Phosphate Molecules Research Articles

Modeling of hydrophobic tetrapeptides as a competitive inhibitor for HMG-CoA reductase

This study presents a modeling of hydrophobic tetrapeptides acting in a competitive manner against 3‑hydroxy-3-methylglutaryl coenzyme A reductase. This enzyme catalyzes the reductive deacylation of 3‑hydroxy-3-methylglutaryl coenzyme A to mevalonate, using two molecules of nicotinamide adenine dinucleotide phosphate as cofactors, and this reaction represents the rate-limiting step in cholesterol biosynthesis. Thus, it is a target of many investigations in order to control a cholesterol level because the elevated cholesterol level is known as a risk factor of hypercholesterolemia. In previous studies, the two hypocholesterolemic peptides were isolated from soy glicinin. Based on these sequences, a number of the tri-, tetra-, hexa- and heptapeptides were designed in order to improve their inhibitory activities. The peptide fragmentation was applied as a main tool in design. Using the developed design method, a new recognized motif in the designed tetrapeptides was identified. According to the design parameter, the IIIP peptide possessed the most rigid structure among the new designed tetrapeptides. The circular dichroism study confirmed that the observed predominant conformation of the IIIP peptide was close to the type I of a β-turn. The IIIP peptide was determined as the strongest inhibitor among the new designed tetrapeptides. The kinetic study revealed the competitive HMGR inhibition by the peptide, which acted as a bisubstrate blocking an access of HMG-CoA and NADPH to their binding sites. The correlation coefficient (r2) between the predicted and observed peptide activities of 0.91 suggests wide possibilities of the proposed approach to design new peptides that may differ from the previously designed peptides in the recognized motif, sequences, lengths and structural preferences.

Influence of the type of phosphate additive and its concentration on the setting kinetics of CA cement bonded refractory castables with special regard to the resulting pH value

During the hydration of CA cement exists a dormant period, which is responsible for the setting kinetics of CA cement bonded refractory castables. The dormant period is believed to be caused by an Al–O–H passivation layer on the CA cement particles. Recent publications indicate that the dissolution (aging) of the passivation layer is closely connected to the prevailing pH value of the pore solution during setting. The higher the pH value, the faster the dissolution of the passivation layer.As phosphate additives, frequently used as dispersing agent, differ in their pH value when dissolved in water it is reasonable that they change the setting kinetics of CA cement bonded refractory castables. Commonly used sodium polyphosphate (S-PP, special case S-TPP for sodium tripolyphosphate) dispersing agents mainly differ in chain length, and therefore in Na+ and phosphate concentration, with different setting kinetics as a result.To investigate the influence of S-(T)PP on setting kinetics, sonic velocity and pH measurements were conducted on S-(T)PP/citric acid dispersed and CA cement bonded refractory castables during their setting. Different phosphates, differing in portion of Na+ to phosphate and medium chain length of the phosphate molecules, were used in varied concentrations within refractory castables to quantify the shift in setting kinetics and verify the role of the pH value during the hydration of CA cement.It was found that the chain length of the phosphate molecule of S-(T)PP influences the setting kinetics, and especially the length of the dormant period of the hydration of CA cement, in an indistinct way. Minor differences within the Na+ concentration at differing chain length S-(T)PP showed a comparable tendency to influence the hydration kinetics of CA cement as the chain length of the phosphate molecule was varied. However, an increase of the concentration of the applied S-(T)PP, which goes along with a distinctly increased Na+ concentration, resulted in a significant shorter dormant period and correspondingly an accelerated main hydration of CA cement. The corresponding pH value during the dormant period of the hydration of CA cement increased concurrently to the increase of the S-(T)PP and Na+ concentration.It is discussed that this increase of the pH value of the pore solution of the refractory castable results from an increase of the Na+ concentration from the S-(T)PP, while phosphate molecules are precipitated as Ca-phosphate. This indicates that the dissolution of the Al–O–H passivation layer accelerates with an increasing Na+ concentration (equivalent to increasing pH value) in the pore solution. Thereby, the dormant period is shorter and the hydration of CA cement starts earlier.The general tendency that additives of alkaline nature are accelerating the setting kinetics could be linked to the pH value during the dormant period. Therefore, the theory of the pH dependent aging of the Al–O–H passivation layer on CA cement particles was confirmed. As a directly applicable result, S-(T)PP may be used as accelerator (accelerating the CA cement hydration) beside their dispersing effect.

Fabrication of hydrogel controlled-released Phosphorus encapsulated in starch-polyvinyl alcohol film

Traditional soluble phosphorous(P) fertilizers can easily leach into water systems causing water eutrophication, a major environmental problem caused by an excess release of nutrients. Controlling the release of P in response to the plant demand could reduce fertilizer’s losses and also reduce environmental pollution. This study establishes a concept of controlled release fertilizer, in which a hydrogel fertilizer film is fabricated by incorporating starch, polyvinyl alcohol and ammonium dihydrogen phosphate fertilizer which tend to immobilize the release of phosphate ions and accelerate responsively their release rate in the presence of water. The experiment aims to study the effect of incorporating Starch, and Polyvinyl alcohol (PVA) to Ammonium Dihydrogen Phosphate fertilizer by varying the composition of PVA-Starch-Ammonium Dihydrogen Phosphate and preparing the films through solution casting method. FTIR is being used to investigate the effect of Starch, PVA, and Ammonium Dihydrogen Phosphate composition on the intermolecular bonding of the fabricated film. A total of 10 samples with different material composition is prepared and the intermolecular bonding between this composition is being compared with that of pure starch, pure PVA and pure Ammonium dihydrogen phosphate fertilizer. The FTIR peak will reveal evidence of hydrogen bonding between phosphate molecules and the functional group of polymer molecules as well as showed all the characteristics band of Starch, PVA and Ammonium Dihydrogen Phosphate. The varying formulation of film corresponded to varying intensity of peak and also stretching vibrations.

Combined Use of Ultrasonic and Electromagnetic Fields for the Study of Bonding Mechanisms between Dexamethasone Disodium Phosphate Molecules

We have investigated the ultrasonically induced birefringence traces of aqueous solutions of dexamethasone disodium phosphate, a derivative of hydrocortisone (cortisol). The stationary birefringence and the transient built-up and decay relaxation processes were studied as a function of solution concentration, ultrasound frequency and intensity, as well as a function of temperature. The results were analyzed in view of structural peculiarities of the system in an effort to gain further insights into the molecular relaxation dynamics and the proposed self-association process occurring in the system. The detected ultrasonically induced birefringence relaxation is motivated by the rotational diffusion of dexamethasone disodium phosphate aggregates due to self-association depending on the solution concentration. The observed relaxation mechanism is directly linked to the hydrodynamic size of the acoustic field-induced self-assembly. The systematic analysis of the transient birefringence signals caused by the applied ultrasonic field allowed us to evaluate the interplay between permanent and induced dipoles with changing concentration, temperature, and ultrasound properties. The birefringence traces are adequately fitted with a stretched exponential law indicating the polydispersive nature of the self-aggregated molecular structures. The obtained results are described in the light of recent studies performed on this system.

Solvent control of water O−H bonds for highly reversible zinc ion batteries

Aqueous Zn-ion batteries have attracted increasing research interest; however, the development of these batteries has been hindered by several challenges, including dendrite growth, Zn corrosion, cathode material degradation, limited temperature adaptability and electrochemical stability window, which are associated with water activity and the solvation structure of electrolytes. Here we report that water activity is suppressed by increasing the electron density of the water protons through interactions with highly polar dimethylacetamide and trimethyl phosphate molecules. Meanwhile, the Zn corrosion in the hybrid electrolyte is mitigated, and the electrochemical stability window and the operating temperature of the electrolyte are extended. The dimethylacetamide alters the surface energy of Zn, guiding the (002) plane dominated deposition of Zn. Molecular dynamics simulation evidences Zn2+ ions are solvated with fewer water molecules, resulting in lower lattice strain in the NaV3O8·1.5H2O cathode during the insertion of hydrated Zn2+ ions, boosting the lifespan of Zn|| NaV3O8·1.5H2O cell to 3000 cycles.

In Situ Polymerized Flame Retardant Gel Electrolyte for High-Performance and Safety-Enhanced Lithium Metal Batteries.

A flame retardant gel electrolyte (FRGE) is deemed as one of the most promising electrolytes to relieve the problems of safety hazards and interfacial incompatibility of Li metal batteries. Herein, a novel solvent triethyl 2-fluoro-2-phosphonoacetate (TFPA) with outstanding flame retardancy is introduced in the polymer skeleton synthesized by in situ polymerization of the monomer polyethylene glycol dimethacrylate (PEGDMA) and the cross-linker pentaerythritol tetraacrylate (PETEA). The FRGE exhibits superb interfacial compatibility with Li metal anodes and inhibits uncontrolled Li dendrite growth. This can be ascribed to the restriction of free phosphate molecules by the polymer skeleton, thus realizing a stable cycling performance over 500 h at 1 mA cm-2 and 1 mAh cm-2 in the Li||Li symmetric cell. In addition, the high ionic conductivity (3.15 mS cm-1) and Li+ transference number (0.47) of the FRGE further enhance the electrochemical performance of the correspondent battery. As a result, the LiFePO4|FRGE|Li cell exhibits excellent long-term cycling life with a capacity retention of 94.6% after 700 cycles. This work points to a new pathway for the practical development of high-safety and high-energy-density Li metal-based batteries.

Inside-Out Oriented Choline Phosphate-Based Biomimetic Magnetic Nanomaterials for Precise Recognition and Analysis of C-Reactive Protein.

Phospholipid-based materials exhibit great application potential in the fields of chemistry, biology, and pharmaceutical sciences. In this study, an inside-out oriented choline phosphate molecule, 2-{2-(methacryloyloxy)ethyldimethylammonium}ethyl n-butyl phosphate (MBP), was proposed and verified as a novel ligand of C-reactive protein (CRP) to enrich the functionality of these materials. Compared with phosphorylcholine (PC)-CRP interactions, the binding between MBP and CRP was not affected by the reverse position of phosphate and choline groups and even found more abundant binding sites. Thus, high-density MBP-grafted biomimetic magnetic nanomaterials (MBP-MNPs) were fabricated by reversible addition-fragmentation chain transfer polymerization based on thiol-ene click chemistry. The novel materials exhibited multifunctional applications for CRP including purification and ultrasensitive detection. On the one hand, higher specificity, recovery (90%), purity (95%), and static binding capacity (198.14 mg/g) for CRP were achieved on the novel materials in comparison with traditional PC-based materials, and the enriched CRP from patient serum can maintain its structural integrity and bioactivity. On the other hand, the CRP detection method combining G-quadruplex and thioflavin T developed with MBP-MNPs showed a lower detection limit (10 pM) and wider linear range (0.1-50 nM) than most PC-functionalized analytical platforms. Therefore, the inside-out oriented choline phosphate can not only precisely recognize CRP but also be combined with biomimetic nanomaterials to provide high application potential.

HIV-1 is dependent on its immature lattice to recruit IP6 for mature capsid assembly.

HIV-1 Gag metamorphoses inside each virion, from an immature lattice that forms during viral production to a mature capsid that drives infection. Here we show that the immature lattice is required to concentrate the cellular metabolite inositol hexakisphosphate (IP6) into virions to catalyze mature capsid assembly. Disabling the ability of HIV-1 to enrich IP6 does not prevent immature lattice formation or production of the virus. However, without sufficient IP6 molecules inside each virion, HIV-1 can no longer build a stable capsid and fails to become infectious. IP6 cannot be replaced by other inositol phosphate (IP) molecules, as substitution with other IPs profoundly slows mature assembly kinetics and results in virions with gross morphological defects. Our results demonstrate that while HIV-1 can become independent of IP6 for immature assembly, it remains dependent upon the metabolite for mature capsid formation.

Effect of the buffer composition on the aggregation state of the zinc(II) tetra-spermine porphyrin derivative

The aggregative state of the Zn(II) tetra-spermine porphyrin derivative, ZnTCPPSpm4, has been investigated in the presence of different buffers at the same pH value: 5K (cacodylate) buffer, phosphate sodium salt buffer, and PBS. The photophysical characterizations (UV-vis, Fluorescence, and RLS) have indicated a precise self-assembly phenomenon depending on the buffered solution used. The porphyrin does not undergo a significant aggregation in 5K buffer, differently from what occurs in phosphate and PBS buffers. Here, the likely specific interaction between the phosphate molecules and spermine pendants leads to spontaneous porphyrin aggregation, as detected by the high fluorescence quenching, enhancement of the RLS signal, and a significant splitting of the porphyrin Soret band. As a result, the current paper aims to highlight the importance of the employed buffer throughout the experimental procedures performed in the presence of porphyrinoids.

Co-generation of palladium nanoparticles and phosphate supported on metal-organic frameworks as hydrogenation catalysts.

In this study, we demonstrated the direct synthesis of sodium dihydrogen phosphate (PA) containing palladium nanoparticles (PdNPs) supported on a metal-organic framework (MOF). The resulting composite containing PA molecules coexisting with PdNPs demonstrated improved hydrogenation catalytic performance compared to the composites without PA.

Anionic ligand-induced chirality in perovskite nanoplatelets.

Perovskite materials passivated by chiral ligands have recently shown unique chiroptical activity with promising optoelectronic applications. However, the ligands have been limited to chiral amines. Here, chiral phosphate molecules have been exploited to synthesize CsPbBr3 nanoplatelets. The nanoplatelets showed a distinct circular dichroism signal and maintained their chiroptical properties after purification with anti-solvent.

Computer quantum chemical simulation of the interaction of magnesium phosphate with essential amino acids

As part of this work, a computer quantum chemical simulation of the interaction of magnesium phosphate with essential amino acids was carried out in order to determine the optimal stabilizer for Mg3(PO4)2 nanoparticles. Quantum chemical modeling was carried out using the QChem software and the IQmol molecular editor. At the first stage, the modeling of the magnesium phosphate molecule and the molecules of essential amino acids was carried out, then the modeling of the molecular complex "amino acid- Mg3(PO4)2" was considered, in which the interaction of magnesium phosphate with an amino acid passed through an amino group. As a result, models of molecular complexes were obtained, and the values of the total energy of the molecular complex, the energies of the highest populated and lowest free molecular orbitals, chemical rigidity and the difference in the total energy of the amino acid and the molecular complex "amino acid- Mg3(PO4)2" were calculated. As a result, it was found that essential amino acids can be effective stabilizers of magnesium phosphate nanoparticles, which is confirmed by the values of the difference in total energy and chemical rigidity of molecular complexes. Due to the fact that the molecular complex of tryptophan and magnesium phosphate, in which the interaction of molecules occurs through the amino group in the in the indole ring of tryptophan, has the highest values of the difference in the total energy (∆E = 1946,223 kcal/mol) and chemical hardness (ε = 0.121 eV), it can be concluded that tryptophan is the optimal stabilizer for nanoparticles magnesium phosphate.

Isolation and Categorization of Plant Growth Promoting Endophytic Bacteria Isolated from Halophytic Suaeda nigra at Salt Stress Area of Srikakulam, Andhra Pradesh

In search of novel endophytic bacteria capable of producing plant growth promoting phytohormones and providing tolerance against biotic and abiotic stress to the plant, present study was carried out during 2021-22. For this, endophytic bacteria were isolated from halophytic Suaeda nigra at salt stress areas of Srikakulam district, Andhra Pradesh. Total of sixteen endophytic bacteria were isolated from roots and aerial parts of Suaeda nigra. Isolates were enumerated, purified and preserved for subsequent studies. All isolates were analyzed for their phenotypic, biochemical, enzymatic assay and molecular characterization was carried out by 16S rRNA molecular method. Isolates were tested for their ability in producing plant growth promoting phytohormones, siderophores, exo enzymes and ability to solubilize the phosphate molecules. Among total isolates extracted, bacteria which was labeled as “SNA7” isolated from aerial parts of Suaeda nigra showed better characters in producing catalytic enzymes like catalase, amylase, protease, phosphate solubilization ability and Indole-3-acetic acid (IAA) production. Isolate SNA7 was gram negative, motile, aerobic, rod shaped, non-spore forming, and no pigmentation which grows best at 42°C, pH 8.3 with tolerate of 8% NaCl nutrient agar. Based on phenotypic, biochemical, nucleotide homology and phylogenetic analysis isolate SNA7showed higher relationship with Pseudomonas pseudoalcaligenes Pseudomonas spp. was characterized as an effective organism to explore its ability in various research fields. In this current study, isolate SNA7 showed higher potential in producing wide range of enzymes and bioactive secondary metabolites and was first of its kind reported and isolated from halophytic Suaeda nigra.

Role of T Cells in the Pathogenesis of Rheumatoid Arthritis: Focus on Immunometabolism Dysfunctions.

Evidence demonstrated that metabolic-associated T cell abnormalities could be detected in the early stage of RA development. In this context, molecular evaluations have revealed changes in metabolic pathways, leading to the aggressive phenotype of RA T cells. A growing list of genes is downregulated or upregulated in RA T cells, and most of these genes with abnormal expression fall into the category of metabolic pathways. It has been shown that RA T cells shunt glucose towards the pentose phosphate pathway (PPP), which is associated with a high level of nicotinamide adenine dinucleotide phosphate (NADPH) and intermediate molecules. An increased level of NADPH inhibits ATM activation and thereby increases the proliferation capabilities of the RA T cells. Defects in the DNA repair nuclease MRE11A cause failures in repairing mitochondrial DNA, resulting in inhibiting the fatty acid oxidation pathway and further elevated cytoplasmic lipid droplets. Accumulated lipid droplets employ to generate lipid membranes for the cell building program and are also used to form the front-end membrane ruffles that are accomplices with invasive phenotypes of RA T cells. Metabolic pathway involvement in RA pathogenesis expands the pathogenic concept of the disease beyond the common view of autoimmunity triggered by autoantigen recognition. Increased knowledge about metabolic pathways' implications in RA pathogenesis paves the way to understand better the environment/gene interactions and host/microbiota interactions and introduce potential therapeutic approaches. This review summarized emerging data about the roles of T cells in RA pathogenesis with a focus on immunometabolism dysfunctions and how these metabolic alterations can affect the disease process.

Adsorption of recalcitrant phosphorus compounds using the phosphate-selective binding-protein PstS.

Currently available wastewater phosphorus (P) treatment technologies target removal of reactive forms of P. Selective adsorption of more recalcitrant soluble non-reactive phosphorus (sNRP) can improve P removal and recovery. A phosphate-selective phosphate-binding protein (PBP), PstS, was immobilized onto NHS-activated beads to assess the ability of this novel bioadsorbent to remove (adsorb) and subsequently recover (desorb) a range of sNRP compounds. Four sNRP compounds representative of wastewater sNRP were selected for use in this study: phytic acid (PA), sodium triphosphate (TrP), beta-glycerol phosphate (BGP), and sodium hexametaphosphate (HMP). Using PBP, adsorption of all sNRP compounds was thermodynamically favorable. The PBP had nearly equivalent binding affinity for PA compared to PBP's typical target, orthophosphate, although it had less affinity for the other sNRP compounds. Adsorption followed pseudo-second order reaction kinetics, with 95% of maximum adsorption occurring within 4min. This was substantially faster sNRP adsorption compared to other adsorbents in the literature. Adsorption was modeled using the Langmuir isotherm, reflecting that one phosphate molecule attached to one PBP binding site. Notably, this selective 1:1 attachment resulted in higher total P removal for sNRP molecules with high P content. The binding site lost activity with increasing pH, and as such, highest desorption was achieved at pH 12, making the system amenable to sNRP removal as well as controlled recovery.

High-Voltage and Intrinsically Safe Sodium Metal Batteries Enabled by Nonflammable Fluorinated Phosphate Electrolytes.

Sodium metal is a promising anode for high-energy-density sodium rechargeable batteries (RSBs). However, the low Coulombic efficiency (CE) of the Na plating/stripping process and the problem of safety hinder their practical application. Herein, we report a facile strategy for employing the fluorinated phosphate solvents to realize highly reversible Na plating/stripping and improve the safety performance. The fluorinated phosphate molecules reduce the polarity of the solvent and lower the coordination number to Na+, which makes it possible to form the anion-induced ion-solvent-coordinated (AI-ISC) structures with high reduction tolerance. Moreover, the fluorination treatment enhances the oxidation resistance of the phosphate solvent, enabling compatibility with the high-voltage Na3V2(PO4)2F3 (NVPF) cathode. As expected, the Na@Al//NVPF full cell with the as-prepared 0.9 M NaFSI/tris(2,2,2-trifluoroethyl) phosphate (TFEP) demonstrates a capacity retention of 83.4% after 200 cycles with an average CE of 99.6%. This work opens a new avenue for designing high-energy-density RSBs with improved safety performance.

Mechanochemical Ionization: Differentiating Pressure-, Shear-, and Temperature-Induced Reactions in a Model Phosphate

Using density-functional theory-based molecular dynamics simulations, we study stress and temperature-induced chemical reactions in bulk systems containing triphosphoric acid and zinc phosphate molecules. The nature of the products depends sensitively on the imposed conditions, e.g., isotropic and even more so shear stress create (zwitter-) ionic products. Free ions also emerge from thermal cycles, but the reactions are endothermic rather than exothermic as for stress-induced transitions and zinc atoms remain four-coordinated. Hydrostatic stresses required for reactions to occur lie well below those typical for tribological micro-contacts of stiff solids and are further reduced by shear. Before zinc atoms change their coordination under stress, proton mobility increases, i.e., hydrogen atoms start to change the oxygen atom they are bonded to within 10 ps time scales. The hydrostatic stress for this to occur is reduced with increasing shear. Our finding suggests that materials for which number, nature, and mobility of ions are stress sensitive cannot have a well-defined position in the triboelectric series, since local contact stresses generally depend on the stiffness of the counter body. Moreover, our simulations do not support the idea that chemical reactions in a tribo-contact are commonly those that would be obtained through heating alone.Graphical

Purification and characterization of inorganic pyrophosphatase for in vitro RNA transcription.

Inorganic pyrophosphatase (iPPase) is an enzyme that cleaves pyrophosphate into two phosphate molecules. This enzyme is an essential component of in vitro transcription (IVT) reactions for RNA preparation as it prevents pyrophosphate from precipitating with magnesium, ultimately increasing the rate of the IVT reaction. Large-scale RNA production is often required for biochemical and biophysical characterization studies of RNA, therefore requiring large amounts of IVT reagents. Commercially purchased iPPase is often the most expensive component of any IVT reaction. In this paper, we demonstrate that iPPase can be produced in large quantities and high quality using a reasonably generic laboratory facility and that laboratory-purified iPPase is as effective as commercially available iPPase. Furthermore, using size exclusion chromatography coupled with multi-angle light scattering and dynamic light scattering, analytical ultracentrifugation, and small-angle X-ray scattering, we demonstrate that yeast iPPase can form tetramers and hexamers in solution as well as the enzymatically active dimer. Our work provides a robust protocol for laboratories involved with RNA in vitro transcription to efficiently produce active iPPase, significantly reducing the financial strain of large-scale RNA production.

Salmon Sperm DNA As a Corrosion Inhibitor on Ductile Cast for Use in Water Distribution System Pipes

Ductile cast iron (DCI) is a high carbon iron alloy with a composition of up to 3.7% C, 2.3% Si, 0.35% Mn and various smaller constitutes. Upon casting of DCI, the high carbon content results in solidification in a secondary phase in the form of graphite nodules. These graphite nodules form around a matrix of ferrite (α-Fe) and pearlite (α-Fe + Fe3C) and impart desirable properties such as high strength properties and corrosion resistance due to graphite’s cathodic potential. DCI is commonly used for water distribution pipework and contribute to 40% of all drinking water distribution pipes in Wales. Several different corrosion inhibitors are used to prevent corrosion of DCI in drinking water distribution applications, such as sodium silicate (Na2SiO3) and ortho-polyphosphates. However, the use of deoxyribonucleic acid (DNA) could provide a novel alternative to conventional corrosion inhibitors currently in service. The DNA molecule is formed by a double helix polynucleotide strand of phosphate and sugar groups via covalent bonds and base pairs bonded by hydrogen bonds to the molecule. The main advantage of DNA as a corrosion inhibitor is the surplus of phosphate molecules available to be chemisorbed to the surface of DCI. Alongside the potential of aromatic heterocyclic compounds found in base pairs, which could also provide corrosion inhibition via physicochemical adsorption.This work aims to assess the use of deoxyribonucleic acid (DNA) on the corrosion of ductile cast iron (DCI) in a corrosive electrolyte. DNA is considered a green, non-toxic inhibitor that shows potential when used in immersion corrosion conditions. Literature has demonstrated the use of DNA as a corrosion inhibitor for other materials such as Magnesium alloys, Copper and X80 steel. However, there is little published work on the use of DNA as a corrosion inhibitor on DCI. The DNA used in this study was extracted from salmon sperm (Sigma-Aldrich) and dissolved into a 0.17 mol dm-3 sodium chloride (NaCl) solution at the concentrations of 50, 100 and 500 mg/L adjusted to pH 7 via Sodium Hydroxide (NaOH). Electrochemical analysis and surface characterisation was carried out over a range of time periods. The corrosion inhibition afforded by DNA was determined through using a variety of electrochemical techniques such as: open circuit potential (OCP), anodic and cathodic polarisation and linear polarisation resistance (LPR). In-situ microscopy was used to study the corrosion mechanisms that occur on the surface microstructure of DCI. Post corrosion, the DCI surface was characterised using scanning electron microscopy (SEM) and FTIR (Fourier transmission infrared spectroscopy).Electrochemical results, performed over a 24-hour period, showed that as concentration of DNA increased an increase in voltage potential and decrease in corrosion rate (mpy) was observed. A decrease of 60% in corrosion rate after 24 hours is provided by 500 mg/L DNA compared to the control of 1% NaCl. However, after 30 minute’s immersion followed by cathodic polarisation studies showed an increased concentration of DNA can behave as a cathodic inhibitor. A theory for this inhibitive effect is that a passivating film forms on the DCI surface and that it is most effective after 30 minutes exposure due to the high efficiency observed during the longer-term studies. This could suggest that a film formed on the surface is most efficient after 30 minutes adsorption due to the high efficiency seen during the longer-term studies. After 72 hours of immersion there is a change in the surface of DCI, with a more robust scale appearing at higher concentrations. This change in coating surface may provide the increase in corrosion inhibition as the pathway for further corrosion attack is blocked by a protective scale. The protective scale is characterised using FTIR to examine the changes in chemical structure of the corrosion layer. Whereby PO-2 and base pairs are identified on the corrosion scale surface after 24-hours immersion in DNA. The corrosion inhibition observed using DNA on DCI in neutral immersion conditions is afforded to the adsorption of inhibitive species onto the DCI surface, providing an insoluble layer.

La-doped activated carbon as high-efficiency phosphorus adsorbent: DFT exploration of the adsorption mechanism

Phosphorus removal and recovery are important because phosphorus is both a water contaminant and present in chemicals used in agriculture and various industries. As an extremely effective approach to achieve this objective, chemisorption has been identified as a suitable technology. Herein, the adsorption materials La-doped powdered activated carbon and granular activated carbon (La-PAC (D), La-GAC (D)) were prepared by a one-pot hydrothermal process. The strategy behind the adsorbents was based on the ability of La to compensate for the electronegativity and poor selectivity of the activated carbon matrix. Furthermore, the mass transfer rate was enhanced through the formation of vacancies in the structure of the doped material resulting in larger pore sizes, more adsorption sites, and contributions to the diffusion of phosphate molecules to the interior. The phosphate adsorption capacities of La-PAC (D) and La-GAC (D) were 202.43 mg g−1 and 181.82 mg g−1, respectively, which were superior to most adsorbents. The excellent properties could be maintained at low phosphorus concentrations in actual wastewater. The employed characterization methods combined with density functional theory calculations revealed that AC, La, and the doping structure improved the adsorption performance, and the main adsorption pathways of phosphate were electrostatic attraction and complexation. La-AC (D) could accelerate the development of adsorption materials for water pollution remediation.