Fourier Transform Infrared Results Research Articles

Targeted delivery of 5-fluorouracil and shikonin by blended and coated chitosan/pectin nanoparticles for treatment of colon cancer

Herein, 5-fluorouracil and shikonin (extracted from Fusarium tricinctum) were loaded in chitosan/pectin nanoparticle (CS/PEC-NPs), prepared by blending (B-CS/PEC-NPs) and coating (C-CS/PEC-NPs) methods. The nanoparticles characterized by Fourier Transform Infrared (FTIR), X-ray diffraction (XRD), Energy-dispersive X-ray (EDX), Scanning Electron Microscope (SEM) and Differential Light Scattering (DLS). Then, some properties of the nanoparticles such as drug release rate and the nanoparticles cytotoxicity were studied. The FTIR, XRD, EDX, SEM and DLS results showed that the nanoparticles synthesized properly with an almost spherical morphology, an average size of 82–93 nm for B-CS/PEC-NPs, an average diameter of below 100 nm (mostly 66–89 nm) for C-CS/PEC-NPs, and hydrodynamic diameter of 310–817 nm. The drug release results indicated the lower release rate of drugs for B-CS/PEC-NPs relative to C-CS/PEC-NPs at different pHs, high release rate of drugs for the nanoparticles in the simulated large intestinal fluids containing pectinase, and Korsmeyer-Peppas model for release of the drugs. The results showed more cytotoxicity of B-CS/PEC-NPs containing drugs, especially B-CS/PEC-NPs containing both drugs (B-CS/PEC/5-FU/SHK-NPs) after treating with pectinase (IC50 of 18.6 μg/mL). In conclusion, despite the limitation of C-CS/PEC-NPs for simultaneous loading of hydrophilic and hydrophobic drugs, B-CS/PEC-NPs showed suitable potency for loading and targeted delivery of the drugs.

Effect of graphite, graphene oxide, and multi-walled carbon nanotubes on the physicochemical characteristics and biocompatibility of chitosan/hyaluronic acid/hydroxyapatite scaffolds for tissue engineering applications

Bone tissue engineering (BTE) is a promising alternative approach to the repair of damaged bone tissue. This study aims to fabricate and characterize scaffolds composed of chitosan (CS), hyaluronic acid (HA), hydroxyapatite (HAp), and a combination of graphite (Gr), graphene oxide (GO), and multi-walled carbon nanotubes (MWCNT) for BTE applications. The Gr and MWCNT were functionalized by acid oxidation, while the GO was synthesized using the improved Hummers' method. The scaffolds were prepared by lyophilization, and the physical, chemical, and biological properties were evaluated. Scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy, mechanical testing, water contact angle, degradation, and biocompatibility assays were used to characterize the scaffolds. The degradation rate was determined using the liquid displacement method. Pores of different sizes were present on the surface of and throughout the scaffold. According to the FTIR results, the scaffolds contained functional groups that promote cell differentiation and proliferation. These scaffolds have compressive strength, Young's modulus, and toughness similar to cancellous bone, with reasonable porosity and controllable degradation rates. Biocompatibility testing confirmed that the scaffolds support cell proliferation and differentiation.

Effect of Rapid Thermal Annealing on CuO Nanoparticles

Abstract This work is a comparative study of the effect of two different annealing methods on copper oxide (CuO) nanoparticle properties obtained previously by direct precipitation method. The prepared samples were annealed in air at various temperatures (300, 400, 500°C) for 1 hour. Then they were characterized by employing scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-Visible, and Fourier Transform Infrared (FT-IR) spectroscopy. The main results revealed an increase in the grain size in both methods as the annealing temperature increases. It reaches 30.93 nm in RTA and 26.75 nm in STA at 500°C. XRD spectra showed, in the case of RTA at 500 °C, a significant decrease in the intensity corresponding to the (002) and (111) orientations. This result indicated that beyond 400 °C, one hour of RTA is not suitable for enhancing CuO nanoparticle crystallinity compared to STA. The optical analysis demonstrated that the energy of the optical band gap in STA is higher than that in RTA. It reaches 2,88 eV at 500°C using RTA which is close to the gap value of CuO in the range of 1.8–2.8 eV. FT-IR results showed, for both methods, the presence of characteristic peaks of the Cu-O bonds in the monoclinic CuO structure without any trace of Cu2O structure. Nevertheless, samples exposed to RTA for one hour are more susceptible to absorbing species of C=O bond (C=O bond is due to the atmospheric CO2 absorption and the presence of organic impurities from the synthesis process) than those of STA. Hence, RTA at 500 °C is far from producing CuO nanoparticles with preferred characteristics; it needs further research to examine the effect of higher temperature by controlling the annealing time.

Property of Modified Bovine Bone Glue as an Environmental Additive in Water-Based Drilling Fluids.

At present, animal bone glue (BG) is being widely used in many fields, but there are no studies reported on oilfield chemistry. In this paper, an environmental water-based drilling fluids additive named bromoethane-modified bone glue (BG) was developed by using bovine bone glue and bromoethane as raw materials, anhydrous ethanol as solvent, sodium hydroxide as alkaline hydrolysis agent, and sodium carbonate as a system pH regulator. The inhibition, filtration performance, and temperature resistance of BG were evaluated. Performance study results show that the linear swelling rate of sodium bentonite (Na-MMT) was decreased from 50.2% (in tap water) to 38.2% (in 4 wt % BG solutions), and filtration loss was reduced from 30 mL (in tap water) to 12 mL (in 5 wt % BG). Hot-rolling experiments show that the BG solution still exhibits good performance even after 16 h × 130 °C. The reasons for BG to achieve excellent performance were analyzed through scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), ζ potential, thermogravimetric analysis (TGA), and microstructure. The results of SEM and FT-IR show that BG can fully dissolve in water and adsorb on the surface of clay particles by relying on its own adsorption functional groups such as -OH and -COOH. When 4% BG was added, ζ potential analysis revealed that the clay particle size declined by 0.502 μm, which indicated that BG can inhibit clay hydration swelling dispersion.

Synthesis and Characterization of Carbonate Hydroxyapatite from Pokea Clam Shells (<i>Batissa Violacea Var. Celebensis</i>) by Precipitation and Hydrothermal Methods

Hydroxyapatite Carbonate (CHA) is a material that is found to have a composition more similar to bone, with a higher bioactivity than Hydroxyapatite (HA). CHA was synthesized using precipitation and hydrothermal methods using (NH4)2HPO4 as a phosphate source, NH4HCO3 as a carbonate source, and Pokea shells as a calcium source. In this study, the Pokea shells were crushed, calcined, and characterized based on physicochemical tests. CaO from Pokea shell contains 74.33% calcium. CHA was successfully produced by precipitation method at room temperature and hydrothermal at 120 C for 8 h. Sample characterization was carried out using X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR), and Scanning Electron Microscope Energy Dispersive X-Ray Spectroscopy (SEM-EDX). Based on XRD data, there are differences in the crystal size of CHA produced via precipitation and hydrothermal methods, where the crystal sizes of Precipitation CHA-1 and Hydrothermal CHA-2 are 6.388 nm and 25.969 nm. The FTIR results of both CHA show the functional groups typical of CHA, namely OH-, CO, CaO, PO43-, and CO32-. From the Ca/P EDX data results, Precipitation CHA-1 and Hydrothermal CHA-2 do not differ much, namely 1.71 and 1.69, and this value indicates that CHA has been formed.

Effective hierarchical ZSM‐5 catalysts for the cracking of naphtha and waste tire‐derived oil to light olefins

AbstractHierarchical ZSM‐5 zeolite materials with different SiO2/Al2O3 molar ratios in the range of 60–300 were synthesized using soft templating and microemulsion methods to generate zeolite materials with narrow mesopore size distributions. The resulting materials were characterized by X‐ray flourescence (XRF), Fourier transform infra‐red (FTIR) spectroscopy, X‐ray diffraction (XRD), scanning electron microscopy (SEM), ammonia temperature programmed desorption (NH3‐TPD), thermo‐gravimetric analysis (TGA), Brunauer‐Emmett‐Teller (BET) surface area measurements, and products from the catalytic tests were analyzed by gas chromatography (GC). The XRF analysis determined that the Si/Al ratios for the synthesized ZSM‐5 were close to the batch ratios. The XRD and FTIR results revealed that the synthesized samples had crystalline ZSM‐5 zeolite structures. The small angle observed from the XRD patterns confirmed the presence of mesopores in the structure of the prepared materials. The SEM results showed that the ZSM‐5 synthesized materials had different morphologies and particle sizes, as well as worm‐like holes indicating that some macropores with average pore sizes ranging between 68 and 85 nm were successfully generated in these materials. NH3‐TPD results showed that the total acidity of the prepared materials decreased with an increase in the Si/Al (SA) ratio following this trend: SA = 71 > 177 > 345. This may be due to the decrease in the aluminum content, which is largely responsible for the formation of acidic sites in zeolites. The acid strength was found to increase with a decrease in the Si/Al ratio, highlighted by the peak shifts to higher temperatures. From the BET results, the SA = 71 was observed to have the highest SSA of 618 m2/g given by its micropore area of 103 m2/g and an external surface area of 515 m2/g. The high external surface area present in the material was due to the development of mesopores with narrow pore size distribution of approximately 6 nm indicating the success of the microemulsion method for the generation of hierarchical zeolites with well controlled pore sizes. The hierarchical ZSM‐5 catalysts were tested for the cracking of various hydrocarbon chain lengths. Low conversions, less than 10%, were obtained in the cracking of hexane; however, when cracking longer chain C12 hydrocarbons, the conversion increased remarkably to 100%. The catalyst with SA = 71 had the highest selectivity towards ethylene and propylene olefins due to its higher acidity in comparison with the other prepared catalysts. Improved activity, selectivity towards ethylene and propylene greater than 60%, and enhanced catalyst stability were demonstrated when using a hierarchical ZSM‐5 compared to the commercial catalyst in the cracking of dodecane. High selectivity towards light olefins was obtained for the cracking of waste tire‐derived oil. The results suggest that these hierarchical materials are suited to the cracking of long chain hydrocarbons and are promising materials for the valorization of waste tire‐derived oils.

Enhancing polyamide 6: Acid hydrolysis for functionalization and amino group quantification

In this study, our primary aim was to increase the presence of amine groups in polyamide 6 fibers. To achieve this, we employed a functionalization process that mainly depended on increasing the number of reactive sites via acid-catalyzed hydrolysis. The effects of several acids were rigorously examined, including hydrochloric acid (HCl), sulfuric acid (H2SO4), and formic acid (HCOOH). Following this comprehensive acid-based treatment, the method that demonstrated the most significant increase in amine groups was selected for further evaluation in dyeing experiments and full characterization. The quantification of amino groups was performed using potentiometry, evaluating the equilibrium state of acid removal from the fibers. To corroborate these results, the acid dye Levaset Blue 2R was employed, which measured the amount of dye bound to the fibers during the dyeing process. Characterization of the polyamide 6 fiber structural changes was conducted using multiple techniques, including tensile tests, Fourier transform infrared (FTIR) spectroscopy, and differential scanning calorimetry (DSC). Among the acid treatments, the 11% HCl treatment exhibited the most significant increase in amine groups, amounting to an approximately 110% increase as measured by potentiometry and an approximately 150% increase using the dyeing method. During the dyeing process, the 11% HCl-treated fibers absorbed 91% of the dye from the dye bath, indicating enhanced color intensity and K/S value, thus affirming the efficacy of the amine group increasing. Tensile testing revealed a decrease in the strength of the functionalized fiber. In the FTIR spectra, there was a notable increase in the intensity of bands associated with the fiber's crystalline regions and hydrogen bonds. DSC tests validated the FTIR results, demonstrating a 9% increase in crystallinity. Furthermore, SEM micrographs depicted surface alterations induced by the hydrolysis process. These results collectively highlight the effectiveness of hydrolysis in introducing functional groups, enhancing color intensity during dyeing with acid dyes, and reducing dye content in the bath. Additionally, the potentiometric method for quantifying amine group demonstrated practicality and accuracy, serving as a valuable contribution to the field.

Evaluation of effect of boric acid on thermoplastic starch: Morphological, mechanical, barrier, and optical properties

AbstractIn this study, starch was modified with different amounts of boric acid, and the degree of substitution of the synthesized compounds at different temperatures and times was determined by Fourier transform infrared (FTIR) and titration methods. The degrees of substitution in both methods showed similar tendency. Optimum conditions were determined, and thermoplastic starch (TPS) and boric acid (B) films were prepared by casting method using glycerol as plasticizer. The morphological properties of the films were studied by scanning electron microscope‐energy dispersive spectrometry (SEM‐EDS). According to the FTIR results, it was observed that the BO and BOC stretching vibrations increased when the amount of boric acid increased. The tensile strength, water barrier (swelling capacity, solubility, and water vapor permeability), and optical properties of samples were investigated. The swelling capacity, solubility, and water vapor permeability of the films decreased with the addition of 0.5% boric acid to the starch, but the highest tensile strength was achieved. The tensile strength for TPSB0.5% increased compared to control group TPS. In addition, the film showed the highest transparency. Thermoplastic film containing 0.5% boric acid can be used as a packaging material due to its improved mechanical and water barrier.Highlights The thermoplastic starch and boric acid composite were successfully produced. The presence of boric acid was confirmed by energy dispersive spectrometry (EDS). The degree of substitution was determined by two different methods. Transparency increased with the addition of boric acid. Tensile strength improved with boric acid content.

Preliminary study of exfoliated graphite (EG) produced by electrochemical exfoliation and EG-TiO2 composite

In this research, Exfoliated Graphite (EG) materials have been synthesized using the electrochemical exfoliation method. The starting materials are graphite sheets, before the exfoliation process, a simple pre-treatment was carried out, by immersing the graphite sheet in a mixture solution of sulfuric acid (H2SO4) and hydrogen peroxide (H2O2) with a ratio of 95:5 to widen the interlayer distance in graphite sheets for the optimum electrochemical exfoliation process. This study used ammonium sulfate solution (NH4)2SO4 as an electrolyte with a concentration 0.25 M. The obtained EG materials are then composited with TiO2 to increase the resulting energy density of the materials. The in-situ sol-gel method was used to synthesize the EG-TiO2 composite assisted by microwave irradiation. The resulting materials were characterized using X-ray diffraction (XRD), Fourier Transform infrared (FTIR), and LCR meter. Based on the XRD results, the EG-TiO2 composite showed an amorphous structure with an average crystallite size of 24.9 - 49.9 nm. It also shows that the XRD pattern of the EG-TiO2 composite has a lower peak intensity than the EG material. The FTIR result shows that the functional group of the rGO-TiO2 composite has a combination of Ti-O-Ti and Ti-O-C vibrations, which indicates the chemical interaction of TiO2 with EGs.

Fabrication and structural modification of graphene oxide-tetraethyl orthosilicate solution via liquid-phase pulsed laser ablation

Liquid-phase pulsed laser ablation (LP-PLA) is a physical deposition technique to fabricate micro- and nanoscale particles of polymer, glass, and ceramic materials. In this work, graphene oxide (GO) that was immersed in tetraethyl orthosilicate (TEOS) and ethanol was used to fabricate the graphene-silicone polymer using the LP-PLA technique. The GO-TEOS solution was ablated with different fluences of the laser. The ablated GO-TEOS solution was characterized by Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM), energy dispersive x-ray, and ultraviolet-visible (UV-Vis) spectroscopy to study the graphene-silicone polymer properties. The FTIR result shows that the laser ablation has provided sufficient laser energy to create or break the chemical species of GO and TEOS compounds as observed on Si–O and C–O bonds. The Raman result shows the changes in the intensity in the D band, which suggests that the carbon atom of the GO has been functionalized with other compounds. Several large flakes were observed in the SEM images, representing the silicon polymer with the GO aggregation. The particle size in the range of 3–8 and 66–110 μm was formed due to the presence of uniformly sized nanoparticles of the GO-TEOS mixture and aggregation of the GO-TEOS nanoparticles into clusters. The zeta potential results indicated that the stability of the GO-TEOS mixture decreases after laser ablation. The UV-Vis result shows a broad absorption band with center at 492 and 532 nm with increasing absorbance at low fluence then saturated and decreased at maximum laser fluence. From the results above, several chemical interactions between GO and TEOS were observed, and the data suggested the laser fluence as the major source to cause both photothermal and photochemical reactions on the samples. In short, laser ablations provide sufficient energy to induce chemical bonding, which further allows structural modification of materials.

Protein Cryoprotectant Ability of the Aqueous Zwitterionic Solution.

Protein cryopreservation is important for the long-term storage of unstable proteins. Recently, we found that N-acetylglucosaminyltransferase-V (GnT-V) can be cryopreserved in a deep freezer without temperature control using a dilute binary aqueous solution of 3-(1-(2-(2-methoxyethoxy)ethyl)imidazol-3-io)butane-1-carboxylate (OE2imC3C) [10 wt %, mole fraction of solute (x) = 7.75 × 10-3], an artificial zwitterion. However, it is unclear which solvent properties are required in these media to preserve unstable proteins, such as GnT-V. In this study, we investigated the melting phenomena and solution structure of dilute binary aqueous OE2imC3C solutions [x = 0-2.96 × 10-2 (0-30 wt %)] using differential scanning calorimetry (DSC) and Raman and Fourier transform infrared (FTIR) spectroscopies combined with molecular dynamics (MD) simulation to compare the cryoprotectant ability of OE2imC3C with two general cryoprotectants (CPAs), glycerol and dimethyl sulfoxide. DSC results indicated that aqueous OE2imC3C solutions can be melted at lower temperatures with less energy than the control CPA solution, with increasing x, primarily due to OE2imC3C having a higher content of unfrozen water molecules. Moreover, Raman and FTIR results showed that the high content of unfrozen water molecules in aqueous OE2imC3C solutions was due to the hydration around the ionic parts (the COO- group and imidazolium ring) and the OCH2CH2O segment. In addition, the MD simulation results showed that there were fewer structured water molecules around the OCH2CH2O segment than the hydration water molecules around the ionic parts. These solvent properties suggest that dilute aqueous OE2imC3C solutions are effective in preventing freezing, even in a deep freezer. Therefore, this medium has the potential to act as a novel cryoprotectant for proteins in biotechnology and biomedical fields.

Water-lipid interface in lipidic mesophases with excess water.

This study investigates the influence of excess water on the lipidic mesophase during the phase transition from diamond cubic phase (Pn3̄m) to reverse hexagonal phase (HII). Using a combination of small angle X-ray scattering (SAXS), broadband dielectric spectroscopy (BDS), and Fourier transform infrared (FTIR) techniques, we explore the dynamics of lipids and their interaction with water during phase transition. Our BDS results reveal three relaxation processes originating from lipids, all of which exhibit a kink during the phase transition. With the excess water, these processes accelerate due to the plasticizing effect of water. Additionally, our results demonstrate that the headgroups in the HII phase are more densely packed than those in the Pn3̄m phase, which agrees with the FTIR results. Meanwhile, we investigate the influence of excess water on the lipid headgroups, the H-bond network of water, the lipid tail, and the interface carbonyl group between the head and tail of the lipid molecule. The results indicate that excess water permeates the lipid interface and forms additional hydrogen bonds with the carbonyl groups. As a result, the headgroups are more flexible in a lipidic mesophase with excess water than those in mesophases without excess water.

SYNTHESIS AND CHARACTERIZATION ANALYSIS OF FE3O4/SiO2 CORE SHELL

Fe3O4/SiO2 core shell synthesis has been carried out, and its characteristics has been analyzed to be used as a photocatalyst using co-precipitation and sol-gel method. Fe3O4 is used as the core material to eliminate the difficulty of separating the photocatalyst powder from the solution medium, SiO2 is used to avoid oxidation by preventing the Fe3O4 core from coming into direct contact with the solution. The samples were then characterized using X-Ray Diffraction (XRD), Fourier Transform Infra-Red (FTIR), and Vibrating Sample Magnetometer (VSM). The XRD and FTIR results showed that the crystal structure and movement of the sample molecules matched the standard characteristics from previous studies. The VSM characterization results show that SiO2 succeeded in reducing the value of the magnetization of Fe3O4, which proves that Fe3O4 has been successfully coated by SiO2.

Development of nanocomposites based on chitosan/reduced graphene oxide for wound healing application

Nanocomposites containing different effective materials have various effects, such as antioxidant, and anti-inflammatory activity, which are desirable for wound dressing. Herein, nanocomposites based on chitosan/reduced graphene oxide (CS/rGO) containing curcumin (CS/rGO/Cur), curcumin and papain (CS/rGO/Cur/Pa), curcumin, papain, and collagen peptide (CS/rGO/CP/Cur/Pa), prepared using ionic gelation method and characterized by Fourier Transform Infrared (FTIR), Differential Light Scattering (DLS), X-ray diffraction (XRD), and Scanning Electron Microscope (SEM). Subsequently, the nanocomposite's potential for wound healing was studied through parameters such as porosity, swelling, degradability, anti-inflammatory, antioxidant, antibacterial, cell viability, and in-vivo. The results of FTIR, XRD, SEM, and DLS showed that the nanocomposites synthesized properly with an almost spherical morphology, an average diameter of below 100 nm (mostly 40–85 nm), and a hydrodynamic diameter of 455–616 nm. The various tests demonstrated the nanocomposite's effectiveness in wound healing. The results showed that CS/rGO/CP/Cur/Pa increased the anti-inflammatory and cell viability up to 99.7 % and 395 %, respectively, which is higher than others. Animal tests on rats showed that CS/rGO/CP/Cur/Pa accelerated the wound healing rate up to 70 %. In conclusion, the results showed that the nanocomposites based on CS/rGO significantly improve wound healing, and the presence of collagen peptides boost their wound healing potency.

Molecular interactions between 2-methyltetrahydrofuran and alcohols: A combination of thermodynamic, spectroscopic and quantum chemistry studies

New data of density (ρ), viscosity (η), and speed of sound (u) have been determined at T = (288.15–303.15 K) and p = 93.2 kPa for the binary mixture of {2-methyltetrahydrofuran + ethanol, or + 1-propanol, or + 1-butanol, or + 1-pentanol} over the entire composition range. These results were used to calculate the excess molar volume (VmE), isentropic compressibility deviation (Δκs), viscosity deviation (Δη), and Gibbs excess activation energy (ΔG*E), which were correlated by a Redlich-Kister polynomial. For all systems studied, the values ​​of the deviation properties were negative, which probably indicates a predominance of structural and chemical effects over physical effects. Five viscosity models were employed to fit the viscosity data. The VmE data were also correlated by the Prigogine-Flory-Patterson Theory (PFP Theory) and the Peng-Robinson-Stryjek-Vera Equation of State (PRSV EOS). Furthermore, a Fourier Transform Infrared (FT-IR) spectroscopy study was performed to explain the hydrogen bonding interactions. Lastly, theoretical calculations using Density Functional Theory (DFT) at B3LYP-GD3(BJ)/6–311++G(3df,2p) level of theory were performed to understand the inter-interactions between the compounds present in the mixtures. The FT-IR and computational results were in good agreement with the experimental data.

Eco-Friendly Synthesis of Silver Nanoparticles Using Aqueous Extract of Ziziphus Spina-Christi Seeds: Characterization and Stability

In this study, silver nanoparticles (Ag-NPs) were prepared using an aqueous extract of Ziziphus Spina-Christi Seeds (ZSCS) powder as an eco-friendly material, reducing agent and capping ligand. The synthesized Ag-NP was characterized using UV-visible absorption spectroscopy (UV-Vis), Fourier transform infrared (FTIR), transmission electron microscopy (TEM) and dynamic light scattering (DLS). From The UV-Vis spectra, the surface plasmon resonance (SPR) absorption band at 443 nm confirmed the formation of Ag-NPs. The TEM results demonstrated that the synthesized Ag-NPs have mostly spherical shapes with a particle size of 21.54 nm. In addition, the particle size and the specific surface area (SSA) of Ag-NPs decreased with increasing ZSCS powder extract volume and AgNO3 concentration. The basic medium was found to be better than the acidic medium to prepare Ag-NPs. At a pH value equal to 9.5, within 30 minutes, the color of the solution was changed from colorless to brownish-orange. SPR absorption band of Ag-NPs demonstrated that the synthesized Ag-NPs have high stability over a period of 8 months. From FTIR results, the stretching of C-O group at 1223 and 1031 cm-1 disappeared after bioreduction of AgNO3, these results may be due to that Ag reduction was carried out by some hydroxyl groups that get oxidized at the expense of Ag+ because Ag+ is reduced to Ag-NPs.

Analysis of Microwave Absorption Properties of Graphene Oxide from Rice Husk Waste

Graphene Oxide (GO) was synthesized with variations in carbonization temperatures of 250 °C, 300 °C, and 350 °C using the modified Hummers method. The results of the synthesis of GO will then be tested for microwave absorbing properties because it can be applied in various fields, such as information technology, medical equipment, industry, polymer synthesis, and organic synthesis. Therefore, in this report, GO uses rice husk waste instead of graphite as a carbon source because rice husk waste is abundant in nature and easy to obtain than graphite. In addition to reducing waste in Indonesia, this study aimed to determine the crystal size and GO functional groups and analyze the properties of microwave absorbers. X-ray diffraction (XRD) was used to determine the crystal size. The GO functional groups were determined using Fourier Transform Infrared (FTIR), and the microwave absorption characteristics of GO were analyzed using a Vector Network Analyzer (VNA). The XRD results show GO peaks between 26° peaks and 44° peaks. In the FTIR results, there are a collection of GO practices, in particular CO, C = C, and C = O. In the VNA results, the best microwave absorption properties are at an ignition temperature of 350 °C with the lowest reflection value - 39.95 dB, the highest absorption coefficient is 99%, and the absorption bandwidth is 0.06 GHz at a frequency of 8.5 GHz

An Experimental and Density Functional Theory Simulation Study of NO Reduction Mechanisms over Fe0 Supported on Graphene with and without CO.

NO reduction over highly dispersed zerovalent iron (Fe0) supported on graphene (G), with and without the presence of CO in the reacting stream, was systematically studied using a fixed-bed reactor, and the reaction mechanism was examined with the aid of in situ Fourier transform infrared (FTIR) spectroscopy and density functional theory (DFT) calculations. The in situ FTIR results showed that NO adsorbed on the Fe0 site is reduced to form active surface oxygen species (O*), which is then reduced by carbon in graphene to form CO2. The presence of CO in the reacting stream helps to reduce the oxidized Fe(O) sites to regenerate Fe0 sites, making NO reduction easier. It was revealed that NO and CO2 are easily adsorbed on the active surface oxygen species (O*) to form nitrate and carbonate, inhibiting their reduction by CO and deactivating the catalyst. The DFT calculations results suggest that the role of Fe is to reduce the energy barrier of the NO adsorption and decomposition, which controls the formation of active surface oxygen species and N2. The combined FTIR and DFT results offer new insights into the possible mechanism of catalytic NO reduction over graphene loaded with Fe, with and without CO.

Lecithin as an ecofriendly amphoteric collector foaming agent for the reverse flotation of phosphate ore

The development of more widely available, effective, economical, and environmentally friendly reagents is one of the major prospects of the phosphate industry. In this work, an eco-friendly reagent based on lecithin was successfully elaborated and adopted as a new amphoteric collector and frother, both for the flotation of phosphate ore. The proposed reagent was evaluated regarding its physicochemical properties (critical micelle concentration CMC, acidity index, composition) by conductivity, and ultra-high performance liquid chromatography (UHPLC). The performance of the collector in phosphate ore flotation was investigated by means of X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscope (SEM) and Fourier transform infrared (FTIR) spectrophotometry. Furthermore, the results of FTIR, SEM, and XRD analyses show that the lecithin collector has a good ability to collet calcite, dolomite and quartz. It has also been observed that francolite and quartz can be successfully separated at a pH of 5 and a lecithin concentration of 40 mg/L. Similarly, an effective separation of francolite and carbonate gangue (dolomite and calcite) can be achieved at pH 8.5 and 40 mg/L lecithin concentration. In addition, flotation tests and X-ray fluorescence show that the required quality of phosphate concentrate was obtained at 31.05% P2O5 with a recovery of 98.21% at pH 5. Similarly, 32.39% P2O5 grade was obtained with 96% recovery at pH 8.5. Thus, the results obtained suggest that lecithin has significant potential as an efficient and environmentally friendly collector for the development of selective flotation in phosphate concentration circuits.

Synthesis and characterization of new targeted pH-responsive heteroatom-doped hexagonal boron nitride nanosheets for controlled drug release

In this study, sulfur doped hexagonal boron nitride (S-h-BN) and fluorine doped hexagonal boron nitride (F-h-BN) were prepared via the exfoliation and heat treatment of bulk boron nitride (B-BN). Then, Human Serum Albumin (HSA) were immobilized onto the obtained hexagonal boron nitride nanolayer (NLs) surfaces to enhance irinotecan loading, which is a fluorescent molecule having excitation and emission at the wavelengths of 299 nm and 436 nm, respectively. The loading and release properties were studied at different pH values. Whereas the maximum loading amounts were achieved at the pH of 4.0 for all nanosheets, the pH value at which the maximum drug release was observed were found to be different for all samples. The physicochemical characterization of the nanosheets were conducted by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy methods. The XRD and FTIR results indicated the successful synthesis of h-BN and the 2D structure of the nanolayers were imaged using SEM and TEM methods. The F and S content inserted into the h-BN structure was determined to be about 2.45 and 0.1 at. % using the XPS method. In addition, the bonding structre of the modified h-BN monolayers were unraveled by the deconvulation of the XPS results.