Impact Of Humic Acid Research Articles

Impact of humic acid on iron (oxyhydr)oxide transport in the presence of phosphate in saturated porous media

The subsurface flow of particular phosphate (P) has been recently regarded as a vital P transport path. Humic acid (HA) and P usually coexist in the natural environment and show a strong affinity to iron (Fe) (oxyhydr)oxide. The impact of P and HA on Fe (oxyhydr)oxide stability and transport is critical for evaluating the vertical transport of particular P and biogeochemical processes of Fe and P. This study investigated the effect of inorganic (IP) and organic (OP) phosphate on the stability and transport of ferrihydrite and goethite with HA through stability tests and column experiments. The adsorption of IP or OP on Fe (oxyhydr)oxide enhanced the stability and transport of Fe (oxyhydr)oxide, and OP showed a stronger enhancement than IP due to its stronger binding capacity and more negative surface. Compared with ferrihydrite, goethite had fewer adsorption sites for IP or OP and showed strong stability and transport at low IP (50 μM) or OP (10 μM) concentration. HA decreased IP or OP adsorption on Fe (oxyhydr)oxide through competition adsorption and electrostatic repulsion. The formed ternary phosphate-Fe (oxyhydr)oxide-HA complex showed a more negative surface and strong stability and transport. Our findings provide direct insights into the distinct role of IP and OP on Fe (oxyhydr)oxide stability and transport in the presence of HA, which provides essential information for evaluating the transport of particular Fe (oxyhydr)oxide-facilitated P in soils and subsurface environments rich in iron, phosphate, and dissolved carbon.

Reevaluating biostimulation strategies: the impact of humic acid on ofloxacin bioadsorption

The exogenous addition of humic acid (HA) is often seen as a biostimulation strategy to expedite the bioremediation of various pharmaceutical pollutants. Nevertheless, the impact of HA on the bioadsorption of ofloxacin (OFL), the main pathway for OFL removal in activated sludge, remains unknown. In this study, the presence of 10 mg/L HA notably decreased the theoretical OFL adsorption capacity from 8.94 to 7.95 mg/g. The inhibitory effect persisted across varying pH and ionic strengths and became more pronounced with increasing HA concentration. The morphological changes on biosolid (BIO) induced by HA indicated that HA was bioadsorbed, which in turn competed with OFL for metal binding sites like Ca and Mg on BIO. Further analysis of the OFL-HA interaction reveals the involvement of hydrogen bonding and electrostatic attraction. The study also demonstrates the bridging role of HA between OFL and BIO through consecutive desorption and re-absorption processes of OFL in the presence of HA. To quantify the direct and indirect adsorption ratios, a new approach was proposed, which determined the mass ratios of direct (OFL:BIO) and indirect bioadsorption (OFL:HA:BIO) as 1:192 and 1:21:854, respectively. These findings suggest that the indirect OFL adsorption through the HA bridge could not compensate for the adverse effects caused by the reduction of metal binding sites. Overall, this study calls for a reassessment of the addition of HA in the bioremediation process of OFL. Considering that HA widely coexists with antibiotics in wastewater, the study also provides valuable insights into OFL removal mechanisms in WWTPs.

Impact of Humic Acid and Sulphur application on growth and yield of Indian Mustard under variable Water moisture regimes

Indian mustard (Brassica juncea L.) is an important oilseed crop cultivated in various regions of the world, particularly in India. However, its productivity faces limitations due to various abiotic factors, notably variable soil moisture. This study aimed to explore the influence of humic acid and sulphur application on Indian mustard growth and yield within different moisture regimes. A field experiment was conducted in rabi season, employing a split plot design with four replications. Four moisture treatments were imposed: (1) no post sowing irrigation, (2) one post sowing irrigation (3) two post sowing irrigation and (4) three post sowing irrigation. Within each moisture regime, four treatment groups were established: (A) control (no application), (B) humic acid alone, (C) sulphur alone, and (D) a combination of humic acid and sulphur. The results revealed significant improvements in various growth and yield parameters when humic acid and sulphur were applied, particularly under moisture stress conditions. Application of humic acid and sulphur enhanced root development, chlorophyll content, and photosynthetic rate, which ultimately led to increased plant height, leaf area, and biomass accumulation. Notably, the combined application exhibited synergistic effects, resulting in the highest yield increments, especially under severe moisture stress. This study provides valuable insights into the potential advantages of incorporating humic acid and sulphur as soil amendments in Indian mustard cultivation, particularly in moisture-variable regions. The results highlight the combined application’s effectiveness in mitigating water scarcity effects, thereby promoting sustainable agriculture and bolstering food security.

Linking the humification of organic amendments with size aggregate distribution: Insights into molecular composition using FT-ICR-MS

Soil organic matter (SOM) plays a pivotal role in enhancing physical and biological characteristics of soil. Humic substances constitute a substantial proportion of SOM and their increase can improve crop yields and promote agricultural sustainability. While previous research has primarily assessed the influence that humic acids (HAs) derived from natural water have on soil structure, our study focuses on the impact of HAs on soil aggregation under different fertilizer regimes. During the summer cropping season, maize was cultivated under organic and synthetic fertilizer treatments. The organic fertilizer treatment utilized barley (Hordeum vulgare L.) and hairy vetch (Vicia villosa R.) as an organic amendment five days prior to maize planting. The synthetic treatment included a synthetic fertilizer (NPK) applied at South Korea's recommended rates. The organic treatment resulted in significant improvements in the soil aggregates and stability (mean weight diameter, MWD; p < 0.05) compared to the synthetic fertilizer application. These improvements could be primarily attributed to the increased quantity and quality of HAs in the soil derived from the organic amendment. The amount of extracted HAs in the organic treatment was nearly twice that of the synthetic treatment. Additionally, the organic treatment had a 140 % larger MWD and a 40 % increase in total phenolic content compared to the synthetic treatment. The organic treatment also had an increased macronutrient uptake (p < 0.001), an 11 % increase in aboveground maize biomass, and a 21 % increase in grain yield relative to the synthetic treatment. Thus, the enhancement of HA properties through the incorporation of fresh organic manure can both directly and indirectly increase crop productivity.

A commercial humic acid inhibits benzo(a)pyrene biodegradation by Paracoccus aminovorans HPD-2

Benzo(a)pyrene (BaP) is posing serious threats to soil ecosystems and its bioremediation usually limited by environmental factors and microbial activity. Humic acid (HA), a ubiquitous heterogeneous organic matter, which could affect the fate of environmental pollutants. However, the impact of HA on bioremediation of organic contamination remains controversial. In the present study, the biodegradation of BaP by Paracoccus aminovorans HPD-2 with and without HA was explored. Approximately 87.4 % of BaP was biodegraded in the HPD-2 treatment after 5 days of incubation, whereas the addition of HA dramatically reduced BaP biodegradation to 56.0 %. The limited BaP biodegradation in the HA + HPD-2 treatment was probably due to the decrease of BaP bioavailability which induced by the adsorption of HA with unspecific interactions. The excitation-emission matrix (EEM) of fluorescence characteristics showed that strain HPD-2 was responsible for the presence of protein-like substances and the microbial original humic substances in the HPD-2 treatment. Addition of HA would result in the increase of soluble microbial humic-like material, which should ascribe to the biodegradation of BaP and probably utilization of HA. Furthermore, both the growth and survival of strain HPD-2 were inhibited in the HA + HPD-2 treatment, because of the limited available carbon source (i.e. BaP) at the presence of HA. The expression of gene1789 and gene2589 dramatically decreased in the HA + HPD-2 treatment, and this should be responsible for the decrease of BaP biodegradation as well. This study reveals the mechanism that HA affect the BaP biodegradation, and the decrease of biodegradation should ascribe to the interaction of HA and bacterial strain. Thus, the bioremediation strategies of PAHs need to consider the effects of organic matter in environment.

Assessment of the Impact of Humic Acids on Intestinal Microbiota, Gut Integrity, Ileum Morphometry, and Cellular Immunity of Turkey Poults Fed an Aflatoxin B1-Contaminated Diet.

A recent study published data on the growth performance, relative weights of the organs of the gastrointestinal tract, liver histology, serum biochemistry, and hematological parameters for turkey poults fed an experimental diet contaminated with aflatoxin B1 (AFB1) and humic acids (HA) extracted from vermicompost. The negative effects of AFB1 (250 ng AFB1/g of feed) were significantly reduced by HA supplementation (0.25% w/w), suggesting that HA might be utilized to ameliorate the negative impact of AFB1 from contaminated diets. The present study shows the results of the remaining variables, as an extension of a previously published work which aimed to evaluate the impact of HA on the intestinal microbiota, gut integrity, ileum morphometry, and cellular immunity of turkey poults fed an AFB1-contaminated diet. For this objective, five equal groups of 1-day-old female Nicholas-700 turkey poults were randomly assigned to the following treatments: negative control (basal diet), positive control (basal diet + 250 ng AFB1/g), HA (basal diet + 0.25% HA), HA + AFB1 (basal diet + 0.25% HA + 250 ng AFB1/g), and Zeolite (basal diet + 0.25% zeolite + 250 ng AFB1/g). In the experiment, seven replicates of ten poults each were used per treatment (n = 70). In general, HA supplementation with or without the presence of AFB1 showed a significant increase (p < 0.05) in the number of beneficial butyric acid producers, ileum villi height, and ileum total area, and a significant reduction in serum levels of fluorescein isothiocyanate-dextran (FITC-d), a marker of intestinal integrity. In contrast, poults fed with AFB1 showed a significant increase in Proteobacteria and lower numbers of beneficial bacteria, clearly suggesting gut dysbacteriosis. Moreover, poults supplemented with AFB1 displayed the lowest morphometric parameters and the highest intestinal permeability. Furthermore, poults in the negative and positive control treatments had the lowest cutaneous basophil hypersensitivity response. These findings suggest that HA supplementation enhanced intestinal integrity (shape and permeability), cellular immune response, and healthier gut microbiota composition, even in the presence of dietary exposure to AFB1. These results complement those of the previously published study, suggesting that HA may be a viable dietary intervention to improve gut health and immunity in turkey poults during aflatoxicosis.

Impact of humic acid on various properties of soil and crop productivity- A review

To raise the amount and quality of agricultural produce, numerous studies have been conducted in recent years. The development of agriculture is not just influenced by mechanization and new hybrid seeds; soil quality also plays a significant role. Lack of organic matter in soil frequently renders it unsuitable for plant growth. To address this problem and increase agricultural yields, humic compounds have started to be applied to soil in many parts of the world. Humic acid (HA) can now be applied to crops or soil using a variety of methods, including soil application, foliar application, seed treatment, root dipping, and drip irrigation, as HA is available in various forms viz., granule, powder, flakes, liquid and also in conjunction with inorganic fertilizers. However, soil application is the most effective in numerous studies. Numerous experiments on crops were carried out to determine the ideal dosage of humic acid, and it was found that character, yield, and soil characteristics all had a favourable impact on crop production. This review clarifies the significance of humic acid for various crops and the health of the soil, as well as how it increases agricultural output.

Impact of Humic Acid and Some Nanomaterials on Alternaria Leaf Spot Disease and Sugar Beet Productivity

Impact of Humic Acid and Some Nanomaterials on Alternaria Leaf Spot Disease and Sugar Beet Productivity

The Impact of Humic Acid and Moringa Treatments on Enhancing Arsenic Tolerance in Broccoli Plants: Modulation of Sulphur Components and Enzymatic Antioxidant Defense

Compared with the lowlands of Asia, the ecological exposure to arsenic (As) in Egypt has not received much attention. Recent studies have discovered geogenic As-polluted soil and groundwater in numerous areas in Egypt. The behavior of metals can be affected by the complexation of humic acid (HA), a significant soil organic component, and moringa leaf extract (MLE), a superb source of phytohormones, amino acids, minerals, and antioxidants. This research investigated whether soaking broccoli in HA (0.1%) or MLE (25%) may boost the vegetable’s tolerance to various doses of As (0, 0.75, 1.50, and 3.0 mM Na2HAsO4. 7H2O; AsV). The results of this research demonstrated that HA and MLE enhanced the tolerance index (TI) of shoots, roots, and thiol compounds in leaves (cysteine (Cys), glutathione (GSH), and non-protein thiols (NPTs)) of As-treated plants. The content of hydrogen peroxide (H2O2) and proline in leaves and roots, phenolic compounds (free and bound), and activity of lipoxygenase (LOX), catalase (CAT), and peroxidase (POD) in leaves under As stress were substantially increased while they were decreased by HA and MLE treatments. These results provide insight into the regulation of As pollution by HA and MLE, which is relatively safer and more adaptable to the environment. Further research in this field is necessary to declare that HA and MLE are the most efficient treatments for As stress.

Antimony(V) removal from water within ferrihydrite transformation: Influence of humic acid

Antimony (Sb), a widely distributed heavy metal pollutant, poses a formidable threat to human health and the delicate ecological environment. Anthropogenic activities such as mining, industrial processes and the widespread use of Sb-containing products aggravate the toxicity and potential risks of Sb to the environment. The mobility and fate of Sb(V) in the water environment is affected by ferrihydrite (Fhy) transformation and humic acid (HA). However, the key role of HA on Sb(V) removal in the transformation of iron minerals remains unclear. In this study, the transformation of Fhy into goethite was significantly inhibited as a result of HA structural coating, while active functional groups of HA enhanced the combination with iron minerals and Sb(V) under acidic conditions. Residual Sb(V) concentration in water was less than 5 µg/L, which meets the United States Environmental Protection Agency (USEPA) recommended Sb concentration of 6 µg/L. Under alkaline conditions, the dissociation of HA provided more negative charges for the surface of transformed hematite and magnetite. Due to the stronger electrostatic repulsion and steric effects of HA, further removal of Sb(V) was limited. This work provided multiple secondary mineralization pathways of Fhy under the impact of HA and mechanistic insights into the removal process of Sb(V), which could contribute meaningful information regarding the interaction between Sb(V) and iron oxyhydroxides.

Influence of humic acid on U(VI) elimination by ZIF-8: Synergistic chemical effect

ZIF-8, a sort of zeolitic imidazolate frameworks (ZIFs), had showed superior adsorptive property of typical radionuclide U(VI), but it reminded uncertain how the performance of ZIF-8 would be affected by adding humic acid (HA). HA could significantly change the surface charge of ZIFs and the transport of U(VI) in natural settings, which affected the eradication of U(VI) in aquatic ecology. Thus the impact of HA for the U(VI) removal by ZIF-8 as well as its mechanism had been analyzed by batch experiments and spectral analyses. It was demonstrated that the addition of HA increased the maximum removal capacity towards U(VI) from 781.2 mg g−1 to 1398.5 mg g−1. Moreover, removal property in acidic solution was improved, and the influence of background ions on ZIF-8 was reduced. The detailed mechanism was further explored by microscopic spectral analysis. The zeta potential showed that HA enhanced the electronegativity of ZIF-8 thus enhancing the electrostatic interaction with positive ions. Moreover, FT-IR and XPS further indicated that HA enhanced the removal capacity by affecting the surface complexation phenomena and strong chemical interactions between U(VI) and ZIF-8. Also, investigations indicated that the incorporation of HA improved the removal efficiency for U(VI), which had far-reaching significance for the application of ZIF-8 in practical environment.

Impact of Humic Acid and some Pre and Post-Harvest Treatments in Improving Storage Behaviour of Hot Pepper Fruits (Capsicum annuum L.) Hybrid Barbarian F1

The experiment was carried out during the 2020-2022 growing seasons in one of the unheated greenhouses at Dhi Qar University, south of Iraq, in order to investigate the impact of adding humic acid, pre and post-harvest treatments and their interaction in the storage behavior of hot pepper fruits hybrid Barbarian F1. Factorial experiment consisted of three factors which were the possible combinations of three concentrations of humic acid 0, 1, 2 g. l−1 and five pre and post-harvest treatments which were aqueous extract of jujube leaves at a concentration of (75) g. l−1, aqueous extract of pomegranate peels at a concentration of 5 ml. l−1, calcium at a concentration of 1.5 ml. l−1, arginine acid at a concentration of 200 mg. l−1 in addition to control treatment (distilled water only). Fruits packed into polyethylene bags of 1 kg capacity containing 8 holes of 5 mm diameter and stored at a temperature of 10 ° C in a refrigerated incubator for two weeks. The experiment was designed out according to C.R.D design with three replicates. The results were analyzed by the analysis of variance and mean values were compared using the Revised Least Important Difference Test at 0.05 probability. Results showed that the fruits treated with humic acid at a concentration of 1 and 2 g.l−1 was superior to control in reducing the percentage of decay and retaining the highest content of vitamin C, total soluble solids, capsaicin and phenolic substances. As for the effect of the type of treatments, the fruits treated with calcium recorded the lowest percentage of decay compared to the rest of the treatments in both seasons. The soaking method outperformed compared to spraying one in retaining fruits content of vitamin C. the most interactions among studied factors were significant in their effect on the most parameters.

Impact of humic acid with organic and inorganic nitrogen sources on growth and yield traits of maize (Zea mays L.)

Impact of humic acid with organic and inorganic nitrogen sources on growth and yield traits of maize (Zea mays L.)

Study on Microstructure of Cemented Organic Soil in Dianchi Lake, China

The organic soil in the Dianchi Lake area contains much humic acid (HA), and the impact of HA on cemented soil has attracted much attention. In this study, test soil is prepared based on the actual HA content of the soil in Dianchi Lake, and cement is added to prepare samples. Unconfined compressive strength (UCS), scanning electron microscopy (SEM), energy-dispersive analysis (EDS), and X-ray diffraction (XRD) tests are conducted on the samples. The strength development and microstructure changes of cemented organic soil are studied. The results show that (1) cemented soil strength decreases with the increase in HA content and increases with the cement mixing ratio; (2) SEM and EDS tests show that with the increase in HA content, the connection between soil particles gradually changed from surface–surface to point–surface, point–edge, or point–point connection. A large overhead structure is inside the cemented soil, and its integrity weakens with increased HA content. However, elements such as Ca, Si, and Al exist in the pores of cemented soil, indicating that cement hydration products are cemented between soil particles. XRD testing shows that with the increase in HA content, the intensity of the diffraction peaks of hydration products in cemented soil gradually decrease. (3) In general, HA will gradually deteriorate the integrity of cemented soil and reduce its strength. When the HA content is more than 15%, the effect of HA on strength is more prominent. However, increasing the cement mixing ratio can effectively weaken HA’s negative effect on cemented soil’s strength. When the cement mixing ratio is between 15% and 25%, the strength of cemented soil with high HA content can be effectively increased. However, this approach is not conducive to the protection of the environment.

Application of humic acid and hydroxyapatite in Cd-contaminated alkaline maize cropland: A field trial

Soil quality is critical to the quality and safety of agricultural products, and remediation of heavy metal contaminated soils is an urgent task to be implemented. This study applied hydroxyapatite (HAP) and humic acid (HA) as remediation materials to Cd-contaminated alkaline cropland. Data on soil pH, electrical conductivity (EC), cation exchange capacity (CEC), soil organic matter (SOM), diethylenetriamine pentaacetic acid (DTPA) extraction, and improved BCR sequential extraction were obtained for different periods. The joint application of HAP and HA enhanced the soil's buffering capacity. During the experiment, treatment groups CK, H1, H2, H3, and H4 showed changes in pH of 0.29, 0.28, 0.21, 0.24, and 0.32, respectively, and changes in the conductivity of 341.4, 183.0, 133.1, 104.6 and 320.2 μS/cm. Soil organic matter had a positive effect on soil's effective phosphorus content. HAP and HA both reduced the BCFgrain/soil of Cd for the maize, but the impact of HA was more substantial (20.19 % reduction compared to CK). HA increased the yield of maize by 44.20 %. The combination of HA and HAP was recommended.

The impact of humic acid on hydrogen adsorptive capacity of eagle ford shale: Implications for underground hydrogen storage

Hydrogen is a clean fuel that is anticipated to play a key role to phase-out fossil fuels and consequently decline the global warming challenges. Large-scale Underground Hydrogen Storage (UHS) is a critical link in hydrogen economy, but it is yet to be successfully achieved at industrial scale, and this is presently a main drawback in the hydrogen economy. Organic-rich shale pores have been suggested as promising geo-storage media for underground storage of hydrogen through the adsorption trapping mechanism. The hydrogen (H2) could be stored as an adsorbed phase on the kerogen surface or clay minerals, thus replacing methane (CH4) on adsorption sites during competitive adsorption. Moreover, methane has been suggested as a promising cushion gas for hydrogen. Experimental measurement of the H2 and CH4 adsorptive capacity of shale is essential for precise description of competitive adsorption behavior between CH4 and H2 in shale, as well as in designing of UHS in shale. Thus, adsorption capacities of methane and hydrogen were measured using a PCTpro adsorption analyzer in this study. Since organic acids are inherently present in geo-storage media, H2 and CH4 adsorption capacities in the fresh shale and shale aged with humic acid (Shale-HA) were compared to evaluate the impacts of adsorbed organic acids on their gas adsorption affinities. Our results showed that at 303 K, the adsorption of hydrogen increased by almost 170 % at 2.5 MPa and 350 % at 4.28 MPa in Shale-HA. The H2 adsorption trends on both shale samples are type IV isotherm adsorption curves that increased steeply with pressure but levelled beyond 3.5 MPa. The low-pressure N2 adsorption-desorption isotherms showed a type II adsorption isotherm. The CH4 adsorption capacity in raw shale was uniformly increased more than that of hydrogen, but there is no significant difference in CH4 adsorption capacity in shale-HA. This work provides fundamental data for hydrogen storage in shale reservoirs, thus facilitates full-scale implementation of hydrogen economy.

Use of Organic Materials to Limit the Potential Negative Effect of Nitrogen on Maize in Different Soils.

This study was launched to test organic materials in the form of humic acids (HA) applied to soil to improve the effect of nitrogen on maize, and to determine an optimal dose of HA, which will be ecologically safe and will counteract potential negative (phytotoxic) influences of excessive nitrogen fertiliser doses, on two soils with different textural composition. The maize plants grown on the loamy sand were characterised by a higher value of the SPAD leaf greenness index, yields, and a lower content of total-N and sulphate sulphur in maize. Urea, and especially UAN, promoted higher SPAD leaf greenness index values during the stem elongation stage and particularly during the tassel emergence stage. The effect of urea on maize yields was positive on both soils, but UAN had a positive effect on this parameter only on the loamy sand. HA tended to increase the SPAD leaf greenness index. The impact of HA on plant height and yields (especially medium dose) was generally positive. However, a negative effect of the interaction of HA with UAN on the plant height and maize yield on the sand was observed. HA caused an increase in the total-N content, and their highest dose also decreased the sulphate sulphur content in maize. The application of HA to soil has a positive influence on the growth and development of plants and can create positive effects by mitigating adverse consequences of intensive agricultural production in the natural environment.

Impact of humic acid, vigamax and potassium phosphate on control of cercospora leaf spot disease

Foliar spray with commercial nutrients, humic acid, vigamax, and potassium phosphate dibasic of sugar beet plants, was evaluated against leaf spot disease incited by Cercospora beticola. Significant reduction of Cercospora leaf spot (CLS) disease severity was reported under natural field infection. Spraying with humic acid (at 20.0 g/l) and mix treatments resulted in the lowest values of disease severity during the two seasons (2018/2019 and 2019/2020) and the highest efficiency against the disease (76.41-89.36%). Retarding of CLS and the reduction of disease severity due to nutrient applications correlated to yield increment. PR1 (SA responsive gene) and LOX2 (JA biosynthesis) genes expression levels were induced and increased in the sugar beet leaves after treatment applications. The nutrients have positive impacts on both sugar beet yield and health. In conclusion, humic acid, vigamax, and potassium phosphate dibasic could be involved in management strategies against Cercospora leaf spot.

Roles of humic acid on vivianite crystallization in heterogeneous nucleation for phosphorus recovery

Vivianite crystallization serves as an intriguing alternative for phosphorus recovery from wastewater, while the impact of humic acid on this technology especially in heterogeneous nucleation is still lacking. This study found that the presence of humic acid in a range of 0–50 mg/L increased the size of crystals from 4.92 ± 0.06 to 8.48 ± 0.16 μm during vivianite crystallization in heterogeneous nucleation. Both experiments and density functional theory calculations revealed that carboxyl groups, the key functional group in humic acid, could initially reduce heterogeneous nucleation rate by elongate the average bond of Fe–O(-P), then increasing the growth rate of vivianite crystallization through reducing the surface charge of crystals, and thus leading to the increase in vivianite size. Compared with aromatic one, this study further elucidated that aliphatic carboxyl groups in humic acid with stronger binding ability and less steric hindrance could lead to lower heterogeneous nucleation and higher growth rates, resulting in larger vivianite crystals. This study may provide us a better understanding on vivianite crystallization for phosphorus recovery from wastewater.

The Removal of Cd2+, Cu2+ and Pb2+ from Aqueous Solution with Palygorskite: The Effects of Humic Acid

To investigate the impact of Humic acid (HA) on Palygorskite (PAL) as the adsorbent for heavy metal ions, this study was carried out to solve the existing dispute in the effects of HA on PAL sorption capacity. The sorption properties of PAL and HA-loaded PAL (HA/PAL) for Cd2+, Cu2+, Pb2+ in batch experiments were evaluated. PAL and HA/PAL effects on metal ion elimination were examined under various test settings (time, dosage and starting concentration) were compared. The sorption efficiency of PAL was significantly higher than that of HA/PAL. The N2 sorption-desorption and FTIR results showed that HA successfully adhered to the PAL surface without changing its crystal structure but reducing its specific surface area. Cd2+, Cu2+, and Pb2+ for PAL and Cd2+ and Cu2+ for HA/PAL were modelled by pseudo-first-order kinetics; the pseudo-second-order rate conformed to Cu2+ for PAL and Pb2+ for HA/PAL. the Langmuir linear fitting was consistent with Cd2+, Cu2+ and Pb2+ for PAL and HA/PAL. Pb2+ for PAL and Cd2+, Pb2+ for HA/PAL were consistent with the Freundlich isotherm. The results proved that HA was not conducive to improving the adsorption performance of PAL.