I have prepared biochar from mixed wood saw dust at 300 degrees. XRD pattern show sharp peaks at 2-theta = 37.8 , 44.06, 64.38 and 77.5. Does it say anything about presence of calcium carbonate polymorphs?
Dear: Mr. Souradeep Gupta
I try to compare it with calcite (CaCO3) (source: http://www.mindat.org/min-859.html). I think there are 2 peaks of your sample close to calcite peaks, they are 37.8 and 44.06 close to 39.4 and 43.2 separately.
You can make sure and find the others materials which match with your sample.
Thank you.
Thak you Heriansyah. I visited the link in your reply. I agree that some of the peaks are close to aragonite and calcite but since they are exactly not same I am wondering if they belong to other metals/compounds.
Please post your raw data in order to obtain more help. It is difficult to tell from just a few peaks; the whole pattern needs to be examined.
Thank you Dr. Slipper. I have attached the complete XRD plot for the material. EDX did show presence of calcium carbonate in the sample but I am not sure which polymorph is present and at what location in the XRD plot.
This does not look like any calcite polymorphs, not even close to calcite or aragonite. I've tried a Hanawalt search on those listed peaks and not found anything very sensible (gold is the closest !!??). Can you post your raw data, not just an image, then it will be possible to analyse rather than just make guesses from a picture.
Thank you Dr. Slipper. I have attached the XRD of biochar and the parent material i.e. saw dust. Please have a look at your convenience.
Thank you.
Souradeep, thank you for that data.
Disregarding the initial sawdust file as the data are rather poor and concentrating on the biochar 300C - you have about 13% crystallinity. The crystalline material seems to be a cubic phase with a=between 4.05A and 4.08A.
The only two phases that I can suggest are beta- silicon carbide and silver. Silver seems a bit unlikely, so I wonder if it is a result of your grinding process. Did you use carborundum to grind?
Thank you for taking effort and suggesting the peaks. Well, I used mortar-pestle ( made of stone) to grind the char followed by sieving.
From your second photograph, I see that all the peaks of biochar(300) overlap with that of silicon carbide peaks. Presence of silicon compound is very likely. Since the biochar is derived from woody biomass, I would expect presence of calcium, magnesium and iron in it.
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