Humic Acid

CONTACT

I no longer work in this field and therefore do not respond to inquiries or comments (15 January 2023)

DISCLAIMER:

I endeavour to answer contacts within two weeks since this is a free service. Answers are given to the best of my knowledge and skills. The field of humic and fulvic acids has many deficiencies and therefore controversies. Any contact for help or information is based on the understanding that I accept no liability for responses.

19 Comments »

  1. Hi,
    Your site is very interesting. I have been working with both humic and fulvic acid and I was wondering if it is possible to convert humic acid into petroleum? Since it is a precursor to petroleum and crude oil, then would a simple decarboxylation reaction form petroleum by-products in the humic acid?

    How would this be accomplished? Is this a chemical reaction or can it be done using microbials?

    Thanks and a reply will be appreciated!

    Regards,
    Marc

    Comment by Marc Rodriguez — 2009 @ 11:45 am

    • Hello Marc
      For some unknown reason I missed your comment and questions. The simple answer to your questions is: “No, humic acids cannot be decarboxylated to form petroleum”. The reason for this is that there appear to be thousands of different polymeric structures, and only some can give petroleum. I actually tried these experiments. Heating humic acids with a mixture of sodium hydroxide/calcium oxide at 220-250 deg C readily decarboxylates humic acids, but petroleum is not formed. In my opinion the correct polymers need to be formed in the first place. In nature petroleum is formed from the polymers that form from algae, while coal is formed from the polymers that form from plants. In theory the correct polymers can be produced under controlled conditions, but this would require a major research effort.

      Reacting humic acids with n-butanol/sulfuric acid followed by solvent extraction or chromatography gives small amounts of oily compounds that are similar to oils obtained from petroleum.

      Regards

      Michael

      Comment by humicacid — 2009 @ 11:12 am

  2. Hi,

    Your site is very interesting. I separating humic acid from soils to study interaction of pesticides with humic acid in order to understand the retention of pesticides on soil and thereafter their degaradation behaviour. Is it neccessary to pass the extracted humic acid through DOWEX resin for its purification? If it is what is its eluant? I lack exact methodology for purification.

    Waiting for you reply.

    Thanks
    Regards
    Anirudh

    Comment by Anirudh — 2009 @ 3:16 pm

    • Hello Anirudh

      Since you are want to determine the degradation of pesticides with humic acids in soil, I suggest that you do not purify the humic acid. The reason for this is that you may obtain results for pure humic acid that are not relevant to soil situations, i.e. it may be too pure. In soils humic acid is complexed to many substances (including clay and metal ions) and this “mixture” determines its properties, which will be different to pure humic acid. However, if you wish to obtain very pure humic acid, this is the procedure that I have used:
      1. Extract soil with 0.1 M sodium hydroxide and separate the liquid
      2. Filter through a 0.4 micron filter to remove particles that will recombine with humic acids in the next step
      3. Adjust pH to ~1 with hydrochloric acid
      4. Extract with n-butanol
      5. Evaporate n-butanol under vacuum with heating

      I have never used the Dowex method for humic acids, but I have used the XAD-7 method for fulvic acids which requires ethanol or ethanol/ ammonia for elution.

      Regards

      Michael

      Comment by humicacid — 2009 @ 4:50 pm

  3. Vuestro procedimiento para separar acidos humicos es el mismo para separar de la loombriz de tierra Eisenia foetida.
    Muchas gracias

    Comment by socorro — 2009 @ 12:33 am

    • Por favor deme detalles de su procedimiento.

      Comment by humicacid — 2009 @ 12:19 pm

  4. Dear Mr Susic

    We have started the fabrication of a Sodium/Potaasium Humate planr and after fabricating close to 80 % we realised that the leonardite deposits in our region have been depleted due to extensive purchase by other factories..now only low grade leonadite with about 30 % humic acidn is available as opposed to 65% earlier….and the prices of this low scale product have also gone very high…….we do have plenty of low grade lignite available……is there any process to recover humic acid from this besides the russian process of grinding the low qua;ity lignite to 200 mesh and than adding 4 to 8 parts water and 4 % nitric acid , mixing and heating it to 200 degrees centugrade , than cooling it ???????

    Regards

    Tariq Gondal

    Comment by Mineral Valley Pvt Ltd — 2009 @ 10:40 pm

    • Hello Tariq

      Nitric acid is ideal for oxidising lignite to humic acid. Allowing the lignite to oxidise in air by allowing it to stand for 1 yr is also used.

      The extraction process also has a big influence on the recovery. After adding the sodium/potassium hydroxide, allow the mixture to stand for 1-2 days with agitation to obtain better extraction efficiency. Repeating the extraction two or three times will also increase the recovery.

      Regards

      Michael

      Comment by humicacid — 2009 @ 3:03 pm

  5. Acabo de leer sus trabajos y me alegro mucho saber un poco de su vida, lo felicito por sus bellos trabajos, son propios de la inspiración del alma humana pura. le agradesco por haber inspirado trabajos sobre las substancias húmicas.
    Grato
    N.M. Rodrigo Leygue-Alba
    NUBITECH RS Brasil

    Comment by rodrigo leygue-alba — 2009 @ 5:28 am

    • Hello Rodrigo

      I will reply in Spanish with my personal email.

      Regards

      Michael

      Comment by humicacid — 2009 @ 7:57 pm

  6. METHOD OF HUMIC ACID 985

    Comment by NITIN — 2009 @ 4:08 am

  7. Hi Michael,
    I know to extracted acid humic from peat,we can use potassium, but I want to do it with smaller price so I use CaCO3, but there is a insoluble humate salt, can I use that insoblue humate for agriculture? could you give me the method to make soluble humate from peat with cheaper price ?

    Regards,

    Comment by Vinh Phuc — 2009 @ 4:26 pm

    • Hello Vinh Phuc
      Soluble humates can only be made with ammonium, potassium and sodium hydroxides. Insoluble humates are not useful. I have previously described how to make potassium humate, and ammonium humate can be made in the same way. Peat usually contains a large amount of humic acid, which is slighltly soluble in water and is a good long-term sustainable source of humate. Peat may also contain fulvic acid, which is water soluble, so raw peat may be the cheapest way to go.

      Regards

      Michael

      Comment by humicacid — 2009 @ 1:01 pm

  8. Hello Mr.Susic
    I am a master’s degree student in chemistry at Hacettepe University (in Turkey)
    I have been researching about humic acid for a month and also, reading your wordpress site for few days. (it was really helpful)
    Our team (at school) mainly use Hansen solubility program and parameters before experiments. As we know, humic acid structure and formula is very complex so i could not find Humic Acid SMILES or InCHl input to calculate solubility parameter on Hansen Program.
    How can i calculate (δ) parameters of humic acid?
    Regards,
    Burcu

    Comment by Burcu — 2009 @ 12:19 am

    • Hello Burcu
      This is an important question and I want to answer it in detail, for your benefit and also the benefit of researchers working in the humic and fulvic acid fields.

      Hansen solubility parameters were developed as a way of predicting if one material will dissolve in another and form a solution. There are 3 parameters:
      (i) The energy from dispersion forces between molecules
      (ii) The energy from dipolar intermolecular force between molecules
      (iii) The energy from hydrogen bonds between molecules

      From these parameters the relative energy difference (RED) of the system is calculated, and if:
      RED 1 the system will not dissolve

      (taken from https://en.wikipedia.org/wiki/Hansen_solubility_parameter)

      This system cannot be used for humic or fulvic acids because there are many different polymers that each slowly change their structure differently depending on their concentration and the solvent that they are being exposed to. There are two important structures that mitigate such change (taken from “STRUCTURE AND ORIGIN OF HUMIC ACIDS AND THEIR RELATIONSHIP TO KEROGEN, BITUMEN, PETROLEUM AND COAL” at https://humicacid.wordpress.com/2011/03/02/from-humic-acids-to-petroleum/)

      Refer to Figure 6. Dehydration of a humic acid gem-diol group.

      Refer to Figure 8. Structure of the conjugate chelate carbonyl group.

      In the solid state the conjugate chelate carbonyl group (Fig. 8) has such powerful intra-molecular forces that only a strong ionic solution such as aqueous sodium hydroxide can break these bonds. However, when excess acid is added to the aqueous hydroxide solution this structure appears to convert to diketo groups. The gem-diol group (Fig. 6) possibly also converts to the keto group, and these molecules can now be extracted with a less polar solvent such as n-butanol. When the n-butanol solution is partially evaporated and an even less polar solvent such as chloroform is added in excess, some of the molecules change to produce more diketo and keto groups in their structure and dissolve in the chloroform. If the process is repeated with carbon tetrachloride and then n-hexane, some of the molecules also dissolve in these solvents.

      This means that some humic acid molecules can change their structure from being soluble in all solvents from aqueous sodium hydroxide to n-hexane. Others will be soluble in solvents with polarity up to carbon tetrachloride, others up to chloroform, others to ethyl acetate, and all to n-butanol. I am not aware of any other known compound that is able to do this. Therefore, humic acids act like a “living molecule”, and energy from dispersion forces, dipolar intermolecular forces and hydrogen bonds cannot be calculated.

      The Organic Chemistry principles behind this are very technical and complex, and it appears that researchers in the field of humic and fulvic acids have not picked this up, even though I published it in December 2003. Therefore, some time in the future I intend to present this clearly in a separate article since I believe that it is the key to unlocking the enigma of humic and fulvic acid structure.

      Regards

      Michael

      Comment by humicacid — 2009 @ 8:32 pm

  9. Hello sir,

    Your knowledge on humic acid has cleared many of my doubts. Thank ypu very for that. I am working on Shilajit and extraction of Humic and fulvic acid from Shilajit. Extracting Humic acid is not a problem but its analysis and characterization is. I am working in the field of pharmacognosy and need a thin layer chromatographic system for its characterization which we dont have. Also, in case of fulvic acid, whatever method which is suggested is through XAD -8 ion exchange chromatography. But, we do not prefer any such methods, we want solvent solvent fractionation for the same. will you please help me with the same.

    Comment by Shefali — 2009 @ 5:01 pm

    • Hello Shefali

      I recently replied to a similar question, so I have copied relevant information from that answer.

      Thin layer chromatography (TLC) cannot be used for humic or fulvic acids analysis because they simply smear over the plate. Solvent/ solvent extraction depends on a number of factors such as the prior history of the humic or fulvic acids, such as what solvents they have been in, whether they have been dried, etc., so it also cannot be used for analysis.

      These problems occur because there are many polymers that each slowly change their structure differently depending on their concentration and the solvent that they are being exposed to. There are two important structures that mitigate such change (taken from “STRUCTURE AND ORIGIN OF HUMIC ACIDS AND THEIR RELATIONSHIP TO KEROGEN, BITUMEN, PETROLEUM AND COAL” at https://humicacid.wordpress.com/2011/03/02/from-humic-acids-to-petroleum/)

      Refer to Figure 6. Dehydration of a humic acid gem-diol group.

      Refer to Figure 8. Structure of the conjugate chelate carbonyl group.

      In the solid state the conjugate chelate carbonyl group (Fig. 8) has such powerful intra-molecular forces that only a strong ionic solution such as aqueous sodium hydroxide can break these bonds. However, when excess acid is added to the aqueous hydroxide solution this structure appears to convert to diketo groups. The gem-diol group (Fig. 6) possibly also converts to the keto group, and these molecules can now be extracted with a less polar solvent such as n-butanol. When the n-butanol solution is partially evaporated and an even less polar solvent such as chloroform is added in excess, some of the molecules change to produce more diketo and keto groups in the structure and dissolve in the chloroform. If the process is repeated with carbon tetrachloride and then n-hexane, some of the molecules also dissolve in these solvents.

      This means that some humic acid molecules can change their structure from being soluble in all solvents from aqueous sodium hydroxide to n-hexane. Others will be soluble in solvents with polarity up to carbon tetrachloride, others up to chloroform, others to ethyl acetate, and all to n-butanol. I am not aware of any other known compound that is able to do this. Humic and fulvic acids therefore act like a “living molecule”.

      Regards

      Michael

      Comment by humicacid — 2009 @ 5:59 pm

      • Thank you sir, I will definitely try with these solvents.
        Sir, how do I confirm the solid obtained is humic acid as they don’t have particular molecular weight to get their mass done?
        Also, how do I extract fulvic acid from it? And how do I confirm whether what is extracted is fulvic acid or not.
        Please again help me…

        Thanks and regards, Shefali

        Comment by pajwanis — 2009 @ 7:33 pm

      • Hello Pajwanis

        To confirm that your solid is humic acid, please refer to my recent research article that you can read online at: Agronomy 2016, 6, 45;doi:10.3390/agronomy6040045.

        To extract fulvic acids from your humic acid use 1 M hydrochloric acid. However, it would be unusual for your humic acid to contain fulvic acids if the source of your humic acid is soil or Leonardite or similar material because fulvic acids usually occur only in peats and microbial broths, or are converted by proprietary (secret) methods from humic acids.

        Fulvic acids will stick to an XAD-7 or 8 exchange column, while humic acids will not.

        Also, fulvic acids have a fluorescence spectrum with a lower maximum wavelength than humic acids, and much lower fluorescence than humic acids above about 400 nm.

        Regards

        Michael

        Comment by humicacid — 2009 @ 12:22 pm


RSS feed for comments on this post.

Leave a comment

Create a free website or blog at WordPress.com.