Concentration Of NH4Cl Research Articles

A synthetic method for lanthanum hydroxychloride suitable for industrialization and its thermal decomposition properties.

A reactive crystallization method for the synthesis of lanthanum hydroxychloride (La(OH)2Cl) was developed to provide a new low-carbon route for the purification of rare earth elements in hydrometallurgy. The synthetic method reported herein represents a unique low-temperature route, short preparation time and inexpensive materials compared with previous methods, thus making it promising for industrial applications. The key factors controlling the product's phase were determined using single factor tests involving temperature, concentration of NH4Cl in the base solution and the molar ratio of NH4OH/La3+ added per minute into the base solution. Otherwise, the outcome is lanthanum hydroxide (La(OH)3). Subsequently, the synthesized products were characterized by employing X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM), and energy dispersive spectroscopy (EDS). Finally, the thermal decomposition behavior of La(OH)2Cl was assessed using thermogravimetry (TG) and differential scanning calorimetry (DSC). Lanthanum oxychloride (LaClO) was obtained at about 360 °C. The thermal transformation from LaClO to La2O3 started at 400 °C and was a slow oxidation process. Pure La2O3 could be obtained when the temperature increased to 1500 °C.

An alternative chlorine-assisted optimization of CdS/Sb2Se3 solar cells: Towards understanding of chlorine incorporation mechanism

The current strategies in the development of Sb2Se3 thin film solar cells involve fabrication and optimization of superstrate and substrate device architectures, with the preferable choice for TiO2 and CdS heterojunction layers. For CdS-based superstrate cells, several studies reported the necessity to apply CdCl2 or other metal halide-based post-deposition treatment (PDT), highlighting improvement of CdS/Sb2Se3 device efficiency. However, the need, effect, and mechanism of such PDT are very often not described. Additionally, the fact that many groups have not succeeded in demonstrating its benefits suggests that this strategy is not straightforward, requiring a deeper understanding towards a more unified concept. The present study proposes an alternative approach to the challenging CdCl2 PDT of CdS in CdS/Sb2Se3 device, involving controllable Cl incorporation in CdS films by systematically varying the concentration of NH4Cl in the CBD precursor solution from 1 to 8 mM. Structural and electrical characterizations are correlated with advanced measurements of Scanning Kelvin Probe, surface photovoltage, and atomic force microscopy to understand the impact of Cl incorporation on the properties of CdS films and CdS/Sb2Se3 devices. The validity of Cl incorporation in the CdS lattice and interdiffusion processes at the CdS-Sb2Se3 interface is confirmed by secondary ion mass spectrometry analysis. It is demonstrated that incorporation of 1 mM of NH4Cl, as a Cl source in CBD CdS, can boost the PCE of CdS/Sb2Se3 by ∼20 %. With this approach, we offer new perspectives on the optimization methodology for Cl-based CdS/Sb2Se3 device processing and complementary understanding of the physiochemistry behind these processes.

PVP-assisted in-situ self-assembly hierarchical BiOCl with oxygen vacancies for efficient photocatalytic oxidation of cyclohexane under air in solvent-free conditions

Cyclohexane (CHA) selective oxidation reactions are crucial in designing advanced organic intermediates but suffering from very challenges as the products of KA oil (cyclohexanol and cyclohexanone) are more readily oxidized to CO2. Herein, we report that a polyvinylpyrrolidone (PVP) coating of fluffy self-assembled morphology of BiOCl by nanosheets with exposed {001} facets are synthesized via the solvothermal method. Moreover, the as-synthesized hierarchical BiOCl exhibits a significant presence of in-situ produced oxygen vacancies during photocatalysis, thereby facilitating efficient CHA oxidation to KA oil with air as an oxidant in solvent-free at room temperature. The crystallinity, micromorphology, and electronic structure of BiOCl can be significantly influenced by the concentration of NH4Cl and PVP. In the photocatalytic oxidation, oxygen vacancies act as traps to inhibit electrons and holes recombination and adsorb-activate the oxygen molecule, producing h+ and ·O2− radical to achieve 466.7 μmol of KA oil (340.8 μmol of cyclohexanone and 125.9 μmol of cyclohexanol) with a selectivity of 93.9 %. The ∙OH radicals play a predominant role in the production of CHA-one. After conducting 5 experimental cycles, a consistent yield of 92 % towards KA oil and unchanged selectivity can still be maintained. The excellent photocatalytic performance can be attributed to the enhanced photo-absorption and narrow energy gap, abundant oxygen vacancies, high exposed {001} facets, smaller size and large specific surface area, and efficient electron-hole separation. The present work sheds light on the synergistic effect of PVP coating and in-situ formed oxygen vacancies on enhancing photocatalytic activity of Bi-based materials.

Bioelectrochemical synthesis of rhamnolipids and energy production and its correlation with nitrogen in air-cathode microbial fuel cells

Microbial fuel cells (MFCs) have been recently proven to synthesise biosurfactants from waste products. In classic bioreactors, the efficiency of biosynthesis process can be controlled by the concentration of nitrogen content in the electrolyte. However, it was not known whether a similar control mechanism could be applied in current-generating conditions. In this work, the effect of nitrogen concentration on biosurfactant production from waste cooking oil was investigated. The concentration of NH4Cl in the electrolyte ranged from 0 to 1 g L−1. The maximum power density equal to 17.5 W m−3 was achieved at a concentration of 0.5 g L−1 (C/N = 2.32) and was accompanied by the highest surface tension decrease (to 54.6 mN m−1) and an emulsification activity index of 95.4%. Characterisation of the biosurfactants produced by the LC-MS/MS method showed the presence of eleven compounds belonging to the mono- and di-rhamnolipids group, most likely produced by P. aeruginosa, which was the most abundant (19.6%) in the community. Importantly, we have found a strong correlation (R = −0.96) of power and biosurfactant activity in response to C/N ratio. This study shows that nitrogen plays an important role in the current-generating metabolism of waste cooking oil. To the best of our knowledge, this is the first study where the nitrogen optimisation was investigated to improve the synthesis of biosurfactants and power generation in a bioelectrochemical system.

Leaching of palladium from spent Pd/Al2O3 catalysts by coupled ultrasound-microwave technique

The recycling and reuse of spent Pd/Al2O3 catalysts have tremendous social, environmental, and economic benefits. Calcined-ClO2 and NH4Cl aqueous leaching method was investigated to recover Pd from spent Pd/Al2O3 catalysts, and ultrasound-microwave was introduced to intensify the leaching process, after which the surface morphology, valence, and content of major elements, and crystalline shape of carriers of the spent Pd/Al2O3 catalysts before and after the leaching were determined and analyzed. The results showed that ultrasonic-microwave-enhancement increased the leaching rate and shortened the leaching time of Pd in comparison with the conventional leaching experiments, and the leaching rate of Pd at 10 min of ultrasonic-microwave-enhanced leaching was 31.1 %, which was 13.6 % higher than that of the conventional conditions. The optimal process conditions: calcination temperature was 200 °C, calcination time was 90 min, the dosage of ClO2 was 15 % (V/Vall), the concentration of NH4Cl was 2 mol/L, the dosage of HCl (1 mol/L) was 15 % (V/Vall), the leaching power was 400 W, leaching temperature was 90 °C, leaching time was 60 min, and the liquid–solid ratio was 10:1. Eventually, the leaching rate of palladium was 80.6 %, and the average retention rate of carrier was about 94 %.

Enhanced recovery of high purity Cu powder from reclaimed copper smelting fly ash by NH3·H2O–NH4Cl slurry electrolysis system

Reclaimed copper smelting fly ash (RCA) is a residue produced during the smelting process of waste miscellaneous copper, containing heavy metals such as Cu, Zn, and Cd. In this study, a slurry electrolysis system was used to recover Cu from RCA. The results showed that the recovery efficiency, current efficiency, and purity of Cu on cathode were 97.11 %, 91.22 %, and 98.47 %, respectively, when the concentration of NH3·H2O was 2 mol/L, the concentration of NH4Cl was 1 mol/L, the concentration of CuSO4·5H2O was 20 g/L, the solid-liquid ratio was 50 g/L, the electric current density was 30 mA/cm2 and the reaction time was 2 h. The content of Zn in the RCA decreased from 144.54 mg/g to 23.7 mg/g and Cd from 0.72 mg/g to 0.005 mg/g after slurry electrolysis, and other heavy metals in the RCA also decreased. The potential difference that occurs between the two poles under the NH3·H2O slurry electrolysis system promotes the leaching of Cu from the RCA, while the leached Cu2+ combines with NH4+ to form the Cu–NH3 complex (Cu(NH3)42+, Cu(NH3)2+), thus increasing the current efficiency and promoting the cathodic copper deposition. The high-purity Cu obtained at the cathode belongs to the face-centered cubic structure (111), (200) and (220) of the Cu crystalline surface. This study provides a new method for the resourceful recovery of copper from RCA.

ВОССТАНОВЛЕНИЯ ДЕТАЛЕЙ СЕЛЬСКОХОЗЯЙСТВЕННОЙ ТЕХНИКИ НАНЕСЕНИЕМ КОМПОЗИЦИОННЫХ ПОКРЫТИЙ НА ОСНОВЕ ЖЕЛЕЗА

Great opportunities for increasing the resource of parts of agricultural machinery that require restoration are opened up by technologies for applying hardening coatings. Options for obtaining galvanic deposits in various electrolytes, which allow depositing metal coatings with various special properties that ensure reliable operation of restored units under appropriate conditions, are considered in the article. Solutions of sulphate, chloride, and hydroboric fluoride salts of divalent iron were used as the electrolyte. Methods of chemical analysis of galvanic deposits were used. The hardness of the deposited layers was determined using a PMT-3 instrument. The effect of various alloying additives on the quality of the precipitates obtained is analyzed depending on the concentration of inclusions. The boundaries of inclusion concentrations are determined. It has been established that for controlled deposition of a composite coating, the concentration of inclusions in the deposited iron-containing coating should not exceed 20 g/l. It has been found that even an insignificant presence of manganese inclusions in an iron-based composite coating, which is of the order of the measurement error, doubles its hardness. The dependence of the concentration of ammonium chloride, as the base material for the extraction of pure manganese, on the hardness of the deposited galvanic precipitate, was studied in the framework of the described study. The highest hardness was achieved at a concentration of NH4Cl in the range of 100–150 g/l, and manganese - 0.4% by weight. Graphical dependences of the main quality indicators of the resulting coatings on the type and composition of the electrolytes used were obtained. The influence of the electrolyte temperature and electrolysis regimes on the hardness of the deposited metal is analyzed.

The trade-off effect of KCl and NH4Cl on the hydrated structure in their mixed aqueous solutions

The hydrated structure of KCl and NH4Cl mixed solution were studied by X-ray scattering, Raman spectroscopy and molecular dynamics (MD) simulation method in the range of 0.00%-28.0% mass fraction at 25 °C. Through the analysis of reduced pair distribution function [G(r)], it was found that when the concentration of KCl in the mixed aqueous solution decreased and the concentration of NH4Cl increased, the main peak of G(r) shifted from r = 2.81 Å to the right of the axis. In the absence of KCl, the position of the main peak was r = 3.15 Å. It was speculated that this phenomenon was caused by the main interaction changed from K-OW and OW-OW (r = 2.80 Å) to NO (r = 3.06 Å) and NH4+-Cl− (r = 3.3 Å). It is indicated by the Raman spectra, when the concentration of KCl is high and the concentration of NH4Cl is low, the destruction of the tetrahedral hydrogen bond network in the solution is more serious. In the MD simulation, the coordination number of OW-OW decreases with the increase of KCl concentration, indicating that the tetrahedral hydrogen bond network is severely damaged, which is concerned with the results of Raman spectroscopy.

Importancia de la relación C/N en la producción de biomasa y actividad antimicrobiana de la bacteria marina Pseudoalteromonas sp

The main objective of this study was to investigate from the physiological point of view, the influence that nitrogen and carbon sources have on the biomass production and activity of the antimicrobial protein of Pseudoalteromonas sp. The impact of the change in the medium initial C/N-ratio on biomass production and antimicrobial activity against S. aureus MRSA was evaluated using two different carbon sources (glucose or citrate) and a fixed concentration of NH4Cl as a nitrogen source. The change in total nitrogen concentration in the medium was evaluated using organic or inorganic nitrogen sources (NH4Cl or yeast extract-peptone) while a fixed glucose concentrations was present. The results showed that the increase in C/N-ratio stimulated biomass production but inhibited antimicrobial activity regardless of the nature of the carbon source. Similarly, the biomass profile and antibiotic activity were dependent in the variation of low nitrogen total concentrations in the medium and especially at concentrations bigger than 3 g L-1 negatively affected the antimicrobial activity. This indicated that the main factor affected the secondary metabolism of Pseudoalteromonas sp. was the nitrogen concentration over C/N-ratio.

Electrodeposition of Fe–Mn alloys from chloride-based bath: A preliminary study for biomedical applications

Abstract Fe–Mn alloys are promising candidates for less-invasive and temporary implants such as bioabsorbable stents. However, their composition and microstructure must be tailored to assess an adequate corrosion rate for the desirable lifespan of the stent. This study aimed to evaluate the development of Fe–Mn alloy and its structure and properties correlation when processed by electrodeposition. Planar samples were produced by potentiostatic deposition at two different potentials, −1.3 and −1.7 V vs. Ag/AgCl, from a chloride-based acidic electrolyte with different amounts of NH4Cl. It was verified that, in more negative deposition potentials, the deposition interface changes from planar to dendritic, leading to more ramified deposits with a high level of defects like cracks and pores. More negative potentials also increased the Mn content in the deposit from 0.8 to 5.2 wt.% Mn. The microstructure was composed of a single phase of (Fe, Mn) solid solution in the −1.3 V vs. Ag/AgCl deposit, while the deposit obtained at −1.7 V vs. Ag/AgCl exhibit two phases, one rich in Mn and the other rich in Fe. A higher concentration of NH4Cl in the electrolyte leads to an increase in the Mn content (5.2 wt.% Mn), maintaining the monophasic microstructure. Although several challenges still remain, these results prove that is possible to obtain Fe–Mn bioabsorbable alloys by electrodeposition, which opens a new processing route for these alloys.

Controllable fabrication of highly visible-light responsive oxygen-rich Ti-based microspheres with the hierarchical surface through a facile and dopant-free hydrothermal route

The oxygen-rich Ti-based composite (ORTC) microspheres with high visible-light photoactivity were successfully synthesized by a facile and dopant-free hydrothermal method. The as-synthesized urchin-like microspheres possess a controllable hierarchical structure that is strongly dependent on the concentration of H2O2 and NH4Cl, and displayed an excellent visible light photoactivity without annealing activation, which is attributed to the formation of the oxygen excess defects. The ORTC prepared in optimal conditions gave the narrowest band gap of 2.31 eV due to its highest oxygen excess defects content, and showed a stable and high-efficiency visible-light photocatalytic performance for organic dyes degradation, exhibiting three-fold as that of the control sample. The synergistic effect of oxygen excess defects, hierarchical structure and strong adsorption capacity was identified as the key factor responsible for the prominent performance. Based on the obtained results, a plausible mechanism for fabricating urchin-like ORTC microspheres with nanofiber branches was proposed and discussed in detail.

Copper Recovery from Rinse Waters after Ammoniac Etching of Printed Circuit Boards

The process of sorption-electrochemical cleaning of rinse waters, obtained after ammonia etching of printed circuit boards from copper ions, is proposed. Cation exchanger KU-2×8 and ampholyte Lewatit MonoPlus TP 207 for the extraction of copper were tested. Capacity up to breakthrough of Lewatit MonoPlus TP 207 is 0.11 g/g and a full dynamic exchange capacity for copper of 0.15 g/g. Various options of a pregnant ion exchanger desorption are considered. The best stripping ability has a 20% solution of sulfuric acid. The possibility of desorption by a partially de-coppered eluate was studied. This scheme allows the use of acid formed in the process of copper electro-winning. The effect of concentrations of NH4Cl and NH4OH on the sorption of copper was studied. It was shown that, with an increase in the concentration of NH4Cl to 100 g/dm3, the capacity of the ion exchanger decreases by 10.42%. Thus, the ion exchanger Lewatit MonoPlus TP 207 effectively absorbs copper even at high salt background. A combined sorption-electrochemical technology has been proposed for treatment of rinse waters. The proposed technology will reduce consumption of fresh water and ammonia for printed circuit boards washing and extract copper in the form of elemental metal.

Electrochemical approach towards the controllable synthesis of nickel nanocones based on the screw dislocation

Densely and orderly Ni nanocones with regular spiral textures had been successfully synthesized via a simple and inexpensive electrodeposition process, named two-step electrode-exchange electrodeposition process, in solutions containing ammonium chloride (NH4Cl). Microstructure characterization indicated that Ni nanocones obtained by electrodeposition were pure Ni and were face centre cubic (fcc) structure, which grown mainly along (111) and (220) crystal face. After analysing the morphology, a more optimized possible growth mechanism of Ni nanocones was proposed, in which the stacking microstructure of Ni nanocones was mainly dependent on the stacking direction of Ni2+ on the crystal face (the same direction and the exact opposite direction). Meanwhile, we found that the microstructure of Ni nanocones would be controlled by adjusting the experiment parameters such as concentration of NH4Cl and electrodeposition time, and that the disintegration of complex ions caused NH4+ to gather in large numbers near the cathode and hinder the movement of subsequent complex ions, which made a great change in the microstructure of Ni nanocones.

The retardation of polyacrylamide by ammonium chloride in high-salinity and high-temperature conditions: molecular analysis

Salinity effects on retardation efficiency of ammonium chloride (NH4Cl) on the polyacrylamide (PAM) that influences the gelation time of PAM-based polymer gel are an interesting phenomenon. This paper presents a concise investigation by quantifying molecular interaction of PAM with NH4Cl in high-salinity and high-temperature conditions. This study quantified the ionic bonding of carboxylate group of PAM with ammonium ion of NH4Cl using zeta-potential, hydrodynamic radius, and hydrolysis degree. Experimental results show that in the absence of NaCl and NH4Cl, the overall magnitude absolute values of zeta-potential, hydrodynamic radius, and hydrolysis degree of PAM show a significant increase. The absolute value of zeta-potential reduces with the concentration of NH4Cl as retarder. On the other hand, the hydrodynamic radius and hydrolysis degree tend to increase with the concentration of NH4Cl, even in high salinity. The retardation process is also fairly affected by the exposure time of polymer to high temperature. These results give better understanding and provide additional knowledge as the conventional research did not fully reveal the efficiency of polymer gel with retarder that was prepared with high salinity for high-temperature application.

The effects of refractory pollutants in swine wastewater on the growth of Scenedesmus sp. with biofilm attached culture

Microalgae have been widely used for treatment of swine wastewater. However, the research on combined treatment of refractory pollutants ammonia nitrogen, Cu (II) and antibiotics from swine wastewater was still scattered. This study, the growth and removal efficiency of NH4Cl, CuSO4, tetracycline, norfloxacin and sulfadimidine with selected Scenedsmus sp. was investigated by biofilm attached culture. The results showed that low concentration of ammonia nitrogen had little effect on algae growth. The highest biomass productivity was 6.2 g/(m2d) at the concentration of NH4Cl of 50.0 mg/L, which was similar to that of a standard growth medium BG 11. Cu (II) concentration of 1.0 mg/L could accelerate the growth of Scenedsmus sp., and the highest biomass was 57.2 g/m2 in 8 days. Moreover, the highest biomass mean values was 59.5 g/m2, 57.1 g/m2, and 58.1 g/m2, respectively, when tetracycline concentration was 20.0 mg/L, norfloxacin concentration was 100.0 mg/L and sulfadimidine concentration was 10.0 mg/L. The removal efficiency of ammonia nitrogen, copper, tetracycline, norfloxacin and sulfadimidine with Scenedsmus sp. at their optimal initial concentration by biofilm attached culture was 85.2%, 64.6%, 74.6%,71.2%, and 62.3%, respectively. This study provides a theoretical basis for the purification of refractory substances from swine wastewater.

Size-fractionated water-soluble ions during autumn and winter: Insights into volatile ammonium formation mechanisms in Shanghai, a megacity of China

Abstract Size-fractionated aerosols were collected by a Micro-Orifice Uniform Deposit Impactor at an urban site in Shanghai during the autumn and winter of 2014. The results showed that the average concentration of PM1.8 increased from 49 μg m−3 in autumn to 74 μg m−3 in winter. By contrast, the relative contribution of the water-soluble inorganic species decreased from 40% in autumn to 31% in winter. This finding suggests that the increase of organic matter (OM) greatly contributed to the deterioration of particle pollution in winter. Compared to autumn, the concentration of sulfate decreased whereas the concentration of NH4Cl increased significantly and became an important constituent of the fine particles in winter. The formation of nitrate in autumn became significant at [NH4+]/[SO42−] > 2, indicating that H2SO4 was fully neutralized by NH3 to form (NH4)2SO4. Our results showed that the regression between [NO3−]/[SO42−] and [NH4+]/[SO42−] drawn an unrealistic nitrate formation mechanism when the particulate NH4Cl was abundant. Replacing [NO3−] with {[NO3−]+[Cl−]} in the regression between [NO3−]/[SO42−] and [NH4+]/[SO42−], it is established that (NH4)2SO4 is preferentially formed before the excess available NH3 can react with HNO3 and HCl to form NH4NO3 and NH4Cl during wintertime. The concentrations of particulate sulfate and nitrate were not positively correlated with the ambient relative humidity, indicating that heterogeneous reactions on wet particles were not the key to haze formation in Shanghai during winter. Our results suggest that more studies are needed to understand the complex haze formation mechanisms in China.

Electricity production and phosphorous recovery as struvite from synthetic wastewater using magnesium-air fuel cell electrocoagulation

This research was based on the investigation of a major principle, regarding the effects of NaCl and KH2PO4 concentrations on struvite recovery, with electricity production using magnesium-air fuel cell electrocoagulation, in accordance with the concentration of phosphorous and chloride. The weight ratio of N:P in the synthetic wastewater was in the range of 1.2–21. The concentration of NH4Cl was fixed at 0.277 M (approximately 3888 ppm as NH3-N and 5000 ppm as NH4), while PO4-P was in the range of 0.006–0.1 M. In addition, the concentrations of NaCl as electrolyte were 0, 0.01, and 0.1 M. Phosphate removal increased linearly with the Mg:P ratio, up to approximately 1.1 mol mol−1, irrespective of the initial concentrations of phosphate and NaCl. The one-to-one reaction as mole ratio between phosphate and the dissolved Mg ions resulted in phosphate removal, with the production of a one-to-one magnesium/phosphate mineral, such as struvite. The average removal rate of phosphorous in experiments without a dose of NaCl was 4.19 mg P cm−2 h−1, which was lower than the relative values of 5.35 and 4.77 mg P cm−2 h−1, in experiments with 0.01 and 0.1 M NaCl. The dissolution rate of Mg with electro-oxidation determined the rate of phosphorous removal with struvite recovery. The average removal rates of phosphorous with dose concentrations of 0.006, 0.01 and 0.02 M KH2PO4 were 4.02, 5.54, 6.9 mg P cm−2 h−1, respectively, which increased with the increase in KH2PO4 dose. However, in experiments with a dose of 0.05 and 0.1 M KH2PO4, the average removal rates of phosphorous decreased to 4.84 and 2.51, respectively. The maximum power densities in the electrolyte mixture of 0.05 M KH2PO4/0.277 M NH4Cl, 0.01 M NaCl/0.05 M KH2PO4/0.277 M NH4Cl, and 0.1 NaCl/0.05 KH2PO4/0.277 M NH4Cl were 25.1, 26.4, and 33.2 W/m2, respectively. The increase in the NaCl dose concentration resulted in an increase in the maximum power density and current density. A dose above 0.05 M KH2PO4 resulted in the decrease of the maximum power densities. However, when the dose was below 0.05 M KH2PO4, the maximum power density increased with the increase in KH2PO4 dose.

CO2 Absorption and Magnesium Carbonate Precipitation in MgCl2–NH3–NH4Cl Solutions: Implications for Carbon Capture and Storage

CO2 absorption and carbonate precipitation are the two core processes controlling the reaction rate and path of CO2 mineral sequestration. Whereas previous studies have focused on testing reactive crystallization and precipitation kinetics, much less attention has been paid to absorption, the key process determining the removal efficiency of CO2. In this study, adopting a novel wetted wall column reactor, we systematically explore the rates and mechanisms of carbon transformation from CO2 gas to carbonates in MgCl2–NH3–NH4Cl solutions. We find that reactive diffusion in liquid film of the wetted wall column is the rate-limiting step of CO2 absorption when proceeding chiefly through interactions between CO2(aq) and NH3(aq). We further quantified the reaction kinetic constant of the CO2–NH3 reaction. Our results indicate that higher initial concentration of NH4Cl ( ≥ 2 mol · L − 1 ) leads to the precipitation of roguinite [ ( NH 4 ) 2 Mg ( CO 3 ) 2 · 4 H 2 O ], while nesquehonite appears to be the dominant Mg-carbonate without NH4Cl addition. We also noticed dypingite formation via phase transformation in hot water. This study provides new insight into the reaction kinetics of CO2 mineral carbonation that indicates the potential of this technique for future application to industrial-scale CO2 sequestration.

THIOCYANATE COMPLEXES OF d-METALS: INFLUENCE OF CONCENTRATION OF KNCS AND NH4Cl ON A TYPE OF COORDINATION OF SCN-IONS BY FTIR SPECTROMETRY

By IR spectrometry thiocyanates aqueous solutions of divalent cations of cadmium, mercury, nickel, manganese, iron, zinc and cobalt were studied. It was found that cadmium (II), mercury (II), nickel (II), iron (II) thiocyanate ions coordinated by type thiocyanate, zinc (II) − according to the type isothiocyanate; cobalt (II) and manganese (II) coordination mode change depending on the concentration of potassium thiocyanate in a solution. These results are consistent with the theory of hard and soft acids and bases. Co2+ ions are intermediate acids, so they can coordinate with SCN− into two types; Zn2+ ions, although they belong to intermediate acids but have a strong affinity to nitrogen atoms, so thiocyanate group coordinated through nitrogen with Zn2+. Cations Hg2+ and Cd2+ are typical soft acids, so only coordinated SCN− ions through sulfur (as a mild base). Mn2+ ions can coordinate SCN− by two types. The effect of additives of the ammonium chloride ions on thiocyanate ions (0.5 mol/l) coordination with cobalt (II) ions was studie. With the increasing concentration of ammonium chloride in a solution a change occurs of coordination type with thiocyanate to isothiocyanate. It has been suggested that the increase in the concentration of potassium thiocyanate leads to the increase in the proportion of Co(NCS)42− and reduce the proportion of «free» water (unrelated with ions in the solution). Therefore, SCN− ions in the case Mn2+ and Co2+ oriented so that the hydrophobic sulfur atoms are external ones.Forcitation:Matveichuk Yu.V., Rakhman′ko E.M. Thiocyanate complexes of d-metals: influence of concentration of KNCS and NH4Cl on a type of coordination of SCN− ions by FTIR spectrometry. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 7. P. 34-41.

Surface topography study of CdS thin film nanostructure synthesized by CBD

Nanocrystalline Cadmium Sulphide (CdS) thin films were synthesized by chemical bath deposition with various concentration of CdCl2, thioria and NH4Cl at 80°C deposition temperature FTO glass coated substrate. X-ray diffraction study indicates of CdS thin film nanostructure a hexagonal structure with 23.2nm crystal size. Optical properties carried out by UV–vis which used also to obtain band gap energy. Surface morphology and cross section of CdS thin films nanostructure were obtained by FESEM. In addition, atomic force microscope (AFM) was employed to investigate the surface topography of CdS thin films nanostructure. Amplitude parameters, functional parameter and hybrid parameters were discussed in details beside granularity cumulation distribution.