Molar Ratio Of NaOH Research Articles

Beta-Hydroxybutyric Acid as a Template for the X-ray Powder Diffraction Analysis of Gamma-Hydroxybutyric Acid

In this paper, we report the possibility of using the X-ray powder diffraction (XRPD) technique to detect gamma-hydroxybutyric acid (GHB) in the form of its sodium salt in different beverages, but because it is not possible to freely buy GHB, beta-hydroxybutyric acid (BHB) and its sodium salt (NaBHB) were used as a model to fine-tune an X-ray diffraction method for the qualitative analysis of the sodium salt of GHB. The method requires only a small quantity of beverage and an easy sample preparation that consists only of the addition of NaOH to the drink and a subsequent drying step. The dry residue obtained can be easily analyzed with XRPD using a single-crystal X-ray diffractometer, which exploits its high sensitivity and allows for very fast pattern collection. Several beverages with different NaBHB:NaOH molar ratios were tested, and the results showed that NaBHB was detected in all drinks analyzed when the NaBHB:NaOH molar ratio was 1:50, using a characteristic peak at very low 2θ values, which also permitted the detection of its presence in complex beverage matrices. Moreover, depending on the amount of NaOH added, shifting and/or splitting of the characteristic NaBHB salt peak was observed, and the origin of this behavior was investigated.

Integrating bead milling and alkaline solubilization for enhanced protein recovery from microalgae: A comprehensive approach

Microalgae, Chlorella vulgaris exhibits substantial potential as a sustainable food ingredient, but its robust cell wall and limited protein solubility hinder industrial scale protein recovery. A comprehensive solution was devised, integrating dry bead milling and alkaline solubilization. In this method, cells were initially disrupted with bead milling followed by alkali (NaOH) treatment. Without bead milling, protein extraction yield was very low (5.0 % with water, 16.8 % with 0.1 M NaOH) at a biomass loading of 20 g/L. However, the integrated approach significantly improved these results, achieving a maximum protein extraction yield of about 47.3 % at a biomass loading of 100 g/L. The optimized conditions for both dry bead milling (frequency 26 Hz, duration 1.0 h) and alkaline solubilization (biomass weight to NaOH molar ratio 200–250 (g/M), 37 °C, mixing time 1.0 h) played a pivotal role in realizing these improved results. This integrated approach effectively addresses the challenges and holds industrial relevance, offering a more efficient way to extract microalgal protein.

Dual-alkali treatment of Y-type zeolite synthesized from lithium-silicon powder waste for enhanced adsorption removal of low-concentration toluene

In this study, the dual-alkali treatment of the Y-ZLSP zeolite recycled from lithium-silicon powder (LSP) waste for enhanced adsorption removal of low-concentration toluene was systematically studied. The results revealed that a mild condition dual-alkali treatment of Y-ZLSP significantly improved its toluene adsorption performance, as well the regenerability and robustness. The Y-ZLSP-NT(1/1) that was obtained under the conditions of NaOH and TPAOH molar ratio at 1/1, total concentration of 0.0050 M, and treated at 55 °C for 0.5 h showed the best adsorption property, with a saturated adsorption capacity (qs) of 139.7 mg/g at 1000 mg/m3 inlet concentration. Importantly, it had an up to 112.1 mg/g high of breakthrough adsorption capacity (qb). Toluene adsorption on Y-ZLSP-NT(1/1) was governed by physical adsorption, primarily due to pore filling and hydrogen bonding. The dual-alkali treatment resulted in a controllable pore evolution and greatly enriched the surface acid functional groups of Y-ZLSP. The evolved microporosity provided more adsorption sites, the mesoporosity afforded mass transfer channels. The toluene adsorption on Y-ZLSP-NT(1/1) follows a pseudo-first-order model and is typically an entropy-driven exothermic process with ΔH, ΔG and ΔS of −1.98 kJ/mol, −8.29 kJ/mol and 34.50 J/(mol·K), respectively.

Effects of agro-industrial by-products as alumina-silicate source on the mechanical and thermal properties of fly ash based-alkali activated binder

The construction industry has a potential to incorporate various agro-industrial waste for development of sustainable construction materials which will eventually results in a cleaner and healthy environment. This research emphasizes on incorporation of agro-industrial wastes such as Rice husk ash (RHA), fly ash (FA), copper slag (CS), bottom ash (BA) and glass powder (GP) to develop ecofriendly alkali-activated blocks. The research studies the effect of blending alumina-silica rich agro-industrial byproduct with fly ash and the influence of resulting oxide ratios on the thermal, mechanical and physical properties of the proposed binder. The experimental study indicates that the combination of CS with FA resulted in the highest strength of 63 MPa among all the combinations. However, the NaOH molar ratio also plays a crucial role in performance of alkali activated block as all the mixes having 12 M NaOH resulted in higher mechanical performance. The findings suggest that the raw materials, curing temperature and NaOH concentration also contribute towards strength development apart from the oxide ratios like Si/Al, Na/Al and Na/Si. Finally, a comparative performance analysis amongst the agro-industrial waste (used in current study) as an ingredient to develop alkali activated binder was provided.

Use of Iron Ore Tailing as Raw Material for Two Products: Sodium Silicate and Geopolymers

In this work, iron ore tailing (IOT) was used for the production of two different materials: sodium silicate and geopolymers. Initially, reactions of IOT with NaOH were carried out by hydrothermal reaction in autoclave at 200 °C (1:1.5 and 1:2.5 SiO2:NaOH molar ratio) and reaction times of 4 and 8 h. X-ray fluorescence by dispersive energy (XRF), X-ray diffraction (XRD), Mössbauer spectroscopy, scanning electron microscopy (SEM-EDS) and titrations showed that IOT:NaOH ratios of 1:2.5 and reaction time 8 h completely dissolved the quartz from the IOT, obtaining a solid fraction consisting mainly of hematite and an aqueous phase of sodium silicate, which showed contents of ca. 23% SiO2 and 19% Na2O. This sodium silicate obtained was then combined with IOT (25 and 50 wt.%) to produce geopolimeric material with excellent physicochemical properties, fast curing time and very good compressive strength results, which ranged from 41 to 58 MPa and many potential applications.

A novel design for biodiesel production from methanol + mutton bone fat mixture

Bioenergy plays a significant role in the green transition. In this work, the conversion of methanol and mutton bone fat oil (as a low-cost feedstock) for bioenergy production was studied. The five-level, three-factor response surface methodology (RSM) was used to optimize the transesterification reaction conditions for produced biodiesel. Twenty ultrasonic-assisted experiments at the frequency of 25 kHz were conducted to investigate the effects of methanol/oil molar ratio (M/O) and concentrations of KOH and NaOH as catalysts on biodiesel yield. A second-order polynomial equation was developed by fitting the RSM experimental data using Design-Expert software. Results showed that the optimum biodiesel yield of 90.087% could be achieved by the KOH catalyst with 2.5 wt% concentration and 15:1 M/O during 3 h of the reaction. Furthermore, the biofuel analyses showed that methanol and mutton bone fat oil can be used as a proper feedstock for biofuel production. In the following, a membrane filtration package system is proposed and modeled. The reaction kinetics was determined based on experimental data. The results of the mathematical modeling showed the reaction time appears to be 6 times shorter in a membrane setup (30 min). Consequently, membrane application is highly recommended for biodiesel production from mutton bone fat oil.

Phase diagram for hydrothermal alkali activation of kaolin and quartz: Optimal digestion for the synthesis of zeolites

Low-temperature activation of quartz and kaolin, two of the most abundant and affordable raw materials as the sources of alumina and silica for the production of zeolites, is highly desirable but is hampered by several challenges such as incomplete activation and the formation of acid-resistant aluminosilicates. In this paper, the hydrothermal alkali activation processes of kaolin and quartz with different Si/Al ratios have been studied in detail, aiming to establish a phase diagram for the optimal digestion of silica and alumina. The effects of the Si/Al ratio, reaction time, reaction temperature, alkali concentration, and doses of hydrothermal alkali activation have been thoroughly investigated and optimized. Sodalite, hydroxycancrinite and analcime are found to be the dominant aluminosilicates as activation products. This is the first demonstration that the molar ratio of NaOH/(Si + Al) is the key factor in controlling the formation of aluminosilicates. The establishment of this phase diagram allows us to avoid the formation of troublesome analcime, and it can be used for effectively converting most natural aluminosilicate materials into sol-gel as platform chemicals for the synthesis of zeolites and other aluminosilicate derivatives.

Physicochemical Foundations of an Energy and Resource Efficient Combined Technology for Processing of Soda Ash Production Wastewater

The production of soda ash by the Solvay method is accompanied by the formation of wastewater, much of which is the distiller liquid containing up to 100 g/L calcium chloride and up to 50 g/L sodium chloride. A highly efficient electrochemical method was proposed to treat the distiller liquid to form calcium hydroxide, sodium hydroxide, and hydrochloric acid. The proposed process consists of two stages. At the first stage, the distiller liquid is treated with alkali to produce calcium hydroxide and a filtrate containing sodium chloride. At the second stage, the filtrate is processed in a membrane electrolyzer to obtain solutions of sodium hydroxide and hydrochloric acid. It was shown that the process of treating the distiller liquid with alkali should be carried out at a CaCl2 : NaOH molar ratio of 1 : 1.25. The processing of the filtrate in the membrane electrolyzer makes it possible to obtain sodium hydroxide at a concentration of up to 4320 g/L and hydrochloric acid at a concentration of 148 g/L.

Adjustable synthesis of polydopamine nanospheres and their nucleation and growth

The growing interest in polydopamine (PDA) nanospheres leads to a strong increase in demand for size-controllable synthesis strategies. Understanding the formation pathways of PDA nanosphere is of utmost importance in order to predictably synthesize these nanoparticles with the desired diameters. In the present study we synthesized PDA nanospheres with various diameters by the self-oxidative polymerization of dopamine (DA) in an alkaline solution. The diverse reaction conditions including the DA:NaOH molar ratio, the DA concentrations, the reaction time and temperature as well as the oxidant types were extensively investigated, and the results of the TEM and DLS analysis clearly showed the dependence of the diameters of the PDA nanospheres on reaction conditions. In addition, the relationships between the polymerization kinetics of DA and the particle size of PDA nanospheres were examined by UV–vis spectroscopy. The polymerization kinetics of DA were significantly accelerated by the presence of more hydroxide ions (OH−) or a strong oxidizing agent, which increased the nucleation rate of PDA, resulting in PDA nanospheres of smaller diameter. The increasing DA concentrations cause the PDA cores to grow, resulting in an increase in diameter. Moreover, the size of the PDA nanospheres increased with the prolonged reaction until a certain time and as long as sufficient precursors are available. It was also found that higher temperatures not only accelerate the nucleation of PDA particles but also promote the diffusion of DA monomers. Based on the results we suggest the DA:NaOH molar ratio as the most promising tool to affect the diameter and the size distribution of PDA spheres due to its influence at the very beginning of the reaction pathway.

A low-cost green approach for synthesis of lead oxide from waste lead ash for use in new lead-acid batteries

Abstract This paper proposes a novel method relating to the recycling of waste lead ash originated from procedure of lead alloy production. The spent lead ash was first disposed by acetic acid leaching system, where lead ash structure wrapping impurities would be destroyed. The synthesis of lead oxide products was conducted at a lower temperature of 90 °C. The effect of molar ratio of CH3COOH to lead content of the ash on leaching efficiency was studied through the acetic acid leaching system. The results demonstrate that 84.6% of lead could be obtained in the leaching solution, while merely 0.7% of Fe blend in solution within a leaching time of 120 min. In the stage of lead oxide synthesis from leaching solution, the yield of lead oxide products could reach up to 94.4% when the molar ratio of NaOH to lead in filtrate was 2.5. This novel green method could shed light on the reuse of lead from exhausted ash with a much more convenient and environmentally friendly procedure.

Reaction mechanism of roasting Zn2SiO4 using NaOH

Abstract The reaction kinetics of roasting zinc silicate using NaOH was investigated. The orthogonal test was employed to optimize the reaction conditions and the optimized reaction conditions were as follows: molar ratio of NaOH to Zn2SiO4 of 16:1, reaction temperature of 550 °C, and reaction time of 2.5 h. In order to ascertain the phases transformation and reaction processes of zinc oxide and silica, the XRD phase analysis was used to analyze the phases of these specimens roasted at different temperatures. The final phases of the specimen roasted at 600 °C were Na2ZnO2, Na4SiO4, Na2ZnSiO4 and NaOH. The reaction kinetic equation of roasting was determined by the shrinking unreacted core model. Aiming to investigate the reaction mechanism, two control models of reaction rate were applied: chemical reaction at the particle surface and diffusion through the product layer. The results indicated that the diffusion through the product layer model described the reaction process well. The apparent activation energy of the roasting was 19.77 kJ/mol.

Effect of dosage of sodium carbonate on the strength and drying shrinkage of sodium hydroxide based alkali-activated slag paste

This study investigated the properties of alkali-activated slag (AAS) pastes with NaOH and a blend of NaOH and Na2CO3 as the alkaline activator. The effects of five different Na2CO3 to NaOH molar ratios (0:10, 0.9:10, 2.5:10, 5.7:10 and 15:10) and three different Na2O contents (4%, 6% and 8%) in the alkaline activator on the setting time, mechanical performance and drying shrinkage were tested. The water to slag ratio was 0.35 by weight. The results showed that both the Na2CO3 to NaOH molar ratios and Na2O contents are major factors influencing the fresh and hardened pastes. Higher Na2CO3 to NaOH molar ratios yielded a longer setting time and higher compressive strength. The Na2O content of 6% was more sensitive to the properties compared with 4% and 8% Na2O. When the Na2O content was 4%, the drying shrinkage increased as the Na2CO3 to NaOH molar ratio increased; however, when the Na2O content increased to 6% and 8%, the drying shrinkage decreased as the Na2CO3 to NaOH molar ratio increased. The main hydration products were C-S-H(I), hydrotalcite, calcite and gaylussite. There was a strong relationship between the drying shrinkage and pore structures of AAS. Consequently, the Na2CO3 to NaOH molar ratio of 15:10 and Na2O content of 6% can be regarded as the optimum mix proportion.

Development of polystyrene-geopolymer composite for thermal insulating material and its properties with special regards to flame resistance

As a first part of the research, systematic experimental series were conducted in order to develop an appropriate fly ash-based geopolymer binder focusing on the workability of the paste. In these series, the NaOH molar ratio and water glass/NaOH ratio were investigated and the fineness of the fly ash was optimized presented in a recent paper. Based on these results the effect of metakaolin on the mechanical properties was studied. After developing the appropriate binder, experimental series were carried out using ground polystyrene as light aggregate in various concentration (from 30 V/V% up to 98 V/V%) and geopolymer as a binder in order to develop a heat insulating material. Compressive and flexural strength, specimen density, flammability, freeze-thaw resistance were determined in order to characterize the composite product. As a result of the experimental investigation, it was found that the flexural strength of the composite was found to be ~400 kPa which is as high as the original polystyrene heat insulating panel. Additionally, the flammability was much better than the original pure PS product, the sample was not ignited even at higher PS content (90%). Furthermore, the freeze-thaw resistance of the composite improved compared with the neat geopolymer.

Synthesis and Characterization of Fly Ash Geopolymer for Water Absorbent Material

Geopolymer as a water absorbent material has been synthesized from fly ash. This research aims to determine the ability of geopolymer to save water content with variations of NaOH molar ratio. In this research, the synthesis of geopolymer was conducted by setting NaOH molar ratio at 3, 4, 5, 6 and 7 M. The resulting material characterization was done by using XRD, FTIR and SEM in order to characterize the geopolymer structures. Water absorption capacity was measured by immersing the geopolymer specimens in water for 24 hours. The results show that the optimum molar ratio of NaOH was 3 M, which water absorption capacity was 11.10%wt.

Synthesis of Diverse Ag2O Crystals and Their Facet-Dependent Photocatalytic Activity Examination.

Sub- to micrometer-sized Ag2O cubes, great rhombicuboctahedra, cuboctahedra, corner-truncated octahedra, octahedra, and rhombic dodecahedra have been synthesized at room temperature using simple molar ratios of NH4NO3, NaOH, and AgNO3 solutions with a short reaction time. In addition, tuning the concentration of NH3 in the solution can provide more particle morphologies including edge- and corner-truncated cubes, small rhombicuboctahedra, and edge-truncated octahedra to enrich Ag2O shape diversity. X-ray photoelectron spectroscopy (XPS) spectra indicate surface composition of various crystals as pure Ag2O. Diffuse reflectance spectra have been used to determine the band gap of Ag2O cubes. Ag2O cubes, octahedra, and rhombic dodecahedra having the same total particle surface area were used for facet-dependent photocatalytic activity comparison in the degradation of methyl orange. Cubes are comparably highly active for this reaction, while octahedra and rhombic dodecahedra give moderate and low catalytic activities, respectively. Electron paramagnetic resonance (EPR) measurements confirm this reactivity order. Although all Ag2O samples show significant etching during photocatalysis, metallic silver is not produced.

Physical Chemical Properties of Leachate in the Process of Improving Vanadium Leaching From Petroleum Coke: Part II

The effects of NaOH concentration, leaching time, temperature, Na molar ratio of NaOH and Na2CO3 and liquid to solid mass ratio on vanadium removal, and physical chemical properties of leachate were investigated. The optimum conditions were 10 g of petroleum coke, 20 mL of oxidation, 6:1 liquid to solid ratio, 150 g/L of NaOH concentration, 62 g/L of Na2CO3 concentration, and 95°C temperature. Physical chemical properties of leachate changed along with the parameters. The microstructures of petroleum coke before and after leaching were also analyzed by scanning electron microscope.

Influence of reaction parameters on carboxymethylation of rice starches with varying amylose contents

The influence of reaction parameters on the carboxymethylation of rice starches with different amylose contents was investigated. Rice starches with varying amylose contents showed various degrees of susceptibility to the reaction conditions. The maximum degree of substitution (DS) for all three rice starches was obtained under similar reaction conditions which involved a reaction medium consisting of isopropanol–water at the ratio of 90:10, a molar ratio of NaOH:AGU at 1.5 and a reaction temperature and time of 40°C and 3h. Under these conditions, the DS for all rice starches was similar; however, when the reaction was performed under conditions using lower NaOH concentration, the effect of starch types on the DS was observed. The results could be explained in terms of the granular/structural features of the different rice starches, their degrees of granular swelling as influenced by the reaction conditions and the accessibility of the etherifying reagents to starch molecules.

Formation of highly crystalline maghemite nanoparticles from ferrihydrite in the liquid phase

Fe5O7(OH)·4H2O ferrihydrite is a low-crystallinity antiferromagnetic material. γ-Fe2O3 (maghemite) magnetic nanoparticles were prepared from a ferrihydrite precursor, by chemically induced transformation in FeCl2/NaOH solution. The magnetization, morphology, crystal structure and chemical composition of the products were determined by vibrating sample magnetometry, transmission electron microscopy, X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy (XPS). Ferrihydrite underwent aggregation growth and transformed into α-FeO(OH) (goethite) particles, which subsequently transformed into γ-Fe2O3 nanoparticles, that became coated with NaCl. The γ-Fe2O3 particles had a flake-like morphology, when prepared from 0.01 mol/L FeCl2 and a FeCl2:NaOH molar ratio of 0.4. The γ-Fe2O3 particles were more spherical, when prepared from a FeCl2:NaOH molar ratio of 0.6. The Fe content of the flake-like particles was lower than that of the spherical particles. Their magnetizations were similar, and the coercivity of the flake-like particles was larger. The differences in morphology and magnetization were attributed to the surface effect, and the difference in coercivity to the shape effect.

Synthesis, Characterization, and Application of PVP-Pd NP in the Aerobic Oxidation of 5-Hydroxymethylfurfural (HMF)

PVP stabilized Pd nanoparticles (Pd NP) were prepared in ethylene glycol at three different NaOH/Pd ratios and characterized by XRD, transmission electron microscopy (TEM), and small-angle X-ray scattering (SAXS). The Pd NP were applied in the aerobic oxidation of 5-hydroxymethylfurfural (HMF) into 2,5-furandicarboxylic acid (FDCA) in an alkaline aqueous solution (T = 90 °C, pO2 = 1 bar). The highest yield of FDCA (90 %) was obtained in the presence of Pd NP with a mean diameter of 1.8 nm, prepared with a 4:1 molar ratio of NaOH:Pd. Thus prepared Pd NP could be stored in their alkaline synthesis solution under ambient conditions and showed consistently good catalytic performances after up to one month storage time, in contrast to Pd NP prepared with 2:1 and 1:1 ratio and stored in neutral or acidic environment.

Synthesis and Characterization of Copper-Silver Core-Shell Nanoparticles by Polyol Successive Reduction Process

ABSTRACTIn this work, spherical copper (core) - silver (shell) nanoparticles with diameter of 40-50 nm were synthesized through polyol successive reduction process in glycerol with addition of sodium hydroxide (NaOH). The process involves microwave-assisted reduction of copper nitrate by glycerol under atmospheric conditions and successive reduction of silver nitrate at the surface of copper nanoparticles synthesized. We investigated the influence of synthesis parameters including molar ratio of NaOH:Cu (0:1, 1:1, 3:1 and 5:1), the molar ratio of Ag:Cu (0.01:1, 0.05:1, 0.10:1, 0.15:1 and 0.20:1) on the size, structure and composition of the resulting particles. High-resolution transmission electron microscopy with energy dispersive X-ray spectroscopy (TEM/EDS), scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis were used to characterize the particles obtained. The average size of the nanoparticles decreased with increasing of the ratio of sodium hydroxide. With the molar ratio of Ag:Cu greater than 0.05:1, the silver protective shell can prevent forming of copper oxide on the surface of nanoparticles.