TG DTG Research Articles

Spectral, XRD, morphological, DFT, and molecular modeling investigations of newly prepared isatin Schiff base complexes

The new Schiff base ligand was designed from a condensation reaction of isatin with 5‐amino‐2‐hydroxy benzoic acid. Then, the metal complexes were prepared. The structures of the prepared compounds were framed from thermogravimetric analyses (TG–DTG), mass spectrometry, elemental analyses, 1H‐NMR, IR, electronic spectra, UV–vis, and conductivity measurements. Surface and size morphology have been studied by X‐ray powder diffraction and scanning electron microscope (SEM) analysis. The IR spectra suggested that the ligand acted as bidentate coordinated with metal ions through deprotonated carboxylate oxygen atom and oxygen of phenolic group. With the exception of the complexes of Cr (III), Fe (III), and Cd (II), which were non‐electrolytes, the molar conductivities demonstrated the electrolytic behavior of all the rest complexes. The X‐ray diffraction (XRD) analysis patterns for the Schiff base complexes indicated their crystalline nature except the Co (II) complex which had amorphous structure. The ligand and its metal complexes were screened for their antimicrobial activities against two G‐positive, two G‐negative bacteria and against Aspergillus fumigatus and Candida albicans fungi. Additionally, the compounds were evaluated against the MFC‐7 breast cancer cell line for their anticancer activity. The outcomes demonstrated their strong antitumor activity. [Fe(HL)Cl2(H2O)2]0.5H2O complex has the lowest IC50 value = 9 μg mL−1. Molecular modeling studies for the ligand and its Co (II) and Fe (III) complexes were accomplished from density functional theory (DFT) analysis. From molecular docking study, the electrophilic moieties in both complexes displayed good binding interactions with the CDK6, aminoglycoside phosphotransferase, and CYP51 targeted proteins.

Systematic assessment of a multi–solid waste cementitious material: Feasibility and environmental impact

This study systematically assessed the feasibility of replacing ordinary Portland cement (OPC) with a multi–solid waste cementitious material (MSC) composed of ground granulated blast furnace slag (GGBS), steel slag (SS), red mud (RM), fly ash (FA), limestone powder (LP), and desulfurized gypsum (DG) in specific proportions of 28%, 25%, 21%, 11.5%, 9%, and 5.5%, respectively. The hydration characteristics were analyzed using hydration heat, XRD, TG–DTG, FTIR, and SEM–EDX tests. The heavy metal content and leaching concentration of the MSC were determined using inductively coupled plasma mass spectrometry (ICP–MS). The unconfined compressive strength (UCS), indirect tensile strength (ITS), and water stability of the MSC-stabilized clayey sand and stone chips were investigated. The results showed that synergistic hydration among multiple solid wastes generated abundant hydration products, including Ca(OH)2, C–(A)–S–H gels, and AFt crystals, which formed dense and compact microstructures. Furthermore, Pb and Cd in the raw material were effectively solidified by MSC hydration, with leaching concentrations as low as 0.181 and 0.002 mg/L, respectively. The contents and leaching concentrations of the other heavy metals were significantly lower than their limits. The pH of the MSC mortar leachate was stable at 11.56 with curing age, which complied with environmental safety standards. Moreover, MSC as a binder demonstrated higher UCS, ITS, and water stability in comparison to OPC. When MSC was added at a 6% dosage to stabilize clayey sand and stone chips, the UCS values measured after 7 days of curing were 2.82 MPa and 4.83 MPa, respectively. Finally, the MSC was successfully applied in practical projects, demonstrating its promising application prospects.

Study on the Influence of Coal Structure and Oxidation Performance by Endogenous Bacterium

In order to solve the defects of traditional coal spontaneous combustion prevention technology in a closed goaf, a strain of aerobic endogenous bacteria was isolated from coal and used as a blocking raw material. Based on the metabolic and reproductive characteristics of microorganisms, the experimental study on the inhibition of coal spontaneous combustion by microorganisms was carried out. The colonies were isolated and purified by the dilution concentration plate method and the scribing plate method. The growth morphology of microorganisms was analyzed, and the growth curve was determined. The strains were identified by seamless cloning technology for high-throughput sequencing. The surface morphology of coal was analyzed by SEM, the differences of oxidation characteristic temperature points were analyzed by TG–DTG–DSC images, a programmed heating experiment was used to analyze the concentration of the indicator gas CO, and the changes in microscopic groups before and after microbial action were analyzed by FTIR and XPS spectra. Therefore, the inhibition of coal oxidation by endogenous bacteria was verified from macroscopic and microscopic perspectives. The results show that the coal bacteria isolated from the coal is Lysinibacilus sp. After the culture of Lysinibacilus sp., the surface of the coal demonstrated less detritus, and was relatively smooth. In the early stage of low temperature oxidation of coal spontaneous combustion, the characteristic temperature point of coal oxidation and the reaction between coal and O2 could be delayed by Lysinibacilus sp., and the total heat release was reduced in the combustion process. Not only that, Lysinibacilus sp. could also reduce the CO concentration during coal heating. After the coal was decomposed by Lysinibacilus sp., the C=C thick ring skeleton structure had little effect; however, the aromatic substitution pattern changed. This bacterium had an effect on the C-O bond, reducing the percentage of -CH2- and increasing the percentage of -CH3. It might also use the crystalline water in coal for life activities. The carboxyl carbon in coal changed the most, with a decrease of 12.03%, so it might become the carbon source required for microbial growth. The reproductive metabolism of microorganisms also affected the form of nitrogen, and the percentage of pyridine nitrogen in coal was reduced. The ratio of single-bond carbon to double-bond carbon in raw coal was about 3:2, but after this bacterial action, the ratio of the two was about 1:1. The analytical conclusions of XPS and FTIR spectra were consistent, and the results supported each other.

Insights into Pyrolysis Kinetics, Thermodynamics, and the Reaction Mechanism of Wheat Straw for Its Resource Utilization

To realize the energy recovery of wheat straw, the pyrolysis behavior of wheat straw was studied at three heating rates (10, 20, and 30 K/min) based on thermogravimetric analysis (TG–DTG). Kinetics and thermodynamics were analyzed using Flynn–Wall–Ozawa (FWO) and Kissinger–Akahira–Sunose (KAS) model-free methods, and the reaction mechanism was determined using the Coats–Redfern (CR) model-fitting method. The results show that there are three weightlessness stages in the pyrolysis process, of which the second stage was the main weightlessness stage and two distinct peaks of weightlessness were observed in this stage. With increasing heating rate, the main pyrolytic weightlessness peaks of the DTG curve shift to the high-temperature side. The pyrolysis activation energies calculated by the FWO and KAS methods are 165.17–440.02 kJ/mol and 163.72–452.07 kJ/mol, and the pre-exponential factors vary in the range of 2.58 × 1012–7.45 × 1036 s−1 and 1.91 × 1012–8.66 × 1037 s−1, respectively. The thermodynamic parameters indicate that wheat straw has favorable conditions for product formation and it is a promising feedstock. Its pyrolysis reaction was nonspontaneous and the energy output is stable. CR method analysis shows that the A1/3 random nucleation model is the most suitable mechanism to characterize the pyrolysis process and random nucleation may be in charge of the main pyrolysis stage. This study can provide a theoretical basis for the thermochemical conversion and utilization of wheat straw.

Influences and mechanisms of pyrolytic conditions on recycling BTX products from passenger car waste tires

Pyrolysis is an effective method for waste tire disposal. However, it has rarely been used to recycle specific highly valuable components (such as benzene, toluene, and xylene (BTX)) from tire rubbers, owing to complicated pyrolytic reactions. This study investigated the pyrolysis process of passenger-car-waste-tires (PCWT) with the help of TG–DTG and Py–GC/MS. Based on response surface methodology (RSM), the effect of pyrolytic parameters on the yields of pyrolytic oil and BTX is evaluated. Furthermore, the BTX generation mechanisms are discussed from the perspective of aliphatic and aromatic hydrocarbon transformations. Additionally, pyrolytic conditions including temperature, rubber particle size, pressure, and gas flow rate were systemically investigated and the optimum pyrolytic condition for yield of BTX (26.5 g per 100 g tire rubber) was obtained [765 K, 0.7 mm, 0.52 MPa and 2.5 mL (g min)−1]. Therein, yield of benzene, toluene and xylene were 1.07, 5.03 and 20.40 g per 100 g tire rubber, respectively. During PCWT pyrolysis, BTX is primarily obtained via the Diels–Alder reactions of small-chain alkenes and transformations of limonene and aromatics. This study elucidates the BTX generation mechanisms during PCWT pyrolysis and clarifies the effects of varying pyrolytic conditions on BTX generation.

Catalytic Steam-Reforming of Glycerol over LDHs-Derived Ni-Al Nanosheet Array Catalysts for Stable Hydrogen Production

In the present work, LDHs–derived Ni–Al nanosheet arrays (NiAl/NA) were successfully synthesized via a one–step hydrothermal method, and applied in the steam-reforming of glycerol reaction for enhanced and stable hydrogen production. The physicochemical properties of catalysts were characterized using various techniques, including XRD, SEM–EDS, XPS, N2–physisorption, Raman, and TG–DTG. The results indicate that smooth and cross–linked Ni–Al mixed metal oxide nanosheets were orderly and perpendicularly grown on the Ni foam substrate. The SEM line scan characterization reveals the metal concentration gradient from the bottom to the top of nanosheet, which leads to distinctly optimized Ni valence states and an optimized binding strength to oxygen species. Owing to the improved reducibility and more exposed active sites afforded by its array structures, the NiAl/NA catalyst shows enhanced glycerol conversion (83.1%) and a higher H2 yield (85.4%), as well as longer stability (1000 min), compared to the traditional Ni–Al nanosheet powder. According to the characterization results of spent catalysts and to density functional theory (DFT) calculations, coke deposition is effectively suppressed via array construction, with only 1.25 wt.% of amorphous carbons formed on NiAl/NA catalyst via CO disproportionation.

Effect of Cementitious Material Composition on the Performance of Low-Carbon Foamed Lightweight Soil

This study simulated the production process of low-carbon foamed lightweight soil (LCFLS) prepared using prefabricated foam technology in real engineering conditions. The preparation and properties of LCFLS with a wet density of 600 kg/m3 were systematically investigated. The effects of different mix designs of large dosing granulated blast furnace slag and fly ash on the properties of LCFLS were investigated. The workability, rheological properties, and mechanical properties of LCFLS were studied. XRD, TG–DTG, and SEM were used to analyze the hydration mechanism of LCFLS. The results showed that fly ash could improve the flowability of LCFLS, while excessive fly ash could lead to foam and slurry delamination. Granulated blast furnace slag improved the mechanical properties of LCFLS, while excess granulated blast furnace slag caused the foam to break and merge, affecting the soil’s homogeneity. The higher the dynamic yield stress of the freshly mixed slurry, the better the homogeneity, and the smaller and more evenly distributed pore sizes formed after hardening. The main hydration products of LCFLS were C-S-H gel and CH, with small amounts of the carbonation products CaCO3, Hc, and Mc. The LCFLS prepared with 30% cement, 30% fly ash, and 40% granulated blast furnace slag had a flowability of 170–180 mm, with slight differences between wet and quasi-dry densities. The rheological properties of the slurry following the Bingham model showed a dynamic yield stress of 9.41 Pa, an average pore size after hardening of around 300 μm, and compressive strengths at 7 d and 28 d reaching 0.92 MPa and 2.04 MPa, respectively.

Novel insight in thermo-oxidative kinetics of vitamin D-based supplement formulation using TG–DTG–DTA, ATR-FTIR and MALDI-MS techniques

Novel insight in thermo-oxidative kinetics of vitamin D-based supplement formulation using TG–DTG–DTA, ATR-FTIR and MALDI-MS techniques

Two Ternary Systems of MnCl2 + Glycine (l-Proline) + H2O at 298.15 K and the Standard Molar Enthalpy of Formation of Their Double Salts

Two phase diagrams of MnCl2 + glycine (l-proline) + H2O at 298.15 K have been drawn. Three double salts of Mn(C2H5NO2)Cl2·2H2O, Mn(C2H5NO2)2Cl2, and Mn(C5H9NO2)Cl2·H2O are prepared in aqueous solution and they are all congruently soluble in water. Their thermal properties are studied by thermogravimetry and differential thermogravimetry (TG–DTG) and their structure information is obtained by powder X-ray diffraction. By means of the molar enthalpies of solution of Mn(C2H5NO2)Cl2·2H2O, Mn(C2H5NO2)2Cl2, and Mn(C5H9NO2)Cl2·H2O and the thermochemical cycles (based on Hess law), standard molar enthalpies of the formation of Mn(C2H5NO2)Cl2·2H2O (−1642.50 ± 1.08 kJ·mol–1), Mn(C2H5NO2)2Cl2 (−1582.4 ± 1.12 kJ·mol–1), and Mn(C5H9NO2)Cl2·H2O (−1336.97 ± 2.30 kJ·mol–1) at 298.15 K have been obtained.

Anticancer and antimicrobial activity of new copper (II) complexes

In this study, three new organic ligands N′-(benzylidene)-6-chloropyrazine-2-carbohydrazonamide (L1), 6-chloro-N′-(4-nitrobenzylidene)picolinohydrazonamide(L2), and N′-(benzylidene)-4-chloropicolinohydrazonamide (L3) and three copper coordination compounds (Cu(L1)Cl2, Cu(L2)Cl2 and Cu(L3)Cl2) based on them were synthesized. All obtained compounds were characterized using appropriate analytical techniques: elemental analysis (EA), thermogravimetric analysis (TG–DTG), Fourier transform infrared spectroscopy (FTIR) and flame-atomic absorption spectrometry (F-AAS). These methods of physicochemical analyses helped to assume that the complexation in three cases proceeds in a bidentate manner. The X-ray investigation confirmed the synthesis pathway and molecular structures for L1 and L3 ligands. The antimicrobial activity of the obtained compounds was then comprehensively investigated, where Cu(L3)Cl2 showed the strongest antibacterial properties against all tested bacteria (Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli). LN229 human glioma cells and BJ human normal fibroblasts cells were treated with tested compounds and their cytotoxicity was evaluated with MTT test. The effect of complexing on antitumor activity has been investigated. The ligand L1 and its complex showed similar activity against normal cells while complexation increases toxicity against cancer cells in concentrations of 50 and 100 μM. For the one pair of ligand/complex compounds the apoptosis detection, cell cycle analysis and gene expression analysis (qRT-PCR) were performed. Cu(L1)Cl2 showed the stronger toxic effect in comparison with L1 due to the population of early apoptotic cells which revealed metabolic activity in MTT assay.

Desorption behavior and mechanism of chloride ions in fresh concrete mixtures under electromigration

Detecting chloride ions in concrete mixtures is the final checkpoint to assess whether the chloride-ion content of hardened concrete is qualified. This paper devises a method to rapidly detect the chloride-ion content of fresh concrete mixtures based on electromigration and then compares it with traditional detection methods. The test results show that the electrochemical method for analyzing the chloride-ion content of concrete is accurate and suitable for various concrete mixture proportions. Moreover, parameter sensitivity analysis demonstrates the dissolution behavior of chloride ions in the concrete mixture when different detection methods are applied. Further, thermogravimetry–differential thermogravimetry (TG–DTG) analysis and scanning electron microscopy–energy-dispersive spectrometry (SEM–EDS) are used to study the desorption mechanism of chloride ions under the action of an electric field at a micro-level. The results of this paper provide technical means for rapidly detecting the chloride-ion content of fresh concrete mixtures, which is vital to ensuring the durability of concrete structures.

Pseudointerpenetrating network nanocomposite hydrogel for temporary plugging in fractured reservoirs

Nanomaterial-enhanced hydrogels have attracted considerable attention as temporary plugging agents for lost circulation control due to their improved strength under high temperature and high pressure (HTHP) conditions compared to conventional hydrogels. In this study, a pseudointerpenetrating network nanocomposite hydrogel (PINNG), which was composed of temperature-resistant polyacrylamide (TSPAM), polyethyleneimine (PEI) and cellulose nanofibrils (CNFs), was proposed. CNF with a fibrous structure exhibited a more significant effect on the rheological behavior and mechanical strength of the hydrogel than nanosilica (nano-SiO2). The reversible CNF network endowed the gelant with increased zero-shear viscosity and significant thixotropy. Furthermore, the presence of CNF noticeably improved the strength of PINNG, and the elastic modulus of PINNG was 1232% greater than that of the blank sample. According to analyses of Fourier transform infrared spectroscopy (FTIR), thermogravimetry-derivative thermogravimetry (TG–DTG) and scanning electron microscopy (SEM), it can be deduced that the strengthening mechanism of CNF was mainly related to physical filling, physical crosslinking, and especially the formation of a pseudointerpenetrating network structure with the crosslinked polymer chains. Due to the strengthening effect of CNF, PINNG exhibited a better pressure-bearing performance than the blank sample and the nano-SiO2 composite sample under 140 °C for the core with 2 mm of fracture width. Additionally, the favorable degradability of the PINNG system demonstrated that PINNG exhibited great potential in the application of lost circulation control as a temporary plugging agent.

Thermal behavior and decomposition mechanism of three nitrate energetic materials: TNNP, TNOP and DNHM

Thermal decomposition of three new energetic materials，5-nitratomethyl-1,3,5-trinitrohexahydropyrimidine (TNNP), 5–methylnitrate‐1,5–dinitrooxazine (TNOP) and 1,3-dinitrohexahydropyrimidine-5-nitrate (DNHM) was investigated by using TG–DTG, DSC, TG-FTIR, and TG-MS techniques. Results show that DNHM is more stable than TNNP and TNOP, while the decomposition process of TNNP and TNOP is more complicated than that of DNHM. TNNP starts to decompose at around 176.1 ºC and the peak temperature is 187.9 ºC with decomposition heat of − 1157.9 J·g−1 at the heating rate of 2.5 ºC·min−1. In comparison, the onset temperature and heat release of TNOP and DNHM are respectively 172.3 ºC, − 486.5 J·g−1 and 180.8 ºC, − 1947.6 J·g−1 at the same condition. The first decomposition step of TNNP follows first-order kinetics (F1) based on DSC data, while the decomposition of TNOP and DNHM follows the random chain scission model (L2) and the phase boundary controlled reaction (contracting area) model (R2), respectively. The main products of these three compounds during the decomposition process are N2, CO2, N2O, CH2O and NO from TG-FTIR and TG-MS.

New Coordination Compounds Based on a Pyrazine Derivative: Design, Characterization, and Biological Study.

New coordination compounds of Mn(II), Fe(III), Co(II), and Ni(II) and the biologically active ligand L (N′-benzylidenepyrazine-2-carbohydrazonamide) were synthesized and characterized by appropriate analytical techniques: elemental analysis (EA), thermogravimetric analysis (TG–DTG), infrared spectroscopy (FTIR), and flame-atomic absorption spectrometry (F-AAS). The biological activity of the obtained compounds was then comprehensively investigated. Rational use of these compounds as potential drugs was proven by ADME analysis. All obtained compounds were screened in vitro for antibacterial, antifungal, and anticancer activities. Some of the studied complexes exhibited significantly higher activity than the ligand alone.

Synthesis, structural elucidation, molecular modeling, and antimicrobial studies of some nanoparticles mixed ligands complexes of cetirizine in presence of 2,2′‐bipyridine

A four mixed ligand metal complexes derived from the interaction of Cu(II), Zn(II), Zr(IV), and Cd(II) with antihistamine cetirizine.2HCl (Cetz) in the presence of 2,2′‐bipyridine (Bipy) were synthesized and characterized by using elemental analyses, Fourier transform infrared (FT‐IR), UV–visible (UV–Vis), 1H NMR, thermal analysis (thermogravimetric–differential thermogravimetry [TG–DTG]), X‐ray diffraction (XRD) analysis, molar conductance, and magnetic moment. The infrared data confirmed that Cetz interacted with metal ion as monodentate ligand through carboxylate oxygen atom, and Bipy chelated through nitrogen atoms. The decomposition mechanism (TG and DTG) for Cetz, Bipy, and their complexes were accomplished, and thermodynamic parameters (Ea, ΔH*, ΔS*, and ΔG*) were determined using Horowitz–Metzger (HM) and Coats–Redfern (CR) methods. The powder XRD analysis of all compounds was carried out to determine the average crystalline size (d) and the nature of the compounds (crystalline or amorphous). The density functional theory (DFT) was achieved to comprehend the optimized geometry for the compounds. All complexes regarded as soft in relation to Cetz, with values ranging from 12.987 to 22.727 eV and equal to 12.658 eV for Cetz. The compounds biological activity was examined against number of bacterial and fungal strains. The data revealed that the investigated complexes have a significant efficiency and may be used as better bactericides.

Utilization of illumination and thermal field in the preparation of jet–fuel components: The photothermic catalysis of Jatropha oil over the M/TiO2–HZSM–5

Under simultaneous illumination and heating, Jatropha oil was converted into jet–fuel components over modified catalysts. XRD, HRTEM, N2 adsorption–desorption, XRF, NH3/CO–NH3–TPD/CO–TPD, UV–Vis and TG–DTG–MS were employed to determine the surface morphology and acidic site content of the modified catalysts. Through the characterizations and experimental results, the band gap of the catalysts modified with titanium dioxide was found to be significantly reduced, which enhanced the visible light adsorption of the catalysts. Moreover, the catalyst loaded with Pt contained the highest amount of weakly acidic sites, which led to the highest conversion and selectivity for the Pt/TiO2–HZSM–5 catalyst at 100 °C and 0.4 MPa H2 pressure. In addition, the pathway of photocatalytic decarboxylation and catalytic cracking of Jatropha oil was found to involve a cascade reaction from fatty acid to Cn–1 alkane and eventually to cracking products.

Spontaneous Combustion Risk of Coal-based Activated Carbon

ABSTRACT Coal-based activated carbon (CBAC) is widely used in several industrial processes and daily life, however, it is susceptible to spontaneous combustion during storage and transportation. Therefore, it is essential to probe the spontaneous combustion risk of CBAC. The oxidation process of briquetting material sample (BM), carbonized material sample (CM), and activated material sample (AM) was studied via thermogravimetric (TG–DTG) analysis. The oxidation mechanism of the samples was investigated via the proximate and ultimate analyses, Fourier transform Infrared (FTIR) spectroscopy, and nitrogen adsorption. Kinetic characteristics of the samples during the combustion were determined using the Kissinger–Akahira–Sunose (KAS) method. Five characteristic temperature points and the five stages of the samples during oxidation were obtained. With an increase in the heating rate, the hysteresis phenomenon was observed during thermal decomposition and combustion of AM in TG–DTG curves. The heating value of BM, CM, and AM were 6678, 6705, and 6776 cal g–1, respectively. AM has a developed pore structure that leads to enhanced oxygen adsorption and limited heat transfer, easy to induce spontaneous combustion. The main functional groups of AM were hydroxyl groups and aromatic hydrocarbons, especially hydroxyl groups that played a key role in the spontaneous combustion of AM. The apparent activation energy (E a) during the combustion of BM, CM, and AM were 110.70, 85.90, and 111.80 kJ mol–1 from the KAS method, respectively. These results are expected to facilitate a better understanding of CBAC spontaneous combustion.

Effect of Swelling by Organic Solvent on Structure, Pyrolysis, and Methanol Extraction Performance of Hefeng Bituminous Coal.

N-methyl-2-pyrrolidone (NMP), pyridine (Py), tetrahydrofuran (THF), and tetralin (THN) were used to swell Hefeng acid-washed bituminous coal (HBCAC). The swelling effect on HBCAC by each solvent is different, among which NMP presented well swelling performance, with a swelling degree of 2.11. FTIR results showed that acid washing and swelling processes presented a marginal effect on HBC, and there was no damage to the macromolecule structure of the coal. TG–DTG profiles of the swollen coals illustrated that the total weight loss of each sample was lower than that of the acid-washing one, while the temperature of the maximum weight loss rate peak was almost unchanged, around 445 °C. Extract yield by methanol followed the order of HBCAC > HBC > HBCAC–NMP (swelled by NMP), showing that acid washing promoted the methanol extraction process, with a higher extract yield of 3.21%, which is twice that of HBC (1.66%).

Recovery of cobalt and nickel from magnesium-rich sulfate leach liquor with magnesium oxide precipitation method

Nickel, cobalt, and magnesium often coexist in the sulphate leach liquor of laterite nickel ores, and magnesium will affect the following refining process of nickel and cobalt. In this paper, magnesium oxide slurry was employed to precipitate and separate nickel and cobalt from magnesium with the precipitation method. The appropriate conditions to maximize the precipitation of nickel and cobalt and minimize the precipitation of magnesium are investigated systematically as follows: magnesium oxide addition (nMgO: (nNi + nCo)) = 2.0, hydrolysis time ≤ 2 h, hydrolysis temperature ≥ 60 °C, and stirring speed ≤ 350 rpm. The equilibrium pH, which can be controlled by adjusting the amount of magnesium oxide and temperature, was found to be the main influence factor, and the optimal equilibrium pH of the sulphate leach liquor should be controlled at 8.98. The high precipitations of 98.1% for nickel and 99.1% for cobalt can be obtained with low precipitation of 0.2% for magnesium. The characterizations of the mixed precipitate by XRD, FTIR, and TG–DTG demonstrate the presence of Ni2(CO3)(OH)2 and NiSO4·2H2O except for the primary Ni(OH)2 and Co(OH)2. The nickel and cobalt in the precipitate can be easily transferred into the low acidic solution by leaching at ambient temperature. The regenerated magnesium oxide powder with a high purity can be obtained by calcining the precipitates, which can be recycled as the precipitating agent again.

Effect of the Glycine Treatment on Synthesis and Physicochemical Characteristics of Nanosized Ni-Mn Mixed Oxides

Magnetic Ni-Mn mixed oxides based on nanoparticles (NPs) have been developed at 700 °C using a ceramic method and a glycine-assisted auto combustion path. The thermogravimetry–derivative thermogravimetry (TG—DTG), infrared radiation (IR), X-ray powder diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX) and high resolution transmittance electron micrographs (HRTEM) techniques have been used to characterize as synthesized nanomaterials by evaluating their thermal behavior, structure, distinguishing the components and establishing the morphology. A vibrating sample magnetometer has been used to estimate the magnetic properties of the materials (VSM). The analyses indicate that using a glycine-assisted auto combustion method resulted in formation of cubic spinel NiMn2O4 NPs as a single phase. The ceramic process, from the other side, led to the development of Mn2O3/NiMnO3/NiMn2O4 nanocomposite. The resulting particles being polycrystalline, including average sizes ranging from 10 to 80 nanometers. The prepared NiMn2O4 NPs showed room-temperature ferromagnetism, with an optimal saturation magnetization value of 5.0216 emu/g, according to the magnetic measurement.