Search results for: porphyrins synthesis and modification

Authors: Pratima Kumari, Sukha Ranjan Samadder

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This research aims to contribute to the sustainable production of graphene materials by exploring the extraction of graphite from spent primary and secondary batteries. The increasing demand for graphene materials, a versatile and high-performance material, necessitates environmentally friendly methods for its synthesis. The process involves a well-planned methodology, beginning with the gathering and categorization of batteries, followed by the disassembly and careful removal of graphite from anode structures. The use of environmentally friendly solvents and mechanical techniques ensures an efficient and eco-friendly extraction of graphite. Advanced approaches such as the modified Hummers' method and chemical reduction process are utilized for the synthesis of graphene materials, with a focus on optimizing parameters. Various analytical techniques such as Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, and Raman spectroscopy were employed to validate the quality and structure of the produced graphene materials. The major findings of this study reveal the successful implementation of the methodology, leading to the production of high-quality graphene materials suitable for advanced material applications. Thorough characterization using various advanced techniques validates the structural integrity and purity of the graphene. The economic viability of the process is demonstrated through a comprehensive economic analysis, highlighting the potential for large-scale production. This research contributes to the field of sustainable production of graphene materials by offering a systematic methodology that efficiently transforms spent batteries into valuable graphene resources. Furthermore, the findings not only showcase the potential for upcycling electronic waste but also address the pressing need for environmentally conscious processes in advanced material synthesis.

Keywords: spent primary batteries, spent secondary batteries, graphite extraction, advanced material synthesis, circular economy approach

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Authors: Sarra Boughaba

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The α-aminophosphonates have received considerable attention in organic and medicinal chemistry because of their structural resemblance with α-amino acids. They are used as antitumor agents, anti-inflammatory and antibiotics. As a result, a number of procedures have been developed for their synthesis. However, many of these methods suffer from some disadvantages such as long reaction times, environmental pollution caused by utilization of organic solvents, and expensive catalyst. On the other hand, thiazole components, particularly 2-aminothiazole is an important class of heterocyclic compounds. They appear in the structure of natural products and biologically actives compounds, thiamine (vitamin-B), and some antibiotics drugs (penicillin, micrococcin). In the past few years, heteropolyacids have received great attention as environmentally benign catalysts for organic synthetic processes, they possess unique physicochemical properties, such as super-acidity, high thermal and chemical stability, ability to accept and release electrons and high proton mobility, and the possibility of varying their acidity and oxidizing potential. In this study, an efficient and eco-friendly process has been developed for the synthesis of α-aminophosphonates containing aminothiazole moiety via Kabachnik-Field reaction catalyzed by H₆P₂W₁₈O₆₂.14H₂O as reusable catalyst, by condensation of aromatic aldehydes, 2-aminothiazole and triethylphosphite under free conditions. The X-ray crystallographic data of obtained compounds were provided. The main advantages of our protocol include the absence of solvent in the reaction, easy work-up, short reaction time, atom-economy and reusability of catalyst without significant loss of its activity.

Keywords: aminophosphonates, green synthesis, H₆P₂W₁₈O₆₂.14H₂O catalyst, x-ray study

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Authors: Houria Hamitouche, Abdellah Khelifa

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Quaternary ammonium salts (QACs) are the most common cationic surfactants of natural or synthetic origin usually. They possess one or more hydrophobic hydrocarbon chains and hydrophilic cationic group. In fact, the hydrophobic groups are derived from three main sources: petrochemicals, vegetable oils, and animal fats. These QACs have attracted the attention of chemists for a long time, due to their general simple synthesis and their broad application in several fields. They are important as ingredients of cosmetic products and are also used as corrosion inhibitors, in emulsion polymerization and textile processing. Within biological applications, QACs show a good antimicrobial activity and can be used as medicines, gene delivery agents or in DNA extraction methods. The 2004 worldwide annual consumption of QACs was reported as 500,000 tons. The petroleum product is considered a true reservoir of a variety of chemical species, which can be used in the synthesis of quaternary ammonium salts. The purpose of the present contribution is to synthesize the quaternary ammonium salts by Menschutkin reaction, via chloromethylation/quaternization sequences, from Algerian petroleum products namely: reformate, light naphtha and kerosene and characterize.

Keywords: quaternary ammonium salts, reformate, light naphtha, kerosene

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Authors: Abdelhadi Adam Salih Denei

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Silver nanoparticles (AgNPs) have been used in cancer therapy, and the area of nanomedicine has made unheard-of strides in recent years. A thorough summary of the development and assessment of AgNPs for their possible use in the fight against cancer is the goal of this review. Targeted delivery methods have been designed to optimise therapeutic efficacy by using AgNPs' distinct physicochemical features, such as their size, shape, and surface chemistry. Firstly, the study provides an overview of the several synthesis routes—both chemical and green—that are used to create AgNPs. Natural extracts and biomolecules are used in green synthesis techniques, which are becoming more and more popular since they are biocompatible and environmentally benign. It is next described how synthesis factors affect the physicochemical properties of AgNPs, emphasising how crucial it is to modify these parameters for particular therapeutic uses. An extensive analysis is conducted on the anticancer potential of AgNPs, emphasising their capacity to trigger apoptosis, impede angiogenesis, and alter cellular signalling pathways. The analysis also investigates the potential benefits of combining AgNPs with currently used cancer treatment techniques, including radiation and chemotherapy. AgNPs' safety profile for use in clinical settings is clarified by a comprehensive evaluation of their cytotoxicity and biocompatibility.

Keywords: silver nanoparticles, cancer, nanocarrier system, targeted delivery

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Authors: M. A. Karakassides, M. Baikousi, A. Kouloumpis, D. Gournis

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Nanocomposites of Carbon Nanorods (CNRs) with Polystyrene (PS), have been synthesized successfully by means of in situ polymerization process and characterized. Firstly, carbon nanorods with graphitic structure were prepared by the standard synthetic procedure of CMK-3 using MCM-41 as template, instead of SBA-15, and sucrose as carbon source. In order to create an organophilic surface on CNRs, two parts of modification were realized: surface chemical oxidation (CNRs-ox) according to the Staudenmaier’s method and the attachment of octadecylamine molecules on the functional groups of CNRs-ox (CNRs-ODA The nanocomposite materials of polystyrene with CNRs-ODA, were prepared by a solution-precipitation method at three nanoadditive to polymer loadings (1, 3 and 5 wt. %). The as derived nanocomposites were studied with a combination of characterization and analytical techniques. Especially, Fourier-transform infrared (FT-IR) and Raman spectroscopies were used for the chemical and structural characterization of the pristine materials and the derived nanocomposites while the morphology of nanocomposites and the dispersion of the carbon nanorods were analyzed by atomic force and scanning electron microscopy techniques. Tensile testing and thermogravimetric analysis (TGA) along with differential scanning calorimetry (DSC) were also used to examine the mechanical properties and thermal stability -glass transition temperature of PS after the incorporation of CNRs-ODA nanorods. The results showed that the thermal and mechanical properties of the PS/ CNRs-ODA nanocomposites gradually improved with increasing of CNRs-ODA loading.

Keywords: nanocomposites, polystyrene, carbon, nanorods

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Authors: Kashif Jabbar

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Milk adulteration is a global concern, and the current study was plan to synthesize Selenium nanoparticles by green method using plant extract of garlic, Allium Sativum, and to characterize Selenium nanoparticles through different analytical techniques and to apply Selenium nanoparticles as fast and easy technique for the detection of salicylic acid in milk. The highly selective, sensitive, and quick interference green synthesis-based sensing of possible milk adulterants i.e., salicylic acid, has been reported here. Salicylic acid interacts with nanoparticles through strong bonding interactions, hence resulting in an interruption within the formation of selenium nanoparticles which is confirmed by UV-VIS spectroscopy, scanning electron microscopy, and x-ray diffraction. This interaction in the synthesis of nanoparticles resulted in transmittance wavelength that decrease with the increasing amount of salicylic acid, showing strong binding of selenium nanoparticles with adulterant, thereby permitting in-situ fast detection of salicylic acid from milk having a limit of detection at 10-3 mol and linear coefficient correlation of 0.9907. Conclusively, it can be draw that colloidal selenium could be synthesize successfully by garlic extract in order to serve as a probe for fast and cheap testing of milk adulteration.

Keywords: adulteration, green synthesis, selenium nanoparticles, salicylic acid, aggregation

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Authors: Mai M. Khalaf, Hany M. Abd El-Lateef

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A new good application for the sol gel method is to improve the corrosion inhibition properties of carbon steel by the dip coating method of Nano TiO2 films and its modification with Poly Ethylene Glycol (PEG). The prepared coating samples were investigated by different techniques, X-ray diffraction, Scanning Electron Microscopy (SEM), transmission electron microscopy and Energy Dispersive X-ray Spectroscopy (EDAX). The corrosion inhibition performance of the blank carbon steel and prepared coatings samples were evaluated in 0.5 M H2SO4 by using Electrochemical Impedance Spectroscopy (EIS) and potentiodynamic polarization measurements. The results showed that corrosion resistance of carbon steel increases with increasing the number of coated layers of both nano–TiO2 films and its modification of PEG. SEM-EDAX analyses confirmed that the percentage atomic content of iron for the carbon steel in 0.5 M H2SO4 is 83% and after the deposition of the steel in nano TiO2 sol and that with PEG are 94.3% and 93.7% respectively.

Keywords: dip-coatings, corrosion protection, sol gel, TiO2 films, PEG

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Authors: Dibyendu Adak, Saroj Mandal

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The fly ash based geopolymer concrete generally requires heat activation after casting, which has been considered as an important limitation for its practical application. Such limitation can be overcome by a modification in the process at the time of mixing of ingredients (fly and activator fluid) for geopolymer concrete so that curing can be made at ambient temperature. This process modified geopolymer concrete shows an appreciable improvement in structural performance compared to conventional heat cured geopolymer concrete and control cement concrete. The improved durability performance based on water absorption, sulphate test, and RCPT is also noted. The microstructural properties analyzed through Field Emission Scanning Electron Microscope (FESEM) with Energy Dispersive X-ray Spectroscopy (EDS) and X-ray Diffraction (XRD) techniques show the better interaction of fly ash and activator solution at early ages for the process modified geopolymer concrete. This accelerates the transformation of the amorphous phase of fly ash to the crystalline phase.

Keywords: fly ash, geopolymer concrete, process modification, structural properties, durability, micro-structures

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Authors: Mamdouh Abu-Zaied, K. Mohamed, Galal A. Nawwar

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Microwave-assisted synthesis of a new class of pyridine or purine thioglycoside analogs from readily available starting materials has been described. The key step of this protocol is the formation of sodium pyridine 4-thiolate 4 and pyrazolo[1,5-a]pyrimidine-7-thiolate 5 derivatives via condensation of 1 with cyanoacetanilide derivative 2 or 5-aminopyrazole derivative 3 respectively under microwave irradiation, followed by coupling with halo sugars to give the corresponding pyridine and purine thioglycoside analogs. The obtained compounds were evaluated in vitro against lung (A549), colon (HCT116), liver (HEPG2), and MCF-7(breast) cancer cell lines. Some of them recorded promising activities.

Keywords: antitumor, cyclic sugars, pyrazoles, pyridines, pyrimidines, purines, thioglycosides

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Authors: Moataz Medhat, Essam Khalil, Hatem Haridy

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The present study investigates the flame structure of turbulent diffusion flame of synthesis fuel in a 300 KW swirl-stabilized burner. The three-dimensional model adopts a realizable k-ε turbulent scheme interacting with two-dimensional PDF combustion scheme by applying flamelet concept. The study reveals more characteristics on turbulent diffusion flame of synthesis fuel when changing the inlet air swirl number and the burner quarl angle. Moreover, it concerns with studying the effect of flue gas recirculation and staging with taking radiation effect into consideration. The comparison with natural gas was investigated. The study showed two zones of recirculation, the primary one is at the center of the furnace, and the location of the secondary one varies by changing the quarl angle of the burner. The results revealed an increase in temperature in the external recirculation zone as a result of increasing the swirl number of the inlet air stream. Also, it was found that recirculating part of the combustion products decreases pollutants formation especially nitrogen monoxide. The predicted results showed a great agreement when compared with the experiments.

Keywords: gas turbine, syngas, analysis, recirculation

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Authors: F. Ghafoori-Najafabadi, R. Sarraf-Mamoory, N. Riahi-Noori

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In this study, nanocrystalline CeO2-MgO powders were synthesized by combustion reactions using citric acid, ethylene glycol, and glycine as different fuels and nitrate as an oxidant. The powders obtained with different kinds of fuels are characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The size and morphology of the particles and the extent of agglomeration in the powders were studied using SEM analysis. It is observed that the variation of fuel has an intense influence on the particle size and morphology of the resulting powder. X-ray diffraction revealed that any combined phases were observed, and that MgO and CeO2 phases were formed, separately.

Keywords: nanoparticle, combustion synthesis, CeO2-MgO, nano-powder

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Authors: Mahnoor Khan, Bashir Ahmad, Khizar Hayat, Saad Ahmad Khan, Laiba Ahmad, Shumaila Bashir, Abid Ali Khan

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The objective of this study was to synthesize the smallest possible size of ZnO NPs using a modified wet chemical synthesis method and to prepare core shell using polyethylene glycol (PEG) as shell material. Advanced and sophisticated techniques were used to confirm the synthesis, size, and shape of these NPs. Rounded, clustered NPs of size 5.343 nm were formed. Both the plain and core shell NPs were tested against MDR bacteria (E. cloacae, E. amnigenus, Shigella, S. odorifacae, Citrobacter, and E. coli). Both of the NPs showed excellent antibacterial properties, whereas E. cloacae showed maximum zone of inhibition of 16 mm, 27 mm, and 32 mm for 500 μg/ml, 1000 μg/ml, and 1500 μg/ml, respectively for plain ZnO NPs and 18 mm, 28 mm and 35 mm for 500 μg/ml, 1000 μg/ml and 1500 μg/ml for core shell NPs. These NPs were also biocompatible on human red blood cells showing little hemolysis of only 4% for 70 μg/ml for plain NPs and 1.5% for 70 μg/ml for core shell NPs. Core shell NPs were highly biocompatible because of the PEG. Their therapeutic effect as photosensitizers in photodynamic therapy (PDT) for cancer treatment was also monitored. The cytotoxicity of ZnO and PEG-ZnO was evaluated using MTT assay. Our results demonstrated that these NPs could generate ROS inside tumor cells after irradiation which in turn initiates an apoptotic pathway leading to cell death hence proving to be an effective candidate for PDT.

Keywords: ZnO, hemolysis, cytotoxiciy assay, photodynamic therapy, antibacterial

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Authors: Ali Rabah

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This research received no grant or financial support from any public, commercial, or none governmental agency. The author conducted this work as part of his normal research activities as a professor of Chemical Engineering at the University of Khartoum, Sudan. Abstract While fossil oil reserves have been receding, the demand for diesel and gasoline has been growing. In recent years, syngas of biomass origin has been emerging as a viable feedstock for Fischer-Tropsch (FT) synthesis, a process for manufacturing synthetic gasoline and diesel. This paper reports the optimization of syngas quality to match FT synthesis requirements. The optimization model maximizes the thermal efficiency under the constraint of H2/CO≥2.0 and operating conditions of equivalent ratio (0 ≤ ER ≤ 1.0), steam to biomass ratio (0 ≤ SB ≤ 5), and gasification temperature (500 °C ≤ Tg ≤ 1300 °C). The optimization model is executed using the optimization section of the Model Analysis Tools of the Aspen Plus simulator. The model is tested using eleven (11) types of MSW. The optimum operating conditions under which the objective function and the constraint are satisfied are ER=0, SB=0.66-1.22, and Tg=679 - 763°C. Under the optimum operating conditions, the syngas quality is H2=52.38 - 58.67-mole percent, LHV=12.55 - 17.15 MJ/kg, N2=0.38 - 2.33-mole percent, and H2/CO≥2.15. The generalized optimization model reported could be extended to any other type of biomass and coal. Keywords: MSW, Syngas, Optimization, Fischer-Tropsch.

Keywords: syngas, MSW, optimization, Fisher-Tropsh

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Authors: Rotimi Larayetana, Yahaya Abdulrazaq, Oladunni O. Falola, Abayomi Ajayi

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The aim of this study was to perform green synthesis of silver nanoparticles (AgNPs) with the aqueous extract of Moringa oleifera Lam (M oleifera) leaves and determine its effects on benign prostatic hyperplasia in Wistar rats. Silver nitrate (AgNO₃) solution was reduced using the aqueous extract of Moringa oleifera Lam leaves, the resultant biogenic AgNPs were characterized by Fourier transformed infrared spectrophotometric, SEM, TEM and X-ray diffraction analysis. Animal experiments involved thirty (30) adult male Wistar rats randomly divided into five groups (A to E; n ₌ 5). Group A received only subcutaneous injection of olive oil daily while the other groups got 3 mg/kg/daily of testosterone propionate (TP) subcutaneously plus 50 mg/kg/daily of AgNPs intraperitoneally (B), 3 mg/kg/daily of TP plus 25 mg/kg/daily of AgNPs (C), 3 mg/kg/daily of TP only (D) and 25 mg/kg/daily of AgNPs only (E). The animals were sacrificed after 14 days, and the prostate gland, liver, and kidney were processed for histological analysis. Phytochemical screening and GC-MS analysis were performed to determine the composition of the M oleifera extract used. Biogenic AgNPs with an average diameter of 23 nm were synthesized. Biogenic AgNPs ameliorated hormone-induced prostate enlargement, and the inhibition of prostatic hypertrophy could be due to the presence of a significant amount of plant fatty acids and phytosterols in the aqueous extract of M oleifera extract. However, the administration of biogenic AgNPs at higher doses impacted negatively on the cytoarchitecture of the liver. Green synthesis of AgNPs with the aqueous extract of Moringa oleifera might be beneficial for the treatment of BPH.

Keywords: benign prostatic hyperplasia, biogenic synthesis, Moringa oleifera, silver nanoparticles, testosterone

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Authors: Kohei Yamamoto, Jae-Ho Kim, Susumu Yonezawa

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The surface of polyethylene terephthalate (PET) was modified with fluorine gas at 25 ℃ and 100 Torr for one h. Moreover, the effect of ethanol washing on surface modification was investigated in this study. The surface roughness of the fluorinated and washed PET samples was approximately six times larger than that (0.6 nm) of the untreated thing. The results of Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy showed that the bonds such as -C=O and -C-Hx derived from raw PET decreased and were converted into fluorinated bonds such as -CFx after surface fluorination. Even after washing with ethanol, the fluorinated bonds stably existed on the surface. These fluorinated bonds showed higher electronegativity according to the zeta potential results. The negative surface charges were increased by washing the ethanol, and it caused to increase in the number of polar groups such as -CHF- and -C-Fx. The fluorinated and washed surface of PET could promote the adsorption of Ag+ ions in AgNO₃ solution because of the increased surface roughness and the negatively charged surface.

Keywords: Ag+ ions adsorption, polyethylene terephthalate, surface fluorination, zeta potential

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Authors: V. E. Messerle, O. A. Lavrichshev, A. B. Ustimenko

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Currently and in the foreseeable future (up to 2100), the global economy is oriented to the use of organic fuel, mostly, solid fuels, the share of which constitutes 40% in the generation of electric power. Therefore, the development of technologies for their effective and environmentally friendly application represents a priority problem nowadays. This work presents the results of thermodynamic and experimental investigations of plasma technology for processing of low-grade coals. The use of this technology for producing target products (synthesis gas, hydrogen, technical carbon, and valuable components of mineral mass of coals) meets the modern environmental and economic requirements applied to basic industrial sectors. The plasma technology of coal processing for the production of synthesis gas from the coal organic mass (COM) and valuable components from coal mineral mass (CMM) is highly promising. Its essence is heating the coal dust by reducing electric arc plasma to the complete gasification temperature, when the COM converts into synthesis gas, free from particles of ash, nitrogen oxides and sulfur. At the same time, oxides of the CMM are reduced by the carbon residue, producing valuable components, such as technical silicon, ferrosilicon, aluminum and carbon silicon, as well as microelements of rare metals, such as uranium, molybdenum, vanadium, titanium. Thermodynamic analysis of the process was made using a versatile computation program TERRA. Calculations were carried out in the temperature range 300 - 4000 K and a pressure of 0.1 MPa. Bituminous coal with the ash content of 40% and the heating value 16,632 kJ/kg was taken for the investigation. The gaseous phase of coal processing products includes, basically, a synthesis gas with a concentration of up to 99 vol.% at 1500 K. CMM components completely converts from the condensed phase into the gaseous phase at a temperature above 2600 K. At temperatures above 3000 K, the gaseous phase includes, basically, Si, Al, Ca, Fe, Na, and compounds of SiO, SiH, AlH, and SiS. The latter compounds dissociate into relevant elements with increasing temperature. Complex coal conversion for the production of synthesis gas from COM and valuable components from CMM was investigated using a versatile experimental plant the main element of which was plug and flow plasma reactor. The material and thermal balances helped to find the integral indicators for the process. Plasma-steam gasification of the low-grade coal with CMM processing gave the synthesis gas yield 95.2%, the carbon gasification 92.3%, and coal desulfurization 95.2%. The reduced material of the CMM was found in the slag in the form of ferrosilicon as well as silicon and iron carbides. The maximum reduction of the CMM oxides was observed in the slag from the walls of the plasma reactor in the areas with maximum temperatures, reaching 47%. The thusly produced synthesis gas can be used for synthesis of methanol, or as a high-calorific reducing gas instead of blast-furnace coke as well as power gas for thermal power plants. Reduced material of CMM can be used in metallurgy.

Keywords: gasification, mineral mass, organic mass, plasma, processing, solid fuel, synthesis gas, valuable components

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Authors: Hassan Bohra, Mingfeng Wang

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Conjugated porous polymers (CPPs) are amorphous, insoluble and highly robust organic semiconductors that have been largely synthesized by traditional transition-metal catalyzed reactions. The distinguishing feature of CPP materials is that they combine microporosity and high surface areas with extended conjugation, making them ideal for versatile applications such as separation, catalysis and energy storage. By applying a modular approach to synthesis, chemical and electronic properties of CPPs can be tailored for specific applications making these materials economical alternatives to inorganic semiconductors. Direct arylation - an environmentally benign alternative to traditional polymerization reactions – is one such reaction that extensively over the last decade for the synthesis of linear p-conjugated polymers. In this report, we present the synthesis and characterization of a new series of robust conjugated porous polymers synthesized by facile direct arylation polymerization of thiophene-flanked acceptor building blocks with multi-brominated aryls with different geometries. We observed that the porosities and morphologies of the polymers are determined by the chemical structure of the aryl bromide used. Moreover, good control of the optical bandgap in the range 2.53 - 1.3 eV could be obtained by using different building blocks. Structure-property relationships demonstrated in this study suggest that direct arylation polymerization is an attractive synthetic tool for the rational design of porous organic materials with tunable photo-physical properties for applications in photocatalysis, energy storage and conversion.

Keywords: direct arylation, conjugated porous polymers, triazine, photocatalysis

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Authors: Artem A. Krylov

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Instrumental seismological researches in water areas are complicated and expensive, that leads to the lack of strong motion records in most offshore regions. In the same time the number of offshore industrial infrastructure objects, such as oil rigs, subsea pipelines, is constantly increasing. The empirical Green’s function technique proved to be very effective for accelerograms synthesis under the conditions of poorly described seismic wave propagation medium. But the selection of suitable small earthquake record in offshore regions as an empirical Green’s function is a problem because of short seafloor instrumental seismological investigation results usually with weak micro-earthquakes recordings. An approach based on moving average smoothing in the frequency domain is presented for preliminary processing of weak micro-earthquake records before using it as empirical Green’s function. The method results in significant waveform correction for modeled event. The case study for 2009 L’Aquila earthquake was used to demonstrate the suitability of the method. This work was supported by the Russian Foundation of Basic Research (project № 18-35-00474 mol_a).

Keywords: accelerogram synthesis, empirical Green's function, marine seismology, microearthquakes

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Authors: Yalçın Kılıç, İbrahim Kani

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The conversion of hydrocarbons to carbonyl compounds by oxidation reaction is one of the most important reactions in the synthesis of fine chemicals. As a result of the oxidation of hydrocarbons containing aliphatic sp3-CH groups in their structures, aldehydes, ketones or carboxylic acids can be obtained. In this study, OSSO-type 2,2'-[1,4-butanedylbis(thio)]bis-benzoic acid (tsabutH2) ligand and [Zn(µ-tsabut)(phen)]n complex (where phen = 1,10-phenantroline) were synthesized and their structures were characterized by single crystal x-ray diffraction method. The catalytic efficiency of the complex in the catalytic oxidation studies of organic compounds such as cyclohexane, ethylbenzene, diphenylmethane, and p-xylene containing sp3-C-H in its structure was investigated.

Keywords: metal complex, OSSO-type ligand, catalysis, oxidation

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Authors: Jenaidullah Batur, Sebghatullah Mudaber

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Currently, there is a list of catalysts that can reduce CO₂ to valuable chemicals and fuels, among them metal oxides such as TiO₂, known as promising photocatalysts to produce hydrogen and CO unless they are at an earlier age and still need to promote activity to able for produce fabricated values. Herein, in this work, we provided a novel, facile and eco-friendly synthesis strategy to synthesize more effective TiO₂-organic composite materials to selectively reduce CO₂ to CO. In this experiment, commercial nanocrystalline TiO₂ and saccharin with Li (LiBr, LiCl) were synthesized using the facile physical grinding in the motel pestle for 10 minutes, then added 10 mL of deionized water (18.2 megaohms) on the 300mg composite catalyst before samples moving for hydrothermal heating for 24 hours at 80 C in the oven. Compared with nanosized TiO₂, the new TiO₂-Sac-Li indeed displays a high CO generation rate of 70.83 μmol/g/h, which is 7 times higher than TiO₂, which shows enhancement in CO₂ reduction and an apparent improvement in charge carrier dynamic. The CO₂ reduction process at the gas-solid interface on TiO₂-Sac-Li composite semiconductors is investigated by functional calculations and several characterization methods. The results indicate that CO₂ can be easily activated by the TiO₂-Sac-Li atoms on the surface. This work innovatively investigates CO₂ reduction in novel composite materials and helps to broaden the applications of composite materials semiconductors.

Keywords: green chemistry, green synthesis, TiO₂, photocatalyst

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Authors: Sarah Triller, Ferdi Schüth

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The challenges encountered in upscaling the mechanochemical synthesis of high surface area α-alumina are investigated in this study. After lab-scale experiments in shaker mills and planetary ball mills, the optimization of reaction parameters of the conversion in the smallest vessel of a scalable mill, named Simoloyer, was developed. Furthermore, the future perspectives by scaling up the conversion in several steps are described. Since abrasion from the steel equipment can be problematic, the process was transferred to a ceramically lined mill, which solved the contamination problem. The recovered alpha-alumina shows a high specific surface area in all investigated scales.

Keywords: mechanochemistry, scale-up, ball milling, ceramic lining

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Authors: Kobauri Sophio, Kantaria Tengiz, Tugushi David, Puiggali Jordi, Katsarava Ramaz

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Biodegradable biomaterials (BB) are of high interest for numerous applications in modern medicine as resorbable surgical materials and drug delivery systems. This kind of materials can be cleared from the body after the fulfillment of their function that excludes a surgical intervention for their removal. One of the most promising BBare amino acids based biodegradable poly(ester amide)s (PEAs) which are composed of naturally occurring (α-amino acids) and non-toxic building blocks such as fatty diols and dicarboxylic acids. Key bis-nucleophilic monomers for synthesizing the PEAs are diamine-diesters-di-p-toluenesulfonic acid salts of bis-(α-amino acid)-alkylenediesters (TAADs) which form the PEAs after step-growth polymerization (polycondensation) with bis-electrophilic counter-partners - activated diesters of dicarboxylic acids. The PEAs combine all advantages of the 'parent polymers' – polyesters (PEs) and polyamides (PAs): Ability of biodegradation (PEs), a high affinity with tissues and a wide range of desired mechanical properties (PAs). The scopes of applications of thePEAs can substantially be expanded by their functionalization, e.g. through the incorporation of hydrophobic fragments into the polymeric backbones. Hydrophobically modified PEAs can form non-covalent adducts with various compounds that make them attractive as drug carriers. For hydrophobic modification of the PEAs, we selected so-called 'Azlactone Method' based on the application of p-phenylene-bis-oxazolinons (bis-azlactones, BALs) as active bis-electrophilic monomers in step-growth polymerization with TAADs. Interaction of BALs with TAADs resulted in the PEAs with low MWs (Mw2,800-19,600 Da) and poor material properties. The high-molecular-weight PEAs (Mw up to 100,000) with desirable material properties were synthesized after replacement of a part of BALs with activated diester - di-p-nitrophenylsebacate, or a part of TAAD with alkylenediamine – 1,6-hexamethylenediamine. The new hydrophobically modified PEAs were characterized by FTIR, NMR, GPC, and DSC. It was shown that after the hydrophobic modification the PEAs retain the biodegradability (in vitro study catalyzed by α-chymptrypsin and lipase), and are of interest for constructing resorbable surgical and pharmaceutical devices including drug delivering containers such as microspheres. The new PEAs are insoluble in hydrophobic organic solvents such as chloroform or dichloromethane (swell only) that allowed elaborating a new technology of fabricating microspheres.

Keywords: amino acids, biodegradable polymers, bis-azlactones, microspheres

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Authors: Steadyman Chikumba, Vasudeva Vereedhi Rao

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This paper reports on the synthesis of FeCrCoNiZn and its characterisation using SEM and nanoindentation. The high entropy alloy FeCrCoNiZn was fabricated using spark plasma sintering at a temperature of 1100ᵒC from powders mixed for 9 hours. The powders mixture was equimolar, and the resultant microstructure had a single crystalline structure when studied under SEM. Several nano Vickers hardness measurements were taken on a polished surface etched by Nital solution. The hardness ranged from 711 Vickers to a maximum of 1773.2. The alloy FeCrCoNiZn showed a nano hardness of 1070 Vickers and a modulus of elasticity of 460.4 MPa. The process managed to fabricate a very hard material that can find applications where wear resistance is desired.

Keywords: high entropy alloy, FeCrVNiZn, nanohardness, SEM

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Authors: Alieh Farshbaf

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Introduction: Current anti-retroviral drugs have some restrictions for treatment of HIV-1 infection. The efficacy of retroviral drugs is not same in different infected patients and the virus rebound from latent reservoirs after stopping them. Recently, the engineering of stem cells and gene therapy provide new approaches to eliminate some drug problems by induction of resistance to HIV-1. Literature review: Up to now, AIDS-restriction genes (ARGs) were suitable candidate for gene and cell therapies, such as cc-chemokine receptor-5 (CCR5). In this manner, CCR5 provide effective cure in Berlin and Boston patients by inducing of HIV-1 resistance with allogeneic stem cell transplantation. It is showed that Zinc Finger Nuclease (ZFN) could induce HIV-1 resistance in stem cells of infected patients by homologous recombination or non-end joining mechanism and eliminate virus loading after returning the modified cells. Then, gene modification by HIV restriction factors, as TRIM5, introduced another gene candidate for HIV by interfering in infection process. These gene modifications/editing provided by stem cell futures that improve treatment in refractory disease such as HIV-1. Conclusion: Although stem cell transplantation has some complications, but in compare to retro-viral drugs demonstrated effective cure by elimination of virus loading. On the other hand, gene therapy is cost-effective for an infected patient than retroviral drugs payment in a person life-long. The results of umbilical cord blood stem cell transplantation showed that gene and cell therapy will be applied easier than previous treatment of AIDS with high efficacy.

Keywords: stem cell, AIDS, gene modification, cell engineering

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Authors: Yuxuan Yang, Zhaoping Zhong

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Municipal solid waste and sludge are important sources of waste energy and their proper disposal is of great importance. Pyrolysis can fully decompose solid wastes and sludge, and the pyrolysis products (charcoal, oil and gas) have important recovery values. Due to the complex composition of solid wastes and sludge, the pyrolysis process at high temperatures is prone to heavy metal emissions, which are harmful to humans and the environment and reduce the safety of pyrolysis products. In this paper, heavy metal emissions during pyrolysis of municipal sewage sludge, paper mill sludge, municipal domestic waste, and aged refuse at 450-650°C were investigated and the emissions and hazards of heavy metals (Pb, Cr, Cd, Cu and Zn) were effectively reduced by adding modified vermiculite as an additive. The vermiculite was modified by intercalation with cetyltrimethylammonium bromide, which resulted in more than twice the original layer spacing of the vermiculite. Afterward, the interpolated vermiculite was made into vermiculite flakes by exfoliation modification. After that, the expansion rate of vermiculite flakes was increased by Mg2+ modification and thermal activation. The expanded vermiculite flakes were acidified to improve the textural characteristics of the vermiculite. The modified vermiculite was analysed by XRD, FT-IR, BET and SEM to clarify the modification effect. The incorporation of modified vermiculite resulted in more than 80% retention of all heavy metals at 450°C. Cr, Cu and Zn were better retained than Pb and Cd. The incorporation of modified vermiculite effectively reduced the risk of heavy metals, and all risks were low for Pb, Cr, Cu and Zn. The toxicity of all heavy metals was greatly reduced by the incorporation of modified vermiculite and the morphology of heavy metals was transformed from Exchangeable and acid-soluble (F1) and Reducible (F2) to Oxidizable (F3) and Residual (F4). In addition, the increase in temperature favored the stabilization of heavy metal forms. This study provides a new insight into the cleaner use of energy and the safe management of solid waste.

Keywords: heavy metal, pyrolysis, vermiculite, solid waste

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Authors: Mudawi M. Nour

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Background: Now a days, the multidisciplinary scientific research conception in the field of nanotechnology has witnessed development with regard to the numerous applications and synthesis of nanomaterials. Objective: The current investigation has been conducted with the main focus on the green synthesis of silver nanoparticles from the leaves of Salvadora persica and its antibacterial activity against MDR pathogens E. coli and S. aureus. Methodology: Silver nanoparticles (AgNPs) were prepared after addition of aqueous extract of Salvadora persica leaves. The UV-Vis spectrophotometer, Transmission Electron Microscopy (TEM), zeta potential and Scanning Electron Microscopy (SEM) were employed to detect the particle size and morphology, besides Fourier transform infra-red spectrometer (FTIR) analysis was performed to determine the capping and stabilizing agents in the extract. Antibacterial assay for the biogenic AgNPs was conducted against E. coli and S. aureus. Results: Color change of the mixture from yellow to dark brown is the first indication to AgNPs formation. Furthermore, 420 nm was the peak value for UV-Vis spectroscopy absorption of the mixture. Besides, TEM and SEM micrographs showed wide variability in the diameter of smaller NPs aggregated together with spherical shapes, and zeta sizer showed about 153.3 nm as an average size of nanoparticles. Microbial suppression was noticed for the tested microorganisms. Furthermore, with the help of FTIR analysis, the biomolecules that act as capping and stabilizing agents of AgNPs are proteins and phenols present in the plant extract. Conclusion: Salvadora persica leaves extract act as a reducing and stabilizing agent for the synthesis of AgNPs, keeping its ability to suppress the MDR pathogen.

Keywords: green synthesis, FTIR, MDR pathogen, salvadora persica

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Authors: Justice Zakhele Msomi

Abstract:

Nanoparticles of CdFe2O4 with particle size of about 10 nm have been synthesized by high energy ball milling and co-precipitation processes. The synthesis route appears to have some effects on the properties. The compounds have been characterized by X-ray diffraction, Fourier Transform Infrared (FTIR), transmission electron microscopy (TEM), Mössbauer and magnetization measurements. The XRD pattern of CdFe2O4 provides information about single-phase formation of spinel structure with cubic symmetry. The FTIR measurements between 400 and 4000 cm-1 indicate intrinsic cation vibration of the spinel structure. The Mössbauer spectra were recorded at 4 K and 300 K. The hyperfine fields appear to be highly sensitive on particle size. The evolution of the properties as a function of particle size is also presented.

Keywords: ferrite, nanoparticles, magnetization, Mössbauer

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Authors: Shradha S. Binani, Pravin S. Bodke, Ravi V. Joat

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An efficient method has been described for the synthesis of 6-(substituted aryl)-4-(2'- hydroxy-5'-chlorophenyl)-1, 6-dihydropyrimidine-2-thiol, as a beneficial antibacterial and antifungal agents. The diketones of title compounds were synthesized in four steps and subsequently these diketones were further reacted with thiourea in the presence of DMF, which led to the formation of dihydropyrimidine derivatives 5 (a-f). Compounds 5 (a-f) were screened for their in vitro antibacterial and antifungal activity by agar well method. Compounds 5b, 5c, 5e, and 5f were exhibited significant antimicrobial potential against tested strains at 50ug/ml and 100ug/ml concentrations. Six novel dihydropyrimidine analogues have been synthesized, characterized and found to be promising antibacterial and antifungal agents.

Keywords: diketones, dihyropyrimidine, antimicrobial activity, thiol group

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Authors: Nikolai A. Khlebnikov, Vladimir N. Krasilnikov, Evgenii V. Polyakov, Anastasia A. Maltceva

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Carbon materials with advanced surfaces are widely used both in modern industry and in environmental protection. The physical-chemical nature of these materials is determined by the morphology of primary atomic and molecular carbon structures, which are the basis for synthesizing the following materials: zero-dimensional (fullerenes), one-dimensional (fiber, tubes), two-dimensional (graphene) carbon nanostructures, three-dimensional (multi-layer graphene, graphite, foams) with unique physical-chemical and functional properties. Experience shows that the microscopic morphological level is the basis for the creation of the next mesoscopic morphological level. The dependence of the morphology on the chemical way and process prehistory (crystallization, colloids formation, liquid crystal state and other) is the peculiarity of the last called level. These factors determine the consumer properties of carbon materials, such as specific surface area, porosity, chemical resistance in corrosive environments, catalytic and adsorption activities. Based on the developed ideology of thin precursor synthesis, the authors discuss one of the approaches of the porosity control of carbon-containing materials with a given aggregates morphology. The low-temperature thermolysis of precursors in a gas environment of a given composition is the basis of the above-mentioned idea. The processes of carbothermic precursor synthesis of two different compounds: tungsten carbide WC:nC and zinc oxide ZnO:nC containing an impurity phase in the form of free carbon were selected as subjects of the research. In the first case, the transition metal (tungsten) forming carbides was the object of the synthesis. In the second case, there was selected zinc that does not form carbides. The synthesis of both kinds of transition metals compounds was conducted by the method of precursor carbothermic synthesis from the organic solution. ZnO:nC composites were obtained by thermolysis of succinate Zn(OO(CH2)2OO), formate glycolate Zn(HCOO)(OCH2CH2O)1/2, glycerolate Zn(OCH2CHOCH2OH), and tartrate Zn(OOCCH(OH)CH(OH)COO). WC:nC composite was synthesized from ammonium paratungstate and glycerol. In all cases, carbon structures that are specific for diamond- like carbon forms appeared on the surface of WC and ZnO particles after the heat treatment. Tungsten carbide and zinc oxide were removed from the composites by selective chemical dissolution preserving the amorphous carbon phase. This work presents the results of investigating WC:nC and ZnO:nC composites and carbon nanopowders with tubular, tape, plate and onion morphologies of aggregates that are separated by chemical dissolution of WC and ZnO from the composites by the following methods: SEM, TEM, XPA, Raman spectroscopy, and BET. The connection between the carbon morphology under the conditions of synthesis and chemical nature of the precursor and the possibility of regulation of the morphology with the specific surface area up to 1700-2000 m2/g of carbon-structured materials are discussed.

Keywords: carbon morphology, composite materials, precursor synthesis, tungsten carbide, zinc oxide

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Authors: Luvindran Sugumaran, Mohd Nashrul Mohd Zubir, Kazi Md Salim Newaz, Tuan Zaharinie Tuan Zahari, Suazlan Mt Aznam, Aiman Mohd Halil

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With the fast growth of integrated circuits and the trend towards making electronic devices smaller, the heat dissipation load of electronic devices has continued to go over the limit. The high heat flux element would not only harm the operation and lifetime of the equipment but would also impede the performance upgrade brought about by the iteration of technological updates, which would have a direct negative impact on the economic and production cost benefits of rising industries. Hence, in high-tech industries like radar, information and communication, electromagnetic power, and aerospace, the development and implementation of effective heat dissipation technologies were urgently required. Pool boiling is favored over other cooling methods because of its capacity to dissipate a high heat flux at a low wall superheat without the usage of mechanical components. Enhancing the pool boiling performance by increasing the heat transfer coefficient via surface modification techniques has received a lot of attention. There are several surface modification methods feasible today, but the stability and durability of surface modification are the greatest priority. Thus, laser machining is an interesting choice for surface modification due to its low production cost, high scalability, and repeatability. In this study, different patterns of laser-processed copper surfaces are fabricated to investigate the nucleate pool boiling heat transfer performance of distilled water. The investigation showed that there is a significant enhancement in the pool boiling heat transfer performance of the laser-processed surface compared to the reference surface due to the notable increase in nucleation frequency and nucleation site density. It was discovered that the heat transfer coefficients increased when both the surface area ratio and the ratio of peak-to-valley height of the microstructure were raised. It is believed that the development of microstructures on the surface as a result of laser processing is the primary factor in the enhancement of heat transfer performance.

Keywords: heat transfer coefficient, laser processing, micro structured surface, pool boiling

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