Hydroxide Compounds Research Articles

Synthesis of Low-Symmetric α-Cobalt(II) Hydroxide-Incorporated Cyanuric Acid Layers with High Néel Temperature and Large Coercivity: Structure and Magnetism.

α-Cobalt(II) (CoII) hydroxide (compound 1) incorporating cyanuric acid layers was synthesized via the solvothermal method. 1 exhibited two distinct characteristics, which were different from reported α-CoII hydroxides. (i) The presence of abundant consecutive hydrogen bonds between the adjacent hydroxide layers enhanced the driving force of crystallization along the direction of the c axis. Thus, 1 revealed high crystallinity without the disorder phenomenon. (ii) 1 showed low symmetry. The configuration of CoTd sites did not follow the regular triangular net. The low symmetry favored the magnetic anisotropy. Thus, 1 revealed ferrimagnetic behavior with a high Néel temperature (TN = 56.8 K) and coercivity (Hc = 36 kOe at 2 K). The ferrimagnetic behavior of 1 was validated via the Hubbard U correction density functional theory.

The Solid‐State Battery Applicational Technology: Material Characteristics and Charge–Discharge Mechanisms of Iron Chloride Electrodes

ABSTRACTThis study delves into the unique characteristics of an iron chloride cathode with a solid‐state electrolyte (SSE) and the construction of a button cell battery (BT cell) for its evaluation. The iron ions in this system can provide either divalent or trivalent ions, which possess a higher electrical capacity (~200 mAh/g) and competitive advantages. The solid‐state electrolyte materials, iron compounds (chloride, oxide), exhibit high activation in electrochemistry. After the cycle test, the ferric chloride electrolyte transforms into another iron hydroxide compound due to its high activation. The study examines iron, ferric oxide (Fe2O3), and ferrous chloride (FeCl2) as cathode materials and evaluates their impact on the battery. Cyclic voltammetry compares the potential and current values of the redox reactions among the three. Finally, transmission electron microscopy (TEM) explores the ferric chloride layer and iron hydroxide in ferrous chloride. The study focuses on the high electrochemical activity of the iron chloride layer and explores the crystal structure and composition for electrochemical analysis. The findings of this study are crucial for understanding the potential of iron‐ion batteries and the role of iron compounds in improving battery performance.

Enhanced Nickel Recovery from Mixed Hydroxide Precipitate Through Selective Leaching with KMnO4 Oxidant

Mixed Hydroxide Precipitate (MHP), a metal precipitate with the dominant nickel and cobalt content in hydroxide compounds, can be leached as a lithium battery precursor. In this study, KMnO4 was used as an oxidant agent to increase the solubility of Ni and Co. The variation of the sulfuric acid concentration (0.5 - 1.5 M) as a leachate reagent, the concentration of KMnO4 (2.5 - 7.5 g/L), and the selective leaching temperature (60 - 80°C) were investigated. Solvent extraction using CYANEX 272 and D2EHPA was performed to separate the Ni, Co, and Mn. Atomic Absorption Spectrometry (AAS), Inductively coupled plasma mass (ICP-OES), and X-ray Fluorescence (XRF) were used to analyze the chemical compositions. At the same time, crystallographic analysis was observed with X-Ray Diffraction. It was observed that potassium permanganate increased the dissolution of Ni and Co to 91.3% and 85.4% but decreased the dissolution of Mn (37.53%) under the following conditions: 1.75 M sulfuric acid, 7.5 g/L potassium permanganate, and 60°C temperature. High purity of nickel crystal (99.64%) was observed with spontaneous nucleation due to the supersaturated nickel solution after solvent extraction with CYANEX 272. Thus, using permanganate ion as selective leaching of Ni and Co from Mn is promising.

Oxidizing Role of Cu Cocatalysts in Unassisted Photocatalytic CO2 Reduction Using p-GaN/Al2O3/Au/Cu Heterostructures.

Photocatalytic CO2 reduction to CO under unassisted (unbiased) conditions was recently demonstrated using heterostructure catalysts that combine p-type GaN with plasmonic Au nanoparticles and Cu nanoparticles as cocatalysts (p-GaN/Al2O3/Au/Cu). Here, we investigate the mechanistic role of Cu in p-GaN/Al2O3/Au/Cu under unassisted photocatalytic operating conditions using Cu K-edge X-ray absorption spectroscopy and first-principles calculations. Upon exposure to gas-phase CO2 and H2O vapor reaction conditions, the composition of the Cu nanoparticles is identified as a mixture of CuI and CuII oxide, hydroxide, and carbonate compounds without metallic Cu. These composition changes, indicating oxidative conditions, are rationalized by bulk Pourbaix thermodynamics. Under photocatalytic operating conditions with visible light excitation of the plasmonic Au nanoparticles, further oxidation of CuI to CuII is observed, indicating light-driven hole transfer from Au-to-Cu. This observation is supported by the calculated band alignments of the oxidized Cu compositions with plasmonic Au particles, where light-driven hole transfer from Au-to-Cu is found to be thermodynamically favored. These findings demonstrate that under unassisted (unbiased) gas-phase reaction conditions, Cu is found in carbonate-rich oxidized compositions rather than metallic Cu. These species then act as the active cocatalyst and play an oxidative rather than a reductive role in catalysis when coupled with plasmonic Au particles for light absorption, possibly opening an additional channel for water oxidation in this system.

Corrosion Behavior of Cu-Ni-Fe-Mn-Cr Alloy in 3.5 wt% NaCl Solution

A novel Cu-10Ni-1.7Fe-0.5Mn-0.2Cr alloy was fabricated and exposed to a neutral 3.5 wt% NaCl solution for various days. The corrosion performance, corrosion film, and corrosion mode of the alloy were investigated in detail. The results suggested that the average corrosion rate reduced from 0.082 mm/a for 1-d immersion sample to 0.037 mm/a for 30-d immersion sample. The reduction in corrosion rate was mainly attributed to the progressive thickness and densification of the corrosion film, leading to increasing the resistance of the corrosion film with the prolonged exposure time. Low-valent oxides and chlorinated compounds were generated over the 1-d immersion sample surface, while high-valent oxides and hydroxide compounds were developed over the 30-d immersion sample surface. The mature corrosion film typically composed of Cu2O, CuO, Cu2(OH)3Cl, γ-FeOOH, MnO2, and Cr2O3. Eventually, the alloys suffered from selective corrosion and intergranular corrosion after a long exposure time in NaCl solution.

Electrochemical characteristics of flexible open-cell supercapacitors employing different electrolyte types: KOH and ionic liquid

A carbonate hydroxide compound with substantial wettability was deposited on a porous Ni foam substrate, employing the Ni-based chemical precursor by a facile hydrothermal method. The resulting Ni2(CO3)(OH)2 electrode exhibits a nanowire structure characterized by a significant surface area. These electrodes represent highly promising materials for faradaic capacitors. They demonstrate high wettability on the electrode surface, facilitating charge and discharge processes on the electrode surface through redox reactions. A flexible hybrid open-cell supercapacitor, designed to operate at 1.5 V, was constructed with the Ni2(CO3)(OH)2 electrode as the positive terminal and graphene as the negative terminal, employing two distinct electrolytes (KOH and ionic liquid named MPPyFSI with 1-Methyl-1-propylpyrrolidinium Bis(fluorosulfonyl)imide structure). The open-cell devices, fabricated with 6 M KOH and MPPyFSI electrolyte, exhibit high energy densities of 39.6 and 24.8 Wh kg−1 and power densities of 1752.1 and 2908.5 W kg−1 at current densities of 2 A g−1, respectively. Furthermore, the energy storage devices utilizing aqueous KOH and MPPyFSI demonstrate excellent stability, maintaining 73.4 and 87.1% of their specific capacity after 5,000 charge/discharge cycles. The mechanical properties of the flexible open-cell device were characterized, and the electrochemical values corresponding to the banding angle of the device were measured.

Evaluation of prenatal calabash chalk geophagy on the developing brain of Wistar rats

Calabash chalk (CaC) is an aluminium silicate hydroxide compound with heavy metal constituents, making it a potential neurotoxicant. Pregnant women often consume CaC as an antiemetic, which may interfere with the normal development of the foetal brain. Here, we evaluated the effects of CaC administration in pregnant rats on the brain of the offspring. Wistar rat dams were assigned to one of three groups: control, 200 mg/kg and 800 mg/kg of a CaC suspension. Administrations lasted 14 days (gestation days 7–20). On day 14, 5-bromo-2′-deoxyuridine (BrdU) was administered and dams were allowed to term. Behavioural tests were performed on different days as the pups matured, and they were sacrificed on post-natal days 30 and 60. Brains were processed for histology and Western blotting. Results showed no significant differences in surface righting reflex, cliff avoidance, negative geotaxis and open-field activity. No hippocampal and somatosensory cortical cytoarchitectonic alterations and no significant signs of glial fibrillary acidic protein (GFAP) activation were observed. Neuronal nuclei counts showed variability in the somatosensory cortex and hippocampus of the CaC group. BrdU-positive cells were significantly lower in the 200 mg/kg group and higher in the 800 mg/kg group. Doublecortin-X-positive cells were not different in all the CaC groups. Astrocytes and microglia Western blotting quantification confirmed no significant increase in pup glial cells in adulthood. Prenatal consumption of CaC at indicated dosages may not be deleterious to the developing brain, especially after cessation of exposure and during maturation of the animal. However, the differences in neuronal and glial populations may be due to their ability to cope with CaC.

ASPHYDROXEL: ASPHALT CARBON DIOXIDE CAPTURE BY SYNTHESIS OF POTASSIUM HYDROXIDE FOR UTILIZATION OF PALM OIL BUNCH ASH WASTE

Environmental pollution is the most common problem faced by Indonesia, for example, industrial waste. The country of Indonesia once occupied the first position in Southeast Asia, as a country with the worst air quality. In addition, Indonesia is the largest producer of crude palm oil (CPO) and palm oil plantations in the world. The industry produces the most solid waste in the form of empty palm oil bunches and requires a large area to store it. In order to reduce the storage area needed, empty palm oil bunches are burned to ashes or palm oil fuel ash (POFA). Therefore, we have the idea of absorbing CO2 gas and utilizing POFA as a mixture of concrete and asphalt, by converting it into a potassium chloride compound. Then, the electrolysis process is carried out to produce potassium hydroxide compounds. The potassium hydroxide compound will later be mixed with asphalt to produce Asphydroxel asphalt, which absorbs carbon dioxide. In implementing Asphydroxel, several parties are involved, such as oil palm smallholders, palm oil mills, asphalt company research teams, asphalt companies, and the government. It is predicte that this idea will prevent the buildup of bunch ash waste and air pollution which cause climate change

Сравнение расчетных и экспериментальных результатов осаждения ионов меди в виде гидроксосоединений из отработанных электролитов

Currently, the most common methods for cleaning spent galvanic solutions from heavy metals are reagent methods based on the deposition of poorly soluble hydroxides. The paper presents the results of the thermodynamic calculation of the minimum solubility and the corresponding pH range of copper hydroxide compounds formed during the precipitation of metal ions in the industrial waste from galvanic production using solutions of sodium hydroxide and sodium bicarbonate. A laboratory experiment was carried out for finding optimal conditions for the deposition of copper from spent acidic sulfuric acid electrolytes of copper plating using 10% solutions of sodium hydroxide and sodium bicarbonate. It has been established that experimental and calculated data are in satisfactory agreement in determining the optimal pH value for the precipitation processes of copper hydroxyl compounds. It is found that there are discrepancies between the calculated and found indicators of the minimum amount of metal ions in solution, which differ for the reagents under study. It should be noted that these indicators differ from each other significantly less compared with the usual use of the solubility product as the main characteristic of the precipitation process. Therefore, when setting the task of determining the optimal precipitators for heavy metal ions in an aqueous medium, the proposed mathematical formulas can be used as guidelines for obtaining the process parameters close to the real values.

Compositional engineering of HKUST‐1/sulfidized NiMn‐LDH on functionalized MWCNTs as remarkable bifunctional electrocatalysts for water splitting

AbstractWater‐splitting reactions such as the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) typically require expensive noble metal‐based electrocatalysts. This has motivated researchers to develop novel, cost‐effective electrocatalytic systems. In this study, a new multicomponent nanocomposite was assembled by combining functionalized multiwalled carbon nanotubes, a Cu‐based metal–organic framework (MOF) (HKUST‐1 or HK), and a sulfidized NiMn‐layered double hydroxide (NiMn‐S). The resulting nanocomposite, abbreviated as MW/HK/NiMn‐S, features a unique architecture, high porosity, numerous electroactive Cu/Ni/Mn sites, fast charge transfer, excellent structural stability, and conductivity. At a current density of 10 mA cm−2, this dual‐function electrocatalyst shows remarkable performance, with ultralow overpotential values of 163 mV (OER) or 73 mV (HER), as well as low Tafel slopes (57 and 75 mV dec−1, respectively). Additionally, its high turnover frequency values (4.43 s−1 for OER; 3.96 s−1 for HER) are significantly superior to those of standard noble metal‐based Pt/C and IrO2 systems. The synergistic effect of the nanocomposite's different components is responsible for its enhanced electrocatalytic performance. A density functional theory study revealed that the multi‐interface and multicomponent heterostructure contribute to increased electrical conductivity and decreased energy barrier, resulting in superior electrocatalytic HER/OER activity. This study presents a novel vision for designing advanced electrocatalysts with superior performance in water splitting. Various composites have been utilized in water‐splitting applications. This study investigates the use of the MW/HK/NiMn‐S electrocatalyst for water splitting for the first time to indicate the synergistic effect between carbon‐based materials along with layered double hydroxide compounds and porous compounds of MOF. The unique features of each component in this composite can be an interesting topic in the field of water splitting.

Determining the efficacy of disinfectants at nucleic acid degradation.

Nucleic acids, particularly antibiotic resistance genes, are commonly found on surfaces within healthcare environments, with levels not reducing following cleaning. Within the UK, there are no regulations for testing disinfectants against nucleic acids. A series of commonplace in vitro methods were used to determine disinfectant-induced physical and functional damage to various nucleic acids; RNA (10 μg), genomic DNA (2 μg), and plasmids (1 μg). Using these methods, the optimal residence time (10 minutes) and working concentration (10%) were determined for a new disinfectant. Furthermore, comparison of disinfectants with different active ingredients including lactic acid (LA), sodium hydroxide (NaOH), chloroxylenol (PCMX), and quaternary ammonium compounds (QACs), were compared to controls. All disinfectants showed greater degradation by gel electrophoresis of genomic DNA and RNA than of purified plasmids. Functional analysis using quantitative polymerase chain reaction (qPCR) and polymerase chain reaction (PCR) demonstrated that no disinfectant tested (apart from control) could damage DNA to the level where PCR amplification was not possible, and only the NaOH reagent could achieve this for RNA. The set of methods described herein provides a platform for future standardization and potential regulation regarding monitoring cleaning solutions for their activity against nucleic acids.

Preparation and properties of hydrophobic micro-arc oxidation/layered double hydroxide composite coating on magnesium alloy

The rapid degradation rate of Mg alloys limited clinical applications. Layered double hydroxide (LDH) compounds are developed as surface coatings for biomedical magnesium (Mg) alloys. In this work, LDH intercalated with myristic acid ion was in-situ formed on micro-arc oxidized ZK60 alloy using a simple one-step hydrothermal process for controllable and stable degradation. Micro-pores in micro-arc oxidation coating (MAO) were sealed by LDH, and the surface became hydrophobic. With hydrothermal treatment time of 8 h, the MAO/LDH composite coating exhibited the maximum hydrophobicity with a contact angle of about 135.6° and the lowest corrosion current density of about 3.51 × 10−9 A·cm−2. During in-vitro immersion, MAO/LDH composite coating became hydrophilic from hydrophobic, but also provided a good protective ability for Mg alloy. This study provides new insights into the surface modifications of Mg alloys for hydrophobic-hydrophilic transition demand.

Specificity of the Thermal Stability and Reactivity of Two-Dimensional Layered Cu-Fe Sulfide-Mg-Based Hydroxide Compounds (Valleriites).

We recently synthesized prospective new materials composed of alternating quasi-atomic sheets of brucite-type hydroxide (Mg, Fe)(OH)2 and CuFe1-xS2 sulfide (valleriites). Herein, their thermal behavior important for many potential applications has been studied in inert (Ar) and oxidative (20% O2) atmospheres using thermogravimetry (TG) and differential scanning calorimetry (DSC) analyses and characterization with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX). In the Ar media, the processes are determined by the dehydroxylation of the hydroxide layers forming MgO, with the temperature of the major endothermic maximum of the mass loss at 413 °C. Sulfide sheets start to degrade below 500 °C and melt at nearly 800 °C, with bornite, chalcopyrite, and troilite specified as the final products. In the oxidative atmosphere, the exothermic reactions with the mass increase peaked at 345 and 495 °C, corresponding to the partial and major oxidations of Cu-Fe sulfide layers. Sulfur oxides captured in magnesium hydroxide layers to form MgSO4 compromised the layer integrity and promoted the oxidation of the sulfide entities. The final products also contained minor MgO, Cu2MgO3, Fe3O4, and MgFe2O4 phases. Samples doped with Al, which decreases the content of Fe in hydroxide layers, show notably impeded decay of valleriite in argon but facilitated the oxidation of Cu-Fe sulfides, while the impact of Li (it slightly increases the number of the Fe-OH sites) was less expressed. The mutual stabilization of the two-dimensional (2D) hydroxide and sulfide layers upon heating in an inert atmosphere but not in oxygen as compared with bulk brucite and chalcopyrite was suggested to explain high thermal resistance across the stacked incommensurate sheets, which slows down the endothermic reactions and accelerates the exothermic oxidation; the high number of Fe atoms in the hydroxide sheets are expected to promote the phonon exchange and heat transfer between the layers.

Intercalated Organic Redox-active Anions for Enhanced Capacity of Layered Double Hydroxides

A Layered Double Hydroxide (LDH) compound LDH ([Mg2Al(OH)6]+ x 2 H2O) intercalated with a redox active organic anion, Anthraquinone-2-sulfonate (AQS), has been envisioned as an electrode material for high power aqueous based battery. The purpose is to use this interlayer redox active molecule for the enhancement of the specific capacity at the LDH composite electrode, which should allow fast charge transfer at the negative electrode for high power storage applications. This is achieved by the reduction of AQS in charge and oxidation in discharge within a redox inactive LDH matrix. The first charge of this new material [Mg2Al(OH)6]+[AQSO3]− x 2 H2O leads to a capacity of 100 mAh g−1 at − 0.78 V vs Ag/AgCl (based on the weight of the active material) when operated in aqueous 1 M sodium acetate electrolyte. However, low cycling stability was observed, since a drastic loss in specific capacity occurs after the first charge. This study focuses at elucidating the mechanism behind this phenomenon via in situ UV/vis experiments. Subsequently, the dissolution of charged AQS anions into the electrolyte during the first charge of the anode has been identified and quantified. Such understanding of fading mechanism might lead to the design of improved LDH-based electrodes, which utilize redox active anions working in the positive potential range with enhanced cycling ability.

Speciation and Ammonia-Induced Precipitation of Neptunium and Uranium Ions.

The pH evolution and corresponding changes in the UV-Vis-NIR absorption spectra of oxygenated neptunium (NpO2+ and NpO22+) and uranyl ions (UO22+) in nitric acid are investigated during titration with an aqueous NH3 solution. The speciation and precipitation regimes between acidic (pH 1.5) and alkaline (pH 10) conditions at room temperature are discussed to assess the suitability of Np(V) or Np(VI) in sol-gel conversion processes for fuel target fabrication. Under the applied experimental conditions, Np(V) hydrolyzes and precipitates into the insoluble hydroxide NpO2OH only above pH values 7.5 and an increase up to pH 10.0 is required to precipitate quantitatively. Np(VI) displays changes in the coordination environment of NpO22+ ions in the pH interval 1.6-4.0, similar to what is observed for U(VI). Precipitation into NpO3·H2O or other hydroxide compounds takes place between pH 4.0 and 5.9, which overlaps largely with precipitation of ammonium diuranate species from the U(VI) solution. The use of concentrated NH3 aqueous solution, as commonly used in the external gelation process, will allow to quantitatively precipitate both Np(V) and Np(VI) species. Internal gelation process conditions, on the other hand, seem incompatible with the high pH required to precipitate Np(V) completely. For fabricating mixed-oxide (U,Np) targets using sol-gel conversion, a feed broth containing Np(VI) and U(VI) will be required to achieve homogeneous gelation.

PH-responsive mesoporous silica nanocontainers based on Zn-BTA complexes as stoppers for controllable release of corrosion inhibitors and application in epoxy coatings

A classical strategy of constructing pH-sensitive release system is to encapsulate mesoporous nanoparticles with insoluble complexes such as copper-benzotriazole (Cu-BTA) complex. In this paper, a new capping material, Zn-BTA complex, was adopted to overcome the promoting effect of Cu2+ ions from the decomposition of Cu-BTA complexes on corrosion of mild steel. Mesoporous silica nanoparticles (MSNs) were synthesized, loaded with BTA and then capped with Zn-BTA complexes as stoppers to form MSN-BTA@Zn nanocontainers. The releasing behaviors of BTA at various pH values were investigated, and it was found that MSN-BTA@Zn could achieve on-command release of BTA in response to decrease of pH caused by anodic reaction of corrosion. MSN-BTA@Zn nanocontainers were introduced to epoxy resin to construct stimuli-responsive coating on mild steel substrate. The composite coating with artificial defects shows a distinct stimuli-responsive performance in 3.5 % NaCl, and the incorporation of MSN-BTA@Zn has no impact on the adhesion of the coating to the substrate. The formation of zinc hydroxide compounds in the cathodic zone of galvanic cell makes contribution to the enhancement of corrosion resistance for the coating.

High-performance supercapacitors using synergistic hierarchical Ni-doped copper compounds/activated carbon composites with MXenes and carbon dots as simultaneous performance enhancers

For the fabrication of high-performance supercapacitors, materials with nano-array architecture and the use of multiple-component electrodes are emerging as the main focus of research. In this work, the novel combination of 0D, 1D, and 2D nanomaterials and 3D-nanostructured materials was reported. Specifically, composite materials based on nanoporous activated carbon (AC) and nanowire nickel-doped copper hydroxide compounds (NiDMR) were utilized as the electrode materials, whereas MXenes and carbon dots (CDs) were employed as the diffusion- and surface-process enhancers, respectively. The AC/NiDMR composite electrode yielded an areal capacitance of 71.2 mF cm−2. Upon adding 10 wt% of CDs and MXenes separately, the capacitance was improved by 122.2% and 158.3%, respectively. The highest specific capacitance of 126.9 mF cm−2 was obtained by adding both 5 wt% of CDs and 5 wt% of MXenes, which corresponds to a 178.2% enhancement compared to the pure AC/NiDMR electrode. Extensive analysis shows the synergistically contributing roles of AC, NiDMR, CDs, and MXenes to the enhanced supercapacitor performance. This ground-breaking supercapacitor has the potential to be used in the next-generation energy storage systems based on its improved electrochemical properties, and this novel strategy features opportunities for the unique utilization of nanostructured, multi-component materials in energy storage devices.

Study on the physiochemical behavior of PE and epoxy composites immersed in an NaOH solution for a long period

A seawater electrolyzer solution has high alkalinity owing to the presence of scale-like hydroxide compounds, Ca(OH)2, and Mg(OH)2 generated from a dimensionally stable anode during electrolysis. This study proposes four different types of composite materials to replace the existing ballast piping materials that are vulnerable to high alkalinity. To this end, composite specimens were prepared and immersed in an NaOH solution for 720 h. Furthermore, their suitability as ballast pipe materials was confirmed through a physical property analysis of the immersed specimens. The results show that all four types of composite specimens deteriorated, but they had different interfacial bonding mechanisms. For specimens with low interfacial bond strength between fibers and resins, the deterioration initiated and propagated from the surface and the internal penetration of the NaOH solution occurred rapidly, resulting in the rapid deterioration of their physical properties. The mechanisms of good and bad interfacial bonding between fibers and resins were determined based on the interfacial bonding force. Thus, this study will help understand the deterioration mechanisms of composite materials immersed in chemical solutions such as NaOH or acid in the future.

Tinjauan Kuat Tekan Dan Absorbsi Mortar Yang Mengandung Air Garam

Mortar is a building material that serves to glue bricks, bricks, plaster, and so on. As an adhesive, mortar has a viscosity that is useful in determining compressive strength. In the manufacture of mortar, SNI 03-6882-2002 requires the use of clean fresh water, but in reality, as an archipelagic country, some of the islands in Indonesia are isolated from fresh water. As a result, freshwater becomes an expensive item, because it is imported from other areas, so it requires transportation costs. If the mortar is required to use water according to SNI standards, the project implementation costs will be expensive. In areas that do not have adequate fresh water, mortar is made using water obtained on-site, including brackish, salt, and sea water. Seawater contains elements of NaCl salts which can bind Calcium Hydroxide (CaOH) compounds, reducing the CaOH compounds in the mortar will increase the compressive strength of the mortar. In this study, a review of brine as a mixture of mortar materials was carried out with the aim of knowing the performance of mortar containing salt water by compressive strength test and Absorption test. The amount of salt water added to the mortar mixture is 0%; 0.5%; 1%; 1.5%; 2%; 2.5% ; 3%; 3.5% of the volume of water used as a mortar mix. Cube test object measuring 50x50x50 mm3 in the amount of 5 in each treatment, made from a mixture of 1PC: 2.75 Sand (based on weight ratio), with a water-cement factor (FAS) of 0.45. The test results obtained the compressive strength value of the mortar with the addition of salt water can reduce the compressive strength value but the use of brine with a content of 3.5% is still in the category of minimum permissible pressure according to SNI03-6882-2002. While the absorption value of the mortar can increase fiber strength with increasing addition of 3.0% brine.

ФОРМЫ МИГРАЦИИ ХИМИЧЕСКИХ ЭЛЕМЕНТОВ В РАДОНОВЫХ ВОДАХ ЮГА СИБИРИ

The paper presents the first results of thermodynamic modeling of the chemical elements migration forms in radon waters of southern Siberia. It was determined that Ca, Mg, Na, K, Mn, as well as, Fe (at nearneutral pH) migrates in the form of free ions, the proportion of which in most cases is more than 90%. Among the complex forms of migration of trace elements, as well as U and Th, associates prevail with a participation of dominant anions HCO3 –, CO3 2–, compounds with Cl– ions are less common. Hydroxide and oxide coordination compounds play a significant role in the migration of Al, as well as Si, U and Th (reaching tens of % of gross content). In oxidizing environment, uranium migrates predominantly in the form of carbonate compounds, in a reducing environment – in the form of oxides and hydroxide ions. The proportion of samples with hydroxide forms decreases with an increase in pH value by more than 8.5, and the proportion of oxide forms increases. Thorium in the studied radon waters migrates mainly in the form of carbonate compounds, namely in the form of (ThCO3(OH)3)–, which accounts for more than 90% in most samples. Its decrease to values of about 60% is typical for slightly acidic waters with a pH of less than 6.5.