Thermogravimetric And Differential Thermal Analysis Research Articles

Structural, spectroscopic and quantum chemical analysis of an exocyclic extended double-bonded chalcone single crystal, with pharmaceutical scanning for breast cancer using MCF-7 cell line and EGFR domain target

A chalcone derivative, (2E)-2-[(2E)-3-(4-methoxyphenyl)prop‑2-en-1-ylidene]-3,4-dihydronaphthalen-1(2H)-one [MPDN] was synthesized by slow evaporation method using Claisen-Schmidt condensation reaction. Single-crystal X-Ray Diffraction (SXRD) analysis was carried out to determine the structure, inter and intramolecular interactions, and conformation of the title molecule. The SXRD study shows that the compound crystallizes in a monoclinic crystal system with a space group P 21/c with lattice parameters; a = 15.178 (2), b = 7.369 (9), c = 14.322 (19) Å and β = 108.113 (4)° and V = 1522.6 (3)Å3. The molecular interactions in the structure were studied using Hirshfeld surface analysis. The Hirshfeld surface mapped over dnorm, electrostatic potential, shape index, curvedness, and energy framework were also analyzed, which provide valuable information about all kinds of available molecular interactions. The compound was further studied theoretically for the molecular structure, crystal geometry, and chemical reactivity descriptors via Density Functional Theory (DFT) calculations. Charge transfer across the energy levels (NBO) and the charge density over the atoms (Mulliken) were also analyzed. Vibration frequencies (stretching/bending) were analyzed using both experimental and theoretical spectra. The Ultra Violet-Visible (UV–Vis) spectrum shows π-π* transitions with a band gap 2.9 eV (Tauc-plot). Thermo-gravimetric and Differential Thermal Analysis (TGA/DTA) thermograms were studied to note the thermal behavior of MPDN. Cytotoxicity on (VERO) and in-vitro investigation (MCF-7) cell lines was done to quantify the material's efficacy as an anticancer agent. The optimized molecule was also docked with a protein target (PDB ID: 1M17) to study its pharmaceutical viability to inhibit cancer proliferation using AutoDock 4.2.6 software and was found to be a potential anticancer agent.

Sunflower waste – manganese iron oxide composite for hazardous dye removal

Sunflower waste (SF), an easily available agricultural waste was used as a primary material in the synthesis of sunflower waste – manganese iron oxide (SF-MIO) composite for the aim of waste recycling and synthesizing new composite material for dye adsorption. The synthesized adsorbent was characterized using various techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric and differential thermal analysis (TG-DTA) and Brauner-Emmett-Teller (BET) analysis. Dye adsorption ability of the SF-MIO composite in the aqueous solution was investigated using the anionic dye Congo Red (CR). Effect of adsorption parameters such as adsorbent dosage, temperature, initial dye concentration and time were investigated. According to the characterization results, manganese iron oxide addition provided porous microstructure to sunflower waste and increased its surface area from 1.1814 to 47.1415 m2/g thus made sunflower waste more suitable for adsorption. Adsorption process was maintained in endothermic nature and maximum adsorption capacity of SF-MIO on to CR was calculated as 45.66 mg/g. Pseudo-first order, pseudo-second order, Elovich kinetic models and Langmuir, Freundlich, Temkin and Halsey isotherms were studied. The adsorption behavior of CR on SF-MIO composite can be well described by Freundlich and Halsey isotherm models (R2=0.996) and pseudo-second order kinetic model (R2=0.999).

Nitrate removal from groundwater using chemically modified coconut husk based granular activated carbon: characterization of the adsorbent, kinetics and mechanism

In this study, a highly porous chemically activated granular activated carbon (GAC) was prepared from coconut husk and tested as an adsorbent to remove nitrate from contaminated groundwater. The prepared GAC was characterized by Fourier-transform infrared spectroscopy (FTIR), thermogravimetric and differential thermal analysis (TGA/DTA), scanning electron microscopy (SEM) and the Brunauer–Emmett–Teller (BET) surface area (SBET) analysis. The effects of various process parameters such as initial nitrate concentration, contact time and adsorbent dose on nitrate removal efficiency (response) by the modified GAC were investigated using the statistically significant response surface methodology and Box–Behnken design of experiments. The experimental data were fitted to well-known adsorption isotherms and kinetic models to ascertain the mechanism of the adsorption process. Analysis of variance (ANOVA) was performed to determine the significance of the individual and the interactive effects of process variables on the response. The BET surface area (SBET) and micropore volume of the prepared GAC from coconut husk was 1120 m2/g and 0.392 cm3/g, respectively. The experimental results showed that physisorption was the main adsorption mechanism governing the process, while the rate of adsorption was limited at initial nitrate concentrations > 10 mg/L. The Langmuir mono-layer adsorption isotherm best fitted the experimental data with a maximum adsorption capacity of 6.0 ± 1.3 mg/g (~ 92.5%) with an adsorbent dose of 0.1 g/50 mL, an equilibrium time of 6 h at 28 ± 2 °C, and at pH 7.6 (± 0.2). Among the tested process variables, the adsorbent dose and initial nitrate concentration showed significant effects on the nitrate removal efficiency.

Coppers film fabrication on glass substrate by complex reduction method for rapid inactivation of SARS-CoV-2 (COVID-19)

A Cu film with the ability to rapidly inactivate the COVID-19 virus was easily fabricated at approximately 23[Formula: see text]C on a Na-free glass substrate. The well-adhered Cu films with thickness of approximately 16 [Formula: see text]m and surface area of 8.71 10[Formula: see text] m2 g[Formula: see text] were obtained by immersion of the glass substrate into an aqueous solution with dissolved Cu (II) complex of ammonia and ascorbic acid. The interface bonded between the film and glass substrate was very strong, such that the film did not peel off even when it was exposed to an ultrasonic wave of 100 mW (42 kHz) in water. The anti-COVID-19 activity in Dulbecco’s modified Eagle’s medium (DMEM) is effective within 2 h and is faster than that of commercial copper plates. The changes in the relative abundance of Cu2O and CuO crystallines on the Cu film due to DMEM treatment and those in surface morphology were examined by X-ray diffraction peak analysis and field emission-scanning electron microscopy, respectively. The flame atomic absorption analyses of the recovered solutions after DMEM treatment indicated that the Cu ions from the Cu film with DMEM treatment for 1 hour at a concentration of 0.64 ± 0.03 ppm were eluted 2.3 times faster than those from the Cu plate. The rapid elution of Cu ions from Cu2O crystallines on the film in the early stage is the primary factor in the inactivation of the COVID-19 virus, as elucidated from the time dependence of eluted Cu ions by DMEM treatment. Results from thermogravimetric and differential thermal analysis (TG-DTA) of the powder scratched from the Cu film suggested that a trace amount of organic residues remaining in the Cu film was important in the rapid activity.

Analysis of solid waste discharged from water treatment plant as a fluoride-absorbing functional material

Solid waste from a surface water treatment plant (WTP sludge) was used as a fluoride adsorbent material for the treatment of water from underground sources by applying the concept of circular flow of materials. The sludge can be used as an alternative economic mineral resource and can be employed in drinking water collection, treatment, and distribution services. Physical and chemical characterization of the WTP sludge was performed via the Brunauer–Emmett–Teller (BET) method, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), differential thermal and thermogravimetric analysis (DTA/TGA), and particle size analysis. The structural characterization indicated that the dominant phases of WTP sludge were quartz, kaolinite, and illite. Chemical analysis demonstrated that the distributions of elements such as aluminum, iron, and silicon in the WTP sludge were identical to those in a clayey residue. Thermal analysis revealed a mass loss of approximately 30% in the sample. The WTP sludge exhibited a fluoride removal ability of approximately 28% as determined by adsorption assays. The Langmuir and Freundlich models were both adequate for representing the removal, particularly the Langmuir model. The pseudo-second-order kinetic model represented the results well, with R2 = 0.9986 and an experimental adsorption capacity (qe) of 0.206 mg/g. The experimental design was based on three factors (pH, initial fluorine concentration, and initial ion concentration) and showed (95% confidence, α = 0.05) that the interaction between the three factors was significant in the response variable. However, these individual parameters were not statistically significant. This study demonstrates the potential of WTP sludge as a groundwater fluoride adsorbent.

Growth of KAlF4 and Na5Al3F14 Aluminum Fluoride Single Crystals by Bridgman Method

AbstractHighly transparent KAlF4 and Na5Al3F14 fluoride bulk single crystals in size of ≈Ф 50 mm × 10 mm are successfully grown for the first time by a modified Bridgman method. The physicochemical properties of the single crystals are investigated with the help of X‐ray diffraction (XRD), thermogravimetric and differential thermal analysis (TG‐DTA), absorption spectrum, Fourier infrared spectroscopy, and Raman spectrum measurements. The KAlF4 and Na5Al3F14 phases of the obtained single crystals are determined from the results of XRD. The melting points of KAlF4 and Na5Al3F14 are measured to be ≈549 and ≈705 ℃ from their DTA curves. The maximum matrix phonon energies of KAlF4 and Na5Al3F14 single crystals are 544 and 530 cm–1 from their Raman spectra. The KAlF4 single crystal shows high transmittance from 2000 to 5500 nm, while Na5Al3F14 from 950 to 6000 nm. The energy gaps of KAlF4 and Na5Al3F14 are calculated to be 5.34 and 5.94 eV based on transmission spectra, respectively.

Neutron-γ discrimination with organic scintillator crystal: 9-Phenylcarbazole (9-PCz) grown by Bridgman – Stockbarger method

Organic scintillator crystal 9-Phenylcarbazole (9-PCz) has been grown using Bridgman -Stockbarger technique. The crystal structure, lattice parameter and bond angle values are measured from single-crystal X-ray diffraction (SXRD) analysis. C–H inplane bending and out of plane bending and skeletal vibrations of 9-PCz molecule were identified from vibrational spectral analysis. UV–visible NIR spectral study shows that the crystal exhibits around 50% of transmittance in the infrared region and the direct optical bandgap energy is calculated to be 3.36 eV. Thermal properties of grown 9-PCz material were measured using thermogravimetric and differential thermal analyses (TG-DTA). The photoluminescence (PL) measurements show two emission bands with a maximum peak at 365 nm and a shoulder peak at 381 nm. X-ray induced luminescence spectrum of 9-PCz crystal exhibits a maximum emission peak at 381 nm. Scintillation decay time measurement shows the major component of 18 ns decay time. The pulse shape discrimination (PSD) capability of the grown crystal sample was studied for the signals induced by α-particles and γ-rays from 241Am and 137Cs sources, respectively. The figure of merit (FOM) is found to be 2.69. The preliminary results showed that the present studied organic crystal (9-PCz) scintillator can be considered in the field of fast neutron detection application.

Chip-Based MEMS Platform for Thermogravimetric/Differential Thermal Analysis (TG/DTA) Joint Characterization of Materials

Combined use of thermal analysis techniques can realize complementarity of different characterization methods. Comprehensive thermal analysis with both thermogravimetric analysis and differential thermal analysis (TG/DTA) can measure not only mass change of a sample but also its temperature change during programmed heating-induced reaction or phase transition processes, thereby obtaining multiaspect thermal information of the material such as dehydration, structural decomposition, phase change and thermal stability. This study proposes and develops a MEMS chip-based TG/DTA microsystem that integrates both programmed heating and detecting elements into a TG chip and a DTA chip to enable the microinstrument performing TG/DTA joint characterization under microscope observation. The TG chip contains a self-heating resonant microcantilever to measure heating-induced mass change of a sample and the DTA chip is with a microheater and a temperature-detecting thermopile integrated on a suspended thermal-insulating diaphragm. Only nanogram and microgram-level samples are needed for the TG and DTA chips, thereby achieving safe measurement to energetic materials such as strong oxidants. The chip-based microinstrument surpasses the state-of-the-art commercial TG/DTA instruments that have, in the long term, suffered from large sample-amount (milligram level) requirements and have been unable to measure energetic materials. Compared with commercial instruments, the chip-based microinstrument is advantageous given its more accurate analysis, much higher heating rate, much smaller instrument volume and much lower power consumption, etc. The microinstrument has been fabricated by using wafer-level MEMS techniques. Testing results show that the mass-detection sensitivity of the TG-chip is as high as 0.45 Hz/pg in air and the temperature sensitivity of the DTA chip achieves 2.9 mV/K under the high heating rate of 25 °C/s. The strong oxidant of KMnO4 is analyzed with the TG/DTA joint characterization under microscopic observation. At the same time as microscope observation of the thermal decomposition phenomena, two-step thermal decomposition process of KMnO4 is identified and the thermal decomposition temperatures are obtained. The TG/DTA microinstrument is promising to be applied for study of various materials.

Synthesis, characterizations and the photocatalytic ability of Co1-xZnxFe2O4 spinels prepared by combustion method

In this research, Co1-xZnxFe2O4 (x=0-0,5) spinel ferrites were synthesized at 5000C by combustion method using glycine and metal nitrates. The powder samples were characterized by thermogravimetric and differential thermal analysis (TG-DTA), X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX). X-ray analysis showed that all samples have single phase cubic spinel structure. Structural parameters of spinels were also determined from XRD datas. The lattice constants, cell volumes increased with the increase in zinc substitution. The average crystallite sizes of the particles were determined with Zn content from 11 to 16 nm. The TEM images reveals the spherical shapes of nanoparticles with an average particle size less than 20 nm. The photocatalytic activity of the spinels were tested by the degradation of methylene blue (MB) in aqueous solution under visible light. The results showed that Zn doped spinels exhibited higher photocatalytic activity than CoFe2O4. Among all the samples, the maximum degradation efficiency was achieved by the 0.4 Zn substituted cobalt ferrite.

Antineoplastic and Cytotoxic Evaluation of Green AgNPs and Crude Extracts from Agave americana, Mentha spicata, and Mangifera indica Leaves

Green silver nanoparticles (AgNPs) and crude ethanolic, methanolic, aqueous, and acetonic extracts from leaves of Agave americana, Mentha spicata, and Mangifera indica were scrutinized for possible antineoplastic and cytotoxic efficacy. In this study, all the synthesized AgNPs were characterized using UV‐Vis spectroscopy, X‐ray diffraction, SEM (scanning electron microscopy), TEM (transmission electron microscopy), EDX‐spectroscopy, and simultaneous thermogravimetric and differential thermal analysis (TG‐DTA). Results of various characterization analyses performed in this study revealed that synthesized AgNPs had the highest absorption at 410‐430 nm, polycrystalline structure with sizes ranging from 23 to 38 nm, and were thermally stable up to 350°C. Furthermore, it was manifested that phytoproduced AgNPs from A. americana revealed good antineoplastic activity (69%). M. indica‐ and M. spicata‐based AgNPs displayed moderate activity against PC‐3 (prostate cancer cell line). Similarly, good cytotoxic aptitude was demonstrated by A. americana‐ and M. indica‐based AgNPs at the highest sample concentration (1000 μL). Excellent cytotoxicity was revealed by ethanol (100%), methanol (100%), and aqueous extracts (100%) of A. americana and methanol extract (83%) of M. spicata at 1000 μL.

Synthesis, growth, DFT, and HOMO-LUMO studies on pyrazolemethoxy benzaldehyde single crystals

Pyrazolemethoxy benzaldehyde (PMB) was synthesized and crystals were grown by slow evaporation solution growth method. PMB was crystallized in a monoclinic crystal system with a centrosymmetric C2/c space group, according to single-crystal X-ray diffraction analysis. The crystalline planes were identified using powder X-ray diffraction analysis. FTIR - FT-Raman spectroscopic techniques were performed to determine the vibrational modes of functional groups for the grown crystal. UV-visible spectral analysis and photoluminescence studies were taken to investigate the linear optical properties of the grown crystal. Thermogravimetric and differential thermal analysis (TG/DTA) were used to determine the thermal stability of the PMB crystal. In addition to this density functional theory (DFT) calculations such as frontier molecular orbital's (FMOs), global chemical reactivity parameters, hyperpolarizability, natural bond orbital (NBO) analysis, Mullikan atomic charge distribution, and molecular electrostatic potential map analysis were carried out in gaseous phase using B3LYP/6-311G* basis set.

Synthesis, growth, structural, spectroscopic, optical, thermal, DFT, HOMO–LUMO, MEP, NBO analysis and thermodynamic properties of vanillin isonicotinic hydrazide single crystal

• The vanillin isonicotinic hydrazide (VINH), an organic single crystal • Single-crystal X-ray diffraction to determine the cell dimensions • Powder X-ray diffraction to evaluate the planes and phase purity of the crystal • Spectral, optical, and thermal properties were studied. • Further, DFT, HOMO–LUMO, MEP, HOMA, NBO analysis were studied • The dipole moment, linear polarizability, and first hyperpolarizabilities have been investigated as molecular parameters. The work is aimed to present the synthesis and physical analysis of vanillin isonicotinic hydrazide (VINH), an organic single crystal, produced by the method of slow evaporation at room temperature. The grown VINH crystal was subjected to (SXRD) single-crystal X-ray diffraction to determine the cell dimensions. The powder X-ray diffraction study was performed to evaluate the planes and phase purity of the crystal. The presence of functional groups were analyzed through FTIR spectroscopy. UV–Vis–NIR spectroscopy study was carried out to enumerate the cutoff wavelength. Thermogravimetric and differential thermal analysis (TGA/DTA) was done to identify the thermal properties of the grown crystal. Further, the density functional theory (DFT/B3LYP) methods with the 6-311++G(d,p) basis set were used to compute the optimized molecular structure, HOMO-LUMO, molecular electrostatic potential surfaces, and vibrational studies of VINH crystal. The low HOMO - LUMO energy gap shows that the charge transfer inside the molecule is possible. NBO analysis proved the presence of intermolecular ON...H hydrogen bonds caused by the interaction of the lone pair of oxygen with the anti-bonding orbital. The dipole moment, linear polarizability, and first hyperpolarizabilities have been investigated as molecular parameters.

Growth, NBO, and vibrational studies combined with intramolecular hydrogen bond interaction of L-Valine lead (II) nitrate complex: DFT

The slow evaporation method was used to grow a new semi-organic L-Valine lead (II) nitrate (LVLN) single crystal. Powder X-ray diffraction was used to examine the crystalline quality of the grown crystal LVLN. Fourier-transform infrared (FT-IR) spectroscopy was used to identify characteristic vibrations, which were then compared to simulated spectra at density functional theory (DFT) method. The lower cut-off wavelength was measured to be 262 nm by UV-visible spectral analysis. Thermal stability and its decompositions were investigated for the title compound using thermogravimetric and differential thermal analyses (TG/DTA). Results of DFT calculations with B3LYP functional and a 6-31++G(d,p) basis set were helpful to identify the ground state molecular geometries, vibrational frequencies, Mulliken population analysis on an atomic charge, HOMO–LUMO analysis, first-order molecular hyperpolarizability (β) properties, and other molecular properties for LVLN. The intramolecular interactions existing inside the crystal have been investigated by Hirshfeld surface evaluation.

Purple nanometrics pigments based on cobalt-doped manganese molybdate: Synthesis, characterization, structural, thermal, optical, colorimetric and chemical properties

This work is related to the characterization of nanometrics materials of the βMnMoO4-βCoMoO4 system, prepared by co-precipitation and sol-gel routes from the corresponding metal salts. The structural, morphological and colorimetric characteristics of the obtained powders were studied using thermogravimetric and differential thermal analysis (TGA-DTA), X-ray diffraction (XRD), infrared and Raman spectroscopy, scanning electron microscopy (SEM) and colorimetry (CIE-L*a*b* system). The surface specific area was calculated using the Brunauer–Emmett–Teller analysis (BET) in the adsorption/desorption isotherm. The X-ray diffraction patterns highlighted the formation of a continuous solid solution Mn1-xCoxMoO4 (0 ≤ x ≤ 1) of monoclinic symmetry (C2/m) isotype to β-MnMoO4 and this regardless of the synthetic route adopted. FTIR and Raman spectroscopy analysis showed that the chemical bonds’ nature in the Mn1-xCoxMoO4 compounds corresponded to the strong Mo–O–Mo, Mo–O and Co–O–Mo vibrational modes. The micrographs (SEM) highlighted the form of nanorods with sizes ranging from 10 to 200 nm for compositions x = 0.3 and x = 0.6, prepared by co-precipitation. The specific surface area measurements indicated that the powders obtained by the sol-gel process present lower values than those prepared by co-precipitation, regardless the cobalt substitution rate. The specific surface area of the purple nanoscale powder (x = 0.6) obtained by co-precipitation was about 7.52 m2/g. Colorimetric parameters analysis of the powders heat treated at 1100 °C showed that the degree of the component (-b*) was significant for compositions x = 0.6, regardless of the synthesis method adopted.

Evaluation of the physical, structural, thermal, and advanced radiation absorption characteristics of SiO2–Na2O–K2O–P2O5–CaO bioactive glasses

We report herein an evaluation of the physical, structural, thermal, advanced photon energy absorption, and fast neutron removal characteristics of a series of bioactive glasses having the compositions 20SiO2-7.5Na2O-7.5K2O-(65–x)P2O5-xCaO, where x = 2.5, 5.0, 7.5, and 10.0 mol.%. X-ray diffraction (XRD) patterns confirmed the amorphous nature of these phosphosilicate glass systems fabricated by the melt-quench technique. To confirm the in vitro bioactivity of the prepared glasses, powdered samples of each composition were compressed into pellets and then soaked in simulated body fluid (SBF) at 37 ± 0.5 °C for 28 days. Soaked samples were investigated by means of XRD, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS/EDX). Thermo-gravimetric and differential thermal analysis (TG-DTA) was applied to determine the glass transition temperature (Tg) and crystallization temperature (Tc) for each glass sample. Fourier-transform infrared (FTIR) measurements were performed in the range 4000–400 cm−1, and showed the bending and stretching motions of different groups and the presence of CO2 and OH− groups in the glasses. Radiation absorption properties, such as mass energy absorption coefficient (μen/ρ), kinetic energy released per unit mass (KERMA) relative to air (ҠR), and mean free path values have been obtained for the bioactive glasses and compared with those of registered 45S5 Bioglass®. The simultaneous variation of mass energy absorption and mass attenuation values with photon energy has been explored to visualize the difference between absorption and attenuation. Linear attenuation coefficients for the present glass samples have been measured at photon energies of 511, 662, 1173, and 1332 keV in narrow-beam transmission geometry, and were in good agreement with theoretical results (error < 2 %). Further, detailed comparative analysis of energy absorption build-up factor (EABF) values for the glass samples has been conducted using two software tools, namely Photon Shielding and Dosimetry (PSD) and EXABCal, as well as on the basis of equivalent atomic number (Zeq) and effective atomic number (Zeff). We also attempted to calculate effective removal cross-sections (∑R) in order to evaluate the neutron absorption performances of these glass samples. The present detailed analysis shows that glass sample S4 with 10 mol.% CaO exhibits the most promising radiation absorption properties, resembling those of 45S5 Bioglass®.

Investigation of spectroscopic, thermal, and biological properties of FeII, CoII, ZnII, and RuII complexes derived from azo dye ligand

In this study, the novel azo dye FeII, CoII, ZnII, and RuII complexes with an azo dye ligand (L: (E)-4-((4-methoxyphenyl)diazenyl)-3-methyl-1H-pyrazol-5-amine) were synthesized. The structures of the complexes were characterized by FT-IR, elemental analysis, UV-Vis, mass spectra (FeII and CoII), NMR spectra (only diamagnetic ZnII and RuII), thermogravimetric and differential thermal analysis (TGA-DTA). All of the newly synthesized compounds were tested for their biochemical properties, including enzyme inhibitory and antioxidant activities. According to the in vitro ABTS, DPPH, CUPRAC, and FRAP antioxidant methods, the ligand and its metal complexes showed close antioxidant activities to the standards (BHA, BHT, ascorbic acid, and α-tocopherol). Enzyme inhibitions of the metal complexes were investigated against glutathione S-transferase (GST), acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) enzymes. The best inhibition values (Ki) were observed for Ru(II) complex against GST (14.36 ± 2.16 µM), AChE (16.86 ± 2.74 µM), and BChE (14.12 ± 2.04 µM).

A novel mesoporous Hydroxyapatite@Montmorillonite hybrid composite for high-performance removal of emerging Ciprofloxacin antibiotic from water: Integrated experimental and Monte Carlo computational assessment

The extensive use of persistent antibiotics to prevent human and animal infectious diseases has emerged as a global environmental concern. In this study, we report the effective removal of Ciprofloxacin (Cipro) antibiotic from aqueous solutions using a novel Hydroxyapatite@Montmorillonite (HAP@Mt) hybrid composite, which was synthesized via a facile co-precipitation route. The as-prepared HAP@Mt composite was thoroughly characterized by scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS), transmission electron microscopy (TEM), N2 adsorption-desorption, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric and differential thermal analysis (TGA-DTA). The adsorption performance of HAP@Mt for Cipro antibiotic was investigated as a function of various physicochemical parameters. The Cipro adsorption process on the HAP@Mt composite was well described by pseudo-second-order kinetics and the Langmuir isotherm.The maximum uptake capacity reached 91.18 mg g−1. The Cipro binding mechanism was predominantly controlled by the electrostatic interactions, hydrophobic interactions, hydrogen bonding and n-π electron donor/acceptor interactions. HAP@Mt exhibited easy regeneration and excellent reusability for Cipro removal. Monte Carlo/SA simulations were performed to more clearly illuminate the atomic-level interactions between Cipro molecule and HAP@Mt surface under different pH conditions. The simulation data correlate well with actual results. The obtained experimental and computational findings provide new relevant insights on the application of HAP@Mt composite as a potential binder material to remove Cipro antibiotic from wastewater.

Performance Improvement of ZnSnO Thin-Film Transistors with Low-Temperature Self-Combustion Reaction

Conventional sol-gel solutions have received significant attention in thin-film transistor (TFT) manufacturing because of their advantages such as simple processing, large-scale applicability, and low cost. However, conventional sol-gel processed zinc tin oxide (ZTO) TFTs have a thermal limitation in that they require high annealing temperatures of more than 500 °C, which are incompatible with most flexible plastic substrates. In this study, to overcome the thermal limitation of conventional sol-gel processed ZTO TFTs, we demonstrated a ZTO TFT that was fabricated at low annealing temperatures of 350 °C using self-combustion. The optimized device exhibited satisfactory performance, with μsat of 4.72 cm2/V∙s, Vth of −1.28 V, SS of 0.86 V/decade, and ION/OFF of 1.70 × 106 at a low annealing temperature of 350 °C for one hour. To compare a conventional sol-gel processed ZTO TFT with the optimized device, thermogravimetric and differential thermal analyses (TG-DTA) and X-ray photoelectron spectroscopy (XPS) were implemented.

Physicochemical studies on the interfacial and aggregation behavior of immidazolium- and pyrrolinidium-dodecyl sulfate in aqueous medium

Salt free surface active ionic liquids (SAILs), 1-butyl-3-methylimidazolium dodecyl sulfate ([bmim]DS) and N-butyl-N-methylpyrrolidinium dodecyl sulfate ([bmp]DS) were synthesised by stoichiometric mixing of ionic liquid (IL) and sodium dodecyl sulfate (SDS). SAILs were characterised by FTIR, 1H NMR, 13C NMR and thermogravimetric analysis and differential thermal analysis (TGA-DTA). Interfacial and aggregation behavior of the SAILs were investigated by surface tension, conductance, UV–visible absorption, emission spectroscopy, dynamic light scattering and isothermal titration calorimetric studies. Results were compared with the precursor surfactant SDS. Critical micelle concentration (CMC) of the surfactants followed the sequence: SDS > [bmp]DS > [bmim]DS. Lower surface excess values of SAILs were due to electrostatic interaction between IL cation and DS-, besides the higher aqueous solubility of DS-, induced by the IL cations. Negative Gibbs free energy of micellization and higher fraction of counter ion binding values further support the proposition. Aggregation number (n) and size (dh) of the micelles were determined by fluorescence quenching and dynamic light scattering studies respectively; both ‘n’ and ‘dh’ values were higher for SAILs than SDS ([bmim]DS > [bmp]DS > SDS). SAIL aggregates, although larger in size with higher aggregation number, were more compact than SDS micelles. Enthalpies of micellization, being exothermic in nature, were higher for SAILs although the micellization processes were entropically controlled. SAILs are considered to have dual advantages of surfactant and IL with substantial decrease in toxicity level.

Oxidation protective coating of Y2O3-Na2SixO2x+1 composite on graphite crucible for high temperature applications

Oxidation and corrosion protective coatings on graphite are essential for its high temperature applications. In the present work, oxidation protective coating on graphite was achieved with a combination of Y2O3 and SiO2 suspension with NaOH in methanol. Study showed that the optimized composition of the desired coating was Y2O3–15 wt% SiO2 (i.e., 2 g mixture of Y2O3 and SiO2 powder containing 0.3 g of SiO2 which is 15% of the total powder content if expressed in weight) with 5 M NaOH in 10 mL methanol. This protective coating on graphite was stable up to 1473 K for 30 min in Ar ambient before visible cracks appeared. The compositions of SiO2: NaOH were varied (5 mmol:5 M, 10 mmol:5 M and 5 mmol:10 M) to examine the roles of these two components in the overall adhesiveness of the coating. SiO2 and NaOH acted as inorganic binders and formed in-situ intermediate layers during sintering which held Y2O3 layer with the graphite surface. The coated graphite blocks and crucibles were characterized by X-ray diffractometer (XRD), field emission scanning electron microscope (FESEM), energy dispersive X-ray spectroscopy (EDS), differential thermal analysis and thermogravimetric analysis (DTA/TGA) and Fourier transform infrared spectroscopy (FTIR). The oxidation protective nature of the coating was tested by heating the coated crucible at 1273 K for 1-15 h in air atmosphere. The effective adhesion of oxidative coating on graphite was explained.