FTIR Spectroscopy Research Articles

Thiolated chitosan nanoparticles encapsulated nisin and selenium: antimicrobial/antibiofilm/anti-attachment/immunomodulatory multi-functional agent

BackgroundThe increase in the resistance of bacterial strains to antibiotics has led to research into the bactericidal potential of non-antibiotic compounds. This study aimed to evaluate in vitro antibacterial/ antibiofilm properties of nisin and selenium encapsulated in thiolated chitosan nanoparticles (N/Se@TCsNPs) against prevalent enteric pathogens including standard isolates of Vibrio (V.) cholerae O1 El Tor ATCC 14,035, Campylobacter (C.) jejuni ATCC 29,428, Salmonella (S.) enterica subsp. enterica ATCC 19,430, Shigella (S.) dysenteriae PTCC 1188, Escherichia (E.) coli O157:H7 ATCC 25,922, Listeria (L.) monocytogenes ATCC 19,115, and Staphylococcus (S.) aureus ATCC 29,733.MethodsThe synthesis and comprehensive analysis of N/Se@TCsNPs have been completed. Antibacterial and antibiofilm capabilities of N/Se@TCsNPs were evaluated through broth microdilution and crystal violet assays. Furthermore, the study included examining the cytotoxic effects on Caco-2 cells and exploring the immunomodulatory effects of N/Se@TCsNPs. This included assessing the levels of both pro-inflammatory (IL-6 and TNFα) and anti-inflammatory (IL-10 and TGFβ) cytokines and determining the gene expression of TLR2 and TLR4.ResultsThe N/Se@TCsNPs showed an average diameter of 136.26 ± 43.17 nm and a zeta potential of 0.27 ± 0.07 mV. FTIR spectroscopy validated the structural features of N/Se@TCsNPs. Scanning electron microscopy (SEM) images confirmed their spherical shape and uniform distribution. Thermogravimetric Analysis (TGA)/Differential Scanning Calorimetry (DSC) tests demonstrated the thermal stability of N/Se@TCsNPs, showing minimal weight loss of 0.03%±0.06 up to 80 °C. The prepared N/Se@TCsNPs showed a thiol content of 512.66 ± 7.33 µmol/g (p < 0.05), an encapsulation efficiency (EE) of 69.83%±0.04 (p ≤ 0.001), and a drug release rate of 74.32%±3.45 at pH = 7.2 (p ≤ 0.004). The synthesized nanostructure demonstrated potent antibacterial activity against various isolates, with effective concentrations ranging from 1.5 ± 0.08 to 25 ± 4.04 mg/mL. The ability of N/Se@TCsNPs to reduce bacterial adhesion and internalization in Caco-2 cells underscored their antibiofilm properties (p ≤ 0.0001). Immunological studies indicated that treatment with N/Se@TCsNPs led to decreased levels of inflammatory cytokines IL-6 (14.33 ± 2.33 pg/mL) and TNFα (25 ± 0.5 pg/mL) (p ≤ 0.0001), alongside increased levels of anti-inflammatory cytokines IL-10 (46.00 ± 0.57 pg/mL) and TGFβ (42.58 ± 2.10 pg/mL) in infected Caco-2 cells (p ≤ 0.0001). Moreover, N/Se@TCsNPs significantly reduced the expression of TLR2 (0.22 ± 0.09) and TLR4 (0.16 ± 0.05) (p < 0.0001).ConclusionIn conclusion, N/Se@TCsNPs exhibited significant antibacterial/antibiofilm/anti-attachment/immunomodulatory effectiveness against selected Gram-positive and Gram-negative enteric pathogens. However, additional ex-vivo and in-vivo investigations are needed to fully assess the performance of nanostructured N/Se@TCsNPs.

Anticancer therapeutic potential of multimodal targeting agent- "phosphorylated galactosylated chitosan coated magnetic nanoparticles" against N-nitrosodiethylamine-induced hepatocellular carcinoma.

Superparamagnetic iron oxide nanoparticles (SPIONs) are extensively used as carriers in targeted drug delivery and has several advantages in the field of magnetic hyperthermia, chemodynamic therapy and magnet assisted radionuclide therapy. The characteristics of SPIONs can be tailored to deliver drugs into tumor via "passive targeting" and they can also be coated with tissue-specific agents to enhance tumor uptake via "active targeting". In our earlier studies, we developed HCC specific targeting agent- "phosphorylated galactosylated chitosan"(PGC) for targeting asialoglycoprotein receptors. Considering their encouraging results, in this study we developed a multifunctional targeting system- "phosphorylated galactosylated chitosan-coated magnetic nanoparticles"(PGCMNPs) for targeting HCC. PGCMNPs were synthesized by co-precipitation method and characterized by DLS, XRD, TEM, VSM, elemental analysis and FT-IR spectroscopy. PGCMNPs were evaluated for in vitro antioxidant properties, uptake in HepG2 cells, biodistribution, in vivo toxicity and were also evaluated for anticancer therapeutic potential against NDEA-induced HCC in mice model in terms of tumor status, electrical properties, antioxidant defense status and apoptosis. The characterization studies confirmed successful formation of PGCMNPs with superparamagnetic properties. The internalization studies demonstrated (99-100)% uptake of PGCMNPs in HepG2 cells. These results were also supported by biodistribution studies in which increased iron content (296%) was noted inside the hepatocytes. Further, PGCMNPs exhibited no in vivo toxicity. The anticancer therapeutic potential was evident from observation that PGCMNPs treatment decreased tumor bearing animals (41.6%) and significantly (p ≤ 0.05) lowered tumor multiplicity. Overall, this study indicated that PGCMNPs with improved properties are efficiently taken-up by hepatoma cells and has therapeutic potential against HCC. Further, this agent can be tagged with 32P and hence can offer multimodal cancer treatment options via radiation ablation as well as magnetic hyperthermia.

Estimation of age and sex from fingernail clippings by using ATR-FTIR spectroscopy coupled with chemometric interpretation.

Fingernails can act as important forensic evidence as they can be a source of DNA that may link the victim or accused to the crime scene and may also contain traces of drugs such as cocaine and heroin, in regular users. Moreover, previous studies have shown that analyzing fingernails with various techniques can reveal important information, such as age and sex. In this work, ATR-FTIR spectroscopy with chemometric tools has been used to estimate the age and sex from fingernails by analyzing 140 fingernail samples (70 males, and 70 females) collected from volunteers aged between 10 and 70 years old. The amide bands obtained from spectra confirmed the presence of keratin proteins in the samples. PCA and PLS-R were used for the classification of samples. For sex estimation, samples were divided into four categories based on age groups, followed by the differentiation of sex in each group. Similarly, for age estimation, all samples were divided into two sets based on male and female followed by differentiation of age groups in each set. The result showed that PLS-R was able to differentiate fingernail samples based on sex in groups G1, G2, G3, and G4 with R-square values of 0.972, 0.993, 0.991, and 0.996, respectively, and based on age in females, and males with R-square values of 0.93 and 0.97, respectively. External validation and blind tests were also performed which showed results with 100% accuracy. This approach has proved to be effective for the estimation of sex and age from fingernail samples.

Molecular docking, ADMET, synthesis and evaluation of new indomethacin hydrazide derivatives as antibacterial agents

Bacterial infections pose an ongoing challenge due to resistance developed by infectious bacteria. So much research targeting designing new antibacterials is published annually. Our goal is to synthesize compounds that have given antibacterial activity according to molecular docking against the chosen target protein and that have acceptable ADMET properties that can be synthesized and used in the future. New 2-(5-methoxy-1-(4-chlorobenzene)-2-methyl-1H-indol-3-yl)acetohydrazide derivatives’ antibacterial efficacy against two common strains of Gram-negative and Gram-positive microorganisms has been developed, produced, and investigated. Sophisticated, modern analytical methods, including ATR-FTIR and 1H NMR spectroscopy, were used to determine their spectral and physicochemical features. Compound YA3N is more effective than ciprofloxacin against K. pneumonia (MIC = 125 µg/mL) and shows good suppression of isolated tests of E. coli (MIC = 125 µg/mL). While compound YA4C demonstrated comparable suppression of S. pyogenes strains (MIC = 250 µg/mL), compounds YA3S and YA4B exhibit lesser activity towards the tested strain of bacteria.

Quantifying the Crystalline Polymorphism in PVDF: Comparative Criteria Using DSC, WAXS, FT-IR, and Raman Spectroscopy

Quantifying the Crystalline Polymorphism in PVDF: Comparative Criteria Using DSC, WAXS, FT-IR, and Raman Spectroscopy

Bioenergy feedstock production in Chlamydomonas reinhardtii (microalgae) cultivated under mixotrophic growth with cellulose hydrolysate from agricultural waste.

In the present study, cellulose purified from finger millet agricultural waste is subjected to enzymatic hydrolysis, and the hydrolysate (predominantly glucose) is used as a carbon source supplement in the media for the mixotrophic growth of Chlamydomonas reinhardtii. Interestingly, a switch between excess starch production and excess lipid (triacylglycerols, TAG) production occurs by a small change in hydrolysate concentration in the media. Starch production increased 4.5-fold with respect to the photoautotrophic control, with a glucose concentration of 3mg/mL in the media after hydrolysate addition. This culture had TAG production enhancement by 1.5-fold. However, mixotrophic cultivation with 4mg/mL glucose concentration in the media with hydrolysate addition resulted in TAG productivity enhancement by 4.2-fold compared to control and starch amount increase of 1.3-fold. The organic carbon source (glucose) and the inorganic carbon source (citrate ions) in the hydrolysate together played a role in this delicate switching between starch and lipid pathways. Proteins, starch, and TAG molecules are analyzed in the microalgal cells grown under different conditions with FTIR spectroscopy, a rapid, high-throughput method of biomolecular estimation. High-resolution single-cell AFM studies of the cell wall structure reveal enhanced corrugations in surface morphology during mixotrophic growth with cellulose hydrolysate, illustrating an adaptive mechanism with improved mechanical stress management. Lipid droplet morphology at the single-cell level points to two distinct mechanisms of lipid accumulation: one in which the lipids are segregated as droplets, and the other in which lipid molecules are uniformly dispersed in the cytosol as unresolved, ultra-small droplets. The present study therefore analyzes both the bulk and the single-cell level changes when cellulose hydrolysate is used as a carbon source for Chlamydomonas reinhardtii mixotrophic cultivation, which serves a four-fold purpose: value from waste, fixation of atmospheric CO2, production of lipids for biodiesel, and starch for bioethanol.

Sustainable Al2O3 nanoparticles in catalytic pyrolysis: Unlocking high-yield bio-oil from Melia azedarach fruit biomass with comprehensive physicochemical analysis

The catalytic pyrolysis of Melia azedarach fruit biomass in the presence of aluminium oxide (Al2O3) nanoparticles was studied using a fixed bed reactor. Cost-effective and sustainable Al2O3 nanoparticles were employed as a catalyst in biomass pyrolysis and these nanoparticles were synthesized by using the extract of Phyllanthus emblica seeds as a reducing and capping agent. The confirmation of fabricated Al2O3 nanoparticles was analyzed by EDS, SEM and XRD characterization techniques. The potential effects of pyrolysis process parameters including catalyst dose, temperature and time were investigated. The optimized catalytic bio-oil was further characterized by FTIR spectroscopy. Moreover, physiochemical analyses were also performed to examine the bio-oil properties as fuel. This study demonstrates that catalytic bio-oil produced from Melia azedarach fruit biomass has the potential to be used as a substitute for fossil fuel for the generation of energy and industrial applications.

Design of efficient benzimidazole-derived N-heterocyclic carbene Ag(I) catalysts for aldehyde–amine–alkyne coupling

A mild catalytic protocol for aldehyde, amine, and alkyne coupling (A3-coupling) allows for the selective synthesis of propargyl amines using 5,6-dimethylbenzimidazole-derived N-heterocyclic carbene (BNHC) silver(I) catalysts. A series of BNHC Ag(Ⅰ) halide complexes were synthesized and their structures have been elucidated through the use of multinuclear NMR and FT-IR spectroscopy. Furthermore, the pseudo-linear geometry of two different compounds was substantiated by single-crystal X-ray diffraction. Silver-based A3-coupling was achieved for both acyclic and cyclic secondary amines using a diverse set of alkynes to afford propargyl amines with yields of up to 95 %. The present approach is environmentally benign and water is generated as the sole byproduct.

Physicochemical and molecular docking studies of tween 20 in the presence of NaX salts and hydrotropes in aqueous media

An investigation has been conducted on the interaction between the plasma protein bovine serum albumin (BSA) and the surfactant T20 using various hydrotropes of sodium salt (NaX, where X is Sal and Benz). The acquired results provide a practical and efficient means to comprehend the binding process of the micellar system T20 to BSA. The predominant forces involved are hydrophobic forces and hydrogen bonding. The further study intends to investigate the impact of NaX (here, X represents Cl, Br, NO3, Sal, and Benz), on the T20 solution using various techniques including density (ρ), viscosity (η), sound velocity (U), dynamic light scattering (Dh), FT-IR spectroscopy, and molecular docking at varying temperatures. The values of ρ, η, and U increase as the concentration of Na salt increases. Conversely, when the temperature increases, the values of ρ and η fall, while the value of U increases. NaSal exhibits higher viscosity compared to other substances. The phase separation model was employed to calculate the standard Gibbs free energy ( Δ G CP 0 ), enthalpy ( Δ H CP 0 ), and entropy ( Δ S CP 0 ). The NaBenz exhibits the highest values of sound velocity while examining at different temperatures. The structural identification was performed using FT-IR data, which revealed good agreement with the available literature.

Ca-doped ZnO nanoparticles for MB dye degradation and adsorptive removal of tinidazole.

Industrial dye degradation involves several processes by which dyes are broken down, ideally into innocuous products. Methylene blue (MB) is one of the most commonly employed dyes in the textile industry and is released into water in routine industry processes. These discharges lead to creating a nocuous nature for humans and animals. Drugs are also discharged into water bodies from various pharmaceutical industries. In these two contexts, in the present work, the green synthesis of calcium-doped zinc oxide nanoparticles (Ca-doped ZnO NPs) is achieved using the aqueous peel extract of Citrus limetta by the solution combustion technique. The structural, morphological, and optical properties of the synthesized Ca-doped ZnO NPs are investigated using XRD, FTIR, SEM, EDX, and UV-visible spectroscopy. The prepared NPs were subjected to photocatalytic degradation of MB dye under visible-light illumination, which shows ~ 95% dye degradation. The synthesized Ca-doped ZnO NPs were also employed to adsorb tinidazole (TDZ), a nitroimidazole antibiotic, from water samples. An excellent adsorptive capacity of the NPs was observed for selectively adsorbing the TDZ ~ 96.2%. The drug TDZ was found to have pseudo-second-order kinetics. The catalyst recycling proved its repeatability; removal of the dye reached up to 92% after three successive usages. Therefore, using waste Citrus limetta peel extract, the multifunctional Ca-doped ZnO NPs were synthesized, which maintained effective adsorption potential and photocatalytic abilities and could be used as an effective material for environmental remediation.

A Piezoelectric Electrospun Nanofiber mat (Kaolin/PVDF) for the Degradation of Methylene Blue in Water

AbstractOrganic compounds of various classes have been identified as major pollutants commonly detected in several environmental freshwaters. As a potential solution, electrospun mat-like nanofibers comprising polyvinylidene fluoride (PVDF) nanofibers and kaolin clay composite were synthesized for the degradation of methylene blue dye in wastewater using piezocatalytic technique. The kaolin/PVDF composites were characterized with SEM, XRD, FTIR, Chronoamperometry and electrochemical impedance spectroscopy. The poling of the piezoelectric charges of the electrospun mat-like nanofibers, enhanced by the presence of the crystalline nature of the kaolin clay occasioned the generation of reactive species upon exposure to ultrasonic vibration. Moreover, ultrasound waves in the system prevented passivation of the mat’s active surface during piezocatalysis through continuous cleaning action. A degradation efficiency of 100% was obtained from the degradation of methylene blue dye using the synthesized kaolin/PVDF composites during piezocatalysis. This result positions the nanofiber as an effective catalyst in wastewater treatment applications. Graphical Abstract

A Piezoelectric Electrospun Nanofiber mat (Kaolin/PVDF) for the Degradation of Methylene Blue in Water

AbstractOrganic compounds of various classes have been identified as major pollutants commonly detected in several environmental freshwaters. As a potential solution, electrospun mat-like nanofibers comprising polyvinylidene fluoride (PVDF) nanofibers and kaolin clay composite were synthesized for the degradation of methylene blue dye in wastewater using piezocatalytic technique. The kaolin/PVDF composites were characterized with SEM, XRD, FTIR, Chronoamperometry and electrochemical impedance spectroscopy. The poling of the piezoelectric charges of the electrospun mat-like nanofibers, enhanced by the presence of the crystalline nature of the kaolin clay occasioned the generation of reactive species upon exposure to ultrasonic vibration. Moreover, ultrasound waves in the system prevented passivation of the mat’s active surface during piezocatalysis through continuous cleaning action. A degradation efficiency of 100% was obtained from the degradation of methylene blue dye using the synthesized kaolin/PVDF composites during piezocatalysis. This result positions the nanofiber as an effective catalyst in wastewater treatment applications. Graphical Abstract

Molecular interactions and thermodynamic modelling of N,N-dimethyl benzyl amine-alkoxy ethanol mixtures: an FT-IR spectroscopy and Jouyban–Acree model approach

ABSTRACT This study examines intermolecular interactions in binary mixtures of N,N-dimethyl benzyl amine (DMBA) with short-chain alkoxy ethanols (2-methoxy ethanol (ME), 2-ethoxy ethanol (EE) and 2-butoxy ethanol (BE)). Densities (ρ), speeds of sound (u) and viscosities (η) were measured from 303.15 K to 313.15 K at atmospheric pressure for all compositions. These data were used to determine excess thermodynamic and transport properties: excess molar volume (V E ), excess isentropic compressibility (κs E ), viscosity deviation (Δη) and excess Gibbs free energy of activation (ΔG *E ). Partial and infinite dilution molar partial properties were also calculated. Results focus on complex formation driven by chemical forces. The Jouyban–Acree model predicted these properties, with accuracy assessed using mean relative deviations (MRDs) and individual relative deviations (IRDs). FTIR spectroscopy provided additional insights into intermolecular interactions.

Physicochemical and Spectroscopic Characterization of Glycogen and Glycogen Phosphorylase b Complexes

Glycogen is a natural polysaccharide used as an energy storage macromolecule. The role of glycogen metabolism in type 2 diabetes mellitus has been under investigation for several years, along with its implication in cancer and cardiovascular and neurodegenerative diseases. Previous studies using pig liver glycogen with rabbit muscle glycogen phosphorylase (RMGPb), which catalyzes the first step of glycogen degradation to glucose-1-phosphate, showed that the surface of an average glycogen molecule is covered by a total of 20 RMGPb dimeric molecules. In this work, we selected oyster glycogen (Glyc) to investigate its interaction with RMGPb by employing biophysical techniques. Dynamic, static, and electrophoretic light scattering were used to investigate the solution behaviors and structures of both the Glyc molecule itself and the formed complexes between Glyc and GPb at different mixing ratios. It was established that the interaction between oyster Glyc and RMGPb is similar to that previously reported for pig liver glycogen. Moreover, the structure of the complexed GPb was monitored by fluorescence and FTIR spectroscopy.

Physicochemical and Spectroscopic Characterization of Glycogen and Glycogen Phosphorylase b Complexes

Glycogen is a natural polysaccharide used as an energy storage macromolecule. The role of glycogen metabolism in type 2 diabetes mellitus has been under investigation for several years, along with its implication in cancer and cardiovascular and neurodegenerative diseases. Previous studies using pig liver glycogen with rabbit muscle glycogen phosphorylase (RMGPb), which catalyzes the first step of glycogen degradation to glucose-1-phosphate, showed that the surface of an average glycogen molecule is covered by a total of 20 RMGPb dimeric molecules. In this work, we selected oyster glycogen (Glyc) to investigate its interaction with RMGPb by employing biophysical techniques. Dynamic, static, and electrophoretic light scattering were used to investigate the solution behaviors and structures of both the Glyc molecule itself and the formed complexes between Glyc and GPb at different mixing ratios. It was established that the interaction between oyster Glyc and RMGPb is similar to that previously reported for pig liver glycogen. Moreover, the structure of the complexed GPb was monitored by fluorescence and FTIR spectroscopy.

Properties of cellulose nitrates produced by nitration of bacterial cellulose using mixed sulfuric-nitric acids

The study set out to investigate the chemical functionalization of bacterial cellulose as an alternative means of satisfying the high demand for nano-sized cellulose nitrates. Using a Medusomyces gisevii Sa-12 symbiotic culture as a microbial producer, bacterial cellulose having a polymerization degree of 3950 was obtained on a synthetic glucose medium. Nitration was carried out using mixed sulfuric-nitric acids differing in their water content, followed by stabilization of the synthesized bacterial cellulose nitrates. Subject to a varying water content (14, 16 and 20 %) in the nitrating mixture, the obtained bacterial cellulose nitrates exhibited a nitrogen mass content of 8.68–11.56 %, a solubility in alcohol-ether mixture of 16.5–91.0 % and a viscosity of 32–255 mPa×s. The bacterial cellulose nitrate fibers were shown to have a nanoscale nature. Coupled thermogravimetric and differential thermal analyses revealed the bacterial cellulose nitrates to have a high chemical purity and energy content. FTIR spectroscopy confirmed the high quality of the bacterial cellulose based on the presence of basic functional groups characteristic of conventional cellulose: 3371, 2943, 1633, 1428, 1371, 1163, and 1112 cm-1. According to their infrared spectra, the detected basic functional groups corroborate that the synthesized products are low-substituted cellulose nitrate esters: 1660–1643, 1282-1276, 847–837, 752–749, and 691–690 cm-1. The relationship between the properties of the synthesized bacterial cellulose nitrates and the water mass content in mixed sulfuric-nitric acids is shown to have a complex nature.

Ammonia and Greenhouse Gas Emissions from Organic Manure Composting: The Effect of Membrane Cover

The current scientific literature predominantly focuses on pilot-scale studies concerning the effectiveness of membrane covers in reducing gas emissions during cattle manure composting. Our study centers on the application of a leading market commercial membrane cover (ePTE-TEXcomm) and a locally manufactured one (ProfiCover®) at industrial processing levels, evaluating their efficacy in mitigating gas emission during the fifth day of the thermophilic phase. Taking into account material inhomogeneities, work environment impact, and efficiency, the results are characteristic of industrial-scale processes rarely discussed in the scientific literature. Our results, obtained with a portable gas sampler and FTIR spectroscopy measurements using corresponding standards, indicate that ePTE-TEXcomm manifested a reduction of 90.8% for NH3 and 59.6% for CO2. CH4 emissions increased, suggesting their potential entrapment. N2O and propane equivalent experienced reductions of 23.1% and 44.8%, respectively. On the other hand, ProfiCover® presented emission reductions for NH3 and CO2 of 93.3% and 85.9%, respectively. CH4, contrasting with ePTE-TEXcomm, showed a significant reduction of 55.6%. N2O and propane equivalent followed with reductions of 56.7% and 84.5%, respectively. All of this divergence in performance implies a potential trade-off in emission reduction efficacy between the covers. Knowledge sharing between researchers and industry partners is key to translating these technologies into widespread adoption.

Metal-free Carbon Material Derived from Lantana Camara for the Detection and Removal of Ciprofloxacin.

This work reports the preparation of a metal-free nitrogen and sulphur functionalized graphitic carbon sheets from a unique and less expensive precursor Lantana camara, which is a common hazardous weed in India. The synthesized material NS-CN-180 was successfully tested for the adsorption and removal of fluoroquinolone antibiotics ciprofloxacin. The surface morphology and elemental composition of NS-CN-180 were investigated through FESEM and XPS analyses. The SEM data reveals the graphitic sheets stacked onto each other with cavities in between them. The presence of various functional groups was identified through FT-IR spectroscopy and the degree of graphitization was calculated from XRD pattern. The probable mechanism of interaction for ciprofloxacin molecule with NS-CN-180 was also investigated with the help of FT-IR and zeta potential analyses. The fabricated material was found to be excellent for ciprofloxacin detection with a limit of detection value 16.08nM. Also, the prepared material efficiently removes the 66.2% ciprofloxacin drug in 1h. Adsorption and desorption experiments were performed to demonstrate the reusability of the material.

An eco-friendly wheat straw adsorbent functionalized with mercaptopropionyl for the removal of Cu(II) from aqueous solution

A novel absorbent called mercaptopropionyl wheat straw (MPWS) was prepared through alkali pretreatment and mercaptopropionyl modification for efficient removal of Cu(II) from aqueous solutions. Single factor experiments were conducted to investigate various parameters affecting the adsorption of Cu(II) with MPWS. Adsorption experiments including kinetics, isotherms, thermodynamics, as well as various characterization methods were employed to discuss the mechanism of Cu(II) uptake by MPWS in this study. The results showed that MPWS exhibited high removal capacity for Cu(II), achieving a maximum removal efficiency of 97.28 % under optimal conditions: oscillation rate at 150 rpm, temperature at 303 K, duration at 2 h, pH value at 6.0, and initial concentration of Cu(II) at 100 mg/L. The fitting results indicated that pseudo-second-order kinetic model better described the experimental data while Freundlich model provided a better fit for isothermal data. Thermodynamic calculations confirmed that the adsorptive process was spontaneous and endothermic. Characterization techniques such as FTIR spectroscopy SEM imaging, and EDS analysis confirmed chemisorption between Cu(II) ions and functional groups present on MPWS including sulfhydryl groups, amine groups, hydroxyl groups, and carboxyl groups. Overall, the main mechanisms governing Cu(II) uptake onto MPWS included coordination, ion exchange, electrostatic adsorption, and physical adsorption.

1,2,4-triazine derived binuclear lead(ii) complexes: synthesis, spectroscopic and structural investigations and application in organic light-emitting diodes (OLEDs).

Two novel binuclear complexes of Pb(ii) were synthesized by reacting a 3-(2-pyridyl)-5-(4-methoxyphenyl)-1,2,4-triazine (PMPT) ligand with different anionic co-ligands (1: bromide, 2: acetate and isothiocyanate) in a 1 : 1 molar ratio of PMPT ligands to lead(ii) salts. The complexes, [Pb2(μ-PMPT)2Br4] (1) and [Pb2(μ-PMPT)2((μ-CH3COO)2(NCS)2] (2), were characterized using various physicochemical techniques such as CHN analysis, FT-IR spectroscopy, and 1H NMR spectroscopy. Additionally, their structures were determined using single-crystal X-ray diffraction. Based on the obtained structural parameters, complex 1 exhibited a PbN3Br2 environment, while complex 2 displayed a PbN4O3 environment, with holodirected and hemidirected coordination spheres, respectively. Within the crystal network of the complexes, there were interactions involving C-H⋯X (X: O, S, N) as well as π-π stacking. The Pb(ii) complexes were further investigated for their potential use as the emitting layer in organic light-emitting devices (OLEDs). The current-voltage and luminescence-voltage characteristics, as well as the electroluminescence (EL) properties of the complexes, were studied.