

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.

Dear Sarawut Chanthinok, the following document and the references therin deals with the case of the influence of carbonates concentration. My Regards

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.

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?

None!

See

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.

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

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.

What the books told us about this subject are out of date. Today, suspended particles includes plastics and denim material from old decayed jeans.

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

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.

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

Dear Dr. Muhammad Bilal,

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

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

Thank U! In fact, I already found that software, but I can not afford it. Anyway have a good day :-)

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.

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.

In case you are dealing with CaO powder; you may consider to pelletize the powder: https://www.researchgate.net/post/which_binder_can_be_used_for_making_pellets_of_snail_shell_based_CaO_powder_and_what_will_b_ethe_method_of_it

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.

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. 😊

This paper could be of great help, especially, to differentiate between

oilfield decline rates and depletion rates:

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.

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

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.

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

About predicting the pH of (pure) Na₂SO₄ aq. solutions; see: https://www.researchgate.net/post/What_do_you_call_the_electrolyte_of_sodium_sulfate_a_base_an_acid_or_neutral

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.

Dear Rizwan Hameed,

Can you explain your question in more detail?

Do you look for an analytical relationship or an empirical one?

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."

Also please have a look at the following relevant article:

In this paper "After cooling, under N2 flow, the samples were washed with distilled water up to pH 7 and dried at 100 °C."

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.

Hello 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

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

You can find downloadable 3D models produced with microCT there:

conodonts: https://skfb.ly/6MIGr

Rugosa coral: https://skfb.ly/6ooZ8

Brachiopod shell: https://skfb.ly/6nnDz

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)