Removal of Fluorescein Dye from Aqueous Solutions Using Natural and Chemically Treated Pine Sawdust

The various factors affecting the removal of fluorescein dye using sawdust from aqueous solutions such as time, initial concentration, pH, and temperature were studied. The optimal conditions for removing the FD are 1 g of sawdust at pH 3 and 120 min time of contact. Dye removal dropped from 93.42% to 80.04% with natural pine sawdust (NPS) and from 96.83% to 81.51% with synthetic pine sawdust (SPS) by increasing their concentration from 2 to 10 mg/L. Isotherm, kinetic, and thermodynamic models were applied for determining their constants. The results indicated that the FD removal equilibrium was effectively defined by the Langmuir, Freundlich, and Temkin models. Kinetic studies showed that the pseudo-second order was well suited for dye removal, and the internal diffusion process was by two steps. The thermodynamic parameter values suggested that FD removal were physical adsorption, exothermic, lower randomness, and spontaneous

Studies on Adsorption of Fluorescein Dye from Aqueous Solutions Using Wild Herbs

The adsorption of fluorescein dye (FD) on wild herb microparticles (Juniperus (JH) and Solenostemma argel (Del) Hayne (SH)) was studied to elucidate the changes in adsorption behavior with various parameters, such as initial concentration, adsorbent dosage, pH, contact time, and temperature. It was determined that the adsorption percentage of JH for FD was as high as 85.5%, which was higher than that of SH (71.9%). The morphologies of JH and SH were analyzed using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) analyses. The JH and SH adsorbents contained different functional groups, which were involved in the binding of the FD molecules during adsorption. The XRD patterns of JH and SH confirmed the presence of a combination of amorphous and crystalline phases in their structures. The SEM images of the surface of JH revealed the presence of deep pores ranging in size from 1.9 to 3.5 μm, while SH contained smaller pores ranging in size from 130 to 350 μm, which could help absorb large quantities of FD. The Freundlich model fitted the adsorption isotherms better than the Langmuir model. The values of the Freundlich equilibrium coefficient and separation factor ranged from 1 to 2 and from 0 to 1, respectively. The maximum adsorption capacities of JH and SH were determined to be 2.91 and 2.565 mg/g, respectively. Four kinetic models were used to analyze the experimental data, and it was determined that the pseudo-second-order kinetic model best described the adsorption process, which involved chemical adsorption and the internal diffusion. Thermodynamic parameters, including the enthalpy, entropy, and Gibbs free energy, were calculated. These parameters indicated that the adsorption of FD on JH was spontaneous and endothermic and the adsorption of FD on SH was unspontaneous and exothermic

Mesomorphic Investigation of Binary Mixtures of Liquid Crystal Molecules with Different Mesogenic Architectonics

Different binary phase diagrams, made from two differently substituted three-rings azo/ester and azomethine/ester compounds of the same terminal alkoxy side chain of six carbons, as opposed to the other terminal polar substituent, which can either donate electrons or withdraw electrons including H. The thermal behavior of the prepared derivatives was investigated by differential scanning calorimetry and phases identified by polarized optical microscope. The first group of the binary mixtures was made from laterally F-substituted azo/ester derivatives and their laterally neat analogues. The second group of binary mixtures was made from laterally methoxy-substituted azomethine/ester derivatives and their laterally neat analogues. The final type of investigated phase diagrams was made from the laterally substituted azo and azomethine components bearing different lateral polar groups and different mesogenic moieties. Results were reviewed using phase diagrams that were produced and it was found that different mesomorphic characteristics were seen to depend on the mesogenic component as well as lateral and terminal polar groups. In all cases, these mixtures have been determined to have low melting-temperature eutectic compositions, while linear or negative deviation of nematic or smectic isotropic composition temperature dependence was observed

Green Synthesis and Pinning Behavior of Fe-Doped CuO/Cu2O/Cu4O3 Nanocomposites

Egg white-induced auto combustion has been used to synthesize undoped and Fe-doped CuO/Cu2O/Cu4O3 nanocomposites in a soft, secure, and one-pot procedure. X-ray powder diffraction (XRD) and Fourier transform infrared (FTIR) investigations have been used to identify functional groups and the structural properties of crystalline phases present in the as-synthesized composites. Scanning Electron Microscopy/Energy Dispersive Spectrometry (SEM/EDS) elemental mapping analyses and Transmission Electron Microscopy (TEM) techniques were used to explore the morphological and compositional properties of these composites. N2-adsorption/desorption isotherm models have been used to examine the surface variables of the as-prepared systems. Based on the Vibrating Sample Magnetometer (VSM) technique, the magnetic properties of various copper-based nanocomposites were detected due to being Fe-doped. XRD results showed that the undoped system was composed of CuO as a major phase with Cu2O and Cu4O3 as second phases that gradually disappeared by increasing the dopant content. The crystalline phase’s crystallographic properties were determined. The average particle size was reduced when the synthesized systems were doped with Fe. The construction of porous and polycrystalline nanocomposites involving Cu, Fe, O, and C components was confirmed by SEM/EDS and TEM measurements. In terms of the increase in magnetization of the as-manufactured nanocomposites due to Fe-doping, oxygen vacancies at the surface/or interfacial of nanoparticles, while also domain wall pinning mechanisms, were investigated. Finally, employing the investigated production process, Fe doping of CuO/Cu2O/Cu4O3 nanocomposite resulted in the development of a single phase (CuO) exhibiting “pinned” type magnetization. This is the first publication to show that CuO/Cu2O/Cu4O3

New Liquid Crystals Based on Terminal Fatty Chains and Polymorphic Phase Formation from Their Mixtures

The physical and chemical properties of three new liquid crystalline derivatives, based on an azomethine core with low-temperature mesophase—namely (4-methoxybenzylideneamino) phenyl palmitate (I), (4-methoxybenzylideneamino) phenyl oleate (II), and (4-methoxybenzylideneamino) phenyl linoleate (III)—were prepared and physically examined using experimental methodologies. Elemental analysis, FT-IR, and NMR spectroscopy were used to confirm their molecular structure. Differential scanning calorimetry (DSC) and polarized optical microscopy (POM) were used to investigate their mesomorphic activity. The results revealed that compound (I) is monotropic smectogenic, possessing the smectic A mesophase, whereas the other two analogues were shown to possess the SmA phase enantiotropically. Two of the saturated and unsaturated prepared derivatives (namely I and II) were used to construct their phase diagram. The eutectic composition of the mixture examined showed a slight enhancement of the stability of the smectic A phase. Polymorphic phases were produced at the eutectic composition of the binary phase diagram of the derivative II with the 4-n-dodecyloxy benzoic acid component

Polyaniline-Supported Nickel Oxide Flower for Efficient Nitrite Electrochemical Detection in Water

A modified electrode with conducting polymer (Polyaniline) and NiO nanoflowers was prepared to detect nitrite ions in drinking water. A simple method was used to prepare the NiO nanoflower (NiOnF). Several techniques characterized the as-prepared NiOnF to determine the chemical structure and surface morphology of the NiO, such as XRD, XPS, FT-IR, and TGA. The activity of the electrode toward nitrite sensing was investigated over a wide range of pH (i.e., 2 to 10). The amperometry method was used to determine the linear detection range and limit. Accordingly, the modified electrode GC/PANI/NiOnf showed a linear range of detection at 0.1–1 µM and 1–500 µM. At the same time, the limit of detection (LOD) was 9.7 and 64 nM for low and high concentrations, respectively. Furthermore, the kinetic characteristics of nitrite, such as diffusion and transport coefficients, were investigated in various media. Moreover, the charge transfer resistance was utilized for nitrite electrooxidation in different pH values by the electrochemical impedance technique (EIS). The anti-interfering criteria of the modified surfaces were utilized in the existence of many interfering cations in water (e.g., K+, Na+, Cu2+, Zn2+, Ba2+, Ca2+, Cr2+, Cd2+, Pd2+). A real sample of the Nile River was spiked with nitrite to study the activity of the electrode in a real case sample (response time ~4 s). The interaction between nitrite ions and NiO{100} surface was studied using DFT calculations as a function of adsorption energy

Physical and Thermal Characterizations of Newly Synthesized Liquid Crystals Based on Benzotrifluoride Moiety

The mesomorphic stability and optical activity of new group-based benzotrifluoride liquid crystals, (E)-4-(((4-(trifluoromethyl) phenyl) imino) methyl) phenyl 4-(alkyloxy)benzoate, or In, were investigated. The end of the molecules connected to the benzotrifluoride moiety and the end of the phenylazo benzoate moiety have terminal alkoxy groups which can range in chain length from 6 to 12 carbons. The synthesized compounds’ molecular structures were verified using FT-IR, 1H NMR, mass spectroscopy, and elemental analysis. Mesomorphic characteristics were verified using differential scanning calorimetry (DSC) and a polarized optical microscope (POM). All of the homologous series that have been developed display great thermal stability across a broad temperature range. Density functional theory (DFT) determined the examined compounds’ geometrical and thermal properties. The findings showed that every compound is entirely planar. Additionally, by using the DFT approach, it was possible to link the experimentally found values of the investigated compounds’ investigated compounds’ mesophase thermal stability, mesophase temperature ranges, and mesophase type to the predicted quantum chemical parameters

High Performance Carbon Material Prepared from Phalsa Using Mild Pyrolytic Process towards Photodegradation of Methylene Blue under the Irradiation of UV Light

In this study, we have used a mild pyrolytic process for the synthesis of luminescent carbon material from phalsa (Grewia asiatica Linn) and utilized it for the photodegradation of methylene blue (MB) in aqueous solution under the irradiation of ultraviolet (UV) light. The carbon material was found to be graphitic in nature and with carbon dot-like properties as demonstrated by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), dynamic light scattering (DLS), and UV-visible techniques. The prepared carbon material was further studied for the elucidation of functional groups through Fourier transform infra-red (FTIR) spectroscopy. The carbon material exhibits the nanostructured phase which makes it a high surface area material for useful surface reactions. Different photodegradation aspects were investigated, such as initial dye concentration, catalyst dose, effect of pH of dye solution, reusability, electrochemical active surface area (ECSA), and charge transfer and scavenger. Optimum conditions of 15 mg carbon material, initial dye concentration of 2.3 × 10−5 M solution, and pH 5 of dye solution gave the highest outperformance degradation efficiency. The degradation mechanism of MB in aqueous solution was dominated by the hydroxyl radicals as verified by the scavenger study. The reaction kinetics of MB degradation was followed by the pseudo first order kinetics and highest values of rate constants in the low initial dye concentration and the acidic pH of the MB solution. Significantly, the carbon material prepared from phalsa was found to be highly stable, as proven by the reusability experiments. Furthermore, the high ECSA and low charge transfer resistance of carbon material enabled it to have better performance. The use of mild pyrolytic process for the preparation of high performance luminescent carbon material from the biomass could be a great roadmap for the synthesis of a new generation of carbon materials for a wide range of applications including bio-imaging, catalysis, energy conversion and environmental applications

Novel Imidazole Liquid Crystals; Experimental and Computational Approaches

The liquid crystalline materials named (E)-4-(2-(4-oxo-5,5-diphenyl-4,5-dihydro-1H-imidazol-2-yl)hydrazineylidene)methyl)phenyl and 4-(alkoxy)benzoate, In, were synthesized and their mesomorphic behaviors were examined. The chemical structures of the produced compounds were confirmed by Fourier-transform infrared spectroscopy (FT-IR), NMR, and elemental analysis. Differential scanning calorimetry (DSC) and polarized optical microscopy were used to investigate the mesomorphic properties of designed heterocyclic derivatives. All the compounds tested had suitable thermal stability and enantiotropic behavior of smectogenic temperature ranges. Furthermore, the enantiotropic smectic C phases were observed to cover all the homologues. Moreover, computational investigations corroborated the experimental findings of the mesomorphic behavior. The reactivity parameters were computed for the derivatives and linked with the experimental data. Theoretical calculations revealed that the polarizability of the studied series increases with the chain length, whereas the HOMO–LUMO energy gap or other reactivity descriptors were less sensitive to the size of the system. On the other hand, the predicted thermodynamic parameters revealed the size dependence of thermal stability of the compounds

Mesomorphic, Computational Investigations and Dyeing Applications of Laterally Substituted Dyes

Two groups of laterally substituted non-mesomorphic and liquid crystalline materials bearing monoazo group were prepared and investigated via experimental and theoretical techniques. The molecular structures of the designed dyes were evaluated by FT-IR and NMR spectroscopic analyses. Mesomorphic examinations for all synthesized dyes were investigated by polarized optical microscopy (POM) and differential scanning calorimetry (DSC). Results revealed that, the thermal and optical properties of investigated compounds are mainly dependent on their molecular geometry. The optimized geometries of the azo derivatives and their electronic absorption of the dyes were carried out using the B3LYP/6-311G level of the DFT method. The azo dyes were measured for their dyeing performance on polyester fabrics. The dyed fabrics have excellent fastness properties with a color strength of 1.49–3.43 and an exhaustion rate of 82–64%. The chemical descriptor parameters of disperse azo dyes in gas phase were calculated and correlated with dyeing parameters