Impact Of Organic Acids Research Articles

Impact of Organic Acids and Biological Treatments in Foliar Nutrition on Tomato and Pepper Plants

As a result of global warming related to the development of industry and agriculture, the proportion of atmospheric carbon dioxide has increased, and temperatures have risen to unprecedented levels. As a result, heat stress, aridity, and salinity in soil has increased, leading to significant research focused on soil deterioration and reduced agricultural productivity. Therefore, it is necessary to provide the means to maintain crop productivity. Agricultural research is seeking novel solutions that guarantee stability and increase the production and quality of crops, including innovative models for feeding crops using non-traditional methods, the most important of which is nourishing plants via their leaves to ensure the cessation of their soil consumption. It is considered an integrated pest-control method, and the technique could be included in plant nutrition. Foliar nutrition has been shown to be a perfect substitute for providing secondary nutrients and micronutrients to plants; however, it cannot be substituted for the fertigation or the fertilization of maintain the soil’s macronutrients (nitrogen, phosphorus, and potassium). This study shed light on the most important research, conclusions, and generalizations on the technique of foliar feeding using organic acids and biological treatments, especially for tomato and pepper plants.

Effect of Organic Acids on CO2 Trapping in Carbonate Geological Formations: Pore-Scale Observations Using NMR

Stearic acid is an example of a carboxylic compound naturally present in geological formations (deep saline aquifers and depleted hydrocarbon reservoirs), which renders the rock hydrophobic (CO2-wet) over a geological time scale. Such hydrophobic surfaces are detrimental to residual CO2 trapping. There is, however, a lack of comprehensive dataset about how traces of these organic molecules affect the rock′s CO2 wettability and residual CO2 trapping. We, thus, used in situ NMR T1–T2 2D images to visualize fluid configurations in the pore network and used T1/T2 ratios to assess the microscopic wettability of the rock to pore space fluids subsequent to each process step. The T2 relaxation time was measured to demonstrate displacement processes and evaluate the trapping behavior at the pore scale, which is closely correlated to reservoir-scale flow functions. The trapping in the CO2-wet sample (14%) was significantly lower than that of the analogous water-wet sample (18%). This reduction in CO2 trapping is due to surface macroscopic flow layers acting as conduits allowing slow desaturation of CO2. Importantly, in the CO2-wet sample, trapping predominately occurred in meso- and micropores, whereas trapping in the analogous water-wet rock primarily occurred in macropores. This work thus provides a comprehensive dataset on the impact of organic acids on residual trapping at the pore scale, which ultimately helps to advance industrial-scale implementation of CGS and EOR project schemes in carbonate reservoirs.

Impact of organic acids and sulfate on the biogeochemical properties of soil from urban subsurface environments

Urban subsurface environments are often different from undisturbed subsurface environments due to the impacts of human activities. For example, deterioration of underground infrastructure can introduce elevated levels of Ca, Fe, and heavy metals into subsurface soils and groundwater. Likewise, leakage from sewer systems can lead to contamination by organic C, N, S, and P. However, the impact of these organic and inorganic compounds on biogeochemical processes including microbial redox reactions, mineral transformations, and microbial community transitions in urban subsurface environments is poorly understood. Here we conducted a microcosm experiment with soil samples from an urban construction site to investigate the possible biotic and abiotic processes impacted when sulfate and acetate or lactate were introduced into an urban subsurface environment. In the top-layer soil (0–0.3 m) microcosms, which were highly alkaline (pH > 10), the major impact was on abiotic processes such as secondary mineral precipitation. In the mid-layer (2–3 m) soil microcosms, the rate of Fe(III)-reduction and the amount of Fe(II) produced were greatly impacted by the specific organic acid added, and sulfate-reduction was not observed until after Fe(III)-reduction was complete. Near the end of the incubation, some genera related to syntrophic acetate oxidation and methanogenesis were observed in the lactate-amended microcosms. In the bottom-layer (7–8 m) soil microcosms, the rate of Fe(III)-reduction and the amount of Fe(II) produced were affected by the concentration of amended sulfate. Sulfate-reduction was concurrent with Fe(III)-reduction, suggesting that Fe(II) production was likely due to abiotic reduction of Fe(III) by sulfide produced by microbial sulfate reduction. The slightly acidic initial pH (~5.8) of the mid-soil system was a major factor controlling sequential microbial Fe(III) and sulfate reduction versus parallel Fe(III) and sulfate reduction in the bottom soil system, which had a neutral initial pH (~7.2). 16S rRNA gene-based community analysis revealed a variety of indigenous microbial groups including alkaliphiles, dissimilatory iron and sulfate reducers, syntrophes, and methanogens tightly coupled with, and impacted by, these complex abiotic and biogeochemical processes occurring in urban subsurface environments.

Geochemical properties of 40-year old forested pyrrhotite tailings and impact of organic acids on metal cycling

Under humid climate, surface layers of old Cu–Ni pyrrhotite tailings impoundments are typically oxidized and characterized by depletion of sulfides and secondary precipitation of gypsum, jarosite and goethite; metal contaminants are dominantly associated with goethite. In eastern Canada, historical reclamation of such tailings consisted of a period of amendment with lime, fertilizers, and seeding with grass/legume mixtures, followed by forestation. The current study combines characterization of a 40-year old site planted with jack pine and laboratory experiments to evaluate the mineral evolution and the role of organic acids on mineral weathering of oxidized pyrrhotite tailings. In contrast to a nearby control site with no vegetation, gypsum, jarosite and goethite were absent or present in negligible amount in the root-colonized 0–15 cm surface layer of the forested tailings. The results suggested dissolution of the initial secondary minerals with changes in geochemical properties (e.g., increase in pH and organic C content) and pedogenetic processes in the forested tailings. In contrast to the notable loss in total Fe and S from the 0–15 cm layer, Cu and most of the Ni were retained. A 2-month column leaching experiment was conducted to evaluate the impact of repeated additions of low amounts of oxalate, a common organic acid in the rhizosphere, on metal mobilization in oxidized pyrrhotite tailings at pH 2.5, 4 or 6. Gypsum was readily leached regardless of pH or oxalate treatments, whereas jarosite dissolution increased with increasing pH and was further enhanced by the input of oxalate. Indirect evidence of accelerated goethite dissolution by oxalate was provided by the close correlation between dissolved Fe and Cu in oxalate treatment at pH 4 and 6. The oxalate exhibited an increased efficiency in mobilizing Cu as the pH increased. This study emphasizes the contribution of organic acids in metal cycling and their potential impact on the long-term change in Cu and Ni speciation in the root-colonized tailings which may affect metal uptake and migration in the environment.

Impact of Organic Acids on the Hardness of Silica Xerogels

In this study, silica xerogels were synthesized via the method known in the literature. Various organic acids were used as catalyst while producing xerogels via Sol-gel method and the impact of these acids on xerogels’ surface area and hardness have been examined. 4 different organic acids (some of them were already mentioned in the literature) was selected, which are HOC(COOH)(CH2COOH)2 (citric acid: SA), HO2CCO2H • 2H2O (oxalic acid: OA) (H2N)C6H4SO3H (sulfanilic acid: SAA) HOCH2CH2N(CH2COOH)2, and (N-(2-hydroxyethyl)iminodiacetic acid: N2h). The characterization of the produced materials was performed by FTIR and EDX, whereas their surface area was measured through BET analysis. Their hardness were measured and calculated with a diamond-tipped microhardness device. The hardest material was the silica xerogel synthesized with N-(2-hydroxyethyl) iminodiacetic acid, whereas the material with lowest hardness was the one synthesized with oxalic acid. The silica xerogel with the largest surface area was the one with the highest hardness. The data indicated that the acid added during the synthesis reaction affect the hardness of the xerogel and hardness can be associated with pKa values of the added acids.

Impact of Organic Acid and Gas Bubbling on Copper and Copper Oxide Etch-Rates in Diluted HF Solution

In the damascene integration scheme, copper is used as an interconnect material. In a damascene integration scheme, the etch treatment by a plasma process leads to the formation of polymer residues, copper sputtered on the dielectric side wall, copper oxidation at the bottom of the via and copper precipitates at the hard mask surface. In order to remove these impurities, a post-via etch cleaning is mandatory [1]. Several aqueous cleaning solutions constituted of diluted HF and an organic acid were tested. Diluted HF was mainly used to remove the polymer residues and the organic acid to clean the copper surface. These mixtures were already studied and compatible with several porous and dense ULK materials [1]. In this paper, the impact of organic acids and gas bubbling in diluted HF solution on copper and copper oxide-dissolution rate is presented. Firslty the copper oxide and the copper etch-rates and the roughness were obtained from the kinetics of copper dissolution determined by X-ray reflectometry characterization [3]. Secondly, speciation calculations were performed in order to explain the copper etch-rates differences as a function of the solutions and gas bubbling.

Enhanced cadmium accumulation in maize roots—the impact of organic acids

Low molecular weight organic acids are important components of root exudates and therefore, knowledge regarding the mechanisms of cadmium (Cd) uptake and distribution within plants under the influence of organic acids, is necessary for a better understanding of Cd behavior in the plant–soil system. In this study, acetic and malic acids increased the uptake of Cd by maize (Zea mays L. cv. TY2) roots and enhanced Cd accumulation in shoots under hydroponic conditions. Concentration-dependent net Cd influx in the presence and absence of organic acids could be resolved into linear and saturable components. The saturable component followed Michaelis–Menten kinetics, which indicated that Cd uptake across the plasma membrane was transporter-mediated. While the K m values were similar, the V max values in the presence of acetic and malic acids were respectively 6.0 and 3.0 times that of the control. Zinc transporters were the most probable pathways for Cd accumulation. It was hypothesized that Cd(II)–organic acid complexes associated with the root zone, could decompose and liberate Cd2+ for subsequent absorption by maize roots; and that in the layer of the roots or within the root free space, depletion of Cd2+ was buffered by the presence of Cd(II)–organic acid complexes. Plant response to elevated Cd levels involved overproduction of organic acids in maize roots as a resistance mechanism to alleviate Cd toxicity.

Cadmium mobilisation and plant availability – the impact of organic acids commonly exuded from roots

The present work highlights metal-organic acid interactions with special reference to their plant availability. Pot experiments were conducted to investigate the effect of various organic (carboxylic and amino) acids on the uptake and translocation of root-absorbed Cd by maize (Zea mays) plants grown in sand and soil culture. Statistically significant increases in Cd accumulation from Cd-treated plants in the presence of increasing concentrations of organic acids, suggest the existence of Cd-organic acid interactions in the soil-plant system. In order to support the above hypothesis of formation of organically bound Cd, separate experiments were performed to synthesize and estimate its various forms viz. cationic, anionic and neutral. The chemical nature of the organically bound forms was ascertained by electrophoretic experiments. Amino acids have been found to be less effective in the mobilisation of cadmium compared to carboxylic acids. The results are discussed on the basis of the potential of organic acids to form complexes with Cd.