Mother Solution Research Articles

Hierarchical Assembly of a {Co24} Cluster from Two Vertex-Fused {Co13} Clusters and Their Single-Molecule Magnetism.

We present the synthesis, structural characterization, and magnetic properties of two high-nuclearity cobalt clusters formulated as [Co13(μ3-OH)3(μ3-Cl)(dpbt)5(ptd)Cl10][Co(H2O)2Cl2]·(CH3)2CHOH (1) and [Co24(μ3-OH)6(μ3-Cl)2(dpbt)10(ptd)2Cl16]·2CH3CH2OH (2), respectively (H2dpbt = 5,5'-bis(pyridin-2-yl)-3,3'-bis(1,2,4-triazole) and H2ptd = 3-(pyridin-2-yl)-1,2,4-triazine-5,6-diol). Compound 1 is composed of an inner [Co4(μ3-OH)3(μ3-Cl)] cubane and an outer [Co9(dpbt)5(ptd)Cl10] defective adamantane. Compound 2 reveals a giant {Co24} cluster possessing a dual-[Co12] skeleton from 1. The hierarchical assembly from 1 to 2 has been established and tracked through high-resolution electrospray ionization (HRESI-MS) analyses from the solvothermal reaction mother solution. Magnetic studies of 1 and 2 revealed the highly correlated spins, a glasslike magnetic phase transition at ca. 8 K, and slow relaxation behavior of SMM nature in the lower-temperature region (below 4 K).

Transformation of Indonesian Natural Zeolite into Analcime Phase under Hydrothermal Condition

Natural zeolite is abundantly available in Indonesia and well distributed especially in the volcano area like Java, Sumatera, and Sulawesi. So far, natural zeolite from Klaten, Central Java is one of the most interesting zeolites has been widely studied. This research aims to know the effect of seed-assisted synthesis under a hydrothermal condition at 120 °C for 24 hours of Klaten’s zeolite toward the structural change and phase transformation of the original structure. According to XRD and XRF analysis, seed-assisted synthesis through the addition of aluminosilicate mother solution has transformed Klaten’s zeolite which contains (mordenite and clinoptilolite) into analcime type with decreasing Si/Al ratio from 4.51 into 1.38. Morphological analysis using SEM showed the shape changes from irregular into spherical looks like takraw ball in the range of 0.3 to 0.7 micrometer. Based on FTIR data, structure of TO4 site (T = Si or Al) was observed in the range of 300-1300 cm-1 and the occupancy of Brønsted acid site as OH stretching band from silanol groups was detected at 3440-3650 cm-1. Nitrogen adsorption-desorption analysis confirmed that transformation Klaten’s zeolite into analcime type has decreased the surface area from 55.41 to 22.89 m2/g and showed inhomogeneous pore distribution which can be classified as micro-mesoporous aluminosilicate materials.

Investigations on Mg-borate kinetics and mechanisms during evaporation, dilution and crystallization by Raman spectroscopy

Raman spectra of boron-concentrated, diluted, and corresponding mother solutions of brine were recorded at 298.15 K. The main polyborate anions present and their interactions in brine during evaporation and dilution were proposed according to the Raman spectra. The polyborate anions B(OH)3, B3O3(OH)4−, B5O6(OH)4−, and B6O7(OH)62− were found to be the main forms in boron-concentrated brine with B3O3(OH)4− ion being the principal form. Diluting brines with water accelerated depolymerization of B5O6(OH)4− and B6O7(OH)62− anions into B(OH)3 and B3O3(OH)4− ions and generated OH– ions, causing the pH of the solutions to increase from 4.2 to almost 8.0. Mg-borates precipitated from all diluted solutions could be classified as either hexaborates or triborates. A mechanism of solid phase transformation was also proposed and discussed based on Raman spectra analysis and solid species and solution pH data.

Structure of A Ni(Ii) Mixed Ligand Complex with 3-Imidazoline Nitroxide, ISO-Propanol, and Water

A mixed ligand complex of Ni(II) with 3-imidazoline nitroxide and iso-propanol [NiL2(i-C3H7OH)2] is sensitive to atmospheric moisture. It is determined that at a high humidity, the air contacts with the mother solution of the compound in iso-propanol with the precipitated [NiL2(i-C3H7OH)2] crystals leads to their spontaneous transformation into [NiL2(H2O)]·i-C3H7OH crystals whose structure is described in the present paper.

Cyclic Utilization of Zinc Borate Mother Solution via a New Method

AbstractZinc borate mother solution is cycled to prepare 2ZnO·3B2O3·7H2O, 3ZnO·5B2O3·14H2O, and 4ZnO·B2O3·H2O based on the properties of borate depolymerization. The results show uniform quadrilateral‐prism‐like and octahedron‐like 2ZnO·3B2O3·7H2O are synthesized at different temperatures. Flake‐like 3ZnO·5B2O3·14H2O is fabricated as reaction time prolonging, and 2ZnO·3B2O3·7H2O changed into 3ZnO·5B2O3·14H2O spontaneously. Meanwhile, resulting 2ZnO·3B2O3·7H2O is investigated to fabricate high aspect ratio of 4ZnO·B2O3·H2O whisker. Impressively, uniform 4ZnO·B2O3·H2O whisker can be resynthesized by the filtrates of 2ZnO·3B2O3·7H2O and 3ZnO·5B2O3·14H2O via the zero‐waste technology.

Synthesis of hydrothermally stable mesoporous aluminosilicates by using urea as additive

Mesoporous aluminosilicates (MAs) with high hydrothermal stability by assembly Y precursors have been a promising materials for cracking heavy oil. A means to reduce the template consumption and water discharge is of vital importance in synthesis of MAs. Mother liquor recycling (MLR) is an eco-friendly and effective method to synthesize (MAs) with largely reduced template consumption and water discharge. However, inorganic salts accumulation especially for SO42− in the mother liquor with continuous recycling has a negative influence on the micellization of the surfactants. The P123 molecules tend to aggregate into much larger particles and the assembly mother solution becomes cloudy. Less ordered MAs with poor hydrothermal stability would be obtained. In this work, well-ordered MAs with high hydrothermal stability were synthesized via MLR method by introducing urea as additives. Urea acting as salting-in additives behaves opposite to the inorganic salts, which could clear the assembly mother solution by breaking down the P123 aggregates into micelles. After hydrothermal treatment in 100% water vapor at 800 °C for 16 h, the obtained sample maintains 37.7% of specific surface area and 62.1% of total pore volume. In contrast, the sample prepared without adding urea just maintains 15.0% of specific surface area and 20.0% of total pore volume. This strategy provides a high efficiency and low cost route to the synthesis of MAs, which sheds a light on the practical application of MAs.

Structure disordering and thermal decomposition of manganese oxalate dihydrate, MnC2O4·2H2O

It is found that the known regular structures of MnC2O4·2H2O (I) do not allow to refine the powder X-ray pattern of (I) properly using the Rietveld method. Implementation of order-disorder scheme [28] via the including of appropriate displacement vector improves the refinement results. Also it is found that in the case of (I) the similar improvement may be achieved using the data on two phases of (I) obtained as result of decomposition MnC2O4·3H2O single crystal in the mother solution after growth. Thermal decomposition of (I) produce the anhydrous γ-MnC2O4 (II) the structure of which is differ from the known α- and β-modifications of VIIIb transition metal oxalates. The solved ab initio from the powder pattern structure (II) (space group Pmna, a = 7.1333 (1), b = 5.8787 (1), c = 9.0186 (2) Å, V = 378.19 (1) Å3, Z = 4 and Dx = 2.511 Mg m−3) contains seven-coordinated Mn atoms with Mn–O distances of 2.110–2.358 Å, and is not close-packed. Thermal decomposition of (II) in air flows via forming of amorphous MnO, the heating of which up to 723 K is accompanied by oxidation of MnO to Mn2O3 and further recrystallization of the latter.

“Freezing” of NaClO3 Metastable Crystalline State by Optical Trapping in Unsaturated Microdroplet

We reversibly controlled phase conversion between a microdroplet of a NaClO3 unsaturated aqueous solution and a metastable single crystal, which is usually a short-lived phase in spontaneous crystallization, simply by irradiating a tightly focused visible continuous-wave (CW) laser to the microdroplet. The laser irradiation allowed the metastable crystal to generate and stably grow without a polymorphic transformation. This successful metastable phase control is attributed to the combination of the advantage of optical trapping-induced nucleation that nucleation takes place from unsaturated mother solution and the advantage of microdroplet method, which suppresses additional nucleation leading to the transformation. In situ observation shows the crystal dissolves when the laser irradiation is stopped, whereas the laser irradiation stabilizes the crystal even if the size of the crystal becomes larger than that of focal spot. These observations indicate that a change in the relative magnitudes of chemical p...

Snapshot and crystallographic observations of kinetic and thermodynamic products for NO2S2 macrocyclic complexes.

Direct observation and structural characterization of a kinetic product and a thermodynamic product for complexes with an NO2S2 macrocycle (L) are reported. L reacts with copper(I) iodide to give a mononuclear complex [Cu(L)]2(Cu2I4)·2CH2Cl2 (1), featuring three separate units. When cadmium(II) iodide was reacted with L, an anion-coordinated complex [Cd(L)I]2(Cd2I6)·4CH3CN (2) with a needle-type crystal shape was formed as the kinetic product. Interestingly, when the needle-type kinetic product was left undisturbed in the mother solution it gradually transformed to the pseudo-dimer complex [Cd2(L)2I2](Cd2I6) (3) with a brick-type crystal shape as the thermodynamic product. The dissolution-recrystallization process resulted in the elimination of the lattice solvent molecules (aceto-nitrile) in 2 and the contraction of two neighboring macrocyclic complex units [Cd(L)I]+, forming the pseudo-dimer 3via an intermolecular Cd⋯I interaction between two monomers. For the entire process from kinetic to thermodynamic products, it was possible to obtain sequential photographic snapshots, single-crystal X-ray structures and powder X-ray diffraction patterns. For the copper(I) and cadmium(II) complexes, competitive NMR results agree with the solid-state data that show copper(I) has a higher affinity for L than does cadmium(II).

Partition of metallic cations between aqueous solutions and mixed crystals of hydrated cobalt and nickel nitrates: Modelling of the influence of temperature and composition

Abstract A systematic study of the solid-liquid equilibria of the H2O-Co(NO3)2-Ni(NO3)2 ternary system enabled to define the liquidus and the solidus curves of the isotherms at 287.15 K and 313.5 K. Two widespread solid solutions, Co(1-σ)Niσ(NO3)2.6H2O and Ni(1-ω)Coω(NO3)2.6H2O, were observed. They were formed by the substitution of Co2+ cations by Ni2+ cations in the monoclinic structure of the cobalt nitrate hexahydrate and the substitution of Ni2+ by Co2+ in the triclinic structure of the nickel nitrate hexahydrate. Two series of tie-lines for each crystallographic structure of these hexahydrates were obtained. The analyses of these tie-lines and those of the previous studies at 258.15 K and 303.15 K enabled a thermodynamic modelling of the solid-liquid equilibria within a temperature range from 258.15 K to 313.15 K. The simple equation system obtained allows to calculate the accurate composition of the mother solution, at a defined temperature, to reach the appropriate cationic ratio in the crystallised solid solution.

Conformation mediated preferential swelling of amphiphilic block copolymer ultrathin films

Steady-state and dynamic swelling characteristics of PEO-PPO-PEO copolymer ultrathin films comprising 2-layered structure, where the bottom layer (L1) is made of one PEO (hydrophilic)-PPO (hydrophobic) bilayer and the top layer (L2) is made of two alternating PEO-PPO bilayers, have been studied at room temperature in precisely controlled environment of 10–93% relative humidity (RH). Swelling, which is monitored by measuring the thickness of the films using X-ray reflectivity (XRR), is found to be largely dissimilar in differently thick films prepared by varying the concentration of mother solutions from 1 g/L to 4 g/L. This is well explained considering a preferential-swelling of amphiphilic block copolymer, where only the hydrophilic PEO blocks contribute in swelling and PPO acts a barrier in the diffusion of water molecules. The swelling kinetics is governed by the thickness/width and coverage of outer PPO block layer.

A Facile, Sustainable Strategy towards the Preparation of Silicone Nanofilaments and Their Use as Antiwetting Coatings

AbstractSynthesis of silicone nanofilaments (SNF) on substrates is a successful approach to fabricate superantiwetting surfaces. However, the yield of SNF is usually very low (≪1 %). After coating reactions, excessive organosilane residues become wastes and are released to the environment. Here, we report a facile, sustainable, high yield strategy to prepare silicone nanofilament coatings by simply exposing trifunctional silane/toluene solution to air. When toluene is exposed to air with relative humidity between 30 % and 45 %, it can trap a suitable amount of water which enables fast and continuous growth of SNF on different substrates. This new finding not only simplifies the fabrication procedure but also enables the preparation of SNF coatings in a sustainable, high‐yield manner. Such a novel technique allows the preparation of superhydrophobic samples on a large scale—hundreds of samples can be prepared in less than 1 day by simply using a mother solution containing a small amount of trifunctional silane.

Maternity waiting homes—a solution for Malawian mothers?

Background: The maternal mortality rate in Malawi remains unacceptably high, and maternity waiting homes might offer an effective solution. The current and previous Malawian Governments both stated that they were committed to improving the maternal mortality rate, and pledged to increase the numbers of maternity waiting homes (MWH). However, it seems that little was documented about the existing maternity waiting homes. Aims: To gather information about one Malawian MWH and the women who attended. Methods: Interviews with a random sample of pregnant women in a waiting home at a local district hospital outside Lilongwe indicated why women choose to use the homes and the challenges they faced. Findings: Of the seven women in the study, six lived between 5 and 10 km from the MWH, and one lived more than 10 km away. Six of the women were primiparous and therefore potentially at risk of prolonged labour. Six women presented late into their pregnancy for antenatal care, and one did not present for antenatal care at all. None of the women knew their expected date of delivery, and all women in the study believed that it was better to deliver a baby in a hospital than in the village or on the way to hospital. Conclusions: More information about more maternity waiting homes throughout the country is needed, in order to make informed decisions about whether maternity waiting homes are useful at all and if so, how they might be optimally effective.

Challenges During Surface-Facility-Project Implementation for a Full-Field Polymer Flood

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE 181615, “Challenges During Execution, Construction, and Operational-Readiness Phase of Surface Facilities in a Full-Field Polymer-Flood Project,” by Santosh Mohanram, Premashis Bhaumik, SPE, and Shagun Jain, SPE, Cairn India, prepared for the 2016 SPE Annual Technical Conference and Exhibition, Dubai, 26–28 September. The paper has not been peer reviewed. This paper presents key challenges in surface-facilities project implementation during the construction and operational-readiness phase of a project and presents results from full-field implementation. The key areas discussed are operational difference in the available technologies for concentrated-polymer dissolution, transfer of viscous polymer mother solution with minimal viscosity loss, efficacy of the pumping facility with high-viscosity non-Newtonian liquid, and supply-chain strategy. Introduction Because of positive responses from an enhanced-oil-recovery pilot, a full-field polymer-flood development plan was implemented in the Mangala field in India. Selecting the right facility design was of paramount importance once the pilot study confirmed the benefits of polymer flood over waterflood. A multilayered pattern drive with 129 injectors in an intense brownfield execution poses immense challenges for facility engineering. Thus, the world’s largest polymer- injection plant was built, primarily by scaling up the pilot. New Facility The current facility setup consists of remote well pads with both producing and injection wells connected with the production-fluid and injection-water network. A central polymer-preparation facility was constructed to prepare the concentrated polymer solution, called the mother solution, at various levels of concentration. The concentrated polymer solution is transferred from the central polymer facility to the well pads through pipeline distribution. Once at the well pads, the concentrated polymer solution is diluted with injection water at a specific ratio and injected into the individual wells. Key Challenges Technologies for Concentrated-Polymer Dissolution. The industry has only two standard technologies for dissolving polymer into water—the eductor-type units and slicing/mixing units. Conventional eductors work on the Venturi principle and allow for the mixing of the polymer powder and water up to certain concentrations. Slicing units, on the other hand, reduce the polymer particle size with a cutting head, reducing the polymer particle to a uniform size and allowing for significantly higher polymer concentrations without affecting the polymer molecular weight. In recent years, the slicing-unit design has become more compact and capable of producing highly concentrated polymer mother solution with less sensitivity to flow variation.

Salt scales on process equipment: Measurement of the induction time for calcium carbonate nucleation

AbstractCalcium carbonate and calcium sulphate scales can lead to an increase in running costs, can decline or stop the flow of fluids, and can cause early equipment fouling and failure in several industrial sectors, such as oil industries and desalted water production plants. A way to delay or hinder the formation of these salts is to use a proper additive, able to modify the nucleation kinetic increasing the induction times for salt nucleation. However, in order to properly understand the overall phenomenon it is worth defining the scenario of calcium sulphate and carbonate salts nucleation kinetics in the absence of any additive. The scope of the work is to measure, with a high resolution and in‐line laser technique previously devised, the induction times for calcium carbonate nucleation on a lab scale plant. The experiments have been carried out at temperatures of 25 °C and 35 °C, with a supersaturation ratio S varying in the interval 2–210, and show that as expected the measured induction times for calcium carbonate nucleation strongly decrease while increasing supersaturation for each fixed temperature, outlining a wide metastable region. The obtained values have been used to evaluate the interfacial tension between salt crystals and mother solution (109.3 mJ/m2 for T = 25 °C and γsl = 95.7 mJ/m2 for T = 35 °C) that are in good agreement with other available literature values.

Effects of physical variables on settling velocities of calcium and strontium phosphates in mother solution

Settling velocity is an important parameter used in modeling solid-liquid flow operations and for evaluating tank volumes in water treatment technology. In the present study, series of bench-scale batch-wise precipitation and settling tests were performed to evaluate the effect of some physical variables such as precipitate concentration, temperature and stirring on settling velocity of tricalcium diphosphate (TCDP) and tristrontium diphosphate (TSDP) in mother solution. Various amounts of TCDP and TSDP precipitates were generated in reaction mixtures, by mixing sub-saturated equi-molar solutions (0.1M) of the respective ions in various metal to phosphate (M/P) volume ratios (10:90ml; 20:80ml; 30:70ml; 40:60ml; 50:50ml; 60:40ml; 70:30ml; 80:20ml; 90:10ml). Settling velocity diagrams of TCDP and TSDP were obtained as functions of M/P volume ratio, temperature, and repeat stirring. The results showed that whereas temperature and stirring variables had a linear relationship with precipitate settling velocity, a non-linear relationship was observed between the precipitate concentration variable and settling velocity. When the temperature of the mixtures were raised from 30oC to 50oC, 0.76- and 0.45- fold increases in settling rate were recorded for TCDP and TSDP, respectively. On the other hand, with repeated stirring of TSDP precipitate, 83% increase in settling velocity was recorded between the first and third stirrings. The results may be employed in settling tank designs for the removal of phosphates in water treatment process. Keywords: settling velocity, mother solution, batch-wise precipitation, temperature, amount of precipitates, Ca3(PO4)2, Sr3(PO4)2.

Oriented growth of ZnIn2S4/In(OH)3 heterojunction by a facile hydrothermal transformation for efficient photocatalytic H2 production

The construction of a composite photocatalyst with two suitable semiconductors is an effective strategy to improve the transport and separation of the photoexcited carrier pairs. Herein, it is the first time to report the new concept of anisotropic heterojunctions (H and J type) in layered ZnIn2S4 nanosheets as an example. Due to the anisotropic conductivity, the resistance of the electron transfer along ZnIn2S4 layers to a second semiconductor (J type heterojunction), is much less than that across the layers (H type heterojunction). As a result, the J type heterojunction can achieve higher photocatalytic activity than H type one. Furthermore, ZnIn2S4/In(OH)3 heterojunction with the J type structure was successfully fabricated by a simple approach, namely, In(OH)3 was selectively assembled at the rims of ZnIn2S4 nanosheets via hydrothermal transformation of the precursor precipitate with its mother solution obtained by adding Na2S into the solution of stoichiometric In3+ and excessive Zn2+. The intimate-contact J type heterojunction with in-situ photodeposited Pt shows efficient photocatalytic H2 evolution under visible irradiation, leading to a high apparent quantum yield of 38.3% at 420nm with a low optimal Pt loading of 0.25wt%. This work provides a new insight for the development of efficient heterojunction photocatalysts with layered semiconductors.

Using stable isotopes (δ17O, δ18O and δD) of gypsum hydration water to ascertain the role of water condensation in the formation of subaerial gypsum speleothems

We analyzed the stable isotopes (δ17O, δ18O and δD) of gypsum hydration water (GHW) in a variety of speleothems, as well as condensation and infiltration waters in five caves of the semiarid gypsum karst of Sorbas basin (Almeria, SE Spain). Microclimate parameters (air temperature, relative humidity and effective condensation rate) were also monitored over an annual cycle. We found that the mother solution from which the majority of gypsum speleothems grow is composed of a mixture of condensation (~60%) and infiltration water (~40%) that undergoes evaporation. Although evaporation of infiltration water alone was thought to be responsible for secondary gypsum precipitation in vadose caves, our results suggest that condensation can be a major source of water for the formation of gypsum speleothems. The modelled d-excess and Δ17O trajectories of water during the evaporative process confirm that the majority of speleothems precipitate from a mixture of condensation and infiltration water under relative humidity of 75–85%, similar to that measured in the cave atmosphere during winter. These findings have important implications for future studies of gypsum speleothems as paleoenvironmental archives.

THE PROPERTIES OF MOTHER LIQUORS OF THE WATER-SOLUBLE SALTS PRODUCTION BY CONVERSION METHOD

The paper deals with the conversion method which leads to the formation of mother liquors as by-products. In some cases, they can be used as commodity products after pre-revision. However, optimization of physical and chemical, and the functional properties of the liquid mixes by empirical way can appear long and inefficient process. The paper employs the physical and chemical analysis of homogeneous systems and a method of mathematical planning of experiment that allows optimizing the liquid mixes both on composition, and on some set functional properties. The paper notes the conversion method of production of potassium nitrate from calcium nitrate and potassium chloride is covered by a number of patents, however, it is not realized in industrial scale so far. The reason for this may be a problem of further use of the mother liquors containing calcium and potassium chlorides and nitrates. In the majority of patents, there are no data on the production of calcium chloride from the mother liquor that testifies to a number of the difficulties connected to crystallization of this salt. The mother liquors of potassium nitrate production can be used as an anti-icing reagent, a coolant, the heat-carrier in power systems, a mineral fertilizer and the heavy liquids in a petroleum industry. However, in each specific case, the certain revision of their composition is required in order to achieve the necessary physical and chemical, and functional properties. The paper analyzes the possibility for using the mother solution in the potassium nitrate production as heavy liquids in the oil industry. Moreover, the paper studies the cuts of the systems CaCl 2 – Ca(NO 3 ) 2 – М – H 2 O where М is the mother solution after the crystallization of potassium nitrate. The density and temperature of the solution freezing are identified in the homogeneous areas of the cuts. It is shown a fundamental possibility for improving the operating characteristics of the mother solutions with the introduction of additional amounts of calcium salts.

Influence of ripening in mother solution on characteristics of magnesium-substituted calcium phosphate powders

Effect of ripening in the mother liquor on the degree of crystallinity and dispersity of mixed powders of calcium and magnesium phosphates is studied as a function of magnesium content with the elemental composition such that (Ca + Mg)/P = 2. Ripening is found to have a positive effect on crystallinity of the apatite phase of powders. Nanocrystals with lowered tendency to aggregation are formed during the ripening period, which affords the powders with specific surface area as high as 80 m2/g. The morphology of the constituent particles depends on the magnesium content. Crystallization processes are essentially completed by the 21st day of ripening.