Progress in Polymer Science
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Humic Acid is a natural polymer with high functionality which is omnipresent in Nature, but was up to now hardly considered as an object of polymer synthesis. We review the known structural properties of natural humic acids which are remarkably uniform, independent of source and origin and environment. We then present its simple retrosynthesis in the lab based on a hydrothermal polycondensation process. The for a polymer very unusual properties of Humic Acid, such as pH and redox buffering, strong ion binding, but also its ability to bind and carry both hydrophobic and very hydrophilic molecules make artificial humic acid also an exciting choice as a functional polymer for technical purposes.
If we have to list common natural polymers, 95 % of us will oversee the most nearby, but also the by far most omnipresent species: it is the humin/humic acid fraction in soil, a partly soluble, partly cross-linked polymer compound. The scale and importance of this “sleeping giant” is unimaginable large: humic matter accounts for up to 80 % of the total organic matter in soil, playing a key role in soil fertility, but also the global carbon cycle . Soil organic matter in fact contains significantly more carbon than even the combination of vegetation and the atmosphere and is a long-lasting, accumulated product of the degradation of land vegetation. Carbohydrates, but also lignin and lipids are the key monomers which are converted and condensed into the more persistent part of soil organic matter (SOM).
Photosynthesis immobilizes more than 220 billion metric tons of CO2 per year world-wide , but only a small amount of this immobilized carbon ends up in SOM, as old plant matter is mostly metabolized and degraded, with little remainders are left via humification reactions to form the soil carbon pool. Nevertheless, this remainder piled up over geological timescales to very large amounts. Together with its tight relative, kerogen , it contains an estimated 1016 tons of carbon, exceeding the total organic content of current living matter by a factor of 10,000 . To illustrate this number again: the annual world crude oil production is another factor 200 smaller, i.e. “only” 4 Gt (4*109 t/a). Talking about humins as a polymer thereby has a significant scale and importance as it is by far larger than all human chemistry activities, a “sleeping giant” hidden in the ground.
Humic substances are organic compounds that are included as a minority component (2−8 wt%) in topsoils, but at higher concentrations also found in peat and brown coal. The analysis of humic matter is as old as chemistry as such, and the notation “humic acid” comes from the fact that strong bases dissolve significant parts of the black-brown polymer, while reprecipitation occurs after back-acidification, which is the typical behavior of a hydrophobic, weak polyelectrolyte. The name “fulvic acids” describes the more hydrophilic part which stays dissolved even after acidification and at higher ionic strength . There are also larger parts of humic matter that remain undissolved, the so-called humin, but it’s very similar chemical character (see below) motivates the simplifying notion that this is only the more hydrophobic or cross-linked part of the same, chemically broad material.
To make it clear: humic matter is well explored in geochemistry, agriculture, and soil biology, it is just that to our opinion a polymer perspective on this relevant class of materials is missing. This goes up to a pure chemical lab-synthesis of humics, their chemical modification, and their valorization as an advanced polymer material, i.e. it is about taking humic acids out of the classical soil context and apply them in modern fields of functional polymers. These all are the tasks of the current review.
Humic acid as traditionally isolated is a condensate complex mixture of monomers that contain acidic carboxyl and phenolate groups so that the mixture behaves functionally as an anionic polyamphiphile. Modern analytics, however, starts to shed light on the inner molecular construction principles, and modern tools such as solid-state NMR [6,7] have remarkably improved our understanding of the chemical architecture. In addition, the modern tools of metabolite analysis were also applied to humus, and the resulting so-called “Humeomics” allowed identification of many of the molecular architectures by advanced spectroscopic, mass spectroscopical and chromatographic methods . We therefore feel confident that the knowledge is mature enough to initiate further developments of materials chemistry.
Natural huminogenesis and chemical retrosynthesis
Huminogenesis describes the organic and biological cascades towards organic humic matter and is thereby a subdomain of pedogenesis. Careful observation of natural processes can teach us some general rules regarding the formation of soil humic substances but also provide a basis for the development of a “synthetic lab approach” to humic matter. Beneficial in this regard is that although the average properties of extracted humic substances will differ depending on the source of biomass, its
Polymer analysis of a traditional humic polymer
The structure of humins is thereby complex and varies in a certain range, according to the origin. Most researchers believe that humus is a polymer with polyphenol and quinone as aromatic core, in which the functional rim contains carboxyl, phenolic, carbonyl, sugar, peptide fragments and other components. The subentities are connected by various bridge bonds, such as O, CH2, CH, NH , SS, etc. The chemical structure of humins is thereby a random polycondensate with a conjugated, aromatic
Obviously, such a highly functional polymer covering amphiphilic properties, ion binding and polyelectrolyte properties, optical properties as well as (phenol-based) redox properties is of high interest for a diversity of applications, both in the classical soil context as also in technology to replace functional polymers by this cheap, omni-available, sustainable, and environmental benign substitute.
Conclusion and outlook
The yearly (natural) production of humic polymers with about 10 Gt/a is one order of magnitude lower than biomass productivity of Earth, but by far larger than any synthetic polymer under consideration. Nevertheless, only little is known in the materials community about this polymer, in spite of the facts which soil scientists have found out throughout long analyses and observations. Humic acids bind water and ions and hydrophobic molecules, they are surface active and change and interact with
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
All authors appreciate the funding of the project by Max Planck Society. Dr. Yang acknowledges the financial support from the National Natural Science Fund for Young Scholars (31600413), the financial support from University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province (UNPYSCT-2017018), Natural Science Foundation of Heilongjiang Province of China (QC2018019).
- J. Shan et al.
Selective digestion of the proteinaceous component of humic substances by the geophagous earthworms Metaphire guillelmi and Amynthas corrugatus
Soil Biol Biochem
- M. Vandenbroucke et al.
Kerogen origin, evolution and structure
- A. Nebbioso et al.
Advances in humeomics: enhanced structural identification of humic molecules after size fractionation of a soil humic acid
Anal Chim Acta
- G. Bordelet et al.
Chemical reactivity of natural peat towards U and Ra
- F. Yang et al.
A hydrothermal process to turn waste biomass into artificial fulvic and humic acids for soil remediation
Sci Total Environ
- Y. Shi et al.
Comparison of global inventories of CO2 emissions from biomass burning during 2002–2011 derived from multiple satellite products
- B. Martin-Mousset et al.
Distribution et caractérisation de la matière organique dissoute d’eaux naturelles de surface
- M. Drosos et al.
Humeomics: A key to unravel the humusic pentagram
Appl Soil Ecol
- W. Tang et al.
Impact of humic/fulvic acid on the removal of heavy metals from aqueous solutions using nanomaterials: a review
Sci Total Environ
- J. Schnurer et al.
Microbial biomass and activity in an agricultural soil with different organic matter contents
Soil Biol Biochem
Sorption of humic acid to soil: the role of soil mineral composition
Effects of humic acids from vermicomposts on plant growth
Eur J Soil Biol
Metal removal from wastewater using peat
Stability constants of metal–humic acid complexes and its role in environmental detoxification
Ecotoxicol Environ Saf
Copper adsorption by esterified and unesterified fractions of Sphagnum peat moss and its different humic substances
J Hazard Mater
Dissolved organic matter in soils-future directions and unanswered questions
Characterisation of humic materials of different origin: a multivariate approach for quantifying the latent properties of dissolved organic matter
Bioavailability of atrazine, pyrene and benzo [a] pyrene in European river waters
Electron shuttling via humic acids in microbial iron (III) reduction in a freshwater sediment
FEMS Microbiol Ecol
Sulfur-free lignins from alkaline pulping tested in mortar for use as mortar additives
Bioresour Technol Rep
Material derived from hydrothermal carbonization: effects on plant growth and arbuscular mycorrhiza
Appl Soil Ecol
Quantitative characterization of humic substances by solid-state carbon-13 nuclear magnetic resonance
Soil Sci Soc Am J
Correlation of poly (methylene)-rich amorphous aliphatic domains in humic substances with sorption of a nonpolar organic contaminant, phenanthrene
Environ Sci Technol
Molecular dynamics simulations of the standard leonardite humic acid: microscopic analysis of the structure and dynamics
Environ Sci Technol
The molecular dynamics of soil humus as a function of tillage
Land Degrad Dev
Isolation of humic acid from the brown algaeAscophyllum nodosum, Fucus vesiculosus, Laminaria saccharina and the marine angiospermZostera marina
J Appl Phycol
Contribution to our knowledge of the chemical nature and origin of humus: II. The influence of “synthesized” humus compounds and of “natural” humus upon soil microbial processes
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Lignite drove phenol precursors to participate in the formation of humic acid during chicken manure composting
2023, Science of the Total Environment
This study set out to explore the impact of lignite on preserving organic matter and promoting the formation of humic acid (HA) during chicken manure composting. Composting test was carried out for control (CK), 5% lignite addition treatment (L1), 10% addition treatment (L2) and 15% addition treatment (L3). The results demonstrated that lignite addition effectively reduced the loss of organic matter. The HA content of all lignite-added groups was higher than that of CK, and the highest was 45.44%. L1 and L2 increased the richness of bacterial community. Network analysis showed higher diversity of HA-associated bacteria in L2 and L3 treatments. Structural equation models revealed that reducing sugar and amino acid contributed to the formation of HA during CK and L1 composting, while polyphenol contributed more to the HA formation during L2 and L3 composting. Furthermore, lignite addition also could promote the direct effect of microorganisms on HA formation. Therefore, the addition of lignite had practical significance to enhance compost quality.
Volatile and semi-volatile organic compounds in landfill gas: Composition characteristics and health risks
2023, Environment International
Gas emitted from landfills contains a large quantity of volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs), some of which are carcinogenic, teratogenic, and mutagenic, thereby posing a serious threat to the health of landfill workers and nearby residents. However, the global hazards of VOCs and SVOCs in landfill gas to human health remain unclear. To quantify the global risk distributions of these pollutants, we collected the composition and concentration data of VOCs and SVOCs from 72 landfills in 20 countries from the core database of Web of Science and assessed their human health risks as well as analyzed their influencing factors. Organic compounds in landfill gas were found to primarily result from the biodegradation of natural organic waste or the emissions and volatilization of chemical products, with the concentration range of 1×10-1–1×106 μg/m3. The respiratory system, in particular, lung was the major target organ of VOCs and SVOCs, with additional adverse health impacts ranging from headache and allergies to lung cancer. Aromatic and halogenated compounds were the primary sources of health risk, while ethyl acetate and acetone from the biodegradation of natural organic waste also exceeded the acceptable levels for human health. Overall, VOCs and SVOCs affected residents within 1,000m of landfills. Air temperature, relative humidity, air pressure, wind direction, and wind speed were the major factors that influenced the health risks of VOCs and SVOCs. Currently, landfill risk assessments of VOCs and SVOCs are primarily based on respiratory inhalation, with health risks due to other exposure routes remaining poorly elucidated. In addition, potential health risks due to the transport and transformation of landfill gas emitted into the atmosphere should be further studied.
Electrochemical properties of humic acid and its novel applications: A tip of the iceberg
2023, Science of the Total Environment
Citation Excerpt :
It is generally believed that the abundant redox-active groups, such as quinone groups, phenolic groups, carboxyl groups, etc., which can combine with protons and ions, or work as electron acceptors/donors, enabled the application of HA as advanced electrochemical materials (Felix Maurer et al., 2012; Tan et al., 2017; Yang et al., 2016a). Recently, Yang and her coworkers have paid great effort on reviewing the applications of HA based on its special structure and superior properties such as redox activity (Yang et al., 2019; Zhang et al., 2020; Yang and Antonietti, 2020a, 2020b; Yang et al., 2021; Peng et al., 2022). They reported that humic substances with a larger specific surface area, abundant carboxyl and phenolic hydroxyl groups plays a prominent role in change of cation exchange capacity (CEC) of soil, binding pollutants such as heavy metals, organic pollutants, and even radionuclides.
The widely existed humic acid (HA) with abundant redox-active groups has been considered to play an important role in biogeochemistry in sediments and soils. Recent studies reported that HA showed great performance in terms of electron transfer capacity (up to HAEDC = 94 mmol e−/mol C, HAEAC = 42 mmol e−/mol C). Since HA is widely available, inexpensive and environmentally friendly, the electrochemistry of HA has been explored to apply in many fields, such as environmental remediation, detection sensor and energy storage. Whereas, these prospective applications of HA and their electrochemical principles were lack of a comprehensive summary. In this review, the electrochemical properties and the prospective electrochemical applications of HA were summarized. Simultaneously, the existing problems like shortages of traditional electrochemical characterization of HA, and future research directions about HA electrochemistry were prospected. This review provides a deeper understanding of HA electrochemistry, and also inspires ideas for environmental remediation, detection sensor and energy storage by exploring the potential application values of HA.
Biochar drives humus formation during composting by regulating the specialized metabolic features of microbiome
2023, Chemical Engineering Journal
Humus formation of composting is crucial for improving organic fertilizer quality. Biochar has been found to be a low-cost, eco-friendly and effective promoter for humus formation, while the mechanisms underlying the biochar-driven humus formation during composting remain unknown. The present study was aimed to explore the effect of biochar addition on humus formation by integrated analyses of fungal communities, functional genes and metabolic features during composting using the advanced techniques of fluorescence spectrometry, high throughput sequencing, metagenomics, and metabolomics. The efficiencies of fulvic acid and humic acid formation were increased by 17.4 % and 39.4 %, respectively, under biochar addition relative to the control at the mature phase. Biochar addition significantly increased temperature, lignocellulose degradation and the activities of urease, peroxidase, manganese peroxidase and lignin peroxidase, and altered the fungal community composition and diversity with the latter significantly correlated with humic acid content. The altered fungal community subsequently resulted in the stimulation of fungal function of Wood Saprotroph and expression of CAZyme genes at the thermophilic and mature phases. Ultimately, biochar addition significantly enhanced the Xenobiotics metabolism (Bisphenol metabolism and Quinone biosynthesis) and Amino acid metabolism (Tryptophan metabolism and Tyrosine metabolism), which were responsible for humus formation via producing metabolic compounds such as quinolines, phenolics and aromatic amino acids at the mature phase. Our findings suggest that biochar addition can effectively stimulate humus formation by selectively regulating fungal communities and metabolic features during composting, so that benefits the improvement of soil fertility and health upon the organic fertilizer application.
Hydrothermal humification of lignocellulosic components: Who is doing what?
2023, Chemical Engineering Journal
The humification behavior of lignocellulosic components (i.e., cellulose, hemicellulose and lignin) under acid-alkali two-step hydrothermal treatment was investigated with particular interest of revealing the contribution of single components as well as their interaction to hydrothermal humic acid (HHA). Lignin with its rich aromatic structures, had the highest HHA contribution (51.8 1.0wt%), while cellulose and hemicellulose only contributed 8.8 1.6wt% and 20.1 4.4wt% HHA yields, respectively. The conversion pathway of these components toward humification indicated that the hydrochar (HC) rather than the hydrothermal solution (HS) had higher humification capability under alkaline hydrothermal conditions because the hydrochar-derived HHA yields of 40.8 2.0wt% (cellulose), 66.2 6.4wt% (hemicellulose) and 55.4 6.1wt% (lignin) were achieved. In addition, co-hydrothermal treatment of cellulose, hemicellulose and lignin under this process improved the HHA production ascribing to the increased HC yield (23.1–53.1%). The chemical characteristics of HHA products from lignocellulosic components (cellulose, hemicellulose, lignin) and their combinations were similar to the acknowledged natural humic acids. The hydrothermal humification of biowaste mainly passes through a top-down pathway (i.e., HHA forms from the oxidation of large fragments of hydrochar) as well as two bottom-up pathways (i.e., the soluble chemicals conduct the polymerization reaction for HHA production and react with the fragments from HC to synthesize the HHA). This study filled the lack of knowledge in the field of biowaste humification.
Revisiting organic waste-source-dependent molecular-weight governing the characterization within humic acids liking to humic-reducing microorganisms in composting process
2023, Journal of Hazardous Materials
Humic acids (HAs) coupled with humic-reducing microorganisms (HRMs) can facilitate contaminants reduction. Molecular-weight (MW) of HA governs the chemical and HRMs behavior. However, MW of HAs with chemical characteristics linking to HRMs in different wastes composting have never been investigated. Results from the HPSEC-UV analysis showed that composting significantly increased weight-average molecular weight (Mw) of HA with a broad range from 675Da to 27983Da, and governing heterogeneous chemical characteristics. In proteinaceous composts, MW<4000Da of HAs were greatly related to alkyl and carbonyl, while MW>20000Da of HAs were presented by oxygen–nitrogenous functional groups, methyl, and alkyl groups. For cellulosic composts, MW<1500Da and 4000–10000Da of HAs were characterized by aliphatic ethers and aromatic groups. MW>20000Da of HAs were constructed by phenols, methoxy and nitrogen functional groups. In lignocellulosic composts, MW>20000Da of HAs were only characterized by aromatic groups. Furthermore, seven groups of HRMs adapted to the heterogeneous chemical characteristics within HAs ranked by MW were recognized. Consequently, the possible routes that composting properties response to the connections of HRMs-chemical structures-MW of HAs in proteinaceous, cellulosic and lignocellulosic composts were constructed, respectively. Our results can help to develop the fine classification-oriented approach for recycling utilization of organic wastes.
Recommended articles (6)
Are humic substances soil microbial residues or unique synthesized compounds? A perspective on their distinctiveness
Pedosphere, Volume 30, Issue 2, 2020, pp. 159-167
Humic substances (HS), which are defined as a series of highly acidic, relatively high-molecular-weight, and yellow to black colored substances formed during the decay and transformation of plant and microbial remains, ubiquitously occur in nature. Humic substances represent the largest stable organic carbon pool in terrestrial environments and are the central characteristic of the soil. However, the validity of the HS concept and the justification of their extraction procedure have been recently debated. Here, we argue that the traditional humic paradigm is still relevant. Humic substances are distinctive and complex because the extracted HS formed during the humification are chemically distinct from their precursors and are heterogeneous among soils. By reviewing the concept, formation pathways, and stabilization of HS, we propose that the key question facing soil scientists is whether HS are soil microbial residues or unique synthesized compounds. Without revealing the distinctiveness of HS, it is impossible to address this question, as the structure, composition, and reactivity of HS are still poorly known owing to the heterogeneity and geographical variability of HS and the limits of the currently available analytical techniques. In our view, the distinctiveness of HS is fundamental to the soil, and thus further studies should be focused on revealing the distinctiveness of HS and explaining why HS hold this distinctiveness.
Humic-like acids from hydrochars: Study of the metal complexation properties compared with humic acids from anthropogenic soils using PARAFAC and time-resolved fluorescence
Science of The Total Environment, Volume 722, 2020, Article 137815
Humic acids (HA) play an important role in the distribution, toxicity, and bioavailability of metals in the environment. Humic-like acids (HLA) that simulate geochemical processes can be prepared by NaOH aqueous extraction from hydrochars produced by hydrothermal carbonization (HTC). HLA can exhibit properties such as those found in HA from soils, which are known for their ability to interact with inorganic and organic compounds. The molecular characteristics of HLA and HA help to explain the relationship between their molecular features and their interaction with metallic species. The aim of this study is to assess the molecular features of HA extracted from Terra Mulata (TM) and HLA from hydrochars as well as their interaction with metals by using Cu(II) ions as a model. The results from 13C NMR, elemental analysis, FTIR, and UV–Vis showed that HA are composed mostly of aromatic structures and oxygenated functional groups, whereas HLA showed a mutual contribution of aromatic and aliphatic structures as main constituents. The interactions of HA and HLA with Cu(II) ions were evaluated through fluorescence quenching, in which the density of complexing sites per gram of carbon for interaction was higher for HLA than for HA. Furthermore, the HLA showed similar values for stability constants, and higher than those found for other types of HA in the literature. In addition, the average lifetime in both humic extracts appeared to be independent of the copper addition, indicating that the main mechanism of interaction was static quenching with a non-fluorescent ground-state complex formation. Therefore, the HLA showed the ability to interact with Cu(II) ions, which suggests that their application can provide a new approach for remediation of contaminated areas.
Chelating properties of humic-like substances obtained from process water of hydrothermal carbonization
Environmental Technology & Innovation, Volume 23, 2021, Article 101688
Recent studies have shown a new way of producing humic-like substances (HLS) from hydrochar prepared by hydrothermal carbonization of biomass. However, studies of HLS extracted from process water (PW) produced in hydrothermal carbonization process to the best of our knowledge are non-existent. In this work, hydrothermal carbonization of sugarcane bagasse and vinasse was performed under two concentrations of H2SO4 (1 and 4% w:w) followed of extraction of HLS from PW (HLS 1% and HLS 4%). The interaction of these compounds with Cu(II) ions revelated a complexation with high conditional stability constant (K ranged from 5.0 to 5.4) and high complexing capacity (CC ranged from 3.1 to 3. mg−1). Elemental analysis and ash content showed that HLS 1% and HLS 4% both have high content of carbon, oxygen and inorganic compounds. In addition, the H/C molar ratio suggests that both HLS have aliphatic nature and O/C molar ratio acidic functional groups. FTIR analysis showed great variety of functional groups and also the presence of inorganic compounds. Excitation–Emission fluorescence matrices applied with complexation studies showed that interaction of HLS and Cu(II) occurs with two humic-like components. Data on Time Resolved Fluorescence Spectroscopy (TRFS) suggests that the mechanism of interaction between both HLS and Cu(II) occur by complexation. Furthermore, the infrared bidimensional analysis indicates that the binding sites for HLS 1% were in affinity order: COOCO> CH aliphatic, while for HLS 4% was: CH aliphatic> CO.
Humic extracts of hydrochar and Amazonian Dark Earth: Molecular characteristics and effects on maize seed germination
Science of The Total Environment, Volume 708, 2020, Article 135000
Inspired by the presence of anthropogenic organic matter in highly fertile Amazonian Dark Earth (ADE), which is attributed to the transformation of organic matter over thousands of years, we explored hydrothermal carbonization as an alternative for humic-like substances (HLS) production. Hydrothermal carbonization of sugarcane industry byproducts (bagasse and vinasse) in the presence and absence of H3PO4 afforded HLS, which were isolated and compared with humic substances (HS) isolated from ADE in terms of molecular composition and maize seed germination activity. HLS isolated from sugarcane bagasse hydrochar produced in the presence or absence of H3PO4 comprised both hydrophobic and hydrophilic moieties, differing from other HLS mainly in terms of phenolic content, while HLS isolated from vinasse hydrochar featured hydrophobic structures mainly comprising aliphatic moieties. Compared to that of HLS, the structure of soil-derived HS reflected an increased contribution of fresh organic matter input and, hence, featured a higher content of O–alkyl moieties. HLS derived from lignocellulosic biomass were rich in phenolics and promoted maize seed germination more effectively than HLS comprising alkyl moieties. Thus, HLS isolated from bagasse hydrochar had the highest bioactivity, as the presence of amphiphilic moieties therein seemed to facilitate the release of bioactive molecules from supramolecular structures and stimulate seed germination. Based on the above results, the hydrothermal carbonization of lignocellulosic biomass was concluded to be a viable method of producing amphiphilic HLS for use as plant growth promoters.
Roles of humic substances redox activity on environmental remediation
Journal of Hazardous Materials, Volume 435, 2022, Article 129070
Humic substances (HS) as representative natural organic matters and the most common organic compounds existing in the environment, has been applied to the treatment and remediation of environmental pollution. This review systematically introduces and summarizes the redox activity of HS for the remediation of environmental pollutants. For inorganic pollutants (such as silver, chromium, mercury, and arsenic), the redox reaction of HS can reduce their toxicity and mobilization, thereby reducing the harm of these pollutants to the environment. The concentration and chemical composition of HS, environmental pH, ionic strength, and competing components affect the degree and rate of redox reactions between inorganic pollutants and HS significantly. With regards to organic pollutants, HS has photocatalytic activity and produces a large number of reactive oxygen species (ROS) under the light which reacts with organic pollutants to accelerate the degradation of organic pollutants. Under the affection of HS, the redox of Fe(III) and Fe(II) can enhance the efficiency of Fenton-like reaction to degrade organic pollutants. Finally, the research direction of HS redox remediation of environmental pollution is prospected.
Efficient phosphorus recycling and heavy metal removal from wastewater sludge by a novel hydrothermal humification-technique
Chemical Engineering Journal, Volume 394, 2020, Article 124832
This publication presents a simple and low-cost hydrothermal humification (HTH) treatment of sewage sludge (SS) together with alkali ash (AA) and biomass for simultaneous implementation of heavy metal removal, nutrient recovery (P) and ash refining. The H/C and O/C atomic ratio plots obtained from elemental analysis demonstrate that dehydration and decarboxylation under hydrothermal conditions are elemental reactions leading to sludge/biomass decomposition and artificial humic matter formation. Introduction of plant biomass into sludge-derived samples and adjustment of KOH or alkali ash (AA) mass effectively improve the recovery of P element, realizing high contents of dissolved phosphorus (DP) (from 7045 to 10075mg/L) at appropriate pH values (6.5 to 7.7). ICP-AES results indicate the drop of Cr and Cd content below detection limit together with a sharp decrease of the elements Cu (from 0.07 to 0.46mg/g), Zn (from 0.15 to 0.98mg/g) and Pb (from 0.067 to 0.142mg/g) after HTH treatment in sludge-derived liquid products and the heavy metal elements enriched in sludge-derived solids can be recovered into industrial salts by subsequent treatment. Pot planting experiments are conducted to investigate the P-availability in both sludge-derived liquids and solids (after treatment of heavy metal recovery) for promotion of plant growth. A higher proportion of shoot-to-root weight (62.1% versus 46.2%) and preserved moisture contents (84.7% versus 83.7%) when compared to the control groups demonstrate the effect of the presence of more nutrients after addition of sludge-derived liquid products. This work could provide a smart, energy utilization and sustainable fertilization route for planting growth.
© 2019 Elsevier B.V. All rights reserved.
What is the role of humic acid in soil application? ›
Humic acid is best applied when preparing the soil for gardening or in potted plants. You should also use humic acid as a soil amendment when transplanting seedlings. Mix two tablespoons of humic acid per cubic foot of potting soil or dilute two teaspoons of humic acid in every gallon of water.What is the role of humic acid in plant growth? ›
Humic acid can enhance plant growth by promoting the bioavailability of nutrients via reform of the soil environment at the roots (Chen et al. 2004). Humic acid was the main source of nitrogen (N), phosphorus (P), and potassium (K) (Panuccio et al. 2001).Is fulvic acid good for you? ›
Fulvic acid benefits include improving gut health and immune function, boosting digestion and nutrient absorption, protecting cognitive health, supporting detoxification, lowering free radical damage and inflammation, and helping to decrease pain and skin conditions.What is the difference between humic and fulvic acid? ›
Fulvic acids are those organic materials that are soluble in water at all pH values. Humic acids are those materials that are insoluble at acidic pH values (pH < 2) but are soluble at higher pH values.What are some of the benefits of humic substances? ›
Humic acid neutralizes acidic and alkaline soils; regulates pH-value of soils, increasing their buffering abilities; and has extremely high cation-exchange properties. Benefits: Improves and optimizes uptake of nutrients and water holding capacity. Stimulates plant growth with its rich organic and mineral substances.Should humic acid be applied before or after fertilizer? ›
To get better results with this acid, you should first apply a natural fertilizer. This will give microorganisms to the soil. Take 2 ounces of liquid humic acid and mix it with a gallon of water.What is the natural source of humic acid for plants? ›
Humic acids are complex molecules that exist naturally in soils, peats, oceans and fresh waters. The one source of humic acids are the sedimentation layers referred to as Leonardite. These layers were originally deep in the earth's crust, but over many years have been exhumed to near-surface location.What is the impact of humic acid? ›
Firstly, humic acid changes the soil nutrient content, which not only increases the total nitrogen, total phosphorus, total potassium content of the soil, but also increases the contents of alkali nitrogen, available phosphorus, and available potassium, thus enabling peanut to absorb more nutrients.How does humic substance impart fertility to soil? ›
Humic substances are the organic material naturally present in soil. Humic substances positively effect's soil quality and fertility by increasing its water holding capacity, stabilisation of soil structure, soil microbial activity, plant physiology.Who should not take fulvic minerals? ›
Autoimmune diseases: Fulvic acid might increase the activity of the immune system. It might therefore worsen some autoimmune diseases, such as multiple sclerosis, systemic lupus erythematosus (SLE), and rheumatoid arthritis (RA). People with these conditions should be cautious or avoid fulvic acid altogether.
What are the side effects of fulvic humic minerals? ›
Fulvic Acid Side Effects
Fulvic acid helps detoxify the body, and in so doing may cause diarrhea, cramps, fatigue, headaches, or nausea. An overdose isn't possible, and it's completely natural.
Foods highest in Fulvic acid will be those found growing in healthy soils such as Radishes, Beetroots, Parsnips, Carrots, Turnips, as well as foods grown in large bodies of natural water such as Seaweed and Kelp.Should I take humic or fulvic acid? ›
While humic acid naturally improves soil health and growth, fulvic acid will help your plants take up nutrients more effectively. This can help save you money and time because you can reduce the amount of nutrients that you supply to your plants. Because they uptake more effectively, the concentration can be lowered.Can you use fulvic and humic acid together? ›
Humic and fulvic acids work well together, with each providing its own benefits for better plant growth. Humic acid improves soil health and growth, while fulvic acid naturally facilitates your plant's absorption and use of available nutrients.Which humic acid is best? ›
Humic acid powder
Agro biochemicals are one of the best humic acid production and manufacturing organizations for better farming results.
Humic acid is a chemical produced by decaying plants. People have used it to make medicine. People sometimes use humic acid to stimulate the immune system, for infections, and many other purposes, but there is no good scientific evidence to support any use.Can humans eat humic acid? ›
Humic acid is a chemical produced by decaying plants. People use it to make medicine. People take humic acid for stimulating the immune system and treating the flu (influenza), avian flu, swine flu, and other viral infections.What is the difference between humic and fulvic for plants? ›
Humic acids are large molecules that function best in soil to provide an optimal growing environment. Fulvic acids are much smaller molecules that work well in both soil and foliar applications, where they transfer vital nutrients through the cell membrane of plants.Can you give a plant too much humic acid? ›
People will also ask if it's possible to apply too much humic acid to the lawn and the answer is no. You won't harm the lawn with too much humic acid but for sure, you will waste it. In other words, throwing down more than the labeled rate will not hurt anything, but it certainly is wasteful and expensive.How often do you apply humic? ›
Apply solution around root zone of existing plants: Water in just enough to soak the root zone (up to 4 inches for most.) Apply as often as every two weeks.
Does humic acid raise or lower pH? ›
The addition of humic acid will exchange H + cations to cause lower soil pH. The soil cation exchange has a capability to greatly influence the content of clay and organic matter. The higher the content of clay and organic matter, the smaller the pH change, as in the case on soil 2.Do plants absorb humic acid? ›
In soil applications, humic acid is a negatively charged ion that binds with positively charged nutrients such as phosphorus, magnesium, and calcium so plants can absorb these nutrients better through the plants' root systems.Can you make your own humic acid? ›
To produce a 6% potassium humate liquid:
Add 1 kg of NTS Soluble Humate Granules™ very slowly to 10 L of water, under vigorous agitation. 10 – 15% of the humates are insoluble; let sit overnight and then siphon the soluble fraction from the top (avoiding insoluble sediment resting on the bottom).
Application of humic acid improves seed germination and seedling growth, stimulating root initiation and root growth. The humic acid doesn't contain rooting hormones; instead, it helps prevent the oxidation and breakdown of rooting hormones, allowing IAA to remain active longer.How long does humic acid last? ›
Humic substances, on the other hand, are stable, long-lasting biomolecules. Components of humus have a mean residence time (based on radiocarbon dating, using extracts from non-disturbed soils) of 1,140 to 1,235 years, depending on the molecular weight of the humic acid.What minerals are in humic acid? ›
Humates are a mix of humic and fulvic acids and contain microbes, trace elements, minerals and metals such as nitrogen, phosphorus, potassium, calcium, magnesium and zinc. Humic acids, the larger of the two molecules in humates can be extracted from peat or lignite deposits.What is the toxicity of humic acid? ›
Humic acids are of low toxicity after oral administration. The LD50 in rats is greater than 11 500 mg/kg bw. However they are toxic after parenteral administration with LD50 values of 54.8 to 58.5 mg/kg bw after intravenous administration in mice and 163.5 to 205.8 mg/kg bw after intraperitoneal administration in rats.What are the four factors responsible for the development of soil structure in humic soils? ›
3.1.4 Parameters related to the structural stability
These include polysaccharides, microorganisms, lipids and humic substances which are known to favors the stability of aggregates in soil.
The common method of extracting of humic substances is by treatment with alkali; dilute sodium hydroxide is generally used. Initially, the soil should be washed with 1 N HCl solution. Humic acid showed broad absorption centered around at 3360, 1406, 1233 and 1060 cm-1 regions.Is humic matter the same as organic matter? ›
Humic substances (HS) represent the organic material mainly widespread in nature. HS have positive effects on plant physiology by improving soil structure and fertility and by influencing nutrient uptake and root architecture.
Can too much fulvic acid hurt you? ›
Bradley, fulvic acid could increase oxidative damage (cell and tissue damage caused by free radicals in your body) at higher doses and have an adverse effect on your immune system, too.What not to mix with fulvic acid? ›
Some immune system therapy drugs that you do not want to take fulvic acid in tandem with include azathioprine, basiliximab, cyclosporine and prednisone, among others.Is fulvic acid anti aging? ›
Organic fulvic acid, the primary skincare ingredient in Fulom's product range, is a natural, simple way to fight the visible signs of aging and improve the look and texture of your skin.Is fulvic acid good for your liver? ›
In the liver, fulvic acid can act as an antioxidant by uncoupling electron transport in liver mitochondria leading to a decrease in reactive oxygen species (ROS) production , which may explain the previous observation that OMC prevents HFD-induced increases in ALT activity .Should I take fulvic acid everyday? ›
Moderate doses of fulvic acid and shilajit appear safe, though research is ongoing. A study in 30 men concluded that a daily dose of 0.5 ounces (15 mL) can be used safely without the risk of side effects. Higher doses may induce mild side effects, such as diarrhea, headaches, and sore throat ( 1 ).Does fulvic acid remove toxins? ›
Fulvic acid has the ability to bind and eliminate toxins in the body such as heavy metals, making it a powerful detox ally.Is fulvic acid good for inflammation? ›
Fulvic acid is shown to induce as well as reduce inflammation.Is fulvic acid good for hair? ›
Your hair can't grow or thrive without the proper building blocks, and you're unlikely to achieve optimal nutrition without a fulvic acid boost to your scalp and locks. fulvic acid benefits for hair include boosting your hair's natural keratin while it repairs your scalp and locks.Who should take fulvic acid? ›
People take fulvic acid by mouth for brain disorders such as Alzheimer's disease, as well as respiratory tract infections, cancer, fatigue, heavy metal toxicity, allergies, and preventing a condition in which the body tissues do not receive enough oxygen (hypoxia).When should I take fulvic humic minerals? ›
Taken with a meal, fulvic acid also helps your body with digestion! It works as a catalyst of nutrients. The electrolytes in fulvic acid actually help your body to absorb minerals better, the nutrition found in that meal's food, or additional minerals that are supplemented.
How do you make fulvic acid at home? ›
DIY Liquid Fulvic Acid Recipe
To produce a 6% potassium humate liquid, add 1 kg of NTS Soluble Humate Granules™ to a bucket containing a small quantity of water and make up to 10 L with water. Agitate vigorously.
Whether you've added nutrients in the form of synthetics or natural fertilizers the soil food web is changed. Humic acid is key to creating humus, or soil, and if you don't have enough and continue to grow crops your soil slowly degrades.What time of day is best to take fulvic acid? ›
It's a good idea to take fulvic acid around the time of eating since it counteracts and detoxifies contaminants — such as pesticides, chemicals, etc., found in foods that are not organic. You can take it a half hour before eating or two hours after eating to improve detox abilities.What does fulvic acid do to your face? ›
It's benefits include strong antioxidant, anti-inflammator and astringent properties making it ideal for cleansing the skin from dead cells, dirt and debris which can dull it's natural glow as well as soothing inflammation from free radicals such as pollution.How often do you use fulvic acid? ›
Fulvic acid can be applied as often as needed, but it's generally recommended to apply it once a month.Does humic acid help with fungus? ›
Humic substances (HS) have a direct impact on living cells, causing a wide range of various biological effects, and stimulating or inhibiting fungal growth.What is humic acid for healing? ›
Humic Acids – Anti-inflammatory from the earth
Well-known for boosting new plant growth, Humic Acids have also been used in traditional therapies to treat human inflammatory conditions for over 3,000 years.
Humic acid has excellent binding properties and electrostatic interactions with heavy metals, leading to metal-organic complexes. These complexes can affect the adsorption of heavy metals on GAC.Does humic acid increase soil pH? ›
Similar to lime, humic acids have a positive effect on the soil and the arable crop. For one thing, they neutralize the pH value in acidic soil - this increases the buffer capacity of the soil, which means that acidic precipitation has less of a negative effect on soil reactions.Can you apply too much humic acid? ›
People will also ask if it's possible to apply too much humic acid to the lawn and the answer is no. You won't harm the lawn with too much humic acid but for sure, you will waste it. In other words, throwing down more than the labeled rate will not hurt anything, but it certainly is wasteful and expensive.
What are the disadvantages of humic acid fertilizer? ›
Stay on the safe side and avoid use. "Auto-immune diseases" such as multiple sclerosis (MS), lupus (systemic lupus erythematosus, SLE), rheumatoid arthritis (RA), or other conditions: Humic acid might cause the immune system to become more active, and this could increase the symptoms of auto-immune diseases.How often should you apply humic acid? ›
Apply solution around root zone of existing plants: Water in just enough to soak the root zone (up to 4 inches for most.) Apply as often as every two weeks.What is the best source of humic acid? ›
The best source of humic acids are the sedimentation layers of soft brown coal, which are referred to as Leonardite. (pic. 1.2, pic. 1.3) Humic acids are found in high concentration here.How long does humic acid stay in soil? ›
Humic substances, on the other hand, are stable, long-lasting biomolecules. Components of humus have a mean residence time (based on radiocarbon dating, using extracts from non-disturbed soils) of 1,140 to 1,235 years, depending on the molecular weight of the humic acid.Does humic acid dissolve in water? ›
Although humic acids are precipitated from water solution at such a low pH it does not mean that all solid preparation will dissolve in (pH neutral) water. Hayes  simply states that humic acids, in their H+-exchanged form, are not soluble in water.Does humic acid loosen soil? ›
Humic acid can help improve soil texture and water retention. It's especially useful for us here in the Dallas area, where we tend to have heavy clay soils. Applying humic acid to clay soils can help loosen them, allowing for better water and air penetration.Can you mix humic acid with fertilizer? ›
Combining humic acid with phosphate fertilizer affects humic acid structure and its stimulating efficacy on the growth and nutrient uptake of maize seedlings.Does humic acid change pH? ›
Adding humic acid to the soil changes its nutrient profile, affecting its pH. It doesn't lower soil pH; instead, it triggers changes in the soil that neutralizes its pH. After treating with humic acid, the nitrogen, phosphorus, and potassium content are increased, making the soil pH more ideal for plant growth.Does humic acid really work? ›
Humic acids are an excellent natural and organic way to provide plants and soil with a concentrated dose of essential nutrients, vitamins and trace elements. Compared to other organic products, Leonardite enhances plant growth (biomass production) and fertility of the soil.What is the pH of humic acid? ›
The humic acids extracted from compost has a CEC of 60-156 me/100g, organic-organic C content of 20-30%, pH value of 6.0, in black color, and slow soluble in water.
Is humic acid necessary? ›
Without humic acids present, some of the nutrients provided by fertilizers become inaccessible to plants, so money is lost and plant health suffers. Thus, humic acids are vital for both the health of plants and for growers' economic well-being.