The present study reports the synthesis, characterization and corrosion inhibition effects of chitosan (CH) and its 5-chloromethyl-8-hydroxyquinoline derivative (CH-HQ) for mild steel in acidic ...medium. The synthesized CH-HQ was characterized using 1H NMR and FT-IR spectroscopic methods. Corrosion inhibition efficiencies of CH and CH-HQ were measured using electrochemical and chemical techniques. The surface protection ability of the inhibitor molecules was also ascertained by surface analysis, while computational study was used to further justify the adsorption tendencies of the molecules on mild steel surface. CH-HQwasobserved to exhibit better protection efficiency than CH, as the highest inhibition efficiencies were recorded to be 78% and 93% for CH and CH-HQ, respectively. Potentiodynamic polarization studies revealed that CH and CH-HQ are mixed-type corrosion inhibitors over the studied temperature range (298 K ± 1 to 328 K ± 1). SEM-EDS studies were performed to demonstrate the adsorption of CH and CH-HQ on the mild steel surface. Adsorption behavior of the CH and CH-HQ was also supported by UV–visible (UV–vis) spectrophotometric analyses. Monte Carlo simulations (MC) and density functional theory (DFT) calculations were carried out to corroborate the experimental results.
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In the present work, a new hydrazone compound, namely N'-(Z)-(4-chlorophenyl)methylidene-2-(5-methoxy-2-methyl-1H-indol-3-yl)acetohydrazide, noted HTH, was selected to protect carbon steel against ...corrosion in 1.0 mol/L HCl. Different chemical, electrochemical, and surface characterization techniques such as scanning electron microscope coupled with X-ray energy dispersion (SEM/EDX) were used to investigate the corrosion inhibition performance. Electrochemical data showed that the effectiveness of the inhibitor improved with increasing concentration, reaching 98% at the optimal concentration of 10-3 mol/L. The results of potentiodynamic polarization measurements showed that hydrazone acted as a mixed-type inhibitor. The EIS results showed an increase in polarization resistance accompanied by a noticeable decrease in Ceff,dl values. In the temperature range of 303 K-333 K, hydrazone protected carbon steel by 89%, showing high resistance to temperature effect. The analysis of the steel surface by SEM/EDX confirmed that the effectiveness of the hydrazone was attributed to the formation of a protective layer on the surface of the metal. Quantum chemical calculations revealed insights into the chemical reactivity of the tested hydrazone while first-principles density functional theory (DFT) and molecular dynamics (MD) simulation supported the experimental conclusions and showed outstanding adsorption ability of HTH on the Fe(110) surface. First-principles DFT simulations showed that the HTH molecule was more stable in a parallel adsorption mode.
The present research delves into a theoretical examination of phosphate chains using the density functional theory method with the RB3LYP/6-311G model. The geometry of the studied chains was ...optimized and their atomic charge densities were evaluated. Various parameters, such as HOMO and LUMO energies, energy difference (ΔE), chemical hardness, chemical potential, softness, and global electrophilicity index were thoroughly investigated. Moreover, vibrational frequencies were explored, highlighting both symmetric and asymmetric vibrations in the chains based on the computed IR and Raman spectra. Subsequently, an investigation into the Zinc ion insertion reaction in the studied phosphate chains was carried out. Several parameters were calculated to determine the electrophilic/nucleophilic character of these two constituents. The outcomes revealed that the phosphate chains display nucleophilic behavior and tend to release electrons, while the Zinc ion exhibits electrophilic tendencies and retains electrons. Notably, electron transfer occurs from the chains to the Zinc ion, with the chains acting as electron donors and the Zinc ion as an electron acceptor. The smaller overall electrophilicity gap between chain III and Zn2+ indicates the weak polar character of this reaction. Furthermore, favorable nucleophilic sites for the attack of the Zinc ion (Zn2+) on chain III were identified using the FUKUI indexes.
It has been found that the addition of certain components, despite their low concentration in raw mix, may accelerate and enhance the reactivity of the cement raw mix. The utilization of mineralizers ...to facilitate and quicken the process of clinkerization backpedals numerous years, the concept of using such mineralizers to burn normal raw mixes at a much lower temperature with the end goal of decreasing the fuel necessities of the furnace and to enhance the cement proprieties has become to be seriously considered over the most recent couple of years. The subject of this paper is to investigate the impact of calcium fluoride as mineralizer on addition during the clinkerization process of industrial raw mixtures and its effect on chemical, mineralogical, and mechanical properties of CPA Moroccan cement. Five different raw meals were utilized and were burned with 2% of calcium fluoride. The resulting clinker was analyzed by X-ray diffraction (XRD) and fluorescence spectroscopy to determine the chemical phases of the obtained clinker, and the mechanical properties of resulting CPA cement were determined. The results show that the addition of 2% of CaF2 to the clinker raw meal induced a decrease in the burning temperature and free lime, while improving the clinker phase formation and the mechanical properties of obtained cement.
Nowadays, the cement industry is the largest emitter of CO2. In 2015, cement production accounts for roughly 8% of global CO2 emissions. In order to reduce this impact, cement plants are working on ...alternative solutions, for instance, producing cement by adding additives like fly ash known for reducing the emissions of CO2 and minimizing production costs. The thermal power stations in Morocco produce more than 500 000 tons per year. For ecological and sustainable development reasons, it is desirable to recycle these quantities according to beneficial methods to their addition in the cement.
This study aims to investigate the influence of grinding fly ash on the physico-chemical and mechanical properties of fly ash blended CPJ45 cement. The addition of the fly ash particles to the grinder leads respectively to the breakage of the particles and to reduce the agglomeration effect in the balls of cement grinder. Fly ash milling was found to improve particles fineness, and increase the silica and alumina content in the cement. Furthermore, milled fly ash blended cements show higher compressive strength compared to unmilled fly ash blended cements, due to improved fly ash reactivity through their mechanical activation.
It has been found that the addition of certain components, despite their low concentration in raw mix, may accelerate and enhance the reactivity of the cement raw mix. The utilization of mineralizers ...to facilitate and quicken the process of clinkerization backpedals numerous years, the concept of using such mineralizers to burn normal raw mixes at a much lower temperature with the end goal of decreasing the fuel necessities of the furnace and to enhance the cement proprieties has become to be seriously considered over the most recent couple of years.
The subject of this paper is to investigate the impact of calcium fluoride as mineralizer on addition during the clinkerization process of industrial raw mixtures and its effect on chemical, mineralogical, and mechanical properties of CPA Moroccan cement. Five different raw meals were utilized and were burned with 2% of calcium fluoride. The resulting clinker was analyzed by X-ray diffraction (XRD) and fluorescence spectroscopy to determine the chemical phases of the obtained clinker, and the mechanical properties of resulting CPA cement were determined. The results show that the addition of 2% of CaF
2
to the clinker raw meal induced a decrease in the burning temperature and free lime, while improving the clinker phase formation and the mechanical properties of obtained cement.
Nowadays, the cement industry is the largest emitter of CO2. In 2015, cement production accounts for roughly 8% of global CO2 emissions. In order to reduce this impact, cement plants are working on ...alternative solutions, for instance, producing cement by adding additives like fly ash known for reducing the emissions of CO2 and minimizing production costs. The thermal power stations in Morocco produce more than 500 000 tons per year. For ecological and sustainable development reasons, it is desirable to recycle these quantities according to beneficial methods to their addition in the cement. This study aims to investigate the influence of grinding fly ash on the physico-chemical and mechanical properties of fly ash blended CPJ45 cement. The addition of the fly ash particles to the grinder leads respectively to the breakage of the particles and to reduce the agglomeration effect in the balls of cement grinder. Fly ash milling was found to improve particles fineness, and increase the silica and alumina content in the cement. Furthermore, milled fly ash blended cements show higher compressive strength compared to unmilled fly ash blended cements, due to improved fly ash reactivity through their mechanical activation.
Radioactive waste arising as a result of nuclear activities should be safely managed from its generation to final disposal in an appropriate conditioned form to reduce the risk of radiation exposure ...of technical personnel and of the public and to limit contamination of the environment. The immobilization of low and intermediate level radioactive wastes in cementitious matrices is the most commonly used technique to produce inexpensive waste matrix that complies with regulatory requirements in order to protect humans and the environment against nuisance caused by ionizing radiation. Cement based materials are used in radioactive waste management to produce stable waste forms. This matrix constitutes the first build engineering barrier in disposal facilities. In this work, the kaolin is used to enhance the mechanical performance of the matrix of confinement of ion exchange resins by gradually replacing the sand in mortar with kaolin clay. The Kaolin clay sample was a special pure product, sourced from a foreign country. The maximum quantity of resins that can be incorporated into the mortar formulation without the packages losing their strength is 13.915% which results in a better mechanical strength at 6.7686 MPA compression with kaolin.
Organic radioactive waste can occur in solid, liquid or rarely gaseous form. In general, organic components of radioactive waste Generally, the organic components of the radioactive waste have a ...contaminant effect stronger than most of the inorganic components, because of their low melting point, of their answer to the radiolyse or of their volatilitydu to their low melting point, to their answer to the radiolyse or to their volatility. This property can significantly affect the strategy adopted for their management. Organic radioactive waste results from the use of radioisotopes in the National Center for Energy, Nuclear Science and Technology (CNESTEN) and from medical applications. Organic radioactive waste requires management steps that take into account not only their radioactivity but also their chemical content. The aim of this study is the optimization of the stabilization of radioactive organic effluents in cementitious matrices. Thus, we study the effects of the addition of the alumina powder on the physicochemical and mechanical properties of the cement paste. The mortar was made by mixing Portland cement, sand, water and alumina powder (88 μm). The study showed that the addition of 12% alumina powder improves the compressive strength.
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