Acid Chelating Research Articles

Reinforcing effect of surface-modified steel fibers in ultra-high-performance concrete under tension

The direct tensile behavior of ultra-high-performance surface-modified steel fiber-reinforced concrete was evaluated in this study. Various chemical modifications were applied to steel fibers, including acetone washing, hydrochloric acid washing, zinc phosphating, silica coating, and chelation using an ethylenediaminetetraacetic acid (EDTA) electrolyte solution, which improved the tensile strength, tensile strain, and g-value to a maximum of 17.76 MPa, 1.22%, and 144.51 kJ/m3, respectively. Acetone washing and EDTA chelating were the most effective methods for improving the tensile strength, whereas silica coating was the best for improving the strain capacity and energy absorption capacity. The optimal treatment time for EDTA chelation treatment was approximately 6 h, and the tensile performance decreased considerably after 12 h of treatment. Comparing these results with those of pullout experiments revealed that a high shear stress should be maintained after the fiber has fully debonded to effectively enhance the post-cracking tensile performance.

Evaluation of safety and tolerability of iron amino acid chelate therapy in pregnant women

Background: Anemia is a major health problem. Iron deficiency is the most common cause of anemia during pregnancy. It can be associated with increased preterm labor, preeclampsia, and maternal sepsis. It can also lead to fetal loss or even perinatal deaths. The aim of the study was to monitor the oral iron therapy [Iron Amino Acid Chelate (IAAC) equivalent to elemental iron 30 mg] administered according to hospital practice and to determine the safety, and tolerability of IAAC in pregnant women.Methods: The data of pregnant women attending the outpatient department of the hospital for antenatal care between March 2020 and February 2021 and prescribed IAAC was retrospectively analyzed. It was of interest to note the changes in the Hemoglobin (Hb) levels and serum ferritin levels. These parameters were considered as the primary efficacy parameter and were analyzed by the paired t-test.Results: The data indicated very well tolerance to IAAC preparation with increase in Hb levels. After 12 week of treatment, there were significant increases in hemoglobin levels with mean rise in Hb level was 7 to 9 gm/dL. A statistically significant difference was observed at the 4th, 8th, and 12th weeks from the baseline value to each evaluation in the Hb level due to the supplementation of oral iron. The change in the serum ferritin levels was found to be statistically significant at the 12th week from the baseline values. Most of the women tolerated the oral IAAC preparationConclusions: This retrospective analysis showcased a significant improvement in the Hb and serum ferritin levels of pregnant women after 12 weeks.

Generalized Multidentate Ligand Chelating‐Grafting Strategy for Construction of Amorphous Metal Oxides Based Triple‐Layered Nanotubes

Intricate hollow transition‐metal oxides (TMOs)‐based hetero‐nanostructures demonstrate intriguing applications in electronics, energy storage, and catalysis owing to their exotic electronic features and geometric complexity; however, manipulating their topological features and interfacial interactions of different subunits, is a grand challenge because most TMOs are intrinsic non‐layered crystals. Herein, a generalized multidentate ligand chelating‐grafting strategy for creating various amorphous TMOs‐based triple‐layered hetero‐nanotubes with face‐to‐face contact is demonstrated, by taking ethylenediamine tetraacetic acid (EDTA) chelating agent and melamine‐cyanuric acid (M‐CA) supramolecular complex‐polymer as a proof‐of‐concept. This strategy primarily depends on controlling the chelation of coordinated covalent bonds and grafting of hydrogen bonds, in which EDTA is utilized to chelate metal ions, and subsequently grafted to M‐CA supramolecular surface, followed by annealing treatment. Merited by the optimized structure in three natures of nanotubes‐interface‐heterolayers, the obtained hollow nanostructure possesses superior photocatalytic performance: the optimized a‐ZnO/C/CN hetero‐nanotube exhibits high hydrogen evolution rate of 400.01 μmol h−1 g−1, outperforming the bulk CN by about 14.29‐fold. The synthesis of various a‐TMOs‐based complex hollow nanostructures and the demonstration of high catalytic activity are expected to enable fundamental studies of cavity, hereto‐interface, and dimensionality effects on their properties and facilitate their use in catalysis and other applications.

Flotation Performance and Adsorption Mechanism of a Novel Chelating Collector for Azurite

Thiophosphate compounds have attracted much attention in coordination chemistry, but their deep adsorption mechanism remains underexplored as flotation collectors. The flotation performance and adsorption mechanism of a novel (dibutoxy-thiophosphorylsulfanyl)-acetic acid (CDDP) chelating collector on azurite surfaces were studied by micro-flotation tests, zeta potential measurements, and Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS) and field emission scanning electron microscopy (FE-SEM) analysis. The micro-flotation results indicated that CDDP exhibited superior collecting performances to direct flotation recovery of azurite and floated over 91.44% of azurite at pH 7. For sodium isopentyl xanthate (NaIX) and Benzohydroxamic acid (BHA) collectors, the addition of Na2S still did not show good collection performance. The results of zeta potential, FTIR, XPS and FE-SEM measurements, all confirmed that CDDP showed a better affinity to azurite surfaces than NaIX and BHA. Furthermore, XPS and FE-SEM provided obvious evidence that CDDP could easily react with Cu2+ sites on azurite surfaces. Using the density functional theory (DFT) method, the collection capacity of azurite was CDDP > BHA > NaIX, which exactly matched the micro-flotation results. In addition, this study provided an atomic-scale understanding of the structure–property relationship of CDDP as chelating agents for copper mineral flotation.

A Comparison of Evans Blue and 4-(p-Iodophenyl)butyryl Albumin Binding Moieties on an Integrin αvβ6 Binding Peptide.

Serum albumin binding moieties (ABMs) such as the Evans blue (EB) dye fragment and the 4-(p-iodophenyl)butyryl (IP) have been used to improve the pharmacokinetic profile of many radiopharmaceuticals. The goal of this work was to directly compare these two ABMs when conjugated to an integrin αvβ6 binding peptide (αvβ6-BP); a peptide that is currently being used for positron emission tomography (PET) imaging in patients with metastatic cancer. The ABM-modified αvβ6-BP peptides were synthesized with a 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetracetic acid (DOTA) chelator for radiolabeling with copper-64 to yield [64Cu]Cu DOTA-EB-αvβ6-BP ([64Cu]1) and [64Cu]Cu DOTA-IP-αvβ6-BP ([64Cu]2). Both peptides were evaluated in vitro for serum albumin binding, serum stability, and cell binding and internalization in the paired engineered melanoma cells DX3puroβ6 (αvβ6 +) and DX3puro (αvβ6 −), and pancreatic BxPC-3 (αvβ6 +) cells and in vivo in a BxPC-3 xenograft mouse model. Serum albumin binding for [64Cu]1 and [64Cu]2 was 53–63% and 42–44%, respectively, with good human serum stability (24 h: [64Cu]1 76%, [64Cu]2 90%). Selective αvβ6 cell binding was observed for both [64Cu]1 and [64Cu]2 (αvβ6 (+) cells: 30.3–55.8% and 48.5–60.2%, respectively, vs. αvβ6 (−) cells <3.1% for both). In vivo BxPC-3 tumor uptake for both peptides at 4 h was 5.29 ± 0.59 and 7.60 ± 0.43% ID/g ([64Cu]1 and [64Cu]2, respectively), and remained at 3.32 ± 0.46 and 4.91 ± 1.19% ID/g, respectively, at 72 h, representing a >3-fold improvement over the non-ABM parent peptide and thereby providing improved PET images. Comparing [64Cu]1 and [64Cu]2, the IP-ABM-αvβ6-BP [64Cu]2 displayed higher serum stability, higher tumor accumulation, and lower kidney and liver accumulation, resulting in better tumor-to-organ ratios for high contrast visualization of the αvβ6 (+) tumor by PET imaging.

Selective separation and recovery of vanadium from acid leaching solution of polymetallic black shale as function of aminophosphonic acid

AbstractBACKGROUNDAcid leaching is an effective method to extract vanadium from polymetallic black shale. However, a large amount of metal impurities, especially iron and aluminum, which accompany V, are released during this process.RESULTSIn this study, a aminophosphonic acid chelating resin was used for the differential adsorption and desorption of vanadium, iron and aluminum ions to achieve deep separation and concentration of vanadium ions present in the acid leaching solution of polymetallic black shale. Results showed that vanadium adsorption efficiency reached 90.17% at a pH of 1.8. After differential adsorption and desorption, the V:Fe and V:Al concentration ratios increased from 1.84 to 64.53 and from 0.24 to 37.92, respectively. When a 2.5 mol L−1 NaOH solution was used as desorbent, the separation factors β(V/Fe) and β(V/Al) reached values of 694.22 and 452.29, realizing the selective separation and concentration of vanadium.CONCLUSIONIt was found that the vanadium, iron and aluminum ions were selectively adsorbed onto the phosphonic acid functional groups (PO(OH)2) and amino functional groups (NH). The vanadium ions existed in the form of the polyvanadate (), which can be directionally adsorbed onto PO(OH)2 under POH bond cleavage and coordination of to the unsaturated phosphorus atom and then desorbed through the exchange between hydroxide anions OH− and . The iron and aluminum ions cannot be desorbed by OH− because the iron and aluminum sulfate moieties and were capable of coordinating to the nitrogen atom of the NH group via its lone electron pair. © 2022 Society of Chemical Industry (SCI).

A general fruit acid chelation route for eco-friendly and ambient 3D printing of metals

Recent advances in metal additive manufacturing (AM) have provided new opportunities for prompt designs of prototypes and facile personalization of products befitting the fourth industrial revolution. In this regard, its feasibility of becoming a green technology, which is not an inherent aspect of AM, is gaining more interests. A particular interest in adapting and understanding of eco-friendly ingredients can set its important groundworks. Here, we demonstrate a water-based solid-phase binding agent suitable for binder jetting 3D printing of metals. Sodium salts of common fruit acid chelators form stable metal-chelate bridges between metal particles, enabling elaborate 3D printing of metals with improved strengths. Even further reductions in the porosity between the metal particles are possible through post-treatments. A compatibility of this chelation chemistry with variety of metals is also demonstrated. The proposed mechanism for metal 3D printing can open up new avenues for consumer-level personalized 3D printing of metals.

Antioxidant, Antimicrobial Activities and Characterization of Polyphenol-Enriched Extract of Egyptian Celery (Apium graveolens L., Apiaceae) Aerial Parts via UPLC/ESI/TOF-MS.

Medicinal plant extracts are increasingly considered a major source of innovative medications and healthcare products. This study focused on preparing a polyphenol enriched water extract of Egyptian celery “Apium graveolens L., Apiaceae” aerial parts (TAE) in an endeavor to accentuate its antioxidant capacity as well as its antimicrobial activity. (TAE) of celery was partitioned against different organic solvents to yield dichloromethane (DCM), ethyl acetate (EAC), and butanol (BUOH) fractions. (TAE) and the organic fractions thereof besides the remaining mother liquor (ML) were all screened for their antioxidant capacity using various protocols viz. monitoring the reducing amplitudes for ferric ions (FRAP), and radical scavenging potentials of oxygen (ORAC), 2,2’-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and metal chelation assays. The examination procedure revealed both (TAE) extract and (DCM) fraction, to pertain the highest antioxidant potentials, where the IC50 of the (TAE) using ABTS and metal chelation assays were ca. 34.52 ± 3.25 and 246.6 ± 5.78 µg/mL, respectively. The (DCM) fraction recorded effective results using the FRAP, ORAC, and DPPH assays ca. 233.47 ± 15.14 and 1076 ± 25.73 μM Trolox equivalents/mg sample and an IC50 474.4 ± 19.8 µg/mL, respectively. Additionally, both (TAE) and (DCM) fraction exerted antimicrobial activities recording inhibition zones (mm) (13.4 ± 1.5) and (12.0 ± 1.0) against Staphylococcus aureus and (11.0 ± 1.2) and (10.0 ± 1.3) against Escherichia coli, respectively, with no anti-fungal activity. Minimum inhibitory concentration (MIC) of (TAE) and (DCM) fraction were 1250 and 2500 µg/mL, respectively. UPLC/ESI/TOF-MS unveiled the chemical profile of both (TAE) and (DCM) fraction to encompass a myriad of active polyphenolic constituents including phenylpropanoids, coumarins, apigenin, luteolin, and chrysoeriol conjugates.

Effects of the Reservoir Environment and Oilfield Operations on the Iron Mineral Surface Charge Development: An Insight into Their Role in Wettability Alteration

Iron minerals are hydrophobic minerals predominately found in sandstone formations with their role in wettability alteration not fully understood. With the reservoir rock being a complex system of multiple minerals, the control of wettability alterations becomes difficult to manage due to the different surface chemistry of constituent minerals. This study presents for the first time the surface charge development of pyrite, magnetite, and hematite minerals in native reservoir environments and the effect of oilfield operations such as acidizing, water injection, polymerization, surfactant flooding, and alkaline flooding on iron minerals, surface charge development. This was achieved using zeta potential measurement, which depicts the type of surface charge and infers the propensity of precipitation. The experimental results show that pyrite, magnetite, and hematite behave similarly under reservoir conditions with all the minerals being positively charged although pyrite and hematite are negatively charged in seawater (SW). Results also show that the surface charge development is controlled by the electrical double-layer effect and ion adsorption on the mineral surfaces. These findings provide key insights into the role of iron minerals in wettability alteration as they provide surfaces that serve as a precursor for polar crude component adsorption. Also, the design of an ion-engineered fluid to control the surface charge of iron minerals was implemented, and the results showed that they behave differently. Furthermore, the effect of low-salinity water on the mineral surface charge was examined. The findings revealed that low-salinity water can produce a negatively charged surface, however, cannot mitigate the iron mineral precipitation challenge as the observed zeta potential values are near zero. Finally, slug and continuous injection of the ethylenediaminetetraacetic acid chelating agent was implemented as an iron mineral precipitation control strategy, with the continuous injection observed to significantly improve the colloidal stability of the iron minerals in the reservoir native state and after SW injection.

Developing an ultrafine Ba0.5Sr0.5Co0.8Fe0.2O3-δ cathode for efficient solid oxide fuel cells

Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) is an excellent mixed ion/electron conducting cathode among solid oxide fuel cells; however, its electrochemical activity is limited by the sluggish oxygen surface exchange. The application range of the BSCF cathode can be widened by preparing BSCF in the form of an ultrafine powder; however, retaining the microstructure of the powder in the cathode is challenging owing to the sintering of cathodes at high temperatures. In this study, we report a combined modification and direct assembly approach for the fabrication of an ultrafine, multi-phase BSCF-based cathode. This novel BSCF cathode powder is first modified by immersing the pre-synthesised micron-sized BSCF perovskite powder in a weakly acidic chelating solution. The modification treatment changes the composition of the powder and results in the formation of an ultrafine microstructure. The ultrafine microstructure of the powder is further retained in the cathode by direct assembly without high-temperature sintering. The peak power density of the ultrafine, multi-phase BSCF cell is 1.25 W cm−2 at 750 °C, much higher than the 0.83 W cm−2 of the pristine BSCF cell. This study provides insights into the facile fabrication and application of ultrafine cathodes for efficient solid oxide fuel cells.

Removal of Alkali and Alkaline Earth Elements from Cobalt Solutions Using Iminodiacetic Acid Chelating Resin

Removal of Alkali and Alkaline Earth Elements from Cobalt Solutions Using Iminodiacetic Acid Chelating Resin

Computational insight into the quantum chemistry, interaction and adsorption energy of aminopolycarboxylic acid chelating agents towards metal cations

In the oil and gas business, aminopolycarboxylic acid chelating compounds are commonly employed to treat and regulate unwanted metal cations. The relationship between molecular orbital and chelating capabilities of commercially available aminopolycarboxylic acids toward metal cations (Ca2+, Ba2+, Mg2+, Sr2+, Fe2+, and Fe3+) is examined in depth in this work. A computational method based on Density Functional Theory (DFT) and Monte Carlo approaches were used. According to DFT quantum chemistry calculations, DTPA has a better electron transfer for improved adsorption properties. In addition, EDTA has the lowest energy required to liberate an electron and become negatively charged, as well as lower electronegativity and global hardness, indicating improved reactivity. According to Monte Carlo calculations, adsorption energy is rated as follows: DTPA > EDTA > CDTA > GLDA > HEDTA > MGDA > HEIDA. All aminopolycarboxylic acid adsorption energies obtained are comparable to stability constant data and other experimental findings.

Dissolution behaviour of different rank coals in L‐glutamic acid N, N‐diacetic acid chelating agent: Implications to enhance coalbed methane recovery by acid stimulation

AbstractAcid stimulation is a promising method in improving coal seam permeability by demineralization in coal cleats. However, using conventional acids such as HCl and mud acid (12 wt.% HCl + 3 wt.% HF) may cause clay breakage, migration, and precipitation, leading to formation damage. In this study, we investigated the effect of L‐glutamic acid N, N‐diacetic acid (GLDA) chelating agent treatment on the dissolution behaviour of lignite (Coal L) and anthracite (Coal A), collected from Er′Lian Basin and Qinshui Basin, China. Characteristics of the raw and acid treated coal samples, including mercury intrusion porosimetry (MIP) results as well as metal elements distribution analysis of reacted leachates, micromorphology, mineral composition, and mass change were taken into consideration. It was found that high‐rank Coal A is more suitable for chemical stimulation. For both Coal L and Coal A, 5 wt.% GLDA solution is preferred to avoid sticking reaction products. Total porosities of Coal L and Coal A were increased by 3.9 and 1.1 times, respectively. Based on the water chemistry analysis of the reacted solutions, we found that acidic condition is beneficial for clay minerals and carbonates dissolution, while alkaline condition is favourable for the dissolution of quartz. Besides, the dissolution of minerals can trigger the release of trace elements, which is a potential environmental risk that needs to be taken into consideration before its in‐situ application in coal fields.

Blood lead level in Chinese adults with and without coronary artery disease.

BACKGROUNDThe Trial to Assess Chelation Therapy study found that edetate disodium (disodium ethylenediaminetetraacetic acid) chelation therapy significantly reduced the incidence of cardiac events in stable post-myocardial infarction patients, and a body of epidemiological data has shown that accumulation of biologically active metals, such as lead and cadmium, is an important risk factor for cardiovascular disease. However, limited studies have focused on the relationship between angiographically diagnosed coronary artery disease (CAD) and lead exposure. This study compared blood lead level (BLL) in Chinese patients with and without CAD.METHODSIn this prospective, observational study, 450 consecutive patients admitted to Beijing Anzhen Hospital with suspected CAD from November 1, 2018, to January 30, 2019, were enrolled. All patients underwent coronary angiography, and an experienced heart team calculated the SYNTAX scores (SXscore) for all available coronary angiograms. BLLs were determined with atomic absorption spectrophotometry and compared between patients with angiographically diagnosed CAD and those without CAD.RESULTSIn total, 343 (76%) patients had CAD, of whom 42% had low (0−22), 22% had intermediate (23−32), and 36% had high (≥ 33) SXscore. BLLs were 36.8 ± 16.95 μg/L in patients with CAD and 31.2 ± 15.75 μg/L in those without CAD (P = 0.003). When BLLs were categorized into three groups (low, middle, high), CAD prevalence increased with increasing BLLs (P < 0.05). In the multivariate regression model, BLLs were associated with CAD (odds ratio (OR): 1.023, 95% confidence interval (CI): 1.008−1.039; P = 0.0017). OR in the high versus low BLL group was 2.36 (95% CI: 1.29−4.42,P = 0.003). Furthermore, BLLs were independently associated with intermediate and high SXscore (adjusted OR: 1.050, 95% CI: 1.036–1.066; P < 0.0001). CONCLUSIONBLLs were significantly associated with angiographically diagnosed CAD. Furthermore, BLLs showed excellent predictive value for SXscore, especially for complex coronary artery lesions.

Impact of amino acids on enhancing trimethyl chitosan as a nontoxic antiproliferative active biopolymer

AbstractThis work evaluates the toxicity of trimethyl chitosan (TMC), which prevents its use as an antiproliferative active compound. We report our trial to enhance its safe application by chelating with various amino acids (phenylalanine, glycine and lysine). The safety evaluation was achieved by studying the behavior of TMC–amino acid chelates against two normal human cell lines (BJ1 and RPE1), in comparison with a negative control and doxrobicin (positive control) standard samples. The results obtained show that phenylalanine and lysine play an effective role in enhancing the safety of TMC against normal cell lines, together with providing high thermal stability. Phenylalanine is superior in synthesized anticancer agents. It had IC50 values against colon HCT116 and breast cancer MCF‐7cancer cell lines of 68.7 and 51.4 μg mL–1 This compound is more acceptable than the previous reported rutin flavonoid as an anticancer agent against HCT116 cell lines. © 2021 Society of Chemical Industry and John Wiley &amp; Sons, Ltd

Effects of Phytic Acid-Degrading Bacteria on Mineral Element Content in Mice.

Trace minerals are extremely important for balanced nutrition, growth, and development in animals and humans. Phytic acid chelation promotes the use of probiotics in nutrition. The phytic acid-degrading strain Lactococcus lactis psm16 was obtained from swine milk by enrichment culture and direct plate methods. In this study, we evaluated the effect of the strain psm16 on mineral element content in a mouse model. Mice were divided into four groups: basal diet, 1% phytic acid, 1% phytic acid + psm16, 1% phytic acid + 500 U/kg commercial phytase. Concentrations of acetic acid, propionic acid, butyric acid, and total short-chain fatty acids were significantly increased in the strain psm16 group compared to the phytic acid group. The concentrations of copper (p = 0.021) and zinc (p = 0.017) in liver, calcium (p = 0.000), manganese (p = 0.000), and zinc (p = 0.000) in plasma and manganese (p = 0.010) and zinc (p = 0.022) in kidney were significantly increased in psm16 group, while copper (p = 0.007) and magnesium (p = 0.001) were significantly reduced. In conclusion, the addition of phytic acid-degrading bacteria psm16 into a diet including phytic acid can affect the content of trace elements in the liver, kidney, and plasma of mice, counteracting the harmful effects of phytic acid.

Antioxidant Activity, Phenolic Profile, and Nephroprotective Potential of Anastatica hierochuntica Ethanolic and Aqueous Extracts against CCl4-Induced Nephrotoxicity in Rats.

Kaff-e-Maryam (Anastatica hierochuntica L.) is extensively used to treat a range of health problems, most notably to ease childbirth and alleviate reproductive system-related disorders. This study aimed to evaluate the effect of A. hierochuntica ethanolic (KEE), and aqueous (KAE) extracts on CCl4-induced oxidative stress and nephrotoxicity in rats using the biochemical markers for renal functions and antioxidant status as well as histopathological examinations of kidney tissue. A. hierochuntica contained 67.49 mg GAE g−1 of total phenolic compounds (TPC), 3.51 µg g−1 of total carotenoids (TC), and 49.78 and 17.45 mg QE g−1 of total flavonoids (TF) and total flavonols (TFL), respectively. It resulted in 128.71 µmol of TE g−1 of DPPH-RSA and 141.92 µmol of TE g−1 of ABTS-RSA. A. hierochuntica presented superior antioxidant activity by inhibiting linoleic acid radicals and chelating oxidation metals. The HPLC analysis resulted in 9 and 21 phenolic acids and 6 and 2 flavonoids in KEE and KAE with a predominance of sinapic and syringic acids, respectively. Intramuscular injection of vit. E + Se and oral administration of KEE, KAE, and KEE + KAE at 250 mg kg−1 body weight significantly restored serum creatinine, urea, K, total protein, and albumin levels. Additionally, they reduced malondialdehyde (MOD), restored reduced-glutathione (GSH), and enhanced superoxide dismutase (SOD) levels. KEE, KAE, and KEE + KAE protected the kidneys from CCl4-nephrotoxicity as they mainly attenuated induced oxidative stress. Total nephroprotection was about 83.27%, 97.62%, and 78.85% for KEE, KAE, and KEE + KAE, respectively. Both vit. E + Se and A. hierochuntica extracts attenuated the histopathological alteration in CCl4-treated rats. In conclusion, A. hierochuntica, especially KAE, has the potential capability to restore oxidative stability and improve kidney function after CCl4 acute kidney injury better than KEE. Therefore, A. hierochuntica has the potential to be a useful therapeutic agent in the treatment of drug-induced nephrotoxicity.

Citric acid and AMF inoculation combination-assisted phytoextraction of vanadium (V) by Medicago sativa in V mining contaminated soil.

The use of citric acid (CA) chelator to facilitate metal bioavailability is a promising approach for the phytoextraction of heavy metal contaminants. However, the role of the CA chelator associated with arbuscular mycorrhizal fungi (AMF) inoculation on phytoextraction of vanadium (V) has not been studied. Therefore, in this study, a greenhouse pot experiment was conducted to evaluate the combined effect of CA chelator and AMF inoculation on growth performance and V phytoextraction of plants in V-contaminated soil. The experiment was performed via CA (at 0, 5, and 10 mM kg-1 soil levels) application alone or in combination with AMF inoculation by Medicago sativa Linn. (M. sativa). Plant biomass, root mycorrhizal colonization, P and V accumulation, antioxidant enzyme activity in plants, and soil chemical speciation of V were evaluated. Results depicted (1) a marked decline in plant biomass and root mycorrhizal colonization in 5- and 10-mM CA treatments which were accompanied by a significant increased V accumulation in plant tissues. The effects could be attributed to the enhanced acid-soluble V fraction transferring from the reducible fraction. (2) The presence of CA significantly enhanced P acquisition while the P/V concentration ratio in plant shoots and roots decreased, owing to the increased V translocation from soil to plant. (3) In both CA-treated soil, AMF-plant symbiosis significantly improved dry weight (31.4-73.3%) and P content (37.3-122.5%) in shoots and roots of M. sativa. The combined treatments also showed markedly contribution in reduction of malondialdehyde (MDA) content (12.8-16.2%) and higher antioxidants (SOD, POD, and CAT) activities in the leaves. This suggests their combination could promote growth performance and stimulate antioxidant response to alleviate V stress induced by CA chelator. (4) Taken together, 10 mM kg-1 CA application and AMF inoculation combination exhibited a higher amount of extracted V both in plant shoots and roots. Thus, citric acid-AMF-plant symbiosis provides a novel remediation strategy for in situ V phytoextraction by M. sativa in V-contaminated soil.

Development of 2-Morpholino-N-hydroxybenzamides as anti-proliferative PC-PLC inhibitors

Phosphatidylcholine-specific phospholipase C (PC-PLC) is a key enzyme involved in the metabolism of the mammalian phospholipid phosphatidylcholine into secondary messengers diacylglycerol (DAG) and phosphocholine. DAG and phosphocholine have been identified to amplify various cellular processes involved in oncogenesis such as proliferation, cell-cycle activation, differentiation and motility, therefore making PC-PLC a potential target for novel anti-cancer treatments. The current literature standard for PC-PLC inhibition, tricyclodecan-9-yl-potassium xanthate (D609), has been shown to arrest proliferation in multiple cancer cell lines, however, it is not drug-like resulting in low aqueous stability, making it a poor drug candidate. 2-Morpholinobenzoic acids have been shown to have improved PC-PLC inhibitory activity compared to D609, with molecular modelling identifying chelation of the carboxylic acid to catalytic Zn2+ ions in the PC-PLC active site being a key interaction. In this study, the carboxylic acid motif was replaced with a hydroxamic acid to strengthen the Zn2+ interaction. It was found that the hydroxamic acid derivatives displayed PC-PLC inhibitory activity similar, or better, than D609. Furthermore, these novel inhibitors had potent anti-proliferative activity in MDA-MB-231 and HCT-116 cancer cell lines, far greater than D609 and previous 2-morpholinobenzoic acids.

Integration of oxalic acid chelation and Fenton process for synergistic relaxation-oxidation of persistent gel-like fouling of ceramic nanofiltration membranes

Ceramic nanofiltration (NF) is a newly-developed technology for water recycling, but is still limited to pilot-scale applications. Lacking efficient and eco-friendly strategies for cleaning ceramic NF membrane impedes its scaling-up in industries. Forward flush, backwash and acidic/caustic cleaning are not efficient enough. In this work, a novel oxalic acid-aided Fenton process was proposed for synergistic relaxation/oxidation of persistent Ca2+-mediated gel-like fouling of ceramic NF membrane. A reactive catalyst layer was online pre-coated on top of the membrane via a pressure-driven cross-flow pre-filtration of Fe3O4 hydrosols. The gel-like fouling was simulated by alginate in the presence of Ca2+ ions. Results show that the Fe3O4 loading could be readily tuned from 0.16 to 1.34 g m−2 by altering the permeate flux during the pre-coating. The membrane permeability loss due to the pre-coating was minimal (<10%). The combination of oxalic acid chelation and Fenton-based oxidation resulted in high flux recovery (85.07%) for the iron-oxide pre-coated membrane, whereas the single treatment by hydrogen peroxide (H2O2) or oxalic acid was inefficient. This synergistic effect was attributed to relaxation of the Ca2+-mediated gel layer via oxalic acid/Ca2+ chelation, which presumably facilitated H2O2 diffusion at the Fe3O4/foulant interface. The iron-oxide pre-coated membrane maintained stable initial normalized fluxes (83.33–90.15%) through the oxalic acid/H2O2 cleaning over five cycles, with no need of refreshing the iron-oxide pre-coat. Additionally, the leaching of iron from the iron-oxide pre-coat by oxalic acid was suppressed by the oxalic acid/H2O2 combination, owing to a reactive shielding by competitive sorption of H2O2 onto the Fe3O4 surface. Overall, the synergistic relaxation/oxidation method, demonstrated in this study, provides new insights into improving reactivity of Fenton-based processes on hybrid catalytic ceramic membranes for water treatment or fouling control.