Concentrations Of Ethylenediaminetetraacetic Acid Research Articles

Effect of EDTA with porous balloon on calcified lesion: An atherosclerotic cadaver study.

Ethylene diamine tetra-acetic acid (EDTA) is a chelating agent used to dissolve calcium deposits but evidence in decalcifying atherosclerotic lesions is limited. We assessed the feasibility and efficacy of EDTA delivered via porous balloon to target calcified lesions in cadaveric below-the-knee (BTK) arteries. Using porcine carotid arteries, EDTA concentration was measured in the arterial wall and outside the artery at the 0-, 0.5-, 4-, and 24-h circulation after the injection through a porous balloon. In cadaver BTK samples, the proximal and distal anterior tibial artery (ATA) and distal posterior tibial artery (PTA) were studied. EDTA-2Na/H2O or EDTA-3Na/H2O were administrated using a porous balloon, then circulated for 6 h for EDTA-3Na/H2O and 24 h for EDTA-2Na/H2O and EDTA-3Na/H2O. Micro-CT imaging of the artery segments before and after the circulation and cross-sectional analyses were performed to evaluate calcium burden. In the porcine carotid study, EDTA was delivered through a porous balloon present in the arterial wall and was retained there for 24 h. In BTK arteries, cross-sectional analyses of micro-CT revealed a significant decrease in the calcium area in the distal ATA segment under 24-h circulation with EDTA-2Na/H2O and in the distal ATA segment under 24-h circulation with EDTA-3Na/H2O. The proximal ATA segment under 6-h circulation with EDTA-3Na/H2O showed no significant change in any parameters of calcium CONCLUSION: EDTA-3Na/H2O or EDTA-2Na/H2O with longer circulation times resulted in greater calcium reduction in atherosclerotic lesion. EDTA may have a potential therapeutic option for the treatment of atherosclerotic calcified lesions.

Unraveling the Impact of Ethylenediaminetetraacetic Acid Chelating Agents on the Oil Recovery Processes: An Insight into Its Role in Fluid-Fluid and Rock-Fluid Interactions.

In recent years, chelating agents have garnered increasing attention due to their unique capabilities in addressing challenges associated with chemically enhanced oil recovery materials. Most previous studies have primarily focused on examining the influence of chelating agents on rock-fluid interactions. However, their effects on fluid-fluid interactions, specifically on interfacial tension (IFT) characteristics under various conditions, remain relatively unknown. This study investigates the effect of crucial reservoir parameters on the performance of ethylenediaminetetraacetic acid (EDTA) chelating agents in the IFT between crude oil and brine. Furthermore, the study evaluated the impact of varying concentrations of this agent on rock wettability alteration, zeta potential, and spontaneous imbibition. The results illustrated that introducing EDTA at high concentration into seawater (SW) solution reduced the IFT by 85%. Additionally, while higher pH levels contributed to IFT reduction due to increased hydroxyl ions, excessive salinity levels resulted in elevated IFT. Raising the temperature from 30 to 75 °C further decreased the IFT, changing the IFT for optimal EDTA concentration from 20.43 to 2.56 mN/m (∼88% reduction). The changes in zeta potential and contact angle measurements indicated that solutions of 5 and 7 wt % EDTA shifted rock wettability from oil-wet to strongly water-wet, resulting in the wettability alteration index of 1.01 and 1.02, respectively. Inductively coupled plasma analysis, on the other hand, revealed substantial chelation of metal ions from both the solution and rock when EDTA was added to the rock/SW system. This resulted in a significant increase in Ca2+ ions and a decrease in Mg2+ ions, attributed to the multi-ion exchange phenomenon.

Coupling interface constructions of ZnO@ZnS@FeOOH for photocatalytic hydrogen production performance

Photocatalysis is a reliable method to solve energy crisis and generate green energy hydrogen. ZnO@ZnS (ZOS) formed heterojunction repressed carrier complexation and thus enhanced photocatalytic performance, but its low photoresponse efficiency limited its photocatalytic performance. Therefore, in this paper, ZnO@ZnS was modified with ethylene diamine tetraacetic acid (EDTA) to form ZnO@ZnS@FeOOH composites with coupling interface. The modification of EDTA could inhibite the oxidation of FeOOH during the synthesis process, and what’s more it could enhance the charge transfer at the heterojunction interface to promote the separation of electron-hole pairs and photoresponsive ability to further enhanced the hydrogen precipitation performance. The concentration of EDTA and Fe sources were regulated to investigate the photocatalytic hydrogen production capacity of the composites. The results indicated that the ternary composite ZnO@ZnS@FeOOH had the superior hydrogen evolution performance with the hydrogen evolution rate of 529.17 umol g−1 h−1, which was 2.4 times higher than that of ZOS. EDTA acts as an electron channel to enhance the inter-interfacial electron transfer capability, and the loading of FeOOH formed a heterojunction structure, which promoted carrier separation and enhanced the photoresponse. It’s the synergistic effect to enhanced the photocatalytic hydrogen production performance. This paper provided a method for the construction of ternary heterojunctions and interfacial charge transport channels.

Polycarboxylate functionalized magnetic nanoparticles Fe3O4@SiO2@CS-COOH: Preparation, characterization, and immobilization of bovine serum albumin

Magnetic nanoparticles with increasing superparamagnetism and magnetic targeting have found widespread application in fields such as food and medicine. In this study, polycarboxylated magnetic nanoparticles (Fe3O4@SiO2@CS-COOH) were prepared by surface functionalizing iron tetraoxide (Fe3O4) nanoparticles with ethylenediaminetetraacetic acid (EDTA) as a modifier. The appropriate degree of functionalization modification was obtained by adjusting the EDTA concentration and the ratio of cross-linking agents. The prepared magnetic nanoparticles were analyzed with structural and property characterization. The results showed that the Fe3O4@SiO2@CS-COOH magnetic nanoparticles prepared with 4 % EDTA and cross-linking agents at a molar ratio of 3:4 were uniform in particle size, with an average size of roughly 7 nm, and possessed an abundant carboxylate content (310.8064 μmol/g) and a high magnetization intensity (35.05 emu/g). As a model protein, bovine serum albumin (BSA) was immobilized on the surface of magnetic particles. The largest amount of immobilized protein was 500.4376 mg BSA/g at pH 4.0 and no extra salt ions. According to molecular docking simulations, its immobilization was due to the interaction of amino and carboxyl groups at the Fe3O4@SiO2@CS-COOH/BSA interface. Fe3O4@SiO2@CS-COOH possesses a large number of carboxyl groups, strong protein immobilization, and magnetic responsiveness, which may have potential applications in biomedical and food fields.

Regulating the distribution of phosphorus in sewage sludge hydrothermal carbonization products by complexation pretreatment

In this study, we investigated the effects of the concentrations of four pretreatment complexing reagents, namely ascorbic acid (AS), citric acid (CA), N, N-bis (carboxymethyl) glutamic acid (GLDA), and ethylenediaminetetraacetic acid (EDTA), on the phosphorus contents and forms in hydrothermally carbonized sludge products. The results showed that among the four complexing reagents, EDTA had the greatest effect on the phosphorus transfer from the solid phase to the liquid phase during the hydrothermal process of the sludge, followed, respectively, by GLDA, CA, and AS. The phosphorus proportion of the liquid phase was 63.96% under hydrothermal process temperature, reaction time, and EDTA concentration of 160 °C, 60 min, and 0.2 mol/L, respectively. The results showed formations of EDTA complexes with Ca, Fe, and Al in the sludge, releasing phosphorus bound to the metal ions into the liquid phase. The highest total phosphorus concentration in the liquid phase was 2533.31 mg/L following the increase in the hydrothermal process temperature from 100 to 160 °C. However, the Fe and Al-EDTA complexes were thermally decomposed after continuously increasing the hydrothermal process temperature to 240 °C, resulting in a readsorption of phosphorus to the solid phase with Fe, Al, and other metals and, consequently, decreasing the phosphorus content to 880.93 mg/L in the liquid phase. The results of this study provide a scientific basis for regulating phosphorus distribution in the solid and liquid phases of hydrothermally carbonized sludge products and effectively recovering phosphorus in the liquid phase.

New insights into the effect of EDTA on pyrite oxidation and N2O emission during pyrite autotrophic denitrification

Pyrite autotrophic denitrification (PAD) is crucial for removing nitrate in groundwater and advanced wastewater treatment. While disulfide is typically seen as the electron donor, the role of iron in pyrite oxidation is often ignored. In this study, Ethylene Diamine Tetraacetic Acid (EDTA) had been proven to have the potential to facilitate pyrite oxidation by promoting the solubility of iron in solution, thereby enhancing the kinetics of pyrite autotrophic denitrification. Firstly, EDTA could improve PAD performance, i.e. the nitrate removal rate at EDTA addition of 5 mM was 0.69 mg N/L•h and twice that of the control. However, high concentrations of EDTA inhibited the activity of the nitrous oxide reductase, resulting in the maximum accumulation of N2O reaching 13.26 mg N/L with an EDTA concentration of 15 mM. Furthermore, the X-ray Photoelectron Spectroscopy (XPS) result indicated that the EDTA addition promoted the production of bioavailable sulfur, with the concentration of S0 at 15 mM EDTA being more than twice higher than that of the control. Transmission electron microscopy (TEM) analysis indicated that EDTA could relieve the damage of iron encrustation on cell activity because it was difficult for EDTA-chelated ferrous iron to penetrate the cell membrane. Microbial community analyses showed an increase abundance of iron oxidizing bacteria, suggesting that EDTA addition promoted the bioavailability of iron for Fe(II) autotrophic denitrification. Overall, this study will provide insights into the understanding of oxidation mechanism of PAD process and the practical application for efficient nitrogen removal and N2O mitigation.

Extraction of copper (II) ions from oxidized ore in the presence of an ethylenediaminetetraacetic acid solution in a basic environment

An experiment was conducted to obtain copper (II) ions in a basic environment using ethylenediaminetetraacetic acid (EDTA) and oxidized copper minerals from Cerro Azoguini in Puno, Peru. Specific objectives included investigating the solubility of Cu2+ ions in a mineral with high silica, limestone, and iron content, as well as studying the influence of pH, EDTA concentration, and extraction time. 1.5 grams of ground mineral at -100 mesh (150 µm), with 80% pass and 6% solids, were leached with a 0.5 M NaHCO3 solution at different pH levels and EDTA concentrations. The results indicated the extraction of 3.5 g/L of Cu2+ ions at pH 10 with 0.12 M EDTA, without agitation, at room temperature (19°C), over a period of 83 hours. It was observed that the NaHCO3 solution extracted copper from the mineral, and EDTA quickly chelated it, forming ionic complexes such as CuHEDTA ∧ (1−), CuHEDTA ∧ (2−), and CuHEDTA ∧ (3−). Other metals present in the gangue were not chelated by EDTA, demonstrating its high selectivity based on solubility constants and precipitation formation at different pH levels. Additionally, high copper extraction rates were obtained at a pH of 13.15, possibly due to decreased protons and increased ions from both the reagent and leached mineral. In conclusion, the physicochemical analyses revealed the feasibility of obtaining Cu2+ ions by solubilizing oxidized minerals, followed by rapid chelation with EDTA to form diverse metal complexes depending on the pH of the medium.

Pattern of Lead Accumulation in Two Vegetable Plants Due to EDTA Treatment

Phytoextraction and phytostabilization are the most consistent patterns or mechanisms of action of phytoremediation. One of the elements influencing the mechanism of action of heavy metal absorption by plant species is Ethylene Diamine Tetraacetic Acid (EDTA). Therefore, this study aimed to determine the pattern of phytoremediation in water spinach and spinach due to the addition of EDTA in the soil. The treatments tested by factor 1 were water spinach (T1) and spinach (T2), and factor 2 was the concentration of EDTA consisting of 3 levels, 0, 3, and 6 g/polybag. Each treatment was repeated three times on five sample plants. Furthermore, growth evaluation was carried out in the first six days after planting and conducted every 3 days. It was carried out on variables such as changes in plant height, leaves area, total root length, Pb content in the soil, fresh and dry weight of shoots and roots, shoot, seeds, and Translocation Factor (TF). The results showed that water spinach and spinach had different mechanisms of action due to the application of EDTA in Pb-contaminated media. Furthermore, water spinach and spinach have a mechanism of phytoextraction and phytostabilization, respectively. Therefore, spinach is safer than water spinach when grown in Pb-polluted land.

Inhibition and Reduction of Biofilm Production along with Their Antibiogram Pattern among Gram-Negative Clinical Isolates.

Bacterial biofilm is a significant virulence factor threatening patients, leading to chronic infections and economic burdens. Therefore, it is crucial to identify biofilm production, its inhibition, and reduction. In this study, we investigated biofilm production among Gram-negative isolates and assessed the inhibitory and reduction potential of ethylene diamine tetra acetic acid (EDTA) and dimethyl sulfoxide (DMSO) towards them. In addition, we studied the antimicrobial resistance pattern of the Gram-negative isolates. Bacterial isolation and identification was done using standard microbiological techniques, following the Clinical and Laboratory Standards Institute (CLSI) guideline, 28th edition. The Kirby-Bauer disk diffusion method was used to determine the antibiotic susceptibility pattern of the isolates, and β-lactamase production was tested via the combination disk method. Biofilm formation was detected through the tissue culture plate (TCP) method. Different concentrations of EDTA and DMSO were used to determine their inhibitory and reduction properties against the biofilm. Both inhibition and reduction by the various concentrations of EDTA and DMSO were analyzed using paired t-tests. Among the 110 clinical isolates, 61.8% (68) were found to be multidrug resistant (MDR). 30% (33/110) of the isolates were extended-spectrum β-lactamase (ESBL) producers, 14.5% (16/110) were metallo-β-lactamase (MBL), and 8% (9/110) were Klebsiella pneumoniae carbapenemase (KPC) producers. Biofilm formation was detected in 35.4% of the isolates. Biofilm-producing organisms showed the highest resistance to antibiotics such as cephalosporins, chloramphenicol, gentamicin, and carbapenem. The inhibition and reduction of biofilm were significantly lower (p < 0.05) for 1 mM of EDTA and 2% of DMSO. Isolates forming biofilm had a higher resistance rate and β-lactamase production compared to biofilm nonproducers. EDTA and DMSO were found to be potential antibiofilm agents. Hence, EDTA and DMSO might be an effective antibiofilm agent to control biofilm-associated infections.

Effects of EDTA on the leaching behaviors of Cs(I) and Co(II) from cement waste forms

Cementation is extensively employed for immobilizing radionuclides in low- and intermediate-level radioactive wastes generated during the decommissioning of nuclear power plants. Ethylenediaminetetraacetic acid (EDTA), used as a decontamination agent during the decommissioning process, can be introduced into the cement waste form containing radionuclides. This study investigated the effects of the EDTA present in simulated radioactive decommissioning wastes on the leaching behaviors of Co and Cs immobilized in the cement waste form. Co leaching was facilitated by the formation of highly mobile Co–EDTA complexes. However, Cs leaching was impeded by the competition for leaching with other metal–EDTA complexes. Moreover, the EDTA-induced carbonated layer with a dense pore structure played a crucial role as a retardation barrier for the Cs leaching. The calcite contents of the samples with 8 wt% EDTA were approximately three times higher than those of the samples without EDTA. The introduced EDTA affected the leaching behaviors of both Co and Cs, as well as the microstructure evolution of the cement waste form. Nevertheless, the addition of EDTA had a relatively low positive effect on the efficiency of Cs immobilization, but also an obvious negative effect on the efficiency of Co immobilization, regardless of the concentration of EDTA. Finally, an EDTA dosage of 1 wt% in the cement waste forms containing Co or Cs is suggested as a potential waste acceptance criterion for solidified low- and intermediate-level radioactive waste.

Effects of ethylenediaminetetraacetic acid on growth and survival of long‐spined sea urchin Diadema antillarum larvae

AbstractObjectiveThe presence of heavy metals in seawater is a major challenge for hatchery culture of sea urchin larvae due to their sensitivity to metal pollution. The impact of heavy metals in seawater for sensitive marine larviculture could be minimized via chelation of metals using chemical compounds such as ethylenediaminetetraacetic acid (EDTA).MethodsIn this study the effects of EDTA were tested for the long‐spined sea urchin Diadema antillarum during larviculture at two concentrations (10 μM and 50 μM) and two exposure durations (6 and 24 days postfertilization). Growth and survival of larvae were evaluated as response variables.ResultSignificant differences in growth and survival of larvae were found among the treatments at different EDTA concentrations and exposure durations. The 10‐μM EDTA treatment enhanced growth and survival of larvae relative to control for both exposure durations. The 50‐μM EDTA treatment was unsuitable for long‐spined sea urchin larviculture due to reductions in growth and survival.ConclusionThe use of 10 μM EDTA during embryo incubation and larviculture is expected to improve long‐spined sea urchin larval fitness, leading to improved hatchery production.

Impact of ethylene diamine tetraacetic acid on physiochemical parameters and yield attribute in two varieties of Brassica juncea under lead stress.

Lead (Pb) is one of the most toxic elements on earth. The harmful effects of Pb at higher concentrations were seen on plant vegetation because plants are directly exposed towards it. Indian mustard, a well-known hyperaccumulator plant is the most promising crop for the environment, engaged in a variety of scenarios for ecological cleanup. In the present study, we used ethylene diamine tetraacetic acid (EDTA), a chelating agent that is of remarkable efficiency. The pot experiments were conducted in soil pretreated with 1000 mgkg-1 Pb with different concentrations of EDTA (2-10 mmol). All the growth parameters were reduced significantly in the plants treated with Pb and EDTA, however, a non-significant effect was observed in 5 mmol EDTA compared to Pb alone treatment. Photosynthetic pigments yield, nitrate reductase activity and NPK content were affected negatively; in contrast, superoxide dismutase and catalase activity was increased in Pb and Pb+EDTA treated in both the varieties. The Pb accumulation was elevated significantly by the augmentation of 5 mmol EDTA in both varieties. Accumulation of Pb in the shoot was higher in PM 25 than in P. Vijay, whereas root Pb accumulation showed the opposite, i.e., more Pb in roots of P. Vijay than PM 25. Moreover, The Pb accumulation per plant was observed more in P. Vijay as compared to PM 25. Hence, the present study implies that the augmentation of Pb-polluted soil with EDTA works well while dealing with B. juncea assisted phytoremediation and P. Vijay to be a stronger variety than PM 25. Further, 5 mmol of EDTA was optimum for phytoremediation of the soil polluted with up to 1000 mg Pb kg-1 soil.

Morphological Analyses of Effects of Endodontic Irrigant Solutions Using a Root Canal Model and an Immersion Model.

This study aimed to compare an experimental model simulating clinical root canal irrigation (root canal model) with a conventional experimental model immersing dentin sample to irrigants (immersion model) to evaluate removal of the smear layer and decalcification of the root canal dentin using sodium hypochlorite (NaOCl) and two different concentrations of ethylenediaminetetraacetic acid (EDTA) solution. Forty-five single-rooted extracted human teeth were prepared using a Ni-Ti rotary file. EDTA, NaOCl, and citric acid were used in the root canal models and the immersion models. After the irrigation protocol, root canal surfaces were observed under scanning electron microscopy. Residual smear and decalcification of the root canal dentin were evaluated objectively by measuring the percentage of the area occupied by visible dentin tubules, the number of visible dentin tubules, and the mean area of a visible single dentin tubule. Root canal and immersion models with the same irrigation protocol showed significantly different results for smear residues and decalcification of root canal dentin. In the root canal model, neither different EDTA concentrations nor the order of EDTA and NaOCl applications significantly impacted smear residues or decalcification of root canal dentin. Furthermore, no erosion of the root canal dentin surface was observed in any experimental groups in the root canal model using EDTA and NaOCl compared to intact dentin. Experimental design affected results for residual smear layer and decalcification of root canal dentin. The order of EDTA and NaOCl use and the concentration of EDTA did not affect results. EDTA and NaOCl irrigation did not cause erosion in the root canal model in this study.

One-step leaching mechanism for total elemental recovery from spent lithium-ion batteries utilizing ethylene diamine tetraacetic acid

A process capable of leaching full component valuable metals including Ni, Co, Mn, and Li from spent lithium-ion batteries (LIBs) without additional reducing agents has been proposed. As a strong chelating organic acid, ethylene diamine tetraacetic acid (EDTA) is suitable for recovering up to 99.9 % of each metal element under optimal conditions of EDTA concentration of 0.5 M, liquid-solid ratio of 30:1 mL g−1, the temperature of 353 K, and leaching duration of 2 h. Kinetic analysis shows that the entire leaching process is controlled by the chemical reaction, accompanied by the apparent activation energy of 56.6 kJ mol−1 for Ni, 68.2 kJ mol−1 for Co, 49.5 kJ mol−1 for Mn, and 53.0 kJ mol−1 for Li, respectively. The thermodynamic mechanism indicates that EDTA acts as a proton chelating agent and Fe/Al exhibits a synergistic reduction effect during leaching process. In addition, the whole process is divided into three stages, where the behavior of each substance is specified. The individual ions in the leachate are separated by precipitation with different reagents and the filtrate can be recycled for the next stage of leaching, which also provides a novel approach for an industrial one-step leaching process.

Advanced Liquid Chromatography with Tandem Mass Spectrometry Method for Quantifying Glyphosate, Glufosinate, and Aminomethylphosphonic Acid Using Pre-Column Derivatization.

Analytical limitations make it challenging to develop effective methodologies for understanding glyphosate-based herbicide levels in drinking water and groundwater. Due to their lack of chromophores and zwitterionic nature, glyphosate-based herbicides are difficult to detect using traditional methods. This paper offers a straightforward method for quantifying glyphosate, glufosinate, and aminomethylphosphonic acid (AMPA) via 9-fluorenylmethylchloroformate (FMOC-Cl) pre-column derivatization and analysis by liquid chromatography with tandem mass spectrometry (LC-MS/MS). Method development was focused on optimizing the critical variables for optimal derivatization using a 24-factorial design. We found that complete derivatization significantly depends on the inclusion of borate buffer to create the alkaline conditions necessary for aminolysis. Ethylenediaminetetraacetic acid (EDTA) addition was critical to minimize metallic chelation and ensure reproducible retention times and peaks. However, EDTA concentrations ≥5% decreased peak intensity due to ion suppression. The FMOC-Cl concentration and derivatization time exhibited a direct proportional relationship, with the complete reaction achieved with 2.5 mM FMOC-Cl after 4 h. Concentrations of FMOC-Cl greater than 2.5 mM led to the formation of oxides, which interfere with the detection sensitivity and selectivity. Desirable results were achieved with 1% EDTA, 5% borate, and 2.5 mM FMOC-Cl, which led to complete derivatization after 4 h.

Kinetic Modeling of the Anodic Degradation of Ni-EDTA Complexes: Insights into the Reaction Mechanism and Products

In this study, an electrochemical advanced oxidation process (EAOP) was employed to effectively degrade complexes of nickel and ethylenediaminetetraacetic acid (EDTA) present in electroless nickel plating wastewaters. Our results show that Ni-EDTA complexes can be effectively degraded by an EAOP with degradation of the complexes occurring at/near the anode surface via interaction with hydroxyl radicals generated on water splitting. Our results further show that the rate of Ni-EDTA degradation is not a function of the rate of any particular chemical reaction but, rather, is controlled by the rate of transport of Ni-EDTA to the anode surface. The oxidation of EDTA to smaller noncomplexing entities releases Ni2+, which is subsequently deposited onto the cathode as Ni0. While complete Ni-EDTA removal and Ni recovery are achieved within 2 h, the overall TOC removal by EAOP is limited, with only 50% TOC removal achieved after 2 h of treatment. The low affinity of small molecular weight EDTA degradation products (such as formic acid, glycine, oxamic acid, and acetic acid) for the anode surface limits oxidation of these compounds and overall TOC removal by the anodic oxidation process. We have developed a mathematical kinetic model that satisfactorily describes Ni-EDTA removal, Ni recovery, and TOC removal over a range of Ni and EDTA concentrations and provides a good description of the oxidation of various EDTA degradation intermediates. The mathematical model developed here, when coupled with the hydrodynamics of the electrochemical cell using a computational fluid dynamics tool, can assist in both cell design and the selection of operating parameters such that the performance of the EAOP process for Ni-EDTA degradation and TOC removal is optimized.

Experimental Investigation and Modeling of Fluid and Carbonated Rock Interactions with EDTA Chelating Agent during EOR Process

The injection of chemical fluids into oil reservoirs is gaining widespread attention in light of the declining conventional oil resources by recovering more hydrocarbons. This study is focused on using a chemical called ethylenediaminetetraacetic acid (EDTA) chelating agent in a carbonate reservoir to shed light on contact angle differences of 625 aged thin sections and rock dissolution under the influence of different pHs, temperatures, chelating times, and various chelating agent concentrations in seawater. According to a rock dissolution test, at least 5 wt % of EDTA chemical is needed to obtain oil recovery. A ζ potential test and scanning electron microscopy (SEM) images revealed that the mechanism of adsorption at low pH values and the expansion of the electrical double layer (EDL) at high pH values were responsible for wettability alteration, and an increase in EDTA concentration intensified each mechanism. Interfacial tension (IFT) measurements also showed that adding 1 and 10 wt % of the EDTA to the seawater solution reduced the IFT by 67.75% and 76.08%, respectively. The contact angle experiments demonstrated an increase in the mechanism that leads rock to behave more hydrophilically as pH, solution temperature, and chelating agent concentration in saltwater increased. Artificial neural network (ANN) methods also led to the introduction of a model to predict the contact angle employing multilayer perceptron neural networks (MPNN) and cascade feedforward neural networks (CFFNN). The CFFNN with two hidden neurons and trained by the Levenberg–Marquardt backpropagation algorithm is the most accurate model when comparing the accuracy of models for predicting contact angle values. The CFFNN model indicated that the weight percentage of the chelating chemical, which has a share of about 90%, had the greatest influence on the contact angle, and chelating time, with a share of less than 10%, had the least.

Inhibition and Activation of Humoral Phenoloxidase and Their Effect on Divalent Cations in the Hemolymph of Freshwater Prawn Macrobrachium rosenbergii (De Man, 1879)

The aim of the present study is to examine phenoloxidase (PO), a copper-containing enzyme that plays a crucial role in the immune responses of arthropods, especially crustaceans and insects. However, PO activity is present in the plasma of the hemolymph without pathogenic infections. Here we report the PO activity in the plasma of M. rosenbergii was spectrophotometrically studied. The phenylthiourea (PTU) inhibition of PO activity was found to be the highest at a 10 mM concentration. The determination of PO activity was also highest activated by trypsin (2 mg.ml-1), detergents like sodium dodecyl sulphate (SDS; 8 mg.ml-1) and laminarin (4 mg.ml-1) enzyme expression. The effect of divalent cations on PO activity like sodium chloride (100 mM), calcium chloride, magnesium chloride, manganese chloride, and potassium chloride (10 mM) affected the activation of PO activity in trypsin, SDS, and laminarin. However, these divalent cations only slightly affected PTU inhibition of PO activity. In addition to calcium chloride, the PO activity with trypsin and laminarin is more or less the same as with control, but a great enhancement was found in SDS, which indicates that the combination of SDS with calcium chloride is required for increasing the PO activity in M. rosenbergii. The concentration of ethylenediaminetetraacetic acid (EDTA) of 1–10 mM has the maximum inhibition in PTU and activation of trypsin, SDS, and laminarin, which indicates that EDTA is a divalent cation chelator that affects the PO activity in M. rosenbergii. Hence, an attempt has been made to optimize the conditions for inhibitor, activators, divalent cations, EDTA sensitivity, and phenoloxidase activity in the plasma of the freshwater prawn M. rosenbergii.

Effect of ethylenediaminetetraacetic acid on the photocatalytic degradation of Rhodamine B under visible light irradiation using graphitic carbon nitride

Graphitic carbon nitride (GCN) is a well-known visible light photocatalyst and it is widely used for the degradation of organic compounds. Melamine is the most commonly used precursor for preparing GCN. However, the photocatalytic efficacy of GCN prepared using melamine is very poor. To improve the efficiency, a mixture of melamine and ammonium chloride (1:4 ratio) was used as a precursor in this study to prepare the modified GCN, named as AGCN. Rhodamine B (Rh B) was chosen as a model pollutant. In addition, the study also aims at to evaluate the effect of addition of ethylenediaminetetraacetic acid (EDTA) on the extent of degradation of Rh B. The photocatalytic ability of AGCN for the degradation of Rh B under visible light irradiation was evaluated using a photoreactor with 140 W LED lamps (Wear and Friction Tech, Chennai). The concentrations of AGCN, Rh B and EDTA were kept constant at 100 mg, 10 ppm and 1 mM, respectively. The Rh B dye solution and AGCN mixture were ultrasonicated for 10 min to effectively disperse the catalyst. Before irradiation, the Rh B-AGCN solution mixture was kept in dark under mechanical agitation (500 rpm) for 30 min to enable them to reach an adsorption–desorption equilibrium. The photocatalytic degradation experiments were conducted for a period of 60 min. An aliquot of the solution mixture was drawn for every 15 min, centrifuged at 4000 rpm and analyzed for its absorbance at 554 nm. The study concludes that AGCN is an effective visible light photocatalyst for the degradation of Rh B and addition of 1 mM EDTA accelerates the rate of degradation. EDTA is a scavenger for photons (h+). However, when superoxide radicals (•O2–) are the main active species, addition of EDTA provides an additional supporting mechanism of suppressing the recombination of electron-hole pairs, thus enhancing the rate of degradation of Rh B.

Visible Light Induces Site-Specific Oxidative Heavy Chain Fragmentation of a Monoclonal Antibody (IgG1) Mediated by an Iron(III)-Containing Histidine Buffer

Fragmentation of therapeutic monoclonal antibodies represents a critical quality attribute. Here, we report a novel visible light-induced heavy chain fragmentation of IgG1 mediated by an Fe(III)-containing histidine (His) buffer. Based on non-reducing sodium dodecylsulfate-polyacrylamide gel electrophoresis and mass spectrometry analysis, IgG1 fragments with apparent molecular weights of ∼130, ∼110, and ∼22 kDa were detected in photo-irradiated samples and were mechanistically rationalized with an oxidative cleavage at Thr259. Specifically, the reactions are proposed to involve the generation of an intermediary alkoxyl radical, which undergoes β-cleavage to yield a glycyl radical. The latter either converts into Gly or adds oxygen and follows a peroxyl radical chemistry. The cleavage process requires the presence of His, while only negligible yields of cleavage products are formed when His is replaced by acetate, succinate, or phosphate buffer. Importantly, the fragmentation can be prevented by ethylenediaminetetraacetic acid (EDTA) only when the EDTA concentrations are in significant excess over the concentrations of Fe(III) and proteins, suggesting a strong binding between Fe(III) and IgG1.