pH Range Research Articles

Fabrication and simulation of silicon nanogaps pH sensor as preliminary study for Retinol Binding Protein 4 (RBP4) detection

In this research, a silicon nanogap biosensor has the potential to play a significant role in the field of biosensors for detecting Retinol Binding Protein 4 (RBP4) molecules due to its unique nanostructure morphology, biocompatibility features, and electrical capabilities. Additionally, as preliminary research for RBP4, a silicon nanogap biosensor with unique molecular gate control for pH measurement was developed. Firstly, using conventional lithography followed by the Reactive-ion etching (RIE) technique, a nanofabrication approach was utilized to produce silicon nanogaps from silicon-on-insulator (SOI) wafers. The critical aspects contributing to the process and size reduction procedures were highlighted to achieve nanometer-scale size. The resulting silicon nanogaps, ranging from 100 nm to 200 nm, were fabricated precisely on the device. Secondly, pH level detection was performed using several types of standard aqueous pH buffer solutions (pH 6, pH 7, pH 12) to test the electrical response of the device. The sensitivity of the silicon nanogap pH sensor was 7.66 pS/pH (R² = 0.97), indicating that the device has a wide range of pH detecting capacity. This also includes the silicon nanogap biosensor validated by simulation, with the sensitivity obtained being 3.24 μA/e.cm² (R² = 0.98). The simulation of the sensitivity is based on the interface charge (Qf) that represents the concentration of RBP4. The results reveal that the silicon nanogap biosensor has excellent characteristics for detecting pH levels and RBP4 with outstanding sensitivity performance. In conclusion, this silicon nanogap biosensor can be used as a new electrical RBP4 biosensor for biomedical diagnostic applications in the future.

Zr-based Metal-organic Framework [Zr6O4(OH)4(3.2b-ttdc)6] for Effective Mercury (II) Sorption from Water

Abstract: The objective of this work is to study MOFs with ligands containing thienothiophene groups as linkers and evaluate their practical application as sorbents for mercury removal from water. This evaluation will be compared with MOFs containing 2,6-naphthalenedicarboxylic acid and terephthalic acid linkers. The study of Hg2+ sorption from solutions was carried out by shaking the MOFs (10 mg) with the solution at 25 °C for 24 hours. Determination of chemical elements in solutions was performed using an Agilent 8800 triple quadrupole ICP-MS spectrometer (ICP-QQQ) equipped with an octopole reaction- collision cell in a standard configuration. Within 24 hours, 97.8% of Hg2+ ions were removed from the solution, even at an initial Hg2+ concentration as low as 1 mg·L-1. An important part of the work was studying the possibility Zr-ttdc regeneration for repeated use. Using iodide solution as a desorbing agent proved more productive, ensuring the desorption of Hg2+ through competitive complex formation due to the high stability constants of the corresponding mercury complexes. With a 0.1 M potassium iodide solution at pH 6.5, 99% of the sorbed mercury was desorbed in one desorption cycle. The efficiency of [Zr6O4(OH)4([3.2-b]ttdc)6] in adsorbing mercury from aqueous solutions was thoroughly evaluated and compared to [Zr6O4(OH)4(bdc)6] and [Zr6O4(OH)4(2.6-ndc)6], which lack sulfur- containing linkers. The findings highlight the potential of functionalized MOFs for water purification as well as application in analytical chemistry for the concentration of mercury. Notably, [Zr6O4(OH)4([3.2-b]ttdc)6] demonstrated stability in water in a wide pH range, underscoring its promise for diverse environmental chemistry applications. result: In this study, investigation of a new member of the MOFs family with thienylthiophenic acid (H2ttdc) as a dicarboxylate bridging ligand, were conducted. To elucidate the mechanism of mercury sorption by MOFs, a series of experiments were performed using sorbents based on various organic blocks, including 2,6-naphthalenedicarboxylic acid, thieno[3,2-b]thiophenic acid, and terephthalic acid. To evaluate the kinetics of the adsorption process, the effect of contact time on the sorption efficiency was studied. Within 24 hours, 97.8% of Hg2+ ions were removed from the solution, even at an initial Hg2+ concentration as low as 1 mg∙L-1. This demonstrates the high sorption efficiency of Hg2+ by Zr-ttdc from aqueous solutions. Depending on the source, a number of other elements (Cu, Pb, Zn, Fe, Mn, etc.) may also be present. Their influence on the efficiency of mercury sorption under optimal conditions was studied and it was shown that interfering effects from cations are practically absent. The situation is completely different for anions. Due to competitive complex formation, mercury sorption can be suppressed. It was shown that anions such as nitrate, sulfate, formate, and acetate at concentrations of 100 mg·L-1 do not affect mercury sorption efficiency. However, in the presence of chloride or iodide, sorption is suppressed. In the case of chloride, the sorption efficiency decreases to 90% and below when the chloride concentration in the solution is 50 mg/L and higher. An important part of the work was studying the possibility Zr-ttdc regeneration for repeated use. Using iodide solution as a desorbing agent proved more productive, ensuring desorption of Hg2+ through competitive complex formation due to the high stability constants of the corresponding mercury complexes. With a 0.1 M potassium iodide solution at pH 6.5, 99% of the sorbed mercury was desorbed in one desorption cycle. The feasibility of reusing the sorbent was demonstrated with potassium iodide solution regeneration over 6 sorption-desorption cycles.

Untangling the role of single-atom substitution on the improvement of the hydrogen evolution reaction of Y2NS2 MXene in acidic media.

The production of hydrogen (H2) fuel through electrocatalysis is emerging as a sustainable alternative to conventional and environmentally harmful energy sources. However, the discovery of cost-effective and efficient materials for this purpose remains a significant challenge. In this study, we explore the potential of the transition-metal-substituted Y2NS2 MXene as a promising candidate for hydrogen production through the hydrogen evolution reaction (HER). Using density functional theory (DFT) calculations, we first analyzed the Pourbaix diagram, and dissolution potential which showed the stability and resistance to corrosion of the sulfur termination. Later, we address the kinetic limitations of HER on bare Y2NS2 by introducing single-atom substitutions of Y atoms with 3d transition metals. Nine distinct structures were evaluated, revealing that Fe-substituted Y2NS2 exhibits the highest HER activity under acidic conditions, as indicated by volcano plot analyses. Further investigation of the bonding characteristics and electronic density of states highlights the crucial role of Fe d-orbitals and the weak interactions at the sulfur-terminated surface in enhancing the HER efficiency. These findings provide insights into the design of advanced, cost-effective materials for HER catalysis, paving the way for their application as efficient electrochemical catalysts across a wide pH range.

Synthesis of zirconium-based metal-organic framework/gelatin aerogel for removing phosphate and fluoride from aqueous solutions.

This study describes the preparation of novel hybrid aerogels derived from gelatin (Gel), incorporating Br-functionalized zirconium-based metal-organic framework (UiO-66-Br; MOF) as modifying agent to effectively eliminate phosphate and fluoride ions from aqueous environments. The adsorption performance of MOF decorated Gel (Gel-xMOF) hybrid aerogels was investigated under different conditions, including agitation time, adsorbent dosage, solution pH, initial phosphate and fluoride concentrations, coexisting ions, and temperature. The functional groups of the gelatin network, coupled with UiO-66-Br, enhanced the adsorption performance of phosphate and fluoride ions from aqueous solutions. The structural features and physicochemical parameters were evaluated using several characterization tools. The mesoporous Gel-1.5MOF aerogels exhibited Langmuir adsorption capacities of 20.81 and 7.42 mg/g for phosphate and fluoride, respectively. Reusability and coexisting experiment results suggest that the as-prepared Gel-1.5MOF aerogels have the potential for practical applications. Electrostatic attraction and ligand exchange primarily govern the adsorption mechanism of both ions, followed by hydrogen bonding and pore-filling mechanisms. This investigation offers new insights into the successful elimination of phosphate and fluoride ions across a broad pH range.

Dolomite dissolution, pH neutralization, and potentially toxic element immobilization in stormwater bioretention beds.

The importance of pH in stormwater bioretention beds cannot be overstated since it impacts plant and microbial populations and removal of potentially toxic elements (PTEs) from stormwater runoff. This study investigated the effects of dolomite amendment on pH neutralization and subsequent PTE immobilization in bioretention media. To assess dolomite dissolution, pH neutralization, and PTE immobilization, engineered bioretention media was amended with different dolomite ratios and samples of dolomite-amended media were collected from two bioretention beds, one and two months after installation. The effects of inflow conditions and operational time on dolomite dissolution and PTE immobilization were investigated through a column study. Laboratory batch experiments revealed that pH neutralization was fast and reached the recommended pH range of 5 to 8 within 5min. Among the 1-D column conditions, intermittent inflow had the highest porewater Mg and Ca concentrations, indicating greater dolomite dissolution. Batch experiments on field-collected media showed that pH neutralization was substantial within 1month, and continued during the second month, due to dolomite dissolution. Dissolved (batch experiments) and column porewater Mg and Ca concentrations supported instantaneous Ca and a relatively slow Mg dissociation during dolomite dissolution. Among the monitored PTEs, dissolved and porewater concentrations (μg/L) were found to decrease with time, in the order Mn>Fe>Zn>Cu>Pb>Cd, with Cr mainly undetected in all experimental conditions. However, as pH became neutralized to slightly basic (pH~8), dissolved and porewater As concentrations increased. The study suggests that pH neutralization and PTE immobilization depend on the soil-to-dolomite ratio and hydrological properties such as inflow rate, dry-wet cycle, and soil-water contact time. Dolomite amendment to engineered media can be an effective measure for intercepting contaminants, improving ecosystem health, and enhancing biochemical contaminant breakdown, though consideration should be given to bioretention bed design features and system hydrology.

Anthracene‐Based Schiff Base Allied Triazolyl Silatranes: A Comparison of Stability and Biological Activity With Open Analog Silane

ABSTRACTIn this article, we have synthesized a series of anthracene‐based triazolyl silatranes (ABSiT 1–7) using their open analogs, that is, anthracene‐based triazolyl tri‐ethoxysilanes via transesterification reaction. All synthesized compounds have been characterized using FTIR, NMR (1H and 13C), DFT techniques, and TGA/DSC analysis to identify the stability and melting temperatures. The prepared silatranes were subsequently subjected to hydrolysis to compare their stability with their open‐chain counterparts and explore their behavior under hydrolytic conditions. The data demonstrate that silatranes are about three times less prone to attack by water than organo‐triethoxysilane and are hydrolytically more stable. Moreover, the thermal stability and pH stability were checked, and it was found that silatranes are stable up to a temperature range of 400°C and at pH 9.4, thus indicating that silatranes are more stable than their corresponding silanes at higher temperatures and large pH range. Moreover, all synthesized silatranes were tested for antioxidant and cytotoxicity activities, and the results disclosed their efficacy. A molecular docking study showed interactions of silatranes with Mutant p53 antitumor protein with binding affinity in the range −8.0 to −9.0 kcal/mol and identified as potent inhibitors.

Development of Extrudable Hydrogels Based on Carboxymethyl Cellulose-Gelatin Complex Coacervates.

This study investigates the 3D extrusion printing of a carboxymethyl cellulose (CMC)-gelatin complex coacervate system. Various CMC-gelatin coacervate hydrogels were prepared and analyzed to achieve this goal. The impact of the CMC-gelatin ratio, pH, and total biopolymer concentration on coacervation formation and rheological properties was evaluated to characterize the printability of the samples. Turbidity results indicated that the molecular interactions between gelatin and CMC biopolymers are significantly pH-dependent, occurring within the range of pH 3.7 to pH 5.6 for the tested compositions. Confocal Laser Scanning Microscopy (CLSM) confirmed the presence of coacervates as spherical particles within the optimal coacervation range. Scanning electron microscopy micrographs supported the CLSM findings, revealing greater porosity within this optimal pH range. Rheological characterization demonstrated that all CMC-gelatin hydrogels exhibited pseudoplastic behavior, with an inverse correlation between increased coacervation and decreased shear viscosity. Additionally, the coacervates displayed lower tackiness compared to gelatin hydrogels, with the maximum tackiness normal force for various CMC-gelatin ratios ranging from 1 to 15 N, notably lower than the 29 N observed for gelatin hydrogels. Mixtures with CMC-gelatin ratios of 1:15 and 1:20 exhibited the best shear recovery behavior, maintaining higher strength after shear load. The maximum strength of the CMC-gelatin coacervate system was found at a biopolymer concentration of 6%. However, lower biopolymer content allowed for consistent extrusion. Importantly, all tested samples were successfully extruded at 22 ± 2 °C, with the 1:15 biopolymer ratio yielding the most consistent printed quality. Our research highlights the promise of the CMC-gelatin coacervate system for 3D printing applications, particularly in areas that demand precise material deposition and adjustable properties.

Characterization of Broad Spectrum Bacteriophage vB ESM-pEJ01 and Its Antimicrobial Efficacy Against Shiga Toxin-Producing Escherichia coli in Green Juice.

Shiga toxin-producing Escherichia coli (STEC) infections have increased in humans, animals, and the food industry, with ready-to-eat (RTE) food products being particularly susceptible to contamination. The prevalence of multidrug-resistant strains has rendered the current control strategies insufficient to effectively control STEC infections. Herein, we characterized the newly isolated STEC phage vB_ESM-pEJ01, a polyvalent phage capable of infecting Escherichia and Salmonella species, and assessed its efficacy in reducing STEC in vitro and food matrices. The phage, belonging to the Tevenvirinae, exhibits effective bacteriolytic activity, a short latent period, large burst size, and stability under a broad pH range and moderate temperatures. Moreover, the phage demonstrated strong anti-biofilm efficacy even at low concentrations. Genomic analysis revealed that the phage was similar to the well-characterized RB49 phage (T4-like phage) but possesses distinct host-specificity-related genes that potentially contribute to its extensive host range. The efficacy of phage vB_ESM-pEJ01 was evaluated in artificially STEC-inoculated green juice samples, where it significantly reduced STEC and the abundance of Shiga toxin-producing genes at 4 and 25 °C. Therefore, these results suggest that the polyvalent phage vB_ESM-pEJ01 is a promising biocontrol agent for foodborne pathogens in RTE foods such as fresh juices.

"Turn-on-off" Fluorescent Probes Based on Carbon Nanoparticles for Hypochlorite and Fe2+ Detection.

The identification of ClO- and iron ions in water medium is a difficult task and has been one of the hot issues in analytical chemistry. For this objective, we synthesized carbon nanoparticles (CNPs) through a solvothermal reaction between 1, 3, 5-trimesic acid and o-phenylenediamine, which served as a sequential fluorescent probe for ClO- and Fe2+ ions. The obtained CNPs were spherical particles with a diameter of 26.5nm, exhibiting excellent fluorescence stability under a wide pH range, high ionic strength, and UV irradiation. Interestingly, the fluorescence of CNPs was selectively enhanced in the presence of ClO-, and the resultant enhanced emission was extremely quenched by Fe2+. In view of this, a "turn-on-off" fluorescent probe was established, which possessed wonderful sensitivity and selectivity for quantitative analysis of ClO- and Fe2+, with corresponding detection limits of 0.15 µM and 0.088 µM, respectively. In addition, the practicality and viability of the developed probe were validated by quantifying ClO- and Fe2+ in tap water and river water.

Nitrogen-doped reduced graphene oxide for high efficient adsorption of methylene blue.

A highly efficient and widely applicable adsorbent for the removal of methylene blue (MB) was created using nitrogen-doped and reduced graphene oxide (NRGO). The effects of NRGO mass, pH, contact time, and the initial MB concentration on the adsorption properties of MB onto NRGO were investigated. The results showed that the adsorption behavior remained stable within the pH range of 2.0-10.0, and the adsorption process gradually reached equilibrium after 24h. Additionally, the adsorption kinetics and adsorption isotherms were discussed to propose a theoretical adsorption mechanism. Meanwhile, some characterizations including Scanning Electron Microscopy, Energy Disperse X-ray Spectroscopy, X-ray Photoelectron Spectroscopy, X-ray Powder Diffraction, Fourier Transform Infrared Spectroscopy, etc. were used to explore potential adsorption mechanism, which indicated the physisorption caused by π-π bonds was the main adsorption mechanism. NRGO exhibits efficient MB absorption and holds significant potential application for the wastewater treatment.

Degradation of ciprofloxacin using CoFe2O4@three-dimensional TiO2@graphene aerogels composite: kinetic, reusability, mineralization, degradation pathway, and toxicity assessment.

An investigation into the degradation of ciprofloxacin (CIP) under visible light was carried out using an efficient photocatalyst, i.e., CoFe2O4@3D-TiO2@GA, synthesized by doping CoFe2O4@three-dimensional-TiO2 into a hierarchical porous graphene aerogel. Optimal conditions for achieving complete removal of CIP involved a reaction time of 60 min, a catalyst dose of 0.6 g/L, an initial CIP concentration of 25 mg/L, and a solution pH range of 3-5. The reusability of CoFe2O4@3D-TiO2@GA was observed to remain high even after four consecutive cycles, as the CIP degradation only slightly decreased from 94.3 to 87.1%. Following a 2-h photocatalytic degradation process, the intermediate products within the CIP solution no longer posed a threat to E. coli. The TOC analysis confirmed that CIP achieved 86% total mineralization. In the raw sewage, the BOD5/COD and BOD5/TOC ratios were 0.774 and 0.232, respectively. However, after a 120-min photocatalytic reaction, these ratios increased to 1.38 and 0.754, respectively. These findings suggest that non-biological sewage can be successfully transformed into biodegradable effluent through photocatalytic degradation. The photocatalytic process has a reaction rate coefficient that is 8.7 to 20.7 times higher than the adsorption process, depending on the concentration. The half-life constant is 117.4 min for the optimal concentration of 10 mg/L for the adsorption process, while for the photocatalytic process, it is 6.24 min. The research has highlighted the importance of integrating adsorption and photocatalysis, whereby primary reactive oxidative species, including superoxide and hydroxyl radicals, were identified. The study presents a pioneering approach for producing CoFe2O4@3D-TiO2@GA, which has promising potential for environmental applications utilizing visible light.

Electro-polymerization of modified carbon paste sensor for detecting azithromycin.

Azithromycin (AM) is one of the prescribed drugs in pandemic medication treatment which has paid great attention. We developed in this study a simply modified carbon paste electrode (CPE) to detect AM using poly-threonine (PT). PT or similar polymers are used as carriers to enhance the delivery and effectiveness of AM. The work was characterised via Cyclic Voltammetry (CV), electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). We take into consideration the effects of pH, scan rate, accumulation time, interference, and calibration curve.A very sensitive response to the oxidation of 1.0 mM from AM in phosphate buffer solution (PBS) over a pH range of 5.0 to 10.0 was observed using the developed poly-threonine carbon paste electrode (PTCPE). The impact of different AM concentrations was investigated resulting in a detection limit of 0.32 µM and a quantification limit of 1.07 µM at PBS (pH 7.4). Finally, the recently used electrode realized acceptable sensitivity and consistency for AM detection in pharmaceutical drugs.

Optimization of Electrocatalytic Chlorazol Yellow Degradation Using PbO2 Nanostructure Immobilized on Stainless Steel Substrate

In this study, an electrochemical approach was utilized to degrade the anionic Chlorazol Yellow (CY) dye in an aqueous solution using a lead oxide-modified stainless steel electrode (denoted as PbO2-SS). The fabrication of this electrode involved scanning a clean stainless steel (denoted as SS) plate within a range of −1.0 V to +1.0 V against Ag/AgCl (saturated KCl) for three cycles at a scan rate of 0.1 V s−1 in a 0.1 M Pb(NO3)2 solution. Analysis via X-ray photoelectron spectroscopy (XPS) confirmed successful fabrication, with Pb4+ being the predominant species observed in the XPS spectra. Additionally, scanning electron microscopy (SEM) imaging of the fabricated electrode revealed the deposition of PbO2 in a flower-like, nanostructured form on the SS surface. To provide a cost-effective method for dye treatment, the PbO2-SS anode was utilized to oxidize chloride ions (Cl−) into hypochlorite ions (ClO−), which subsequently oxidized CY molecules. Optimization of parameters such as the voltage, supporting electrolytes, and solution pH was conducted to determine the most effective degradation conditions. The method achieved a degradation efficiency of approximately 97% over a wide pH range within 20 min, indicating its applicability across various pH conditions. Consequently, this technique presents a promising approach for the treatment of industrial wastewater.

Stability of lead immobilization by Aspergillus niger and fluorapatite under different pH conditions.

The combination of Aspergillus niger (A. niger) and fluorapatite (FAp) has been applied in lead (Pb) immobilization. However, the different pH can affect the stability of the immobilized Pb minerals. This experiment explored the stability of Pb immobilization by A. niger and FAp under different pH conditions. A. niger can grow normally in a pH range from 2.5 to 6.5 conditions. Meanwhile, more than 99 % of Pb cations were removed by A. niger and FAp under a pH range from 3.5 to 6.5. More importantly, only less than 1.23 % Pb was released again under pH 3.5-5.5. The strong acidic conditions (pH 1.5) inhibited the growth of A. niger and caused a lower Pb removal ratio of 37.86 %. In addition, the formed minerals of lead oxalate and lead/calcium oxalate coprecipitate dominate the Pb remediation by A. niger and FAp. The pH > 5.5 condition could decrease the stability of Pb immobilization via the low calcium/lead ratios. The combination of A. niger and FAp shows great potential in Pb remediation at a pH range from 3.5 to 5.5, suitable for fungal growth and Pb minerals stability. This research provides new insight into Pb remediation by phosphate-solubilizing fungi and FAp in various acidic environments.

Pseudomonas fungipugnans sp. nov., a potently antifungal bacterium isolated from moss.

A novel strain, 681, was isolated from a moss sample taken from the Chrutzelried woods in Canton Zürich, Switzerland. The strain showed potent activity against several fungi and oomycetes. It was affiliated to the Pseudomonas genus by 16S rRNA gene sequence phylogeny. Genome sequencing showed a G+C content of 59.9 mol%. The highest average nucleotide identity was 86.63%, and the highest digital DNA-DNA hybridization value was 32.2% (with Pseudomonas nunensis ln5), considerably below the thresholds for species delineation. Multi-locus phylogeny using 81 concatenated sequences indicated that the strain represented a new species within the Pseudomonas mandelii subgroup. This study details its characterization as a new species. The 681 genome was screened in silico using antiSMASH to reveal candidate secondary metabolite clusters for the strong antifungal activity exhibited by 681. Of the 15 clusters identified, we disrupted the seven best and tested for activity against Fusarium solani. The pyrrolnitrin, rhizoxin, novel PKS-NRPS and acaterin gene clusters contributed significantly to the observed antifungal activity. Phenotypic analyses found that strain 681 cells were aerobic, Gram-negative, motile rods (mean length 2.60 µm and mean width of 0.67 µm) with one to three polar flagella. Optimal growth was at 30 °C, but growth also occurred at 8 °C. The pH range was 6-7, with some growth at pH 8. Robust growth occurred at 0-3% (w/v) NaCl and weak growth at 4% (w/v) NaCl, with the optimum at 1% (w/v) NaCl. Strain 681 was oxidase positive, hydrolysed arginine under anaerobic conditions, showed intense fluorescence on King's medium B and produced a hypersensitive response in tobacco leaves. Following our investigations, we propose the designation Pseudomonas fungipugnans sp. nov. for this new species. The type strain, 681, is available from the DSMZ and LMG/BCCM culture collections under the designations DSM 115721 and LMG 33039, respectively.

Performance of Ti/TiO2-ZIF-67 photoanode under LED irradiation applied to the photoelectrodegradation of the antidepressant venlafaxine (VEN) in municipal wastewater effluent

This work describes the direct deposition of ZIF-67 metal-organic framework (MOF) onto Ti/TiO2 nanotubes forming a photoanode for the degradation of the antidepressant Venlafaxine (VEN). This material combines the excellent characteristics of ZIF-67 MOF in enhancing photocatalytic reduction and oxidation reactions induced by UV LED irradiation, as well as the storage of VEN molecules in its pores. Ti/TiO2-ZIF-67 features an eco-friendly technology for degradation of pharmaceutical micropollutants such as antidepressants. The photoanode was prepared, characterized and applied in the degradation of VEN by photocatalysis (PC), electrocatalysis (EC), photolysis (PL) and PEC processes. PEC process presented the best performance when compared to the others processes in both simulated solutions and real wastewater, achieving 100% and 89% degradation of VEN after 60 and 90 min, with TOC removal rates of 50% and 4%, respectively. The lower mineralization rate suggests that the degradation of VEN in complex matrices such as that of real wastewater produced recalcitrant by-products that are difficult to convert into CO2 and H2O. Zeta potential measurement showed that at pH 6 and 8 there is an effect of attraction of opposite electrostatic charges between the surface of ZIF-67 (positive) and VEN (negative), favoring the degradation of VEN in this pH range. The good performance of the Ti/TiO2-ZIF-67 can be attributed to the formation of the Z-scheme heterojunction between the TiO2 nanotubes and the ZIF-67 MOF which contributed to a lower rate of electron-hole (e-/h+) pairs recombination, favoring VEN degradation mainly to higher generation of •OH radical and less contribution of O2•- superoxide produced by UV irradiation forming some degradation by-products through demethylation and oxidation reactions.

Solution Temperature Compensation Factor for the Measured pH Value of Cement‐Based Materials

Most of the conventional pH measurements were carried out in acidic to slightly alkaline solutions. In this pH range, the effect of temperature during the measurement is negligible and can be ignored. However, the pH value for highly alkaline solutions is considerably sensitive to their temperature change. A slight difference in temperature can affect the accuracy of the pH test result. Cement‐based materials (CBMs) are highly alkaline. The influence of temperature shall be minimised to compare the pH values of different CBMs precisely. In the literature related to pH measurement for CBMs, the solution temperature during the pH measurement was not recorded, whilst the room temperature recorded was in the range of 20°C–30°C. Therefore, solution temperature compensation (STC) shall be introduced into the pH measurement for CBMs to convert the measured pH into the pH value at a reference temperature of 25°C. To this end, firstly, the pH–temperature profile of the solutions was generated to identify the STC factor (fSTC, also known as solution temperature coefficient). Then, the solution temperature‐compensated pH (pHSTC) was calculated using fSTC to present the pH value in the reference temperature of 25°C. However, no standardised method exists for the generation of this pH–temperature profile. In this study, a simple method for generating pH–temperature profile and calculating pHSTC for CBMs was introduced.

Composite Sorbents Based on Chitosan Polymer Matrix and Derivatives of 4-Amino-N'-hydroxy-1,2,5-oxadiazole-3-carboximidamide for Uranium Removal from Liquid Mineralized Media.

Composite adsorbents based on a natural biopolymer matrix of chitosan, to which 4-amino-N'-hydroxy-1,2,5-oxadiazole-3-carboximidamide and its Se derivative were attached, were synthesized. A complex of physicochemical analysis methods indicates that the direct introduction of a matrix with high ionic permeability into the reaction mixture contributes to the formation of homogeneous particles of composite with developed surface morphology, which enhances the kinetic and capacitive parameters of uranium sorption in liquid media. It has been established that the direct introduction of a matrix with high ionic permeability into the reaction mixture contributes to the formation of homogeneous particles with a developed surface morphology, which enhances the kinetic and capacitive parameters of uranium sorption in liquid media. The synthesized materials had increased sorption-selective properties towards uranium in the pH range from 4 to 9 under static sorption conditions. The formation of the Se derivative of amidoxime during its attachment to the polymer matrix (Se-chit) contributes to the creation of a more chemically stable and highly effective adsorbent, compared to the direct binding of 4-amino-N'-hydroxy-1,2,5-oxadiazole-3-carboximidamide with chitosan (43AF-chit). The optimal parameters for the synthesis of materials were established. It was demonstrated that the ratio of amidoxime to chitosan should be within the range of 2:1 to 1:2. As the mass content of chitosan increases, the material gradually dissolves and transforms into a gel, resulting in the formation of liquid radioactive waste with a complex chemical composition. It was found that the kinetic sorption parameters of composite materials increase 2-10 times compared to those of non-composite materials. The sorption capacity of uranium in solutions with pH 6 and pH 8 can reach approximately 400-450 mg g-1. Under dynamic sorption conditions, the effective filtration cycle values (before uranium slips into the filtrate ≥ 50%) improve significantly when transitioning from a non-composite adsorbent to a composite one: increasing from 50 to 800 b.v. for pH 6 and from 2700 to 4000 b.v. for pH 8. These results indicate that the synthesized sorbents are promising materials for uranium removal from liquid media, suitable for both purification and the recovery of radionuclides as valuable raw materials.

Purification, characterization, optimization, and docking simulation of alkaline protease produced by Brevibacillus agri SAR25 using fish wastes as a substrate.

Recycling of protein-rich environmental wastes and obtaining more valuable products from these recycled products is a topic of interest for researchers. This study aims to produce, purify, and characterize the physicochemical and structural properties of the protease enzyme produced from Brevibacillus agri SAR25 using salmon fish waste as substrate and also to evaluate the effect of protease on the chicken feather, enzyme-ligand interactions, and active site surface area. The production of protease was optimum on 50g/L fish waste, pH8, 40°C, 96h, and 150rpm. The alkaline protease was isolated using three-phase partitioning (TPP), a straightforward and efficient one-step method for purifying enzymes in industrial applications. TPP achieved a purification efficiency of 115% with a 3.1-fold increase in concentration. As a result, the molecular weight of the purified protease was determined to be 50kDa under optimal conditions of pH9 and 45°C. The 3D structure of the alkaline protease enzyme with the determined ligands was predicted by homology modeling using UCSF Chimera 1.17.3 software. Tween-20 ligand showed the best binding affinity by hydrogen bonding with amino acids 106A, Asn 133A, Gly 198, Asn 226, Glu 232 and hydrophobic interaction with His 135, Leu 283 in the active site of the alkaline protease enzyme, thus leading to the discovery of new semisynthetic enzymes of salmon fish waste. The activity and stability of Brevibacillus agri SAR25 alkaline protease over a wide range of temperatures and pH, and its relatively high stability in the presence of various metal ions, organic solvents, and surfactants indicate that it can be used as a biocatalyst for different industrial applications. This could lead to the creation of new enzymes made from recycled biological materials.

Pseudomonas retamae sp. nov., a novel endophytic bacterium with plant growth-promoting potential, isolated from root nodules of Retama monosperma in Northwestern Algeria.

A thorough polyphasic taxonomic study, integrating genome-based taxonomic approaches, was carried out to characterize the RB5T strain isolated from root nodules of Retama monosperma growing on the coastal dunes of Bousfer Beach (Oran, Algeria). The 16S rRNA gene sequence analysis revealed that strain RB5T had the highest similarity to Pseudomonas granadensis LMG27940T (98.94%) and Pseudomonas gozinkensis IzPS32dT (98.73%). Phylogenetic studies, including both 16S rRNA gene sequence and multilocus sequence analysis using 16S rRNA, gyrB and rpoD housekeeping genes, positioned RB5T in a distinct branch alongside its closest relative, P. granadensis LMG27940T. Phylogenomic analysis using the Bac120 marker set and Type (Strain) Genome Server confirmed the unique position of RB5T and its close relationship with P. granadensis LMG27940T. Similarly, genomic comparisons using average nucleotide identity based on blast (ANIb) and digital DNA-DNA hybridization (dDDH) revealed values of 92.85 and 59.3%, respectively, when compared with its closest relative, P. granadensis LMG27940T. Both values fall below the established species delimitation thresholds of 95-96% for ANIb and 70% for dDDH, providing strong genomic evidence that strain RB5T represents a novel species. Further average nucleotide identity comparisons with unclassified Pseudomonas spp. (384 genomes) and metagenomic-derived genomes from the Genome Taxonomy Database (GTDB) showed values between 84.27 and 89.2%, indicating that strain RB5T belongs to a unique evolutionary line. The genome of RB5T, with a size of 6 311 310 bp and a G+C content of 60%, harbours several key genes associated with plant growth-promoting traits, making it a promising candidate for sustainable agriculture. Phenotypically, RB5T strain is an aerobic, rod-shaped, Gram-negative, non-spore-forming bacterium that is motile with a single polar flagellum. It grows under a wide range of temperature (4-42 °C) and pH (5-10) conditions and tolerates up to 6% (w/v) NaCl. The main cellular fatty acid composition of RB5T includes C16:0, C17:0 cyclo and the summed features 3 consisting of C16:1 ω7c/C16:1 ω6c. Based on the phylogenetic, phenotypic, chemotaxonomic and genome comparison analyses, strain RB5T was identified as a novel species of the genus Pseudomonas, for which the name Pseudomonas retamae sp. nov. is proposed. The type strain is RB5T (=DSM 117471T=LMG 33633T=CIP 112482T).