Role Of Humic Acid Research Articles

Combined Effect of Potassium Fertiliser, Saline Irrigation Water and Humic Acids On Soil Acidity and Yield Components of Pepper (Capsicum annuum L)

A field experiment was conducted to adapt seedlings of sweet pepper, also called “California Wonder”, to salinity and the role of humic acid and potassium fertiliser in reducing the effect of salinity on the plant. A three-factorial field experiment was conducted according to the Complete Random Block Design, with three replications during the spring season of 2018 to study the humic acid and potassium fertiliser role in enhancing the salt tolerance of pepper plants. The first factor included four levels of saline water irrigation, namely 2, 4, 6 and 8 dS.m-1. The second factor included a foliar application of three levels of humic acids i.e., 0, 25 and 50 kg.h-1. The third factor represents the addition of three levels of potassium fertiliser (potassium sulphate of 50% K2O according to the fertiliser recommendation of 0, 75 and 150 kg. h-1. The considered plant and soil traits were branch per plant, stem diameter (mm), percentage of protein in the fruits and soil pH. The results obtained from the experiment can be summed up above the treatment of air conditioning at saline level 6 ds m-1 in branch per plant with 12.3 and the most significant results obtained from the experiment can be summed up above the treatment of air conditioning at saline level 4 ds m-1 in stem diameter 2.03 mm. The results showed a decrease in branch per plant and stem diameter (mm) by increasing the salinity of irrigation water by 8 ds m-1 and the increase in the addition of humic acid and potassium fertiliser. The results showed a decrease in soil acidity (pH) increasing the salinity of irrigation and increasing fruit protein content by increasing the salinity.

New insight into nanomaterial-mediated dissemination of phage-borne resistance genes: Roles of humic acid and illumination

Bacteriophages are key reservoirs of antibiotic resistance genes (ARGs) and are pivotal for their acquisition, maintenance, and dissemination. As extensively distributed contaminants, nanomaterials can interfere with the horizontal transfer of phage-borne ARGs. However, the effects of environmental factors on this process remain unclear. Therefore, the effect of nanoscale titanium dioxide (nTiO2) on the dissemination of ARGs via bacteriophage transduction under humic acid (HA) and Ultraviolet A illumination was investigated in this study. In the dark, 20 mg/L nTiO2 did not promote the propagation of ARGs and attenuated the positive effect of HA on the transductive transfer of ARGs. Further evidence revealed that nTiO2 can absorb HA on its surface and decrease the free HA content, thereby mitigating the instability of the outer membrane and leading to diminished transductant formation. Conversely, coexposure to HA and nTiO2 synergistically promoted transduction under Ultraviolet A illumination. Massive superoxide radicals produced by photoexcitation of the HA-nTiO2 complex elevated the membrane permeability and boosted intracellular oxidative stress, resulting in the enhanced dissemination of ARGs through phage transduction. The results of this study provide insights into the roles of environmental factors in transductive ARGs dissemination mediated by nTiO2 and are beneficial for the risk assessment of nanomaterials.

New Insights into the Role of Humic Acid in Permanganate Oxidation of Diclofenac: A Novel Electron Transfer Mechanism.

Humic acid (HA) ubiquitously existing in aquatic environments has been reported to significantly impact permanganate (KMnO4) decontamination processes. However, the underlying mechanism of the KMnO4/HA system remained elusive. In this study, an enhancing effect of HA on the KMnO4 oxidation of diclofenac (DCF) was observed over a wide solution pH range of 5-9. Surprisingly, the mechanism of HA-induced enhancement varied with solution pH. Quenching and chemical probing experiments revealed that manganese intermediates (Mn(III)-HA and MnO2) were responsible for the enhancement under acidic conditions but not under neutral and alkaline conditions. By combining KMnO4 decomposition, galvanic oxidation process experiments, electrochemical tests, and FTIR and XPS analysis, it was interestingly found that HA could effectively mediate the electron transfer from DCF to KMnO4 in neutral and alkaline solutions, which was reported for the first time. The formation of an organic-catalyst complex (i.e., HA-DCF) with lower reduction potential than the parent DCF was proposed to be responsible for the accelerated electron transfer from DCF to KMnO4. This electron transfer likely occurred within the complex molecule formed through the interaction between HA-DCF and KMnO4 (i.e., HA-DCF-KMnO4). These results will help us gain a more comprehensive understanding of the role of HA in the KMnO4 oxidation processes.

Transcriptomic analysis of humic acid in relieving the inhibitory effect of high nitrogen on soybean nodulation.

Nitrogen fertilizer intake promotes soybean growth before the formation of nodules, but excess nitrogen has an inhibitory effect on soybean nodulation. It is important to balance nitrogen levels to meet both growth and nodulation needs. the nitrogen level suitable for soybean growth and nodulation was studied, the role of humic acid (HA) in alleviating the inhibition of high nitrogen on soybean nodulation was analyzed, and transcriptomic analysis was performed to understand its mechanism. The results showed that a lower level of nitrogen with 36.4 mg urea per pot could increase the number of nodules of soybean, and a higher level of nitrogen with 145.9 mg urea per pot (U4 group) had the best growth indicators but inhibited nodulation significantly. HA relieved the inhibitory effect at high nitrogen level, and the number of nodules increased by 122.1% when 1.29 g HA was added (H2 group) compared with the U4 group. The transcriptome analysis was subsequently performed on the H2 and U4 groups, showing that there were 2995 differentially expressed genes (DEGs) on the 25th day, accounting for 6.678% of the total annotated genes (44,848) under the test conditions. These DEGs were enriched in mitogen-activated protein kinase signaling pathway-plant, flavonoid biosynthesis, and plant hormone signal transduction based on the -log10 (P adjusted) value in the Kyoto Encyclopedia of Genes and Genomes pathway (KEGG). HA balanced the nitrogen level through the above pathways in soybean planting to control the number of nodules.

Role of humic acid in the transformation of hexavalent chromium in a sulfidated ferrihydrite system

Ferrihydrite (Fh) often coexists with organic matter (i.e., humic acid (HA)) in the environment; however, its impacts on the transformation of hexavalent chromium (Cr(VI)) is poorly understood during the sulfidation of Fh. Upon exposed to 2 mM sulfide for 12 h, the total amount of Fe(II) (Fe(II)tot, 0.78 mM) in treatments with HA (300 mg HA/L) was higher than that (0.67 mM) in treatments without HA, since HA could enhance the solubility of Fe(II). After then, the Cr(VI) was reduced by sulfidated Fh. Aqueous Cr(VI) concentration (Cr(VI)aq) declined from 0.67 to 0.43 mM with the increase of HA concentration from 0 to 400 mg/L, which was partly ascribed to the inhibition of surface passivation by HA. Moreover, the increase in Fe(II) during the sulfidation of Fh also exerted a strong impact on the transformation of Cr(VI) subsequently. In addition of HA, batch experiments suggested that EDTA could also promote the formation of Fe(II) (Fe(II)tot, 0.80 mM), rendering a lower Cr(VI)aq (0.59 mM) in EDTA-300 treatments. This study further demonstrated that HA played an important role in the transformation of Cr(VI), hence providing a theoretical basis for in-situ remediation of Cr(VI) in the future.

New insights into the adsorption behavior of thiacloprid at the microfibers/water interface: Role of humic acid

Dissolved organic matter regulates the interaction between microplastics (MPs) and organic pollutants. Here, this paper investigated the effect and mechanism of humic acid (HA) on the adsorption behavior of thiacloprid at two microfibers (MFs)/water interface, and compared the differences in the performance of MFs and pure MPs. The results showed that 10 mg L−1 HA decreased the adsorption capacity and the partition coefficient KD of thiacloprid on MFs and pure MPs. Spectral analysis showed that HA could form hydrogen bonds and van der Waals forces with both MPs and thiacloprid, ultimately affecting the adsorption behavior of thiacloprid at MPs/water interface via competitive adsorption and bridging effect. Furthermore, two-dimensional correlation spectroscopy demonstrated that thiacloprid was preferentially adsorbed onto MPs compared with HA. Finally, density functional theory calculation demonstrated that phenolic-OH, –COOH, and alcoholic-OH played critical roles in competing adsorption and bridging effect. This study offers a theoretical foundation for a better comprehension of the adsorption behavior of organic pollutants at the MPs/water interface.

EFFECT OF ORGANIC MATTER ON THE DEGRADATION OF CEFALEXIN WITH TiO2

In this study, the transformation mechanism of cefalexin (CFX) via TiO2 photocatalysis and the roleof humic acids extracted from two agro-industrial residues, coffee (HAc) and rice (HAa) husks wereevaluated. During the TiO2 photocatalysis, 90% CFX degradation was found after 180 min ofirradiation (365 nm); in the presence of HAc and HAa, 37% and 61% CFX degradation wereobserved, respectively. This shows that the extracted humic acids do not promote the formation ofreactive oxygenated species; further, they act as scavengers of hydroxyl (.OH). Additionally, it wasfound that CFX degradation by heterogeneous catalysis with TiO2 is mainly associated with holeoxidation (47%) and it is caused by •OH radicals in solution (38%). Finally, we can conclude that therole of humic acids as photosensitizers or scavengers is related to their structural properties.

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.

Quality and Yield of Rice Grain: Effects of Humic Acid and Bean Cake Fertilizers Under Water-Saving Conditions

Rice quality and yield traits response to fertilizers under varying field conditions were obtained in our previous study. A better understanding of the intrinsic mechanism of fertilization in regulating rice quality and yield supports field operations and recommendations. This study investigated the potential role of humic acid and bean cake fertilizers as opposed to traditional nitrogen fertilizer (urea) in regulating rice quality and yield traits under water-saving conditions by identifying the quality and yield indicators. Results demonstrated that the application of humic acid and bean cake fertilizers affected the quality and yield compared with the traditional nitrogen fertilizer (urea), which alleviated the deterioration of rice quality and yield caused by excessive fertilizer amounts. The conclusions are that the addition of humic acid and bean cake fertilizers can improve grain quality.

Opposite Role of Humic Acid in Capacitive Desalination System Using Intercalation Electrode: Effect of Electrode Crystal Structure

Opposite Role of Humic Acid in Capacitive Desalination System Using Intercalation Electrode: Effect of Electrode Crystal Structure

Role of Humic Acid and Chemical Fertilizer in NPK Concentration, Growth and Yield of Broccoli Under Salinity Conditions

A field experiment was conducted during the winter agricultural season 2020. To study the effect of humic acid and fertilizer recommendation, humic acid was supplied with irrigation water at two levels i.e., 0 and 0.25 gm L-1. Nine levels of the fertilizer recommendation were applied according to the fertilizer recommendation of 92kg N.h-1, 200 kg P. h-1 and 150 kg K. h-1 taking the symbols of F1to F9. The results showed the superiority of the treatments of humic acid application( 0.25 gm l-1) in the traits of plant height, Weight of broccoli head, total yield, nitrogen, phosphorous and potassium concentrations, by giving 32.64 cm, 246.5 gm plant-1, 8.215 tons ha-1, 5.541%, 0.3816%, and 3. 641% respectively, the treatment of adding chemical fertilizer at a level of 125% N + 125% P + % K 125 of the fertilizer recommendation(F2) gave the highest plant height of 36.60 cm, Weight of broccoli head of 269.2 g plant-1, total yield of 8.972 tons H-1, nitrogen concentration 5.817% and concentration Phosphorous 0.3141% compared to treatment F9, while treatment F5 gave the highest potassium concentration 3.893% compared to treatment F9 (1.914%).

Role of Humic Acids in the Detoxification of Petroleum Hydrocarbons in Soil

Role of Humic Acids in the Detoxification of Petroleum Hydrocarbons in Soil

Photochemical behavior of pretilachlor on black soil surface

In any agricultural soil, humic-substances are the storehouse of multiple chromophores, which may degrade soil-applied herbicides under sunlight. In the present study, the role of humic acid (HA) on the photolysis of pretilachlor in soil was investigated. Experiments on the photolysis of pretilachlor were conducted on the surfaces of glass, HA-coated glass, black soil, organic matter free (OMF) black soil, and HA-coated OMF-black soil. The half-life values were found 27.72, 43.31, 115.5, 63.00, 138.6 hour, respectively. Thus, the rates of reaction on HA-containing surfaces were slower than that on surfaces devoid of HA, because HA provided either a quenching or shielding effect protecting pretilachlor from sunlight. The photoreaction of pretilachlor generated at least 12 photoproducts through two major routes - the deacylation on amide linkage and the cleavage of the ether linkage. The product 2,6-diethylaniline, one of the photoproducts characterised, is a potent mutagen and has the capacity to contaminate groundwater.

Role of humic acid in bioleaching of copper from waste computer motherboards

In recent years, an increasing attention has been paid to the bioleaching of copper from waste computer motherboards. Here, we investigate the effect of humic acid on the bioleaching of waste computer motherboards using the mixed culture HQ0211. For this, the response surface methodology (RSM) is employed to investigate the effect of pulp density, initial pH and humic acid content on copper recovery. Samples leached at optimized experimental conditions according to RSM were analyzed by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS). The results show that under optimum conditions; the initial pH = 1.53, pulp density = 1.35% (w/v) and humic acid addition = 0.31 g/L, a complete the copper leaching could be achieved. According to the results, the effectiveness of the bacterial and its capability to oxidize humic acid was proved. Overall, the biological leaching was found to be more effective than the chemical leaching. Humic acid can promote the bioleaching of waste computer motherboards, reducing its environmental hazards.

The Role of Humic Acids in Aquaculture: A Review

The Role of Humic Acids in Aquaculture: A Review

The Role of Humic Acid, PP Beads, and pH with Water Backwashing in a Hybrid Water Treatment of Multichannel Alumina Microfiltration and PP Beads.

Photooxidation oxidizes most organic compounds by mineralizing them to small inorganic molecules. In this study, the effects of dissolved organic matter (DOM), pH, and polypropylene (PP) beads concentration on membrane fouling were investigated in a hybrid water treatment process consisting of seven-channel alumina microfiltration (pore size 1.0 μm) and pure PP beads water backwashing with UV irradiation for photooxidation. The synthetic feed was prepared with humic acid and kaolin and flowed inside the microfiltration (MF) membrane. The permeate contacted the PP beads fluidized in the gap of the membrane and module with outside UV irradiation. Membrane fouling resistance (Rf) increased dramatically with an increase in the concentration of humic acid (HA) from 6 mg/L to 8 mg/L. The treatment efficiency of DOM increased dramatically, from 14.3% to 49.7%, with an increase in the concentration of HA. The Rf decreased with an increase of PP beads concentration. However, maximum permeate volume (VT) was acquired at 5 g/L of PP beads. The maximal treatment efficiency of DOM was 51.3% at 40 g/L of PP beads. The Rf increased with an increase in the pH of feed, and the maximum VT was acquired at a pH of 5. The maximal treatment efficiency of DOM was 52.5% at pH 9.

ALLEVIATING THE SALT STRESS EFFECTS IN Salvia splendens BY HUMIC ACID APPLICATION

Salt stress is a serious problem in urban landscape of arid and semi arid regions. To overcome the adverse impacts of salinity, the application of organic matter and plant nutrients in the growth media for improving of plant growth is essential. An experiment was conducted in order to determine the response of Salvia splendens to salinity levels and also the role of humic acid in the salt stress alleviation. In the current experiment five salinity (0, 20, 40, 60, and 80 mM NaCl) and three humic acid (0, 100, 500 and 1000 mg l−1) treatments were prepared. The effects of these treatments were investigated on some growth parameters, physiological characteristics and also biochemical compounds. The results indicated that the growth parameters decreased in saline-treated plants than control plants. Different salinity levels significantly affected relative water content, evaporation rate and also electrolyte leakage. Salinity caused the increase in proline, malondialdehyde, sugar content, DPPH, total phenol content and decrease in chlorophyll, compare to the control plants. Application of humic acid on Salvia splendens, decrease leaf area and plant height compared to the control plants. Thus, regarding the growth parameters, it is probable that the effect of humic acid on the biochemical compounds is similar to salinity effect. The findings suggest that Sage is a sensitive ornamental plant to salinity and humic acid (in the studied levels) could not alleviate the negative effects of salt stress on this plant.

Interfacial interactions of bare and functionalized nanoparticles with quartz sand: Role of humic acid and coexisting divalent cations

Effective application of nanoparticles for in situ groundwater remediation strongly depends on their transportability across a sandy media. Retainment of the nanoparticles within the media is undesired as it will limit their reachability to the treatment zone. Henceforth, the interfacial interactions between the nanoparticles and the sand need to be fully understood. Present work aims to elucidate the retention of iron oxide nanoparticles by quartz sand in solution that are relevant to the typical environmental condition using batch mode mixing study. Results showed that the presence of humic acid and Ca2+ notably alters the nanoparticle-sand interaction in different manners. Bare nanoparticles (BNPs) was found to favourably retained by the sand under acidic medium (94%); while the counterpart that was functionalized with poly(sodium 4-styrenesulfonate), i.e. PSS-NPs, exhibited better rejection from the sand. The addition of humic acid further shield the attraction between PSS-NPs and sand, resulted in 0% retention. Interestingly, in the presence of 1–10 mM Ca2+ ions, the amount of PSS-NPs that was retained by the sand increased to 55%. Such observation may ascribe to the role of Ca2+ in bridging the PSS-NPs and the sand and in screening the repulsion force between both entities. Nevertheless, the retention percentage was successfully reduced to 11.8% when humic acid coexists. Outcome of this work provides an overview on the fate of the bare and surface functionalized nanoparticles upon released into the environmental system.

The role of humic acids on gemfibrozil toxicity to zebrafish embryos

Climate change is expected to alter the dynamics of water masses, with consequent changes in water quality parameters such as dissolved organic carbon (DOC) concentration. DOC levels play a critical role in the fate of organic chemicals, influencing their bioavailability and toxicity to aquatic organisms. This study aimed to evaluate the effects of DOC, particularly humic acids (HA), in the toxicity of gemfibrozil (GEM) - a human pharmaceutical frequently detected in surface waters. Lethal and sublethal effects (genotoxic, biochemical and behavioural alterations) were evaluated in zebrafish embryos exposed to several concentrations of GEM and three HA levels, in a full factorial design. HA significantly increased GEM LC50 values, mainly in the first 72 h of exposure, showing a protective effect. At sublethal levels, however, such protection was not observed since HA per se elicited adverse effects. At a biochemical level, individual exposure to HA (20 mg/L) elicited significant decreases in cholinesterase and glutathione S-transferase activities. Regarding behaviour, effects of individual exposure to HA appear to surpass the GEM effects, reducing the total distance moved by larvae. Both GEM and HA significantly increased DNA damage. Hence, this study demonstrated that abiotic factors, namely HA, should be considered in the assessment of pharmaceuticals toxicity. Moreover, it showed that lethality may not be enough to characterize combined effects since different patterns of response may occur at different levels of biological organization. Testing sublethal relevant endpoints is thus recommended to achieve a robust risk assessment in realistic scenarios.

Deposition Kinetics of Colloidal Manganese Dioxide onto Representative Surfaces in Aquatic Environments: The Role of Humic Acid and Biomacromolecules.

The initial deposition kinetics of colloidal MnO2 on three representative surfaces in aquatic systems (i.e., silica, magnetite, and alumina) in NaNO3 solution were investigated in the presence of model constituents, including humic acid (HA), a polysaccharide (alginate), and a protein (bovine serum albumin (BSA), using laboratory quartz crystal microbalance with dissipation monitoring equipment (QCM-D). The results indicated that the deposition behaviors of MnO2 colloids on three surfaces were in good agreement with classical Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. Critical deposition concentrations (CDC) were determined to be 15.5 mM NaNO3 and 9.0 mM NaNO3 when colloidal MnO2 was deposited onto silica and magnetite, respectively. Both HA and alginate could largely retard the deposition of MnO2 colloids onto three selected surfaces due to steric repulsion, and HA was more effective in decreasing the deposition rate relative to alginate. However, the presence of BSA can provide more attractive deposition site and thus lead to greater deposition behavior of MnO2 colloids onto surfaces. The dissipative properties of the deposited layer were also influenced by surface type, electrolyte concentration, and organic matter characteristics. Overall, these results provide insights into the deposition behavior of MnO2 colloids on environmental surfaces and have significant implications for predicting the transport potential of common MnO2 colloids in natural environments and engineered systems.