Applied Chemical Engineering

Abstract Schiff bases were synthesized to explore their potential as effective antioxidant agents. The synthesis involved the condensation of aromatic aldehydes with 4H-1,2,4-triazole-3,5-diamine. The structures of the resulting compounds were confirmed using various spectroscopic techniques and elemental analysis. Furthermore, theoretical studies, including in silico computations with Density Functional Theory (DFT) calculations, supported the efficiency and stability of the synthesized compounds. The antioxidant activity of the samples was evaluated using the DPPH radical scavenging method, which indicated that the compounds exhibited good antioxidant properties.

Abstract Used engine lubricating oil contains degradation products and wear-derived metals that require controlled treatment before any recovery option can be considered. This study evaluated five used-oil samples (three gasoline-engine oils and two diesel-engine oils) and examined a staged process comprising settling, magnetic separation, filtration, dewatering, acetic-acid treatment, solvent flocculation, and treatment with two synthesized non-ionic surfactants. Physicochemical properties were measured using standardized methods for density (15 °C), kinematic viscosity (100 °C), flash point, pour point, carbon residue, and ash content, while elemental concentrations were determined by ICP-MS. For surfactant-1-treated samples, gasoline-engine oils showed densities of 0.8714-0.8904 g cm−3, kinematic viscosities of 9.51-13.59 mm2 s−1, and ash contents of 0.010-0.014 wt%, whereas diesel-engine oils showed densities of 0.8934-0.8954 g cm−3, viscosities of 13.16-20.26 mm2 s−1, and ash contents of 0.011-0.012 wt%. Treatment reduced Fe from 40.93 to 28.56 ppm, Zn from 47.26 to 38.83 ppm, and Al from 10.50 to 8.15 ppm; however, sulfur remained high at 407.39 ppm, and no engine, bench, anti-wear, moisture-balance, or long-term stability tests were performed. The results therefore support physicochemical improvement and partial contaminant removal, but they do not establish that the regenerated oil is suitable for direct reuse in engines; operational validation and additive rebalancing are required.

Abstract Starch, a natural polymer, is modified for drug delivery by chemical, physical, and enzymatic methods to alter its structure and properties for improved drug loading, release, and biocompatibility. Chemical modifications include esterification, etherification, and oxidation to enhance properties like gel strength, stability, and hydrophilicity. Physical methods like annealing can increase molecular mobility, aiding in controlled release. Enzymatic treatments can also alter starch structures. These modified starches are used in drug delivery systems, acting as polymers or excipients in hydrogels, nanoparticles, and films for targeted and controlled release of active pharmaceutical ingredients. Advanced pharmaceutical materials are a requirement of human health as companies seek to develop medical treatment to obtain the best results. A new types of polymer drugs were used in this study: paracetamol, amoxicillin, ampicillin, Salbutamol. sulphathiazole, and cefotaxime as new modified polymer used against microorganism. Natural starch, a polysaccharide compound, was used as a binder to form new active groups in the drug composition. The esterification mechanism was used in the reaction, resulting in the formation of starch acetate containing acetate groups after water withdrawal and pH adjustment to 7. Maleic anhydride was added to the starch acetate polymer by refluxing for 6 hours at 153C o with DMF as solvent to produce polymer the starch acetate maleate as (S3) compound. The selected standard antibiotic samples were reacted with the starch acetate maleate polymer to produce new pharmaceutical compounds such as amoxicillin starch acetate polymer and so on. The new pharmaceutical compounds were identified using FTIR, thermal gravimetric analysis (TGA) and proton nuclear magnetic resonance spectroscopy (HNMR) A study was conducted by the new pharmaceutical compounds to study their physiological and inhibiting activity on microorganism as the E.coli and the Staphylococcus with concentration of 1000 ppm. The result appears increasing in cell number for theS3- sulphametaxiol drug as 21 mm and for the S3-Cefotaxin drug as 39mm against the E.coli in addition the increasing via the S3 polymer with value of 41mm while most of the new pharmaceutical polymers showed effectiveness against Staphylococcus bacteria. In addition to study the impact of some of the new drugs on cell line. The results showed that the new drug has activity against living organisms (E. coli bacteria and Staphylococcus bacteria) in addition to its activity under normal laboratory conditions, Docking and cytotoxicity results showed a possible correlation. Sulphamethoxazole had the strongest binding (–10.8 kcal/mol), while Salbutamol was the weakest (–9.3 kcal/mol). Cefotaxime showed the highest anticancer activity, and Ampicillin the lowest. Overall, stronger docking interactions may suggest higher anticancer potential.

Abstract Two azo-containing materials, an acrylamide-derived azo compound (AZO 1) and a chitosan-derived azo material (AZO-chitosan 2), were prepared by diazo coupling with o-cresol under alkaline conditions at 0–5 °C. The acrylamide-derived monomer was subsequently converted to an azo polymer by free-radical photopolymerization under nitrogen using 1-hydroxycyclohexyl phenyl ketone (Irgacure 184) as the photoinitiator. The products were characterized by FTIR, ¹H NMR, and ¹³C NMR spectroscopy, and their thermal behavior was evaluated by TGA and DSC. The acrylamide-derived azo compound was obtained in 78% yield, whereas the AZO-chitosan product was obtained in 70% yield. The spectral changes support formation of the azo-containing products and consumption of the polymerizable double bond. The two polymer samples showed TGA onset temperatures of 110 and 100 °C, 50% mass-loss temperatures of 260 and 270 °C, and residues of 92% and 90% at 600 °C, respectively. DSC gave glass-transition temperatures of 180 and 250 °C. These results establish the structural and preliminary thermal characteristics of the prepared materials. Molecular-weight distribution and photoisomerization were not measured and therefore remain subjects for further study.

Abstract The co-precipitation approach was used in this work to create cadmium oxide nanoparticles (CdO NPs) from cadmium nitrate. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to assess the size and shape of the produced CdO NPs. As thioimidazolidine derivatives, new heterocyclic compounds with azide groups were created. Schiff bases were initially prepared using p-nitro, p-chloro, and p-bromo benzaldehydes with CdO. NPs as a catalyst. Filtration was used to successfully recover the catalyst. The target compounds (4a–c) were obtained by reacting these intermediates with ethyl chloroacetate, chloroacetyl chloride, and sodium azide. Spectroscopic methods such as FT-IR, ¹H-NMR, and ¹³C-NMR were used to characterize the produced compounds. The spectral analyses indicated that the synthesized compounds were obtained in a pure form, as no significant impurity signals were observed. Characteristic absorption bands were visible in the FT-IR spectra, especially for the azide group (N₃) at about 2115 cm⁻¹. Additionally, the synthetic substances' biological activity were assessed. Preliminary data on their safety profile was obtained by estimating acute toxicity by computing LD50 values. Strong broad-spectrum antibacterial activity was shown by the compounds against both Gram-negative bacteria like Escherichia coli and Klebsiella spp. and Gram-positive bacteria like Staphylococcus aureus and Staphylococcus epidermidis. Additionally, encouraging antifungal efficacy against the pathogenic yeast Candida albicans was noted.

Abstract This study focuses on the absorption and emission (fluorescence) spectra of two organic dyes, Rhodamine and Fluorescein. The dyes are prepared as liquid samples dissolved in a polyvinyl alcohol (PVA) polymer solution at different concentrations (0.01, 0.02, 0.03, and 0.04 mM). Solid samples in the form of PVA polymer films doped with Rhodamine and Fluorescein are also prepared using the casting method, in which the dyes are directly mixed with the polymer solution at different concentrations (0.01, 0.02, 0.03, and 0.04 mM), while maintaining a constant film thickness of 120 μm. The absorbance values of all prepared samples are measured using a UV–Vis spectrophotometer. The results indicate that increasing dye concentration affects the linear optical properties of the prepared samples, resulting in increased absorbance and decreased transmittance, consistent with the Beer–Lambert law. Increasing the dye concentration also results in higher calculated linear optical coefficients, including the linear refractive index and linear absorption coefficient, for all samples. Fluorescence spectra are measured using a fluorescence spectrometer, and the fluorescence lifetime and quantum efficiency are calculated to evaluate the emission properties of the studied dyes. The results indicate that the Rhodamine- and Fluorescein-doped PVA films possess promising optical properties, demonstrating their potential for advanced photonic and laser applications.

Abstract In this study, a new heterocyclic Schiff base ligand was synthesized from 4-aminobenzamide and indoline-2,3-dione, followed by the preparation of its Cu (II), Zn (II), and Co (II) complexes. The prepared compounds were characterized with the use of different spectroscopic methods, such as FTIR, UV-Vis, 1HNMR, 13CNMR, the melting point determination, and the molar conductivity measurements. The findings indicated that the ligand is a bidentate ligand with nitrogen and oxygen donor atoms to form octahedral metal complexes. The biological activity of the copper (II) complex was tested against human colon cancer cells (HCT116) and normal cells (HDF). The complex had a great inhibitory effect against the cancer cell proliferation, as confirmed by the IC50 values. This shows that the compound under study can be developed in future to be used for pharmaceutical applications. Moreover, the electronic properties of the copper complex were studied by Density Functional Theory (DFT) calculations. The HOMO-LUMO, ELF and NBO analyses revealed the good electronic stability, charge transfer behavior and electron localization around the donor atoms. The findings offer theoretical insight into the electronic characteristics, charge-transfer behavior, and stability of the prepared copper complex, thus facilitating the experimental characterization and biological assessment.

Abstract Now I've completed my pre-research study; I want to analyze the effects caused by copper oxide (CuO) nanoparticles created using laser ablation and precipitation methods. This includes an overview of how much the CuO nanoparticles inhibited the growth of Staphylococcus aureus, Escherichia coli, and a few other bacteria, as well as how the CuO nanoparticles' inhibitory activity compares using scanning electron microscopy (SEM) or X-ray diffraction (XRD) to analyse structural properties of the nanoparticles compared to traditional bactericidal substances, and to what extent UV-Vis spectroscopy can be utilised to determine bactericidal activity (bactericidal effectiveness) and/or to help determine potential non-toxic concentrations of CuO nanoparticles towards host-type mammalian cells. The CuO nanoparticles produced by using different synthesising methods produced different uniformities of the CuO nanoparticles, which led to inconsistencies between CuO nanoparticle synthesis and the formation of individual CuO nanoparticles. However, overall the CuO nanoparticles had high anti-bacterial properties (low bactericidal concentration) and low toxicity towards mammalian host cells (mammalian cell toxicity).

Abstract Nanotechnology has emerged recently as a successful technique to enhance cement-based material performances. When nanoparticles, polymers and other material are added to the cement, it changes microstructure of cement composites drastically. This study synthesized a nano chitosan incorporated PVA-Corn Cob Ash (CCA) hybrid composite by using ultrasonic dispersion and incorporated it in the cement mortar. Mortar mixes were made with a cement-to-sand ratio of 1:2.75 and a water-to-cement ratio of 0.485. The hybrid composite was added at one percent by weight of cement. As per ASTM C109, the compressive strength was evaluated at 7 days and water absorption and density were determined as per ASTM C642. The time of setting was measured as per ASTM C191. The findings indicate that the hybrid composite enhances compressive strength and yields a denser cement matrix than the control mixture. The improved properties are due to the nuleation of the nano-chitosan particles, the formation of polymer film by PVA, and the pozzolanic reaction of corn cob ash. The use of agro waste materials in a hybrid system is useful for sustainable construction.

Abstract Covalent bonding composite are formed in amide bonds between the wall of oxidized nanotubes that are covalently bonded by the interaction of the carboxyl groups of nanotubes with the amine groups of other amino compounds and the formation of highly effective Composite against some bacteria. It can also have other applications. The composite Create (K3) (N- (benzathiazol-2-yl) nanotube hydrazide. From the treatment of oxidized nanotubes (K1) with some derivatives amino compounds (K2), The Synthezid composite was subjected to a comprehensive and rigorous characterization to evaluate its structural, morphological, and thermal properties. Fourier-transform infrared spectroscopy (FT-IR) was employed to identify the functional groups and confirm the chemical cross-linking between the composite components. These findings were further supported by X-ray diffraction (XRD) analysis to investigate changes in the crystalline structure and calculate the average crystallite size. Morphologically, Scanning Electron Microscopy (SEM) was utilized to examine the surface topography and particle distribution, while Thermogravimetric Analysis (TGA) revealed the thermal stability and degradation behavior of the final product."

Abstract This study investigates a new series of cycloparaphenylene based dyes for photovoltaic applications. The parent CPP-1 molecule was modified by introducing phenyl ethylene units (CPP-2 to CPP-4) and an indacene fragment (CPP-5) to tune its electronic and optical properties The electronic structures and photophysical behavior were examined using DFT and TDDFT at the B3LYP level. Calculations employed SDD for all systems. Key parameters, including geometries, frontier orbital energies, energy gaps, uv visible spectra, density of states and photovoltaic properties, were analyzed. Results indicate that excitation facilitates transport of electrons to the conduction band from the dyes, suggesting efficient charge injection. The modified dyes show improved electronic coupling and enhanced photoelectric performance compared to CPP-1. These results demonstrate the possibility of cycloparaphenylene functionalization as a method for creating effective organic dyes for solar cells that are dye-sensitized.

Abstract The prepared phthalocyanine derivatives and their polymeric analogues were investigated using FT-IR, ¹H NMR, and UV–visible spectroscopy. GPC measurements were available for the metal-free and nickel-containing polymeric products and indicated narrow apparent molar-mass distributions. The antibacterial activity of polymeric compounds 8–14 was evaluated against Staphylococcus aureus and Escherichia coli using the agar diffusion method. Reported inhibition zones ranged from 10 to 17 mm for S. aureus and from 10 to 18 mm for E. coli. These observations support further investigation of the materials, while additional analytical evidence is needed to establish the proposed A₃B composition and purity.

Abstract In this work, the synthesis of Azo compound [A1-A3] from different amines, was carried out and then converted to the 2-substituted benzimidazole compound [B1-B3], through the interaction of the resulting azo compounds with O-phenylenediamine. The structures of all new synthesized compounds were determined by FT-IR, 1H NMR and 13C NMR and their physicochemical properties, among them solubility, color, and melting point. The synthesized benzimidazole compounds were also evaluated for their antioxidant activity using the DPPH radical scavenging assay and for their antibacterial activity against selected Gram-positive and Gram-negative bacteria. The results demonstrated that the synthesized compounds exhibited antioxidant and antibacterial activities with different levels of activity among the tested compounds.

Abstract Cu(II), Ag(I), and Au(III) complexes were synthesized from a new organic Schiff base ligand (PMBD),4-(pyridin-3-ylimino)methyl) benzene-1,3-diol, derived from a pyridine heterocycle, and 2,4-dihydroxybenzaldehyde. Spectroscopy techniques, XRD, and SEM data confirmed that the ligand acts as a bidentate mono-deprotonated coordinator, yielding nanoparticle-sized complexes with octahedral, tetrahedral, and square planar structures, respectively. The antibacterial activity in vitro against Escherichia coli and Staphylococcus aureus using the agar well diffusion method, minimum inhibitory concentration (MIC), and minimum microbicidal concentration (MMC) tests was supported by computational work simulating molecular docking against DNA gyrase units (1KZN and 2XCS). The experimental results showed that synthesizing the metal complexes significantly enhanced antibacterial activity compared to the free Schiff base ligand. The Cu(II) complex showed the strongest activity, with the largest inhibition zones measuring 37 mm, followed by the Ag(I) complex (26 mm), and finally the Au(III) complex (14 mm). Computational molecular docking binding studies indicate that the [Cu(L)2(H2O)2] Complex has the highest affinity against E. coli (1KZN) with a binding score of -7.3 kcal/mol and the lowest Ki value (4.42 µM) compared to the free Schiff base ligand (Ki = 12.21 µM). Conversely, the [Au(L)Cl2] complex displayed a lower binding energy of (-5.4 kcal/mol) and a higher Ki (109.43 µM) against 2XCS, aligned with its reduced experimental potency. The synthesized Schiff base ligand and its metal complexes demonstrate promising in vitro and in silico antibacterial activities via potential DNA gyrase inhibition. These findings suggest their high potential for further development in pharmaceutical and industrial antimicrobial applications.

Abstract Serum proteins such as albumin undergo structural and biochemical alterations associated with chronic hyperglycemia, particularly in Type 2 Diabetes Mellitus (T2DM). Understanding the interactions between serum albumin and inorganic nanomaterials provides a useful foundation for investigating nanoparticle–protein interactions in biomedical research. In this study, zinc oxide (ZnO), nickel oxide (NiO), and titanium dioxide (TiO₂) nanoparticles were synthesized by chemical precipitation and characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), and field-emission scanning electron microscopy (FE-SEM). The adsorption behavior of serum albumin toward these metal oxide nanoparticles was evaluated under selected nanoparticle concentrations and incubation conditions using a modified Bromocresol Green (BCG) assay. The quantitative results demonstrated that nanoparticle composition and physical form influenced the observed albumin adsorption behavior. For dry powder interfaces, the magnitude of adsorption followed the order ZnO > NiO > TiO₂, whereas for dispersed aqueous suspensions at 1.0 mg/mL, the order was NiO > TiO₂ > ZnO. In human serum samples, ZnO nanoparticles showed a statistically significant difference in albumin adsorption between diabetic and healthy groups (p = 0.03), whereas NiO suspensions exhibited high but not significantly different adsorption between the two groups (p = 0.18). These findings indicate differences in albumin–nanoparticle interactions between diabetic and healthy serum samples and provide preliminary experimental evidence for further investigation of metal oxide nanoparticles in biomedical and future nanodiagnostic research.

Abstract The nanocomposite was created and prepared in a process aimed at creating highly efficient nanosensors and adopting the necessary tests for that. The plasma technique was used to prepare the (Zn) and (Fe) nano-metals. These nano-metals were identified by FAAS technique to find out their concentrations. It was also diagnosed using FTIR, UV-Vs, FESEM, and XRD techniques. In addition to the preparation of graphene oxide by Hummer method to make a nanocomposite of oxide and nanometals with a mixing ratio of 10:1:1. Gaseous sensitivity tests were carried out on the (GO/Zn+Fe) nanocomposite towards H2S gas, and it gave good sensitivity to the gas. The process of mixing two metals with graphene oxide to create this composite has proven to be more successful than using iron alone.

Abstract This study focused on improving the optical properties of the Congo Red pigment using different nanoparticles (SiO2, MgO, and TiO2) at different weight concentrations (0.002, 0.004, and 0.006 g). The results showed that the addition of nanoparticles led to a significant improvement in absorbance (A), refractive index (n), and dielectric constant, while the transmittance (T) decreased. Regarding absorbance at the highest concentration (0.006 g): the pure dye recorded an absorbance of 0.204, while it increased to 0.325 with the addition of SiO₂, to 0.361 with MgO, and reached its maximum value of 0.626 with TiO₂. Conversely, the transmittance (T) decreased at the same concentration: from 0.623 for the pure dye, to 0.473 with SiO₂, 0.435 with MgO, and recorded its lowest value of 0.236 with TiO₂, indicating the high light-blocking efficiency of titanium dioxide. Fluorescence results also showed that the quantum efficiency (QE) decreased with Increasing the concentration for all samples, the highest quantitative efficiency was recorded at the lowest concentration (0.002 g) and the values were as follows: 0.0459 with SiO2, 0.04 with MgO, and the highest 0.0475 with TiO2.

Abstract The magnetic electron scattering form factors of the 17O, 19O, and 25Al nuclei were investigated using the Bohr–Mottelson collective model within the framework of the nuclear shell model. Calculations were performed in the SDPF model space using the NuShellX@MSU code, while harmonic oscillator wave functions were employed to describe the single-particle states. The one-body density matrix elements (OBDMs) were obtained from the shell-model eigenvectors and used in the calculation of elastic and inelastic magnetic form factors. The contributions of the M1, M3, and M5 multiple components were analyzed for the selected transitions. The calculated form factors were compared with the available experimental data. Good agreement was obtained for the 17O nucleus over most of the momentum-transfer region, demonstrating the capability of the Bohr–Mottelson model to describe magnetic electron scattering observables in light nuclei. The results provide additional insight into the nuclear structure and electromagnetic transition properties of Sd-shell nuclei.