Humic acid: comprehensive review of production, structure, characterization and applications
Abstract
Humic acid represents an intricate heterogeneous compound of organic compounds of large molecular weight, which are synthesized in protracted soil throughout the humification of plant and animal deposits. This actuarial review in basic to applied approach considers humic acid, definition, sources, production process, structure properties, analytical estimation, physicochemical properties with multifunctional his use in agricultural, industrial and environmental areas etc. higher peat, soil organic materials, leonardite and lignite (80-50%) in ancient deposite of coal. The processes involved in the production consist of the usual alkaline extraction through the natural beds and the recent production processes based on biotechnology which involves a fungal fermentation. Molecularly, the chemical structure of the HAs is an aromatic and aliphatic backbone with functional groups of carboxylic, phenolic, quinone and methoxy functional groups and provides them with chemical characteristics of novel chelating, buffering, and bioactivity. The characterization is conducted analytically with the aid of a series of methodologies such as elemental, UV-visible (E4/E6-ratio), FTIR, NMR, and colorimetric. Part of this is in the form of molecular weights between the 1,700- 6,000Da, amphiphilic as well as pH buffering and metal binding capabilities. Applications Uses Agricultural soil amendments, plant growth bidder, industrial applications- batteries, ceramics, environmental cleanup and cosmetic supplements/ food supplements. The possible effects of limitations to the environment are by affecting the quality of water, cost, regulatory, as well as lack of full knowledge of the ecological effects in the long run. The review gives an overview of the available knowledge covering science and technology of humic acid with of primary concerns of its enhanced sustainable use in the varied fields through highlighting of opportunities and challenges.
Keywords:
Humic acid, Humification, Organic matter, Alkaline extraction, Molecular characterization, Agricultural applicationsDOI
https://doi.org/10.22376/ijpbs.v17i1.161References
1. Steelink, C. (1963). What is humic acid? Journal of Chemical Education, 40, 379. DOI: https://doi.org/10.1021/ed040p379
2. Vašková, J., Stupák, M., Ugurbaś, V., Žatko, D., & Vaško, L. (2023). Therapeutic efficiency of humic acids in intoxications. Life, 13(4), 971. DOI: https://doi.org/10.3390/life13040971
3. Yang, F., & Antonietti, M. (2020). Artificial humic acids: Sustainable materials against climate change. Advanced Science, 7(5), 1902992.DOI: https://doi.org/10.1002/advs.201902992
4. Ampong, K., Thilakaranthna, M., & Gorim, L. (2022). Understanding the role of humic acids on crop performance and soil health. Frontiers in Agronomy, 4, 848621. DOI: https://doi.org/10.3389/fagro.2022.848621
5. De Melo, B., Motta, F., & Santana, M. (2016). Humic acids: Structural properties and multiple functionalities for novel technological developments. Materials Science & Engineering C, 62, 967–974. DOI: https://doi.org/10.1016/j.msec.2015.12.081
6. Nandi, M., Mitra, B., & Ghosh, P. (2024). Humic acid: A rarely explored, robust, green catalyst for solvent-free synthesis of heterocyclic compounds. Research on Chemical Intermediates, 50(4), 1757–1775.DOI: https://doi.org/10.1007/s11164-024-05149-0
7. Souza, A., Olivares, F., Peres, L., Piccolo, A., & Canellas, L. (2022). Plant hormone crosstalk mediated by humic acids. Chemical and Biological Technologies in Agriculture, 9, 1–25. DOI: https://doi.org/10.1186/s40538-022-00345-9
8. Rathor, P., Upadhyay, P., Ullah, A., Gorim, L., & Thilakarathna, M. (2024). Humic acid improves wheat growth by modulating auxin and cytokinin biosynthesis pathways. AoB Plants, 16, plae018. DOI: https://doi.org/10.1093/aobpla/plae018
9. Canellas, L., Olivares, F., Canellas, N., Mazzei, P., & Piccolo, A. (2019). Humic acids increase the maize seedlings exudation yield. Chemical and Biological Technologies in Agriculture, 6, 1–14.DOI: https://doi.org/10.1186/s40538-019-00159-3
10. Chianese, S., Fenti, A., Iovino, P., Musmarra, D., &Salvestrini, S. (2020). Sorption of organic pollutants by humic acids: A review. Molecules, 25(4), 897. DOI: https://doi.org/10.3390/molecules25040897
11. Ke, Y., Zhu, X., Wang, K., Wang, L., Zhou, S., & Zhang, Z. (2025). Role of humic acid on benzo[a]anthracene.DOI: https://doi.org/10.1016/j.envpol.2024.125723
12. Zhang, J., Wang, C., Huang, N., Xiang, M., Jin, L., Yang, Z., et al. (2022). Humic acid–promoted activation of peroxymonosulfate by Fe₃S₄ for degradation of 2,4,6-trichlorophenol. Journal of Hazardous Materials, 434, 128913.DOI: https://doi.org/10.1016/j.jhazmat.2022.128913
13. Wang, Y., Liu, X., & Lu, Y. (2024). Humic acid roles in environmental remediation. Environmental Chemistry Letters.DOI: https://doi.org/10.1007/s10311-024-01685-6
14. Zhu, R., Yan, M., Zhang, Y., Zou, H., Zheng, Y., Guo, R., & Fu, S. (2023). Insights into the roles of humic acids in facilitating the anaerobic digestion process. Waste Management, 168, 25–34. DOI: https://doi.org/10.1016/j.wasman.2023.05.034
15. Tian, K., Zhang, J., Zhou, C., Liu, H., Pei, Y., Zhang, X., & Yan, X. (2023). Revealing the roles of carbonized humic acid in biohydrogen production. Bioresource Technology, 369, 129506. DOI: https://doi.org/10.1016/j.biortech.2022.129506
16. Huculak-Mączka, M., Hoffmann, J., & Hoffmann, K. (2018). Evaluation of the possibilities of using humic acids obtained from lignite in the production of commercial fertilizers. Journal of Soils and Sediments, 18, 2868–2880. DOI: https://doi.org/10.1007/s11368-018-1958-7
17. El-Hameed, H., & Mahgoub, N. (2023). Comparative analysis of humic and fulvic acids extraction and characterization from different organic sources. Sinai Journal of Applied Sciences. DOI: https://doi.org/10.21608/sjas.2023.274181
18. Gusfiyesi, G., Arizon, A., & Efendi, R. (2023). Studi penetapankadarasamhumatdenganmetodegravimetri dan spektrofotometri UV-Vis. SAINTI, 20(2). DOI: https://doi.org/10.24252/sainti.v20i2.34201
19. Khodair, A. A., & El-Rahman, M. H. A. (2021). Foliar application of humic acid on pomegranate trees improves fruit quality. Agricultural Sciences. DOI: https://doi.org/10.3390/agriculture11010030
20. Schwartz, A. (2017). Humic substances in lignite: Extraction and utilization. Fuel Chemistry Journal. DOI: https://doi.org/10.1016/j.fuel.2017.08.028
21. Stevenson, F. J. (1994). Humus Chemistry: Genesis, Composition, Reactions (2nd ed.). John Wiley & Sons. ISBN: 978-0471594741
22. Tan, K. H. (2014). Humic Matter in Soil and the Environment: Principles and Controversies (2nd ed.). CRC Press. ISBN: 978-1466552449
23. Piccolo, A. (2002). The supramolecular structure of humic substances: A novel understanding of humus chemistry and implications in soil science. Advances in Agronomy, 75, 57–134. DOI: https://doi.org/10.1016/S0065-2113(02)75003-4
24. Sutton, R., & Sposito, G. (2005). Molecular structure in soil humic substances: The new view. Environmental Science & Technology, 39(23), 9009–9015.DOI: https://doi.org/10.1021/es050898g
25. Milori, D. M. B. P., Martin-Neto, L., dos Santos, L. F., & Benites, V. M. (2022). Structural heterogeneity and supramolecular behavior of humic substances: An updated perspective. Chemosphere, 307, 135723. DOI :https://doi.org/10.1016/j.chemosphere.2022.135723
26. Shahbazi, M., Yousefian, M., & Rezaee, M. (2019). Innovative approaches for removal of phenolic compounds from water using biosorption and degradation: A review. Journal of Environmental Chemical Engineering, 7(3), 103056. DOI: https://doi.org/10.1016/j.jece.2019.103056
27. Marzi, E., Sebastiani, M., & Stanković, M. (2022). Optimization of spectrophotometric methods for the determination of humic acid in complex mixtures: A comparative study. Talanta, 240, 123054.DOI: https://doi.org/10.1016/j.talanta.2021.123054
28. Lamar, R., & Monda, H. (2022). Quantification of humic and fulvic acids in humate ores, DOC, humified materials and humic substance-containing commercial products. Journal of Visualized Experiments, (178). DOI: https://doi.org/10.3791/63898
29. Francioso, O., Rose, M. T., Morra, M. J., &Quaggiotti, S. (2003). Humic substance effects on plant growth. Soil Biology & Biochemistry, 35(4), 763–770.DOI: https://doi.org/10.1016/S0038-0717(03)00035-7
30. Traina, S. J., Novak, J. M., & Griffis, T. J. (1990). An ultraviolet absorption method of estimating the percentage aromatic carbon of humic acids in sodium hydroxide extracts from organic soils. Journal of Environmental Quality, 19(3), 414–416. DOI: https://doi.org/10.2134/jeq1990.00472425001900030006x
31. Chen, Y., Aviad, T., & Clapp, C. E. (1977). Information provided on humic substances by E4/E6 ratios. Soil Science Society of America Journal, 41(2), 352–358. DOI: https://doi.org/10.2136/sssaj1977.03615995004100020022x
32. Masini, J. C., de Cristóvão, A. C. P., & de Oliveira, D. (1998). Comparison of different analytical methods to determine phenolic hydroxyl groups on humic materials. International Journal of Environmental Analytical Chemistry, 71(3–4), 273–282.DOI: https://doi.org/10.1080/03067319808029436
33. Fukushima, M., Davison, A. W., & Davis, L. C. (1996). Enhancing the removal of toxic compounds by humic substances: Oxidation and precipitation. Chemosphere, 33(7), 1341–1353.DOI: https://doi.org/10.1016/0045-6535(96)00342-8
34. Tadini, A. M., Gine, M., Santos, E. P., & dos Santos, R. M. (2022). Spectroscopic characteristics of humic acids extracted from tropical soils: Implications for UV–Vis and FTIR-based assessment. Environmental Research Communications, 4(4), 041003. DOI: https://doi.org/10.1088/2515-7620/ac5f56
35. Spietz, T., Hinderberger, D., & Maciel, G. S. (2024). Characterization of humic acid salts and their physicochemical properties. Minerals, 14(1), 121. DOI: https://doi.org/10.3390/min14010121
36. Zhang, S., et al. (2021). Characterization of ultrafiltration-fractionated humic acid from weathered coal: Molecular weight distribution and properties. Agronomy, 11(1), 55. DOI: https://doi.org/10.3390/agronomy11010055
37. Michalska, J., et al. (2023). Evaluation of the applicability of selected analytical methods for humic substances: Strengths, limitations and recommendations. Science of the Total Environment 854, 159350.DOI: https://doi.org/10.1016/j.scitotenv.2022.159350
38. Chen, H., et al. (2022). Enhanced photosynthesis and growth of lettuce by the application of humic substances: Metabolite and transcript profiling studies. Soil & Tillage Research, 223, 105470.DOI: https://doi.org/10.1016/j.still.2022.105470
39. Kishor, P., et al. (2020). Role of humic acid in improving soil fertility and productivity. Journal of Environmental Management, 273, 111171.DOI: https://doi.org/10.1016/j.jenvman.2020.111171
40. Khaled, H., &Fawy, H. (2018). Effect of different levels of humic acids on the nutrient content, plant growth, and soil properties under conditions of salinity. Australian Journal of Basic and Applied Sciences, 12(4), 223–231.DOI: https://doi.org/10.22607/AJBAS.2018.12c.12
41. Ibrahim, M. M., et al. (2024). Effects of humic acid on growth and physiological responses of wheat under drought stress. Plant Physiology Reports, 29(3), 456–467. DOI:https://doi.org/10.1007/s40502-024-00713-5
42. Noroozisharaf, A., & Kaviani, M. (2018). Effect of humic acid on essential oil content and composition in Thymus vulgaris L. Industrial Crops and Products, 115, 290–297.DOI: https://doi.org/10.1016/j.indcrop.2018.02.018
43. Zhao, L., Wang, X., Chu, G., & Sun, J. (2023). The effect of humic acid application on heavy metal accumulation in rice and soil health under saline conditions. Environmental Pollution, 321, 121161.DOI: https://doi.org/10.1016/j.envpol.2023.121161
44. Yang, X., & Hodson, M. E. (2019). Biochar and humic acid amendments alleviating lead (Pb) stress in plants: Mechanisms and impacts on phytoremediation potential. Science of the Total Environment, 655, 276–287.DOI: https://doi.org/10.1016/j.scitotenv.2019.07.075
45. Shao, L., et al. (2021). Synthetic humic acid-like materials from biomass for carbon capture and soil amendment. Journal of Environmental Chemical Engineering, 9(5), 105809. DOI: https://doi.org/10.1016/j.jece.2021.105809
46. Socol, M. (2023). Biological activities of humic acids: Antioxidant and antiviral perspectives. Frontiers in Pharmacology, 14, 1209437. DOI: https://doi.org/10.3389/fphar.2023.1209437
47. Miao, Q., Liu, X., & Taheri, P. (2018). Photothermal and photoacoustic imaging using sodium humate. ACS Applied Materials & Interfaces, 10(2), 1811–1821. DOI: https://doi.org/10.1021/acsami.7b17241
48. Kraiem, N., et al. (2018). Effect of humic acid on Anammox bacterial activity in wastewater. Bioresource Technology, 270, 184–192.DOI: https://doi.org/10.1016/j.biortech.2018.09.038
49. Boguta, P., Długosz, M., &Sokołowska, Z. (2019). Metal complexation stability of humic acid as a function of pH. Environmental Geochemistry and Health, 41, 3325–3334.DOI: https://doi.org/10.1007/s10653-019-00414-3
50. Kholif, A., et al. (2021). Humic acid supplementation in dairy cows and its effects on performance and health. Animal Feed Science and Technology, 277, 114932. DOI: https://doi.org/10.1016/j.anifeedsci.2021.114932
51. Tyc, O., Gagg, G., & van Elsas, J. D. (2022). Ultrasound-assisted extraction of humic substances from peat: Process intensification and yield optimization. Waste and Biomass Valorization, 13(7), 1683–1695. DOI: https://doi.org/10.1007/s12649-021-01641-5
52. Shao, L., Zhang, H., & Liu, Y. (2023). Hydrothermal synthesis of humic acid-like substances from corn stalk hydrochar: Process optimization and product characterization. Journal of Environmental Chemical Engineering, 11(3), 109231.DOI: https://doi.org/10.1016/j.jece.2023.109231
53. Rani, S., Kumar, R., & Mehta, P. (2024). Extraction and purification techniques of humic substances: A review. Environmental Technology & Innovation, 35, 103746.DOI: https://doi.org/10.1016/j.eti.2024.103746
54. Staden, J. V., et al. (2024). Advances in the analysis of humic substances: A review. Environmental Science & Ecotechnology, 11, 100282. DOI: https://doi.org/10.1016/j.ese.2024.100282
55. Xu, H., et al. (2022). Humic acid-assisted carbon sequestration and pollutant immobilization in soils: Mechanisms and field applications. Environmental Pollution, 308, 119662. DOI: https://doi.org/10.1016/j.envpol.2022.119662
Published
Abstract Display: 33 
PDF Downloads: 31 How to Cite
Issue
Section
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
How to Cite
.