FTIR Analysis Research Articles

Anticandidal effect of cinnamic acid characterized from Cinnamomum cassia bark against the fluconazole resistant strains of Candida.

Candida spp., causes invasive fungal infections, especially in immune-compromised patients and the propensity of antifungal resistance against azole-based drugs need to be addressed. This study is thus aimed to characterize the anticandidal effect of the cinnamic acid extracted from the barks of Cinnamomum cassia. Five species of Fluconazole-resistant Candida sp. were retrieved from the department repertoire. The extraction of CA was performed by three different methods followed by silica gel column chromatography. Eluant was subjected to FTIR and XRD analysis for confirmation. The anticandidal activity of the CA was checked by the agar disc diffusion method and the MIC and MFC were determined. The anti-biofilm effect of CA was assessed using the CLSM technique followed by the biocompatibility check using MTT assay in normal HGF cell lines. CA was best extracted with the hot maceration method using ethanol with a maximum yield of 6.73mg. Purification by column chromatography was achieved using benzene, acetic acid, and water (6:7:3) mobile phase. CA was confirmed by FTIR with absorption peaks and by XDR based on strong intensity. CA was found to possess promising anticandidal activity at 8µg/mL with MIC and MFC values determined as 0.8µg/mL and 0.08µg/mL respectively. Antibiofilm activity by CLSM analysis revealed biofilm inhibition and was biocompatible at 8.5µg/ml concentrations in HGF cell lines until 24h. The study findings conclude that CA is the best alternative to treat candidal infection warranting further experimental preclinical studies.

Keratin-based pet food produced through proteolytic hydrolysis of chicken feather: Characterisation and palatability study

Valorisation of poultry co-products can fulfil the protein demand of the pet food sector thereby supporting a circular bioeconomy. In this investigation, keratin was produced through an optimised reduction (0.8% sodium sulphite, for 90min) and hydrolysis (using papain for 120min) with a yield of 56.87%. FTIR analysis, in vitro digestibility, SEM imaging, and amino acid profiling of the derived keratin were done and it was subsequently used for pet formulations. Results revealed significant alteration in secondary protein structure post-hydrolysis with in vitro digestibility of 90%. Higher levels (>100% increase) of histidine, arginine, lysine, and methionine were observed in the hydrolysate compared to conventional feather meal. Pet food was formulated with 20% protein replacement that showed maximum palatability in single and two-bowl tests for 2-4 year old Labrador dogs. The developed pet food exhibited desirable colour, water activity (0.5), moisture (4.7%), and relatively lower TBARS value (0.8mg/kg) than the critical value.

Redefining Water Purification: gC3N4-CLDH's Electrochemical SMX Eradication

The contamination of water sources by pharmaceutical compounds presents global environmental and health risks, necessitating the development of efficient water treatment technologies. In this study, the synthesis, characterization, and evaluation of a novel graphitic carbon nitride-calcined (Fe-Ca) layered double hydroxide (gC3N4-CLDH) composite for electrochemical degradation of sulfamethoxazole (SMX) in water yielded significant outcomes are reported. SEM, XRD, FTIR, and XPS analyses confirmed well-defined composite structures with unique morphology and crystalline properties. Electrochemical degradation experiments demonstrated >98% SMX removal and >75% TOC removal under optimized conditions, highlighting its effectiveness. The composite exhibited excellent mineralization efficiency across various pH levels, with superoxide radicals (O2●–) and hydroxyl radicals (●OH) identified as primary reactive oxygen species. With remarkable regeneration capability for up to 7 cycles, the gC3N4-CLDH composite emerges as a highly promising solution for sustainable water treatment. Humic acid (HA) in water significantly slows SMX degradation, suggests complicating SMX degradation with natural organic matter. Despite this, the gC3N4-CLDH composite effectively degrades SMX in groundwater and industrial wastewater, with slight efficiency reduction in the latter due to higher impurity levels. These findings highlight the complexities of treating pharmaceutical pollutants in various water types. Overall, gC3N4-CLDH’s high removal efficiency, broad pH applicability, sustainability, and mechanistic insights provide a solid foundation for future research and real-world environmental applications.

Synthesis of Azo Polymers and Their Catalytic Performance in Hydrogen Production via NaBH4 Methanolysis

The extensive use of fossil fuels has a profound impact on ecosystems and contributes to global warming through the emission of greenhouse gases. To mitigate these effects, alternative energy sources such as hydrogen are crucial. In this study, a green synthesis approach was used to prepare an azo cross-linked polymer containing 4-aminophenyl ether and resorcinol. The synthesized polymer was thoroughly characterized by FT-IR, BET, TGA, Zeta Potential and SEM-EDS analyses. The catalytic performance of the polymer in hydrogen production from NaBH4 via methanolysis was then investigated. Various parameters affecting hydrogen production, including catalyst and NaBH4 amounts, methanol volume and temperature, were systematically investigated to identify the optimum conditions. The polymer exhibited maximum hydrogen generation rate (HGR) of 12619 mL H2 min⁻¹ gcat⁻¹ at 60°C, respectively, with an activation energy of 24.22 kJ mol⁻¹. After optimization, the reusability of the polymer was evaluated over five cycles and the theoretical hydrogen generation rates were consistently achieved; however, the hydrogen generation time increased with each subsequent cycle. The primary objective of this research was to highlight novel azo linked polymers with potent catalytic activity in hydrogen generation, demonstrating the significant potential of the polymer to advance hydrogen generation. Ultimately, this study highlights the promising role of azo cross-linked polymers as effective catalysts for hydrogen production, offering new avenues and perspectives towards sustainable energy solutions.

Natural and environmentally friendly rhamnolipid functionalized luffa fibers for adsorptive removal of pharmaceutical contaminant: Batch and fixed-bed column studies

This study aims to explore the potential of utilizing rhamnolipid functionalized luffa fibers as an environmentally sustainable solution for removing pharmaceutical contaminants from water. The efficiency of the developed adsorbent for removing acetaminophen has been investigated in batch and fixed bed column modes. The adsorbent has been characterized via FTIR, XRD, and SEM analyses which revealed the rhamnolipid nanomicelles formation with bi-pyramidal morphology and the presence of functional groups on the surface of the adsorbent. The optimum conditions have been reported (pH: 5.0, adsorbent dosage 2 g/L, initial acetaminophen concentration: 20 mg/L, and contact time: 80 min). The highest adsorption capacity for acetaminophen was 37.03 mg/g at the optimized conditions. Fixed-bed column experiments examined flow rate and initial acetaminophen concentration effects, with the Thomas model assessing column performance. This research investigates the potential of RL-LF for effective water remediation, offering insights into practical applications and optimization strategies.

Single Crystal, Conformational, Quantum reactivity, Hirshfeld surface, Molecular interactions, ADMET, and Molecular Docking Investigations on HIV-1 site of 3-isopropyldiphenyl-1-(2-(thiophen-2yl)acetyl)piperidin-4-one

The 3-isopropyl-2,6-diphenyl-1-(2-(thiophen-2yl)acetyl)piperidin-4-one (IPTP) single crystals were grown by slow evaporation method and the structure is confirmed through FT-IR, 1H NMR, and 13C NMR spectral analyses. Single crystal X-ray diffraction revealed that the title compound having chair conformation of the piperidine ring, with an axial orientation of phenyl rings at C-2 and C-6 positions and an isopropyl group at C-3. Hirshfeld surface analysis was employed to examine intermolecular contacts and strong and weak attractive, repulsive, and van der Waals interactions in the molecule were determined using the reduced density gradient method (RDG). The geometrical parameters obtained through Density Functional Theory are compared with experimental values and also conducted to optimize structural parameters, frontier molecular orbitals (FMOs), and molecular electrostatic potential surface analysis (MEPS). NBO calculations were employed to investigate intermolecular and intramolecular charge movement, as well as the molecule's stability. Vibrational Energy Distribution Analysis (VEDA) software facilitated potential energy decomposition (PED) analysis using FT-IR wave numbers. The title compound molecular docking data were compared with the markedly available FDA-approved anti-HIV drug of Nelfinavir and their results were discussed, ADME analysis studies were discussed concerning FDA-approved anti-HIV drugs, including Nelfinavir, Betulinic Acid, Haloperidol, and Donepezil.

Electrochemical performance of MXene/Fe3O4 composite derived from recycled carbon for vanadium redox flow battery

MXenes are emerging 2D materials that have demonstrated excellent combined metallic electrical conductivity and hydrophilicity. They have been extensively studied in applications like energy storage, catalysis, optoelectronics, and so on. In this work, the carbon sourced from carbon soot extracted from fossil fuel combustion wastes was used to produce Ti3C2Tx MXene for the first time. The recyclable carbon-derived MXene/iron oxide (Fe3O4) composites with different concentrations of Fe3O4 were synthesized via a hydrothermal route. The successful synthesis of the MXene/Fe3O4 composites was confirmed by the SEM, HRTEM, EDX, UV–Vis, XRD, FTIR, and XPS analyses. Electron images morphologically revealed the existence of Fe3O4 within the as-synthesized composites, while UV–Vis spectra detected the surface plasmon resonance peaks of MXene and Fe3O4, respectively. The XRD spectra identified the crystalline structure of MXene at 5.7° (002) and 25.3° (006), as well as the magnetite Fe3O4 at 18.2° (111) and 38.2° (311), which aligned well with the presence of Ti-O and Fe-O bands observed in the FTIR data. The XPS study also confirmed the presence of the Fe element within the composites. The electrochemical performance of composite as electrode material towards the cathode VO2+/VO2+ redox reaction was investigated. The synergistic effect of both MXene and metal oxide improved the electrode kinetic activity towards the redox reaction, as evidenced by the voltage peak separation (ΔE) and the ratio of peak currents (IO/IR) values determined in cyclic voltammetry (CV), and the charge transfer process probed by electrochemical impedance spectroscopy (EIS). The specific capacity of the battery with the composites was increased along with the improvement of retention strength. The MXene/Fe3O4 5 wt% composite displayed the highest electrochemical catalytic activity with the lowest ΔE (124 mV), IO/IR of about 1, producing specific capacities of 10.2 Ah L-1 and energy efficiency of 70.1 %. The nature of MXene and Fe3O4, morphological features, and higher surface area of composites increased the kinetic activity of the electrode, enabling the composites to be potentially applied in the vanadium redox flow battery (VRFB) system.

Simultaneous removal of CTRX and Cr(Ⅵ) by CQDs-doped bifunctional molecular imprinted BiOCl/Bi3NbO7 photocatalyst: The enhanced selective performance and charge separation abilities

As a commonly used additive in breeding industry, the complex pollutants and metabolites formed by antibiotics and heavy metals in aquaculture wastewater have the characteristics of strong persistence, refractory degradation and easy accumulation, and exist in the environment and human body for a long time, which caused seriously ecological, environmental and health problems. Their effective removal studies are very essential. In this paper, a CQDs-doped bifunctional molecular imprinted BiOCl/Bi3NbO7 heterojunction photocatalyst (CQDs-MIP-BNO) was fabricated and the micromorphology along with photoelectric characteristics were explored by SEM, XRD, FTIR, XPS, UV-Vis and PL analysis. The photocatalytic performance experiments implied that 10 % doping of CQDs showed the highest selectivity and photocatalytic activity for the 94 % removal rate of Ceftriaxone Sodium (CTRX) and 80 % of Cr (VI) within 45 min. On this basis, a photocatalytic reactor loaded with the as-synthesized bifunctional catalyst through a sponge mesh covered with CS/PVA film was set up and the actual operation potential was further explored. The results showed that the enhanced removal performance of this bifunctional photocatalyst for CTRX and Cr(VI) made it feasible to efficiently remove one or more low-concentration, high-toxicity antibiotics and heavy-metal pollutants from the water column to validate the utility of combining molecular imprinting and photocatalytic technologies for the treatment of aquaculture wastewater.

Valorisation of citrus peel industrial wastes for facile extraction of extractives, pectin, and cellulose nanocrystals through ultrasonication: An in-depth investigation

In this work we developed an eco-friendly valorisation of Citrus wastes (CWs), through a solvent-assisted ultrasonication extraction technique, thus having access to a wide range of bio-active compounds and polysaccharides, extremely useful in different industrial sectors (food, cosmetics, nutraceutical). Water-based low-amplitude ultrasonication was examined as a potential method for pectin extraction as well as polar and non-polar citrus extractives (CEs), among which hesperidin and triglycerides of 18 carbon fatty acids were found to be the most representative ones. In addition, citric acid:glycerol (1:4)-based deep eutectic solvent (DES) in combination with ultrasonic extraction was utilized to extract microcellulose (CMC), from which stable cellulose nanocrystals (CNCs) with glycerol-assisted high amplitude ultrasonication were obtained. The physical and chemical properties of the extracted polysaccharides (pectin, micro and nanocellulose) were analysed through DLS, ζ-potential, XRD, HP-SEC, SEM, AFM, TGA-DSC, FTIR, NMR, and PMP-HPLC analyses. The putative structure of the extracted citrus pectin (CP) was analysed and elucidated through enzyme-assisted hydrolysis in correlation with ESI-MS and monosaccharide composition. The developed extraction methods are expected to influence the industrial process for the valorisation of CWs and implement the circular bio-economy.

SUPERPARAMAGNETIC HYDROPHILIC MOLECULARLY IMPRINTED NANOPARTICLES FOR AN EFFICIENT AND SELECTIVE REMOVAL OF TETRACYCLINE FROM WATER

In this work, a novel superparamagnetic hydrophilic molecularly imprinted nanomaterial for the removal of tetracycline (TC) was synthesized utilizing magnetite (Fe3O4) as the magnetic core, TC as the template molecule, 3-aminopropyltriethoxysilane (APTES) as the functional monomer, and tetraethoxysilane (TEOS) as the cross-linker. Initially, Fe3O4 magnetic nanoparticles (MNP) coated with SiO2 (MNP@SiO2) were synthesized, followed by TC molecular imprinting on the nanoparticles. Initially, Fe3O4 MNP coated with SiO2 (MNP@SiO2) were synthesized, followed by TC molecular imprinting on the nanoparticles. The synthesis method for MNP@SiO2 was optimized, and DLS analysis of 10 replicates showed a nanoparticle size of 70.1 ± 5.8 nm, indicating high method reproducibility. The MNP@SiO2, as well as the imprinted (MNP@SiO2-MIP) and non-imprinted (MNP@SiO2-NIP) nanomaterials, were characterized by FTIR, TEM, VSM, XRD, DLS, Z potential, and BET analysis. The saturation magnetization (Ms) values were 43 emu/g for MNP@SiO2 and 32 emu/g for both MNP@SiO2-MIP and MNP@SiO2-NIP, confirming suitability for magnetic separation using external magnets. Batch binding experiments conducted in water and methanol assessed adsorption isotherms and binding kinetics, with data fitting the Langmuir isotherm model better than the Freundlich model. The developed MIP exhibited significant selectivity against other molecules with similar functional groups and size. In water, the adsorption capacity of the MNP@SiO2-MIP was 23 mg/g, with an imprinting factor of 2.2. Furthermore, the MIP demonstrated good regeneration performance. The material was tested on TC-spiked tap water samples, achieving 80.1% TC removal with high reproducibility (3.2%, n=3). Combining hydrophilic superparamagnetic nanoparticles with molecular imprinting enhances their potential applications in environmental remediation, antibiotic purification, and drug delivery.

Improving O₂ Absorption in PVDF Membrane with Cross-Linked Polymer Coatings

Surface modification of polyvinylidene fluoride (PVDF) membranes using various polymers, including chitosan, nylon, dopamine, and EDA, was examined through SEM and FTIR analyses. SEM imaging unveiled the preservation of membrane porosity post-modification, affirming successful polymer integration without pore obstruction. Nylon coatings induced alterations in surface morphology, with enlarged pore apertures and roughened surfaces attributed to formic acid exposure during dissolution. FTIR spectroscopy confirmed the presence of the respective polymers, exhibiting characteristic peaks for each. Notably, membranes coated with EDA exhibited enhanced CO2 absorption flux owing to their inherently hydrophilic nature and larger pore dimensions. Optimization of EDA coating parameters, including deposition time and concentration, revealed a direct correlation between increased EDA deposition and enhanced CO2 absorption flux, emphasizing the significant impact of these parameters on membrane performance in gas absorption. Consequently, tailored surface modifications offer a promising avenue for enhancing membrane functionality in gas separation applications

Pulsed Electric Field-Assisted Extraction of Inulin from Ecuadorian Cabuya (Agave americana)

Inulin is a carbohydrate that belongs to fructans; due to its health benefits, it is widely used in the food and pharmaceutical industries. In this research, cabuya (Agave americana) was employed to obtain inulin by pulsed electric field-assisted extraction (PEFAE) and FTIR analysis confirmed its presence. The influence of PEFAE operating parameters, namely, electric field strength (1, 3 and 5 kV/cm), pulse duration (0.1, 0.2 and 0.5 ms), number of pulses (10,000, 20,000 and 40,000) and work cycle (20, 50 and 80%) on the permeabilization index and energy expenditure were tested. Also, once the operating conditions for PEFAE were set, the temperature for conventional extraction (CE) and PEFAE were defined by comparing extraction kinetics. The cabuya meristem slices were exposed to PEFAE to obtain extracts that were quantified, purified and concentrated. The inulin was isolated by fractional precipitation with ethanol to be characterized. The highest permeabilization index and the lowest energy consumption were reached at 5 kV/cm, 0.5 ms, 10,000 pulses and 20%. The same extraction yield and approximately the same amount of inulin were obtained by PEFAE at 60 °C compared to CE at 80 °C. Despite, the lower amount of inulin obtained by PEFAE in comparison to CE, its quality was better because it is mainly constituted of inulin of high average polymerization degree with more than 38 fructose units. In addition, TGA analyses showed that inulin obtained by PEFAE has a lower thermal degradation rate than the obtained by CE and to the standard.

The interaction mechanisms of algal organic matter (AOM) and various types and aging degrees of microplastics

Algal blooms can produce substantial amounts of algal organic matter (AOM). Microplastics (MPs) in aquatic environments inevitably interact with AOM. Meanwhile, the aging and type of MPs may increase the uncertainty surrounding interaction. This study focused on polyethylene (PE) and polylactic acid (PLA) to investigate their interaction with AOM before and after aging. The results shw that PLA has a stronger adsorption capacity for AOM than PE. Meanwhile, aging enhanced and weakened the adsorption of PE and PLA for AOM. Compared to unaged PE (UPE) and aged PLA (APLA), aged PE (APE) and unaged PLA (UPLA) more significantly promote the humification of AOM and alter its functional groups. 2D-IR-COS analysis reveals that the sequence of functional group changes in AOM interacting with MPs is influenced by the type and aging of MPs. After interacting with AOM, surface roughness increased for all MPs. FTIR and XPS analyses show that the addition of AOM accelerated the oxidation of MPs surfaces, especially for UPE and APLA, with oxygen content increasing by 9.32 % and 1 %. Aging enhances the interaction between PE and AOM, while weakening the interaction between PLA and AOM. These findings provide new insights into understanding the interplay between AOM and MPs.

Anti-inflammatory potential of aconitine produced by endophytic fungus Acremonium alternatum.

Argemone mexicana belonging to family Papaveraceae is a traditional medicinal plant widely utilized by tribal people in India for treating various ailments like skin infections, wounds and inflammation. This plant is very rich in alkaloidal content, which has a great potential in the treatment of anti-inflammatory disorders. Therapeutically promising bioactive molecules are often produced by endophytic fungi associated with medicinal plants. In this investigation, endophytic fungi were isolated from various parts of A. mexicana and screened for alkaloidal content. Among these, one of the fungal isolate, Acremonium alternatum AMEF-5 producing maximum alkaloids showed significant anti-inflammatory activity. Fractionation of this crude fungal extract through column chromatography yielded eight fractions, which were further screened for anti-inflammatory activities. Fraction 3 exhibited significant anti-inflammatory activity by the inhibition of lipoxygenase enzyme (IC50 15.2 ± 0.09µg/ml), scavenging of the nitric oxide radicals (IC50 11.38 ± 0.35µg/ml), protein denaturation (IC50 14.93 ± 0.4µg/ml), trypsin inhibition (IC50 12.06 ± 0.64µg/ml) and HRBC stabilization (IC50 11.9 ± 0.22µg/ml). The bioactive alkaloid in fraction 3 was identified as aconitine which was confirmed by UV, FTIR, HPLC, HRMS, 1H NMR, and 13C NMR analysis. This study demonstrates that endophytic fungi serve a potential source for sustainable production of therapeutically important alkaloids.

Valorization of toxic methylene blue dye adsorption by sodium alginate/carboxymethyl cellulose/activated carbon ternary composites

In the present study, the performance of the sodium alginate/carboxymethyl cellulose/activated carbon (SA/CMC/AC) ternary composite microbeads containing different weight ratios of AC for the adsorptive removal of hazardous methylene blue (MB) from aqueous solutions. Firstly, the composite beads were prepared by adding AC with weight ratios of 10%, 20%, and 30% concerning the polymer amount. Then the composite beads were prepared by crosslinking in 2 wt. % CaCl2 solution. Initially, adsorption studies were carried out to determine the optimum properties, and the highest performance was obtained at pH = 7 and 298 K by using the composite containing 30% AC. Adsorption data were applied to several isotherms, and the Langmuir isotherm was found to be the best isotherm model for adsorption. The highest adsorption capacity was calculated as 308.6 mg/g at 298 K using this isotherm. Studies on adsorption kinetics revealed that the process followed a quasi-second-order kinetic model. FTIR-ATR analyses showed the interactions between dye molecules and the adsorbent and also indicated that the hydroxyl and carboxyl groups functioned as active adsorption sites. Furthermore, SEM analyses proved the presence of the dye particles on the surface of the adsorbent. This study demonstrated that the produced composite microbeads may be employed as a promising adsorbent for removing cationic contaminants from aqueous solutions.

One-Pot Phyto-Mediated Synthesis of Fe2O3/Fe3O4 Binary Mixed Nanocomposite Efficiently Applied in Wastewater Remediation by Photo-Fenton Reaction

A binary Fe2O3/Fe3O4 mixed nanocomposite was prepared by phyto-mediated avenue to be suited in the photo-Fenton photodegradation of methylene blue (MB) in the presence of H2O2. XRD and SEM analyses illustrated that Fe2O3 nanoparticles of average crystallite size 8.43 nm were successfully mixed with plate-like aggregates of Fe3O4 with a 15.1 nm average crystallite size. Moreover, SEM images showed a porous morphology for the binary Fe2O3/Fe3O4 mixed nanocomposite that is favorable for a photocatalyst. EDX and elemental mapping showed intense iron and oxygen peaks, confirming composite purity and symmetrical distribution. FTIR analysis displayed the distinct Fe-O assignments. Moreover, the isotherm of the developed nanocomposite showed slit-shaped pores in loose particulates within plate-like aggregates and a mesoporous pore-size distribution. Thermal gravimetric analysis (TGA) indicated the high thermal stability of the prepared Fe2O3/Fe3O4 binary nanocomposite. The optical properties illustrated a narrowing in the band gab (Eg = 2.92 eV) that enabled considerable absorption in the visible region of solar light. Suiting the developed binary Fe2O3/Fe3O4 nanocomposite in the photo-Fenton reaction along with H2O2 supplied higher productivity of active oxidizing species and accordingly a higher degradation efficacy of MB. The solar-driven photodegradation reactions were conducted and the estimated rate constants were 0.002, 0.0047, and 0.0143 min−1 when using the Fe2O3/Fe3O4 nanocomposite, pure H2O2, and the Fe2O3/Fe3O4/H2O2 hybrid catalyst, respectively. Therefore, suiting the developed binary Fe2O3/Fe3O4 nanocomposite and H2O2 in photo-Fenton reaction supplied higher productivity of active oxidizing species and accordingly a higher degradation efficacy of MB. After being subjected to four photo-Fenton degradation cycles, the Fe2O3/Fe3O4 nanocomposite catalyst still functioned admirably. Further evaluation of Fe2O3/Fe3O4 nanocomposite in photocatalytic remediation of contaminated water using a mixture of MB and pyronine Y (PY) dyestuffs revealed substantial dye photodegradation efficiencies.

Aesthetic synthesis and comparative study of graphitic carbon nitride for energy storage applications

ABSTRACT Graphitic carbon nitride (gCN) has emerged as a suitable 2D material for various applications, such as photocatalysis, energy storage, and conversion. Due to their abundance of active sites, their unique layered structure, metal-free characteristics, high physicochemical stability, generous in nature, being environmentally friendly and having unique electrical characteristics. In this study, we use a one-step pyrolysis procedure to address these limitations and propose robust, low-cost, and scalable ways to synthesise materials. The synthesised gCN material graphitic phase is confirmed by X-ray diffraction analysis, the layered structure of the sp2 hybridised C-N bonding features is shown by FT-IR analysis. FESEM analyses provide insights into the morphology of gCN. Elemental identification and oxidation states were investigated using X-ray photoelectron spectroscopy (XPS). The electrochemical properties of gCN are performed using a two-electrode system with PVA/KOH electrolyte. The gCN nanostructure shows a specific capacitance of 183.20 F/g at a current density (CD) of 2 A/g, an energy density (ED) of 30.44 Wh/kg, and a power density (PD) of 2739.6 W/kg. Furthermore, the gCN nanostructure shows an excellent cycle life with 87.11% capacitance retention and 98.13% coulombic efficiency. These investigations clarify the electrochemical properties of gCN as an electrode material for supercapacitors.

Mechanisms of alkali-activation of limestone: Reaction kinetics and influence of drying parameters

This paper focuses on the study of the reaction between limestone and sodium hydroxide solution. This reaction is used to produce alkali-activated mortars after curing and in the presence of unreactive siliceous sand. The kinetics of this reaction is investigated by semi-adiabatic calorimetry experiments. The formulation parameters are fixed but the curing parameters are tested: temperature (38 and 45°C) and time of drying (14, 25, 27 and 28 days). Their impact on reaction products (identified by FTIR and thermal analysis), on microstructure (SEM observations and porosity measurements) and on mechanical strength (flexural and compressive tests) are determined. The reaction was fast and a temperature drying was required to obtain stabilized hydration products in mortars. The products of the alkali-activation of limestone are double sodium/calcium carbonate (mainly pirssonite and with specific conditions of curing gaylussite) and calcium hydroxide. The microstructure and the proportions of reaction products, impacted by drying conditions, influence the mechanical strength of mortars. With an appropriate time (25 days) and temperature of drying (45°C), the compressive strength reached, after 28 days, almost 25 MPa.

Bioactive compound from marine seagrass Streptomyces argenteolus TMA13: combatting fish pathogens with time-kill kinetics and live-dead cell imaging.

Actinobacteria, pervasive in aquatic and terrestrial environments, exhibit a filamentous morphology, possess DNA with a specific G + C content and production of numerous secondary metabolites. This study, focused on actinobacteria isolated from marine seagrass, investigating their antibacterial activity against fish pathogens. Among 28 isolates, Streptomyces argenteolus TMA13 displayed the maximum zone of inhibition against fish pathogens-Aeromonas hydrophila (10mm), Aeromonas caviae (22mm), Edwardsiella tarda (17mm), Vibrio harveyi (22mm) and Vibrio anguillarum (12mm) using the agar plug method. Optimization of this potent strain involved with various factors, including pH, temperature, carbon source and salt condition to enhance both yield production and antibacterial efficacy. In anti-biofilm assay shows the maximum percentage of inhibition while increasing concentration of TMA13 extract. Minimal Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) assays with TMA13 crude extract demonstrated potent activity against fish pathogens at remarkably low concentrations. Time-kill kinetics assay showcased growth curve variations over different time intervals for all fish pathogens treated with a 100µg/ml concentration of crude extract, indicating a decline in cells viability and progression into the death phase. Additionally, fluorescence microscopic visualization of bacterial cells exposed to the extracts emitting green and red fluorescence, enabling live-dead cell differentiation was also studied. Further characterization of the crude extract through GC-MS and FT-IR analyses performed and identified secondary metabolites with functional groups exhibiting significant antibacterial activity. This study elucidates the capacity of Streptomyces argenteolus TMA13 to enhance the production of antibiotic compounds effective against fish pathogens.

Simple and selective detection of trifluralin herbicide in underground waters based on modified silver nanoparticles by 4-mercaptophenylbronic acid

ABSTRACT Due to the increase in agricultural contaminants in tap water and the importance of contaminant detection analysis, we report a sensitive and accurate colorimetric sensor based on the silver nanoparticles (AgNPs) to detect Trifluralin (TFA) in tap water. Silver nanoparticles were modified with 4-mercaptophenylbronic acid (MPBA) and for obtaining better responses from MPBA-AgNPs as a colorimetric sensor, Conditions affecting the reactions were optimised. The surface morphology, chemical structure and size of the MPBA-AgNPs sensor in different conditions were examined by FE-SEM, FT-IR, DLS and TEM analyses. Finally, it was used as a sensor to detect and measure the TFA herbicide with LOD = 3.20 ppm and RSD = %3.30. The recovery was obtained in the range of %87.15–%105.45, which indicated that the presented method is very practical and highly accurate for measuring this herbicide in its real samples.