نشریه شیمی و مهندسی شیمی ایران
سال چهل و سوم شماره 1 (پیاپی 111، بهار 1403)

Thermogels, having unique sol-gel phase transition properties, have recently received much attention. These types of hydrogels show a phase transition when exposed to temperature changes. This feature is the key to the application of thermogels in medicine. The thermogelling behavior is the result of a combination of multiple heat response mechanisms. These mechanisms include the behavior of the lowest critical temperature of the solution, micellization and micellar aggregation of thermogel-forming polymers. Thermogels have wide applications in medical engineering and especially in tissue engineering. Injectability is one of the most important properties of thermogels for use in tissue engineering, which induces high compatibility, easy loading of cells and growth factors, and help in tissue regeneration to these hydrogels. In recent years, the use of thermogels in drug delivery and the study of thermogel drug delivery systems have become very common. Thermogels can deliver the drug to the desired location in a targeted manner and increase the life of the drug by protecting the drug in the body. Thermogels have also been considered as a suitable cell culture medium in various researches due to their three-dimensional porous structure. In addition, these materials have been used as self-cleaning membranes due to their ability to reduce fibrous encapsulation and facilitate analyte diffusion in biosensors. In this article, an attempt was made to review the research conducted in the field of functional mechanisms of thermogels and the progress achieved in this field. In the following, with a practical attitude, the research conducted in the field of using thermogels in medical engineering, such as use in drug delivery, tissue engineering, 3D culture of cells/stem cells, and membranes and sensors, was examined.

Nowadays, supramolecular hydrogels as a new type of three-dimensional compounds based on non-covalent interactions have attracted the attention of many scientists of different sciences due to their diverse and easy preparation methods and unique characteristics compared to their covalent counterparts. Therefore, in the present research, green cellulose nanoparticles was prepared from cotton by acid hydrolysis process and then separately functionalized with citric acid and pyridine pendant groups in order to create anionic and cationic components. Next, supramolecular hydrogels were prepared through electrostatic interactions between the mentioned components. The successful preparation of hydrogel was investigated using Fourier transform infrared spectroscopy, SEM and X-ray diffraction. Study of the morphology of the hydrogel showed a porous structure containing holes of different sizes. Also, the investigation of the crystal structure of the hydrogel showed its high crystallinity. Finally, the removal of methylene blue cationic dye from industrial wastewater was investigated through the absorption process and using the prepared hydrogel as an adsorbent. Also, the effect of methylene blue initial concentration and contact time at room temperature on the absorption process was investigated. The study of absorption kinetics showed that the absorption process follows the second-order absorption kinetics. The maximum absorption capacity obtained for this adsorbent was 97 mg/g. The present study showed that the prepared supramolecular hydrogel, in addition to features such as biocompatibility, avalability, and simple and fast preparation, has a good potential for methylene blue absorption.

The G-protein receptor kinases are members of the most effective enzymes in the incidence of some important disease such as cardiovascular diseases, hypertension and Alzheimer’s disease. One of these enzymes is a protein with PDB code: 3v5w in the protein data bank. The in-silico study on the interaction of variety of inhibitor ligands with this enzyme was performed. The results of the interaction between selected ligands and target protein were investigated and analyzed using molecular screening by molecular docking simulation methods. The calculations of some factors such as binding energy between ligands and target protein, non-bonding interactions of ligands in the active site of enzyme and analysis of the result of molecular docking scoring were performed. The results were compared with a standard inhibitor (Paroxetine). Furthermore, to better evaluate and correct the selection of the lead compound, the related properties of absorption, distribution, metabolism, excretion and toxicity (ADMET) of high-scored ligands were compared with pharmacokinetic factors of Paroxetine using ADMETLab 2.0 data server platform. As the result, the compound L10, (4R,5S)-5-(1,3-benzodioxol-5-yloxymethyl)-4-(4-fluorophenyl)piperidin-2-one was introduced as a novel potent inhibitor ligand which has the better potency, more binding energy and more  appropriate pharmacokinetic properties.

Computed tomography imaging can help in the diagnosis of diseases in the early stages and provide important information about the pathology of processes. Computed tomography imaging relies heavily on the development of complex contrast agents to detect biological processes even in the cells. Nano contrast agents have a significant advantage over iodine-based molecules like creating high contrast and long circulation in blood. In this study, Tungsten trioxide nanoparticles were fabricated by the co-precipitation method to improve the contrast in computed tomography images; and to stabilize and increase contrast, Ultravist was used as coating utilizing the ultrasonic bath method. To determine the characteristics of Tungsten trioxide nanoparticles, scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction test (XRD), vibrating sample magnetometer (VSM), dynamic light scattering (DLS), and zeta potential were performed. The result of the SEM test indicates nanoparticles morphology. The result of X-ray diffraction analysis showed that nanoparticles have the chemical formula (WO3) and have more adjustment with Monoclinic Crystal system coding JCPDSNO-43-1035. The vibration Sample Magnetometer proved that the nanoparticles are Ferromagnetism agents. To illustrate the suspension stability and also particle dimension, zeta-potential and optical Dynamic-Dispersion have been used. Zeta potentiality was 25±2 Millivolt (mv) and optical Dynamic-Dispersion was 383.7, 2616.2 nm. And finally, Scanning findings have been compared with iodine-based molecules indicating that in similar density, nanoparticles (WO3) with Ultravist cortex have higher contrast and better image clarity.

The use of organic coatings is the most common and cost-effective way to protect against corrosion and increase the useful life of many metal structures in corrosive environments. However, once the protective coating is damaged, the degradation processes spread rapidly. To achieve long-term coating performance in a corrosive environment, applied active protection along with self-healing defects is essential. In this review article, firstly, the characteristics of self-healing materials for anti-corrosion applications are stated, then the classification of the encapsulation process, which includes physical and chemical encapsulation, is discussed, and finally, a summary of recent works in the field of new multi-level protection systems is presented. It is based on the controlled release of anticorrosive species from smart micro- and nano-carriers in a polymer coating field. Also, this paper examines a self-healing approach that includes several damage prevention and repair mechanisms, including trapping of corrosive ions, corrosion inhibition, and water displacement from active defects. In the other part of the article, a review of the methods of evaluating the performance of self-healing coatings using electrochemical, surface and microscopic techniques is provided, and also suggestions for alternative electrochemical techniques for evaluating the self-healing coating are reviewed. Finally, in terms of modeling, computational research on self-healing materials is discussed.

In this work, new nanocomposite coatings based on epoxy with different percentages (wt.%) of organic clay containing iron oxide and zinc oxide nanoparticles as additives have been prepared. In this context, iron oxide (Fe3O4) and zinc oxide were primarily prepared by a chemical coprecipitation method. Next, intercalated montmorillonite K10 (Mont K10) was synthesized by stabilization of surface-active ingredients such as cetyltrimethylammonium bromide (CTAB) and diethylenetriamine penta methylene phosphonic acid (DTPMP). The prepared Fe3O4 or ZnO were then located within the interlayers and on the external surface of the organoclay to fabricate the novel additives. These additives were dispersed in the epoxy resin and used as nanocomposite coating on the substrate. The structure and morphology of coatings were characterized using XRD, FT-IR and SEM. The effect of adding nanoparticles on the corrosion resistance behavior and mechanical properties of the coatings were investigated by Electrochemical Impedance Spectroscopy (EIS), Salt Spray, pull off and Hardness test. The results of EIS and Salt Spray tests showed that the corrosion resistance of the coating significantly improved by incorporation of CTAB-modified clay in the epoxy matrix. Furthermore, according to the results of pull off and Shore D tests, the mechanical properties such as interfacial adhesion and hardness of coating containing CTAB-clay showed the best performance. In addition, SEM images showed that embedded nanostructures in epoxy coating resulted in a denser, more uniform and less porous layer in comparison with pure epoxy which can effectively prevent the corrosion of the underlying metal by creating high blocking properties.

In this research, a method for treating colored wastewater is proposed by magnetic nanoabsorbents coated with humic acid. The surface of the mentioned nanoabsorbent was modified with humic acid as a combination that includes hydroxyl, carboxyl and amine groups. Iron(III) oxide/humic acid nanoparticles were prepared by co-precipitation method and analyzed using dynamic light scattering techniques, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy and vibrating sample magnetometer. The average diameter of nanoparticles was measured around 15 nm. The effect of adsorbent dose, contact time and initial concentration was also investigated. The best results are obtained by using 15 mg/ml of nanoparticles in 45 min for methylene blue dye, 20 mg/ml of nanoparticles in 30 min for indigo-carmine dye and 5 mg/ml of nanoparticles in 20 min for 4-(2-pyridylazo)resorcinol dye was obtained. In these conditions, 95.96, 99.34 and 99.11% of methylene blue, indigo carmine and 4-(2-pyridyl azo) resorcinol can be removed from the solutions made in the laboratory ,respectively. The maximum absorption capacity for methylene blue, indigo carmine, and 4-(2-pyridyl azo)resorcinol was 0.0085, 0.0439, and 0.0307 mmol/g respectively, which was based on the Freundlich isotherm model for methylene blue and for indigo carmine and 4-( 2- Pyridyl azo) resorcinol was fitted to the Langmuir isotherm model. In the reuse of nanoabsorbents, an average of 12.94% of each color was removed from the aqueous medium. The results indicate the efficiency of the nanoabsorbent for the removal of colored wastewater.

In this research, at first, nanoporous zeolite-NaY was functionalized through reaction with 3-chloropropyltriethoxysilane (organic linker) and then with N-methylimidazole group. Then magnetic nanoparticles (Fe3O4) were formed and stabilized under ultrasonic energy conditions on the surface and internal pores of zeolite-Y (1-MeIm IL@ZY-Fe3O4). The structure of zeolite-ionic liquid prepared as a magnetic nanohybrid using the techniques of FTIR, FESEM, EDS, TGA, BET, XRD and VSM instrumental analyses were identified and confirmed. At the next step, its catalytic performance in the synthesis of a number of 4-aryl-2-amino benzopyran (chromene) or 4-aryl-2-amino naphthopyran (benzochromene) derivatives was investigated through the three-component condensation reaction of aromatic aldehydes, malononitrile and dimedone or β-naphthol, at ambient temperature and aqueous medium. The advantages of this method include the use of cheap, safe and reusable nanocatalyst, easy separation of the heterogeneous catalyst from the reaction medium with the using of a magnet, short reaction time, high yield, easy and fast separation of the product, and the use of non-toxic water solvent, that has made this method in simplicity, be in the scope of "green chemistry".

this research, a Schiff base-cobalt (II) catalyst containing crown ether, stabilized on cellulose nanoparticles (Crowned Imine-Co (II)@CNC) was prepared. This catalyst was identified by SEM, IR, TGA, XRD, EDX and TEM techniques. This compound was used as a heterogeneous catalyst in the synthesis of chromenes. Chromenes were synthesized with good efficiency (77% to 99%) and within a short time of 20 minutes through the reaction between diketones, malononitrile and various benzyl alcohol derivatives in water solvent. Reusing the recycled catalyst (up to 4 times) did not change the reaction efficiency. The difference between this method and other methods of synthesizing chromenes is by using benzyl alcohol derivatives instead of benzaldehyde.

Five 8-hydroxyquinoline complexes of tin were prepared by reacting diphenyltin dichloride with 8-hydroxyquinoline and its derivatives for using as fluorescent materials in organic light-emitting diodes (OLEDs). The elemental analysis and IR, UV–vis, 1H and 119Sn NMR spectroscopes were used to characterize the prepared compounds. The details and features of the reaction were described and discussed. The prepared compounds were utilized as the green-yellow EL dopant materials to fabricate OLED devices with a general configuration of ITO/PEDOT:PSS(90 nm)/PVK:PBD:tin-complex(80 nm)/Al(200 nm). PVK (polyvinyl carbazole) and PBD (2-(4-Biphenylyl)-5-phenyl-1,3,4-oxadiazole) as hole-transporting and electron-transporting materials, respectively, were doped within tin compounds as the emissive layer. The results of the investigation of electroluminescent (EL) and photoluminescence (PL) properties of prepared complex showed that the electron donating or withdrawing substituent groups on 8-hydroxyquinoline have a significant effect on the tuning and changing of emission wavelengths.

In this project, a simple and low-cost method for the simultaneous extraction of dimenhydrinate and omeprazole from blood serum, urine and pharmaceutical samples is reported. The proposed method is based on dispersive solid phase microextraction by modified graphene oxide adsorbent. The polyphenols of rosemary extract are polymerized in the presence of amino acid lysine and formaldehyde and functionalize the surface of graphene oxide. Fourier transform-infrared spectroscopy (FT-IR), field emission-scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and Raman were used to identify the synthesized composite. Simultaneous analysis of dimenhydrinate and omeprazole was performed by high performance liquid chromatography equipped with ultraviolet/visible detector (HPLC-UV). The results of the work evaluation led to the achievement of a linear range of 1-400 µg/L, detection limits of 0.33-0.48 µg/L, and the coefficient of determination (R2) of more than 0.9991 for both analytes. The recovery % (more than 94.3) obtained from the analysis of real samples of blood serum and urine shows the high accuracy of the method and the absence of matrix effect. The F-test was used to compare the precision and the t-test was used to compare the accuracy of the proposed method with ultraviolet/visible spectroscopy methods on dimenhydrinate tablets and omeprazole capsules, and the results showed that there is no significant difference between the answers obtained from the two methods.

Cistanche tubulosa, a perennial parasitic plant, is one of the herbal sources allowed as (Cistanche herb) in the Japanese-Chinese pharmacopoeia and grows in arid and semi-arid desert areas. This plant is considered as a solution for desertification and prevention of global warming. The phenolic and non-phenolic compounds present in this plant have various medicinal effects and antioxidant properties, which are of great importance in living cells. The purpose of investigating the compounds present in the Cistanche tubulosa plant is to systematically evaluate the antioxidant behavior and establish a relationship between the chemical structure and antioxidant activity of the effective compounds of this plant by examining the mechanism of free radical formation and the dissociation energy of the considered bonds in the chemical structure of the compounds present in it. Investigations carried out with density functional theory (DFT) method and DFT/B3LYP/6-311++G(d,p) level of theory in gas and water phases showed that the lowest amount of bond dissociation enthalpy (BDE) and dissociation proton enthalpy (PDE) among the radicals created from Kankanol and Argiol structures belongs to Argiol radical number 4, which is created as a result of removing a hydrogen atom from its carbon number 10 (C10). The results of calculations show that this compound also had the best results in dealing with oxygen radicals such as hydroxide radicals (the most negative value obtained for enthalpy (ΔH) and Gibbs free energy (ΔG) changes).

In this study, the effect of electron beam (EB) irradiation of shrimp shells as well as the time and concentration of HCl and NaOH on the process of chitin extraction and chitosan production, were investigated. The products characteristics were evaluated by Fourier-transform infrared spectroscopy, atomic absorption spectroscopy, X-ray diffraction spectroscopy, thermogravimetric analysis, viscometry measurement, water and fat binding capacity determination and antimicrobial analysis. The extent and rate of demineralization and deproteinization increased initially by increasing of HCl and NaOH concentrations, respectively, and then leveled off. According to the results, demineralization with 0.5 M HCl for 6 h and deproteinization with 1.0 M NaOH at 65 °C for 6 h were proposed as suitable procedure for chitin extraction. EB irradiation of shrimp shells, in the range of 10-99 kGy, led to a decrease in the time required for both demineralization and deproteinization processes. Remained calcium in unirradiated and 30 kGy irradiated shells, after 6 h treatment with 0.5 M HCl, were 13.75 and 9.75 mg/g, respectively. Increasing of irradiation dose, led to a decrease in molecular weight (MW), an increase in deacetylation degree (DD) and a decrease in the crystallinity of chitosan. Depending on the irradiation dose and deacetylation reaction conditions, chitosan with DD varied between 60-95% and MW varied between 2.1×105-2.3×104 were produced. MIC and MBC of resultant chitosan samples, varied between             0.6-0.8 and 1.4-2.5 mg/ml against E. coli, as well as between 0.5-0.70 and 0.8-1.5 mg/ml against S. aureus, respectively. With increasing irradiation dose from 0 to 99 kGy, the diameter of inhibition zone against E. coli and S. aureus increased from 3.7 to 17.2 and from 5 to 18.8, respectively. According to the results, it seems that EB irradiation is a promising method for producing chitin and chitosan with unique properties suitable for different applications.

Properties of the ionic liquids can be controlled by using different combinations of the cations and anions for specific purposes. In this work, density functional theory has been used at M06-2X/6-311++G(2d,2p) level of theory to investigate the effect of different substitutions on the electrochemical, physical and chemical properties of the pyridinium-based ionic liquids including 4X-Dimethylpyridinium cations ([4X-DMPy]+, X: NH2, OMe, Me, H, Cl, CHO, CF3, CN and NO2) and tetrafluoroborate anion ([BF4]-). Cathodic potential limit and anodic potential limit, electrochemical window, charge transfer values, structural parameters and topological properties of the ionic liquids were calculated. The results show that the strength of the interaction between the cations and anion increases with the increase in the electron withdrawing strength of the substituents on the 4 position of the pyridinium cation ring. According to the calculated interaction energies (from -104.71 to -90.59 kcal/mol), the stability of the studied ionic liquids is as follows: [NO2-DMPy][BF4] > [CN-DMPy][BF4] > [CF3-DMPy][BF4] > [CHO- DMPy][BF4] > [Cl-DMPy][BF4] > [H-DMPy][BF4] > [Me-DMPy][BF4] > [OMe-DMPy][BF4] > [NH2-DMPy][BF4]. Comparing the charge of the atoms from natural bond orbital analysis show that hydrogen bonding in the designed ionic liquids is accompanied by some charge transfer from anion to the cations, and the charge transfer for electron-withdrawing substituents (CHO) is greater than other substituents in [4X-DMPy][BF4] ionic liquids. According to the electrochemical window values of the studied ionic liquids (from 2.73 to 4.32 V), it is predicted that the ionic liquids containing electron-donating substituents are more suitable electrolytes than other ionic liquids in electrochemical reactions.

Compressibility of suspension plays an essential role in the performance of modern dewatering equipment such as paste thickeners and filters. Since compressibility of mineral suspensions is affected by interparticle forces, investigating the forces may lead to find a practical solution to enhance the compressibility of suspensions. Utilizing the surfactants is an essential method to manipulate the interparticle forces and enhance the compressibility of suspension. In this work, THE EFFECT OF anionic surfactants known as Sodium dodecyl sulfate (SDS) and Sodium Lauryl Ether Sulfate (SLES) on the compressibility and filterability of tailings of iron ore processing and their mechanism of performance was investigated. In this order, Buchner funnel tests were conducted to evaluate the effect of surfactants on the compressibility and filterability of the suspension. Then, settling tests were performed to evaluate the possible interaction between the surfactants and flocculant. Finally, measurement of zeta potential, drop shape analysis, FTIR and TG-DTA tests were conducted to assess the mechanism of the surfactants performance. The results revealed that the moisture content of the filter cake reduced by three percent in the presence of surfactants. It was also found that the mechanism of surfactants performance is changing the zeta potential and making the hydrophobic solids surfaces. Eventually, an interaction observed between flocculant and surfactants which caused the settling rate increased by five times. These results are promising to enhance compressibility (in paste thickeners and filters) in the presence of these surfactants and achieving more recycled water from tailings of iron ore processing would be viable. Thus utilizing advanced tailings disposal methods such as stacking and achieving sustainable mining in the presence of SDS and SLES.