Ratio Of Metal Cations Research Articles

Hollow microspheres of layered double hydroxides through surfactant-free method enhanced heavy metals removal from soil

A three-dimensional MgAl layered double hydroxides hollow microsphere (HMS-LDH) is fabricated by surfactant-free method. The microstructure and the formation mechanism of HMS-LDH are investigated by XRD (X-ray diffraction), SEM (Scanning Electron Microscope), EDS (Energy dispersive Spectrometer) and XPS (X-ray photoelectron spectrometer). The morphology of LDHs could be varied by changing the ratio of metal cations to urea. The adsorption properties of HMS-LDH for heavy metals from soil are investigated. The results of experiments demonstrates that the adsorption kinetics of Cu(Ⅱ), Pb(Ⅱ), As(Ⅴ), Cr(Ⅵ) are in good agreement with the pseudo-second-order kinetic and intraparticle diffusion model. The adsorption isotherm data of Cu(Ⅱ)/Pb(Ⅱ) is accordance with the Langmuir-Freundlich model, while the equilibrium adsorption of As(Ⅴ)/Cr(Ⅵ) follow the Generalized-Langmuir isotherm model well. Site energy distribution theory denotes the hollow microsphere structure increases the adsorption sites of heavy metals, which is conducive to the adsorption process. The different mechanisms of precipitation for Cu(Ⅱ)/Pb(Ⅱ) removal and interlayer adsorption for As(Ⅴ)/Cr(Ⅵ) removal are proposed. The effects of coexisting cations and column leaching experiments on the performance evaluation are also investigated, which indicate most the ions have no effect on the adsorption of Cu (Ⅱ)/Pb(Ⅱ) and As(Ⅴ)/Cr(Ⅵ). This work proposes a simple approach to prepare LDHs hollow microspheres and demonstrates their excellent properties for the remediation of heavy metal polluted soil.

Correlating Molecular Precursor Interactions with Device Performance in Solution-Processed Cu2ZnSn(S,Se)4 Thin-Film Solar Cells.

Research efforts aimed at improving the crystal quality of solution-processed Cu2ZnSn(S,Se)4 (CZTSSe) absorbers have largely employed delicate pre- and postprocessing strategies, such as multistep selenization, heat treatment in mixed chalcogen atmospheres, and multinary extrinsic doping that are often complex and difficult to reproduce. On the other hand, understanding and tuning chemical interactions in precursor inks prior to the thin-film deposition have received significantly less attention. Herein, we show for the first time how the complexation of metallic and chalcogen precursors in solution have a stark influence on the crystallization and optoelectronic quality of CZTSSe absorbers. By varying thiourea to metal cation ratios (TU/M) in dimethylformamide (DMF) and isopropyl alcohol (IPA)-based inks, we observed the formation of nanoscale metal-organic complexes and submicron size aggregates which play a key role in the morphology of the precursor layers obtained by spin-coating and drying steps. We also identify the primary cations in the complexation and assembling processes in solution. The morphology of the precursor film, in turn, has an important effect on grain growth and film absorber structure after the reactive annealing in the presence of Se. Finally, we establish a link between metal complexes in precursor solutions and device performance, with power conversion efficiency increasing from approximately 2 to 8% depending on the TU/M and Cu/(Zn + Sn) ratios.

Li-doped transition metal high-entropy oxides (Li/TM-HEOs) as Li-Ion batteries cathodes: a first report on capacity fading and cycling stability

High-Entropy Oxides (HEOs) have gained significant attention for their wide range of compositions and potential applications across various sectors, including rechargeable batteries. This study explores the characterization of two distinct HEO systems as potential cathode materials for Lithium-ion batteries (LIBs). A series of rock salt structured HEOs with varying Li loadings (16Li/RS-HEO, 25Li/RS-HEO, 33Li/RS-HEO, and 41Li/RS-HEO) and a spinel-structured HEO with 16 mol% of Li loading (16Li/SP-HEO) were firstly synthesized through co-precipitation. Electrochemical analyses via cyclic voltammetry revealed stark differences in the behavior of these structures. The Li/SP-HEO sample displayed broad and strongly irreversible hysteresis cycles, while the Li/RS-HEO series manifested thin, narrow hysteresis cycles with single oxidation peaks between 0.5 V and 0.7 V. As the lithium content increases in the RS-HEO system, the cycling stability of the cell decreases, most likely due to the reduced ratio of transition metal cations to lithium ions. Although there was a noticeable decrease in capacity under higher current rates, the higher lithium loadings positively impact the cell capacity, albeit with notable capacity fading under higher current rates. Li-doped rock salt structured high entropy materials show potential for LIB cathodes in terms of high specific capacities; the observed stability issues at medium and high current densities indicate a rapid electrode degradation.

MgO-MgAl2O4: An Efficient Catalyst for Multicomponent Synthesis of Substituted 4H-pyran

Background: The 4H-pyran compounds are an important class of heterocyclic compounds due to their diverse biological and pharmaceutical properties. Moreover, 4H-pyran is a crucial structural component commonly encountered in the pharmaceutical industry. Thus, it has recently gained significant attention from industry researchers and academic organizations. Herein, we report an efficient and eco-friendly one-pot strategy to synthesize bioactive compounds containing 4H-pyran motifs via a multicomponent reaction. This reaction occurs by reacting equimolar amounts of ethyl acetoacetate, malononitrile, and substituted aldehyde under mild conditions in the presence of a solid catalyst, MgO-MgAl2O4. This latter, was obtained by heat treatment, at 800°C, of a layered double hydroxide with the metal cation ratio of Mg2+/Al3+ = 3:1, and it was characterized by some techniques including XRD, TG-DTA, FT-IR and N2 adsorption-desorption. Therefore, bioactive compounds containing the pyran unit may possess intriguing biological properties. The synthetic protocol offers advantages such as a simple procedure, good to excellent yields, and easy catalyst separation from the reaction mixture. Methods: Substituted 4H-pyran derivatives were prepared by the condensation reaction of substituted aldehydes, ethyl acetoacetate and malononitrile using MgO-MgAl2O4 catalyst under mild conditions. This study aims to develop an efficient methodology for synthesizing 4H-pyran heterocyclic compounds that have potential applications in biological sciences. The study utilizes MgO-MgAl2O4 as a highly effective heterogeneous catalyst. Results: The present research details the synthesis of 4H-pyran bioactive compounds using sustainable reaction conditions, which resulted in high yields and facilitated the easy separation of the catalyst from the reaction mixture. Conclusion: In summary, the MgO-MgAl2O4 spinel nanostructure has been successfully prepared and fully characterized by using different physicochemical techniques such as XRD, TG-DTA, FT-IR and N2 adsorption-desorption. Afterwards, its catalytic activity was investigated through the one-pot condensation of aryl aldehyde, malononitrile and ethyl acetoacetate. Moreover, it exhibits good catalytic activity for the synthesis of 4H-pyran derivatives under green conditions. These latter have many benefits, such as simple procedure, good to excellent yields and easy separation of the catalyst from the reaction mixture.

High-efficient and rapid removal of anionic and cationic dyes using a facile synthesized sole adsorbent NiAlFe-layered triple hydroxide (LTH)

It would be extremely momentous to familiarize a low-cost sole adsorbent NiAlFe-layered triple hydroxides (LTHs) having a strong sorption affinity towards both anionic and cationic dyes. Using the urea hydrolysis hydrothermal method LTHs were fabricated and by altering the ratio of participant metal cations the adsorbent was optimized. BET analysis revealed that the optimized LTHs possess an elevated surface area (160.04 m2/g) while TEM and FESEM analysis portrayed the stacked sheets-like 2D morphology. LTHs were employed for the amputation of anionic congo red (CR) and cationic brilliant green (BG) dye. The adsorption study showed that within 20 and 60 min, respectively, maximum adsorption capacities were achieved at 57.47 mg/g and 192.30 mg/g for CR and BG dye. Adsorption isotherm, kinetics, and thermodynamics study revealed that both chemisorptions with physisorptions were the assertive factor for the dye encapsulation. This enhanced adsorption performance of the optimized LTH for the anionic dye is attributed to its inherent anions exchange properties and new bond formation with the adsorbent skeleton. Whereas for the cationic dye, it was because of the formation of strong hydrogen bonds, and electrostatic interaction. Morphological manipulation of LTHs, formulates the optimized adsorbent LTH111, provokes the adsorbent for this elevated adsorption performance. Overall, this study revealed that LTHs have a high potential for the effectual remediation of dyes from wastewater as a sole adsorbent at a low cost.

Синтез и исследование никель-алюминиевого катализатора для переработки тяжелого нефтяного остатка

Structural characteristics of catalytic systems obtained by modification of activated carbon with Al and Ni metal oxides have been studied. Modification of activated carbon was carried out by impregnating them with metal hydroxides from salt solutions with a Ni+2/Al+3 ratio of 2:1 and 3:1, followed by calcination in a stream of nitrogen and hydrogen until oxide phaseswere formed. With an increase in the ratio of metal cations in the impregnating solution in activated carbon, the specific surface area and the number of micropores increase, and the total volume and average pore diameter. Ignition in a hydrogen flowat the final stage of activated carbon modification leads to a decrease in the pore space and a decrease in the specific surface area of the catalytic system. The optimal combination of specific surface values and maximum average pore diameters for the processing of heavy oil residue have Ni/Al (2:1) catalytic systems obtained in nitrogen and hydrogen.

Variation of citrate to metal cation ratio for dense and phase pure BaZrO3 via autocombustion synthesis

AbstractIn this work, we demonstrate how the metal–citrate complex structure formed in the gel reflects the true stoichiometry of the redox mixtures to yield a highly dense BaZrO3 ceramic obtained as a combustion product in the sol‐gel autocombustion technique. By systematically varying the citric acid to metal cation ratio (C/M) between 0.56, 1.0, 1.5, and 2, we show that the optimal synthesis parameters correspond to C/M ratio of 1.5, at which ratio complete chelation of citrates happen with nitrates. This was confirmed using TGA, which showed a single‐step weight loss peak corresponding to C/M =1.5 but multiple peaks in C/M ratios of 0.56 and 1. PXRD and FTIR measurements on all the burnt powders showed multiphase peaks for the C/M ratios 0.56 and 1 but only peaks corresponding to BaZrO3 for C/M = 1.5, apart from a very tiny BaCO peak. Combustion behavior of each sol‐gel corresponding to C/M ratios 0.56, 1.0, 1.5, and 2.0 is described in detail, wherein 0.56 and 1.0 sol‐gels were found to belong to the smouldering/less intense flame‐type combustion, while 1.5 and 2 belonged to the intense flame combustion, contradicting oxidant to reductant ratio (O/R) calculations that require a stoichiometric combustion for C/M ratio of 0.56 to result in an intense flame combustion. This discrepancy was explained by the optimal usage of NO ions in the gel structure corresponding to C/M ratio of 1.5 since a complete chelation of citrates to nitrates ions happen for C/M = 1.5. The observed combustion behavior, phase purity, and other characteristics of stoichiometric/ nonstoichiometric combustion products are illustrated by means of the extent of the 3D metal–citrate complex network formed as a function of C/M. The density of the sintered pellets that were sintered at a temperature of 1650C was found to be the best at 99.6 for the C/M ratio 1.5. This is the highest ever reported density for BaZrO3 ceramic demonstrating that C/M ratio of 1.5 represents that metal to cation ratio for which best chelation of citrates happen with nitrates resulting in the formation of dense BaZrO3 ceramics. A comparison of BaZrO pellet made by solid‐state synthesis technique yielded a low value of density of 97.5. Impedance spectroscopy measurements done on all BaZrO pellets yielded the lowest grain‐boundary resistance for the pellet made by the sol‐gel technique with C/M ratio of 1.5.

Reconstruction and intercalating anion exchange of ZnAl-layered double hydroxide

Layered double hydroxides (LDHs) have recently attracted considerable attention as a promising multi-functional material due to their controllable properties depending on the type and composition ratio of metal cations and interlayer anions. Despite active research on controlling the composition to improve the properties of LDHs, anion intercalation techniques capable of obtaining the desired morphologies of LDHs have rarely been investigated. Herein, we report the anion exchange of ZnAl-LDHs grown on a silicon substrate using a post-treatment-based reconstruction process. Structural and chemical investigations verified that the calcined ZnAl-LDH was reconstructed by a NaCl solution during the anion exchange process. The anion exchange rate and the reconstructed fraction of the ZnAl-LDH increased as the NaCl concentration increased from 0.15 M to 0.60 M, though they decreased when the NaCl concentration exceeded 0.90 M. Therefore, the anion composition and morphology of the ZnAl-LDHs could be modulated by controlling the NaCl concentration during the reconstruction process. These results provide important information about the probability of controlling the structure and composition of LDHs intercalated with desired anions for a wide variety of device applications, such as memory, sensor, and energy storage.

Синтез и исследование никель-алюминиевых оксидных катализаторов на углеродном носителе

Activated carbons, which have a highly developed specific surface area and large pore sizes, have recently been increasingly considered as economically available carriers of catalytic systems for deep processing of heavy hydrocarbon feedstock. In this work, samples of catalysts obtained by impregnation of active carbon with oxides of NiO and Al2O3 were studied. It is shown that an increase in the ratio of metal cations Ni/Al in the impregnating solution from 2:1 to 3:1 leads to a decrease in the average pore diameter and an increase in the specific surface area of activated carbon by 1.5 times. Activated carbons impregnated with Ni/Al metal oxides with a ratio of metal cations in an impregnating solution of 3:1, calcined in a stream of hydrogen, have the largest pore area with a diameter of 10–200 nm. Heat treatment of Ni-Al oxide catalysts on a carbon carrier at a temperature of 450°С in a hydrogen flow leads to an increase in the pore size and a decrease in the specific surface area. Mechanical activation of oxide catalysts on a carbon carrier by ultrasonic action increases the area of the outer surface of the particles by more than two times.

A solution-based route to compositionally complex metal oxide structures using high-entropy layered double hydroxides

Although complex metal oxides with tailored compositions are increasingly in demand for applications in advanced technologies, their preparation by solution-based routes, which are typically low cost and easy to scale up, is challenging. Here, we report high-entropy layered double hydroxides (HE-LDHs) having complex compositions as precursors for complex metal oxides. Furthermore, we reveal that the ionic radii are the key factors determining the incorporation of the metal cations into the hydroxide layers, which can contain up to 10 different kinds of metal cations simultaneously having a metal cation ratio inherited from the reaction solution. Furthermore, spinel-based complex oxides can be prepared by heat treating the HE-LDHs in air, and their metal cation ratios are maintained over expansive heat-treatment temperatures (up to 1,200°C). Therefore, the results reveal that complex oxides with tailored compositions can be prepared using solution-based approaches, enabling the large-scale fabrication of oxides with precisely controlled physicochemical properties for various applications.

Electronic and catalytic engineering in two-dimensional vdW metal–organic frameworks through alloying

Bimetallic metal-organic framework (MOFs) alloys, in which heterogeneous metal clusters are incorporated into their backbone, are capable of highly selective separations and catalysis. Due to limitations in our fundamental understanding of their alloying, however, established methods result in phase-separated or amorphous two-dimensional (2D) MOFs or lack precise control over alloy ratios. Here, our results demonstrate 2D MOF alloys where metal cation ratios (M1 and M2) in M1xM21-xBDC (M1 or M2= Zn, Cu, Ni, Co, Fe, Mn) can be engineered on demand by controlling the metal salt dissociation constants. Resulting MOF alloys exhibit a highly 2D nature with excellent crystallinity and minute control over metal cation ratios. Our experimental and theoretical results show that their electronic bandgaps and photoexcited carrier lifetimes can be engineered by metal cation alloying. Interestingly, 2D alloyed MOFs enable high-efficiency photo-catalytic water reduction performance in Co/Ni MOF alloys owing to the spatially separated metal clusters in 2D MOF alloys.

Синтез и исследование каталитической активности смешанных оксидов цинка и железа для гидротермального облагораживания тяжелой нефти

The effect of the molar ratio of metal cations Zn2 +/Fe3+ in precursors of double hydroxides on the structure of Zn-Fe oxides of mixed phase composition has been established. With an increase in the ratio of metal cations from 1: 1 to 1:4, in the composition of Zn-Fe mixed oxides consisting of oxides ZnO and Fe3O4, the amount of complex oxides ZnFe2O4 with an isomorphic spinel structure decreases, with an increase in the specific surface area from 27.075 to 34.556 m2/d the pore diameter values of 23.8 nm remain constant. The results of experimental studies of the effect of the composition and structure of Zn-Fe mixed oxides on the component composition of heavy oil of naphthenic aromatic base during its upgrading in a hydrothermal fluid at a temperature of 380°C and a pressure of 22 MPa are presented. The maximum increase in the content of saturated hydrocarbons against the background of a noticeable decrease in the amount of asphaltenes is characteristic of hydrothermally converted oil in the presence of mixed oxides Zn-Fe (1: 4), the content of n-alkanes of the composition C10–C14 increases.

Investigation of color and anticorrosive properties of pigments in the Fe-Al-Mg-O-H system by the simplex lattice method

PurposeThe purpose of this paper is to study the patterns of formation of anti-corrosion properties, the development of compositions for pigments by using the method of co-precipitation and subsequent heat treatment.Design/methodology/approachTo obtain co-precipitated hydroxides, aqueous solutions of salts were used. The conditions of synthesis varied according to the following parameters: the nature of the starting salts of metals; and the ratio of metal cations. The anticorrosive activity of the pigments was evaluated by the potentiodynamic method, by comparing the anodic and cathodic polarization curves, and calculated potentials and corrosion currents on the basis of regions of Tafel on curves. Polarization curves were obtained by using Potentiostat/Galvanostat/ZRA Gamry, which connected to the PC, and by using the program Gamry Framework. The measurement results were processed by using the method of simplex-lattice planning. X-ray diffractograms of pigments were recorded on a DRON – 2.0 diffractometer (monochromatic copper radiation with a nickel filter).FindingsThe paper deals with the results of research the dependence of colour characteristics and anticorrosion properties of synthesized compositions on their nature and composition. The presence of aluminium cations leads to the formation of solid solutions of ferrum and aluminium oxyhydroxides.Originality/valueThe main technological properties of pigments are determined by the anionic and cationic composition. Colour characteristics are determined by the cation-chromophore. The anti-corrosive properties of non-calcined pigments are determined to a greater extent by the presence of the formed hydroxyl ions and the composition of the compounds. The greatest protective effect is observed when using double compounds of metals, the dissociation constants of which differ significantly. The protective effect is mainly determined by the slowdown of the anode process. Anions containing aluminium atoms accelerate the corrosion processes.

Towards a reliable bridge joint between REBCO coated conductors

REBa2Cu3O7-x (REBCO; RE = Y, Gd) coated conductor wires are commercially available up to a length of about 1 km. However, for large-scale devices like superconducting coils for high-field magnets several kilometres of a coated conductors are required. Therefore, it is desirable to use joints, which exhibit similar superconducting properties as the coated conductor itself. In this study, we jointed commercial REBCO coated conductors by a two-step procedure. At first, a superconducting soldering solution was developed and deposited on unstabilized coated conductors via chemical solution deposition. The soldering precursor is based on a Cu-rich solution with a metal cation ratio Y:Ba:Cu of 1:2:4. Secondly, a piece of the coated conductor was delaminated between the superconducting and the buffer layer and used as bridge between two other conductors covered with the soldering layer. Annealing the resulting bridge joint under pressure results in a mechanical stable configuration.

Sonication accelerated formation of Mg-Al-phosphate layered double hydroxide via sol-gel prepared mixed metal oxides

Single-phase magnesium-aluminium layered double hydroxide (LDH) intercalated with dihydrogen phosphate was successfully produced by hydration of nanopowder of the respective mixed metal oxide (MMO) obtained using sol-gel based method followed by a two-step anion exchange hydroxide-to-chloride and chloride-to-phosphate. The MMO with the metal cation ratio of Mg/Al = 2:1 was prepared using the aqueous sol-gel method. Processes of the parent Mg2Al-OH LDH formation and the successive anion-exchanges, ОН− → Cl− and Cl− → H2PO4−, were considerably accelerated via the application of high-power (1.5 kW) ultrasound. The crystalline phases formed at all stages of the Mg2Al-H2PO4 LDH production were characterized using X-ray diffraction, scanning electron microscopy, scanning transmission electron microscopy, inductive coupled plasma optical emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Based on the data of chemical analysis and the XRD data, the type of the intercalated phosphate anion was determined and the arrangement of this anion in the interlayer was modelled.

Atomic layer deposition of amorphous tin-gallium oxide films

A wide range of applications benefit from transparent semiconducting oxides with tunable electronic properties, for example, electron transport layers in solar cell devices, where the electron affinity is a key parameter. Presently, a few different ternary oxides are used for this purpose, but the attainable electron affinity range is typically limited. In this study, the authors develop a low-temperature atomic layer deposition (ALD) process to grow amorphous Sn1–xGaxOy thin films from dimethylamino-metal complexes and water. This oxide is predicted to provide a wide selection of possible electron affinity values, from around 3 eV for pure Ga2O3 to 4.5 eV for pure SnO2. The ALD process is evaluated for deposition temperatures in the range of 105–195 °C by in situ quartz crystal microbalance and with ex situ film characterization. The growth exhibits an ideal-like behavior at 175 °C, where the film composition can be predicted by a simple rule of mixture. Depending on film composition, the growth per cycle varies in the range of 0.6–0.8 Å at this temperature. Furthermore, the film composition for a given process appears insensitive to the deposition temperature. From material characterization, it is shown that the deposited films are highly resistive, fully amorphous, and homogeneous, with moderate levels of impurities (carbon, nitrogen, and hydrogen). By tailoring the metal cation ratio in films grown at 175 °C, the optical bandgap can be varied in the range from 2.7 eV for SnO2 to above 4.2 eV for Ga2O3. The bandgap also varies significantly as a function of deposition temperature. This control of properties indicates that Sn1–xGaxOy is a promising candidate for an electron transport layer material in a wide electron affinity range.

ZnO/ZnAl₂O₄ Nanocomposite with 3D Sphere-Like Hierarchical Structure for Photocatalytic Reduction of Aqueous Cr(VI).

Three dimensional (3D) ZnO/ZnAl2O4 nanocomposites (ZnnAl-MMO) were synthesized by a simple urea-assisted hydrothermal process and subsequent high-temperature calcination. The as-prepared samples and their precursors were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectroscopy (DRS), and Photoluminescence spectra (PL). It was observed that the morphology of ZnnAl-MMO nanocomposites could be tuned from cubic aggregates, hierarchically flower-like spheres to porous microspheres by simply changing the molar ratio of metal cations of the starting reaction mixtures. The photocatalytic performance of ZnO/ZnAl2O4 nanocomposites in the photoreduction of aqueous Cr(VI) indicated that the as-prepared 3D hierarchical sphere-like ZnnAl-MMO nanocomposite showed excellent photocatalytic activity of Cr(VI) reduction under UV light irradiation. The results indicated that the maximum removal percentage of aqueous Cr(VI) was 98% within four hours at 10 mg/L initial concentration of Cr(VI), owing to the effective charge separation and diversion of photogenerated carriers across the heterojunction interface of the composite. Our study put forward a facile method to fabricate hierarchical ZnO/ZnAl2O4 composites with potential applications for wastewater treatment.

Metal Flux Growth of Complex Alkaline Earth/Rare Earth Metal Silicides with a Homologous Series of Metal Phosphide Structure Types

Three new metal silicides were grown as competing products from reactions of silicon with barium and ytterbium in Mg/Al flux; the dominant product is determined by the heating profile as well as by the reactant ratio. The compounds Ba2Yb0.88Mg11.12Si7, Ba5Yb2.26Mg16.73Si12, and Ba20Yb4.7Mg61.3Si43 all exhibit hexagonal crystal structures that are analogous to those of ternary metal phosphides (Zr2Ni12P7, Ho5Ni19P12, and Ho20Ni66P43, respectively). The structures feature building blocks composed of silicon anions surrounded by nine metal cations; these tricapped trigonal prismatic Si@(Mg/Yb/Ba)9 polyhedra share faces to form the overall structures. Magnetic susceptibility measurements show Pauli paramagnetic behavior for all three compounds, indicating the ytterbium is divalent. The silicides have a 2:1 ratio of metal cations to silicide anions and are therefore charge-balanced. This should result in semiconducting or semimetallic behavior; the latter is supported by electronic structure calculations. The formation of these compounds indicates that a large family of complex silicides is accessible from reactions of silicon and divalent metals (Ca, Sr, Ba, Eu, Yb) in magnesium-based fluxes.

Effect of metal cation ratio on chemical properties of ZnFe2O4/AC composite and adsorption of organic contaminant

Porous woody char is biochar prepared through pyrolisis. The biochar can be used as adsorbent. In this research, ZnFe2O4/AC composite was synthesized through imregnation of the woody biochar with ZnFe2O4 to study effect of mol ratio of Fe(III) and Zn(II) toward their physicochemistry and adsorption of drug wastewater. Paracetamol was used as adsorbate model. This research was conducted in several steps, including activation of the woody biochar using KOH activator at temperatur 500 °C for 15 min to produce the activated carbon, fungsionalization of the carbon using H2SO4 oxidator (6M) at temperature of 80 °C for 3 h, impregnation of the oxidized activated carbon with Zn-Fe-LDH (Layered Double Hydroxide) at various mol ratio of Fe(III) and Zn(III), including 1:2, 1:3 and 1:4 using NaOH solution (5M) for coprecipitation, and calcination of Zn-Fe-LDH/AC at 950 °C for 5 min to produce ZnFe2O4/AC. FTIR diffraction characterization indicated existence of M-O (M = Zn(II), Fe(III)) and OH functional groups. FTIR spectra showed increasing of bands connected to –OH by increasing of the ratio till the ratio was achieved at 1:4, then decreased again. The ratio mol showed effect on the adsorption of paracetamol. Profile of adsorption value was fit with changing of functional groups. The highest adsorption was achieved at the ratio of 1:4. After calcination it gave the adsorption value of 17,66 mg/g.

Identification and Quantification of Intracoordination Water in Insoluble Pectinates Cu<sup>2+</sup> and Pb<sup>2+</sup>

By derivatography in insoluble pectins Cu2+ (РCu2+) and Pb2+ (РPb2+), the presence of “a high-temperature component” (150°C- 165°C) is established. During potentiometric alkalimetric titration of РCu2+ and РPb2+, endpoints are established at рН accordingly 4.87 and 4.95, proving acid properties of PM. Obtained data show the presence of water in the internal sphere of PM. Considering the loss of this water and the known ratio of metal cations and monomers of pectin (L-), the simplest formulas of pectins are established: [Cu(L-)2(H2O)2], [Pb(L-)2(H2O)4].