Barium Hydroxide Research Articles

Synthesis, crystal structures, DFT calculations, and oxygen radical absorbance capacity of 5-arylidene-thiazolidine-2,4-dione derivatives

A new green methodology has been developed for the synthesis of a series of substituted 5-arylidene-2,4-thiazolidinediones (ATZDs) 3a-q through Knoevenagel condensation, using barium hydroxide as an efficient heterogeneous catalyst. All compounds were characterized by ¹H NMR, ¹³C NMR, and HRMS spectroscopy. Additionally, seven compounds were analyzed by X-ray diffraction (XRD). Furthermore, some selected TZD derivatives were screened for their antioxidant activity using oxygen radical absorbance capacity (ORAC) assays. The results showed that five compounds exhibited excellent antioxidant properties, with ORAC values ranging from 4.73 TE to 6.31 TE, surpassing the reference antioxidants ferulic acid (3.70 TE) and melatonin (2.45 TE). Computational investigations based on the DFT method revealed that these compounds exert their antioxidant activity primarily through the HAT mechanism, preferentially from the OH bond rather than the NH bond. This study highlights the advantages of this methodology, providing products of high purity, with good yields and short reaction times, and proposes 5-arylidene-thiazolidine-2,4-dione derivatives as promising antioxidants.

Study on Phase Change Materials' Heat Transfer Characteristics of Medium Temperature Solar Energy Collection System.

Within the next five years, renewable energy is expected to account for approximately 80% of the new global power generation capacity, with solar power contributing to more than half of this growth. However, the intermittent nature of solar energy remains a significant challenge to fully realizing its potential. Thus, efficient energy storage is crucial for optimizing the effectiveness and dependability of renewable energy. Phase-change materials (PCMs) can play an important role in solar energy storage due to their low cost and high volumetric energy storage density. The low thermal conductivity of PCMs restricts their use for energy storage, despite their immense potential. Hence, the primary goal of this study is to experimentally investigate the energy storage capacity of two blended phase-change materials (paraffin and barium hydroxide octahydrate) through integration with a medium-temperature solar heat collection system. The experimental findings reveal that the blended PCMs possess the highest cumulative charge fraction (0.59), energy capacity, and low energy loss compared to each PCM alone. Furthermore, the phase change storage tank achieves higher heat storage (27%) and exergy storage efficiency (18%) compared to the stored tank water without any PCMs. The blended PCMs enhanced their performance, exhibiting improved interaction and excellent thermal storage properties across a range of temperatures, offering an opportunity for the design of an energy-efficient, low-cost storage system.

Exploring Structural and Optical Properties of Nanoparticles of Barium Titanate and Iron doped Barium Titanate and Their Potential Application in Antibacterial Activity

Background: Barium Titanate (BaTiO3) is a good candidate for a variety of applications due to its excellent dielectric, ferroelectric and piezoelectric properties. Methods: Pure and doped Barium Titanate (BTO) nanoparticles have been synthesized by the sol-gel method. Barium hydroxide octahydrate (Ba (OH)2.8H2O) and titanium (IV) iso-propoxide (Ti {OCH[CH3]2}4) were used as starting materials. Apart from pure Barium Titanate nanoparticles, Fe-doped BaTiO3 nanoparticles of three different concentrations: 0.1, 0.2 and 0.3 in mol% were prepared and characterized using X-ray diffraction (XRD), UV visible spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR). Results: From the X-ray diffraction pattern, the particle size was found to be varied in a range of 17-25nm. By using UV visible spectroscopy it was observed that the band gap energy of pure BaTiO3 NP is 3.2eV. As the pure BaTiO3 nanoparticles are doped with 0.1% Fe, the band gap reduces to 3.175eV. For BaTiO3 doped with 0.2% and 0.3% Fe, the band gap energy values are 2.709 and 2.652 respectively. FTIR spectra were used to analyze the vibrational modes of BaTiO3. From the result obtained from FTIR, we can see that the absorption spectrum ranges from 450cm-1-4000cm-1. The prominent peak of pure BaTiO3 is at 500cm-1 which is due to the vibration of the Ti-O band in crystal lattice. For BaTiO3 doped with Fe2O3, the wave number of the absorption peak is shifted from 500cm-1 in pure BaTiO3. The antibacterial studies were conducted on Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli. Conclusion: Both pure and iron-doped Barium Titanate showed significant antibacterial properties, confirming the antibacterial property of Barium Titanate nanoparticles.

Conservation of Yuan Dynasty Caisson Paintings in the Puzhao Temple, Hancheng, Shaanxi Province, China

Caisson paintings are an integral part of the unique interior decoration ceiling of traditional Chinese architecture. There are a large number of Yuan Dynasty caisson paintings in the Puzhao Temple, in Hancheng, Shaanxi Province, China. These caisson paintings have exquisite patterns and rich colors, which are rare artistic treasures of the Yuan Dynasty. In the history of nearly 700 years, due to various environmental and human factors, the caisson paintings have experienced various degradation; for example, the paper of the caisson paintings is acidified, the surface is polluted, the color is faded, mottled, and it is difficult to identify. Therefore, their protection is vital. In order to ensure the scientific and targeted development of the protection scheme, this study conducted a comprehensive and in-depth analysis of the paper fibers, pigments, adhesives, wood supports, and pollutants of the caisson paintings and carried out a series of protection experiments in the field and laboratory, providing a step-by-step review of the protection treatment application for the caisson paintings. Mechanical and wet cleaning were used to remove the pollutants. The caisson painting was deacidified with a barium hydroxide ethanol solution, and the paper and pigments of the caisson painting were strengthened with water-based fluorine. Several conservation problems, such as the removal of pollutants, the deacidification of acidified paper, and the reinforcement of flaking paper and pigments, were solved. Meanwhile, good conservation and restoration results for caisson paintings were obtained. This research method of combining theory and practice has greatly improved the scientificity and success rate of conservation work. These research results provide valuable experience and reference for other caisson paintings in similar environments.

Enhanced Hydrolysis of Carbonyl Sulfide in Coking Oven Gas Utilizing an Efficient Ca-Ba-γ-Al2O3 Catalyst

China possesses a substantial capacity for coke production, resulting in the annual generation of over 100 billion standard cubic meters of the by-product coke oven gas. The comprehensive utilization of this gas has emerged as a matter of significant concern within the coking industry. The removal of carbonyl sulfide (COS) from coke oven gas is crucial for enhancing gas quality, mitigating equipment corrosion, minimizing environmental pollution, elevating the quality of recovered products, and fostering the production of high-quality steel. A novel Ca-Ba-γ-Al2O3 catalyst has been devised, employing γ-Al2O3 as the catalyst matrix and integrating calcium hydroxide (Ca(OH)2) alongside barium hydroxide octahydrate (Ba(OH)2·8H2O) as the alkaline activating components. The impact of various factors, including reaction temperature, humidity, and the number of activating components loaded, on the hydrolysis efficiency of COS has been meticulously investigated. Furthermore, the catalytic reaction mechanism has been elucidated utilizing advanced characterization techniques such as X-ray diffraction (XRD) and Brunauer–Emmett–Teller (BET) analysis. The outcomes of this research reveal that, under optimal conditions of a reaction temperature of 55 °C and a humidity of 56%, the Ca-Ba-γ-Al2O3 catalyst achieves a remarkable COS hydrolysis efficiency of 95.22%.

Boron removal from wastewater via coordinative adsorption assisted by Fenton-Induced Oxoprecipitation/Flocculation

Chemical precipitation is widely used for boron removal from water in industrial-scale processes, though a following post treatment is generally required to meet the concentration set by current international standards.In this work, chemical precipitation of boron (B) in water by different precipitating agents was combined with Fenton treatment to enhance the boron removal effectiveness. This approach achieved residual boron concentration of less than 0.5 mg/L, hard to achieve through conventional precipitation methods.Batch tests were performed at different dosage of Fenton reagents, and selected Fe2+/H2O2 weight ratios were evaluated with or without adding precipitating agents. The effect of pH on the process was also investigated, to assess the optimal conditions to maximize boron removal. At the end of the process, barium hydroxide was used to remove effectively excess sulfate ions.The sludge produced was characterized by XRD, SEM and FTIR analysis, and the mechanism of boron removal was investigated.An oxoprecipitation mechanism was induced by the Fenton process: boron-based species were converted into borate ion, thus predisposing them to a coordination-type adsorption on the surface of iron and calcium hydroxide, assisted by aluminum sulfate at pH 12.5.The process was then successfully tested on real boron −contaminated wastewater, thus confirming the effectiveness of the process while simultaneously decreasing the organic content.

Latent heat absorption of alkali metal hydrates enables delayed ignition and improved flame retardancy of epoxy resin

In this work, alkali metal hydrates, barium hydroxide octahydrate (BHO) and sodium acetate trihydrate (SAT) were added into epoxy resin (EP) to prepare a series of flame-retardant EP composites. It showed that EP samples can pass the V-0 rating of UL-94 when the amount of hydrated salt exceeds 45 wt%. When the additional amount of SAT is 50 wt%, the LOI of the EP sample increases to as high as 39% compared to 19% of pure EP. In addition, the time to ignition (TTI) of EP with 50 wt% SAT was prolonged to 157 s from 63 s of pure EP, which can provide valuable time for fire escape. The peak heat release rate (PHRR) was reduced by 63.9% compared with that of pure EP (from 1392.4 kW/m2 to 502.18 kW/m2), which indicated that phase change heat absorption plays a crucial role in reducing fire hazards of EP.

A comparative study between aqueous and methanol solutions of barium hydroxide: implications for applying barium protectants in gypsification calcareous relics

Gypsification is a common problem in weathered calcareous relics. In previous studies, the solutions of barium hydroxide in water and methanol were used as protectants for gypsification calcareous relics and showed significant differences in permeability. In this study, the underlying reasons for permeability differences between these two solutions were investigated using optical microscopy, ultraviolet–visible spectrophotometry, X-ray diffractometry, Fourier transform infrared spectroscopy, the phenolphthalein test and physical property characterizations. The results indicated that the permeability differences were primarily caused by the solutions’ reactivity. Specifically, owing to the high reactivity of barium hydroxide in water, it reacted rapidly with atmospheric CO2 and gypsum (the weathering product) to generate barium carbonate, barium sulfate and calcium hydroxide precipitates. These precipitates hindered the penetration of solution into weathered relics. In contrast, barium hydroxide in methanol did not react with atmospheric CO2 or weathered relics, which also kept the solution in a liquid state during the infiltration process. Therefore, the solution of barium hydroxide in methanol exhibited high permeability. Based on the above findings, this study is meaningful for applying barium protectants in the conservation of gypsification calcareous relics.

Preparation of nano-CuO@BaSO4 under room temperatures and its application in PA6 composites

In this work, by simply using barium hydroxide (Ba(OH)2·8H2O) to react with cupric(II) sulfate pentahydrate (CuSO4.5H2O) in methanol under room temperatures, cupric oxide and barium sulfate co-precipitates (CuO@BaSO4) were one-step prepared, and the methanol can be recycled after separating the co-precipitates. The CuO@BaSO4 co-precipitates were then blended with polyamide 6 (PA6) to prepare PA6-CuO@BaSO4 composites and composites fiber via melt extrusion and melt spinning methods to improve the mechanic and antibacterial properties synchronously. The as-prepared CuO@BaSO4 co-precipitates have a regular size of 30–50 nm and are highly compatible with the PA6 matrix. Further investigations disclosed that the CuO@BaSO4 co-precipitates had a good dispersion in the PA6 matrix and synchronously improved the mechanical properties and thermal stability. What’s more, the PA6-CuO@BaSO4 composites showed excellent antibacterial performance and high spinnability. The bactericidal rate reached 100% when adding tiny content (0.24 wt%) of Cu2+ into PA6 fibers.

Molten Ba(OH)2.8H2O as an efficient and rapid etchant for detecting α-particles using a diallyl maleate-allyl diglycol carbonate detector

In the present study, for the first time, nuclear tracks of α-particles were created on diallyl maleate-allyl diglycol carbonate (DAM-ADC) using molten hydrated barium hydroxide (MBH). We used 17 DAM-ADC plates with dimensions of 1.0 cm × 1.0 cm × 0.1 cm. The bulk etching rate was calculated at various etching temperatures based on changes in the thickness of the DAM-ADC plates. DAM-ADC was irradiated with α-particles to etch at various temperatures for different durations in order to determine the characteristic etching parameters, such as the bulk and track etching rates, etching efficiency of the detector, and critical angle of etching. Photographs of the etched DAM-ADC samples were obtained with a calibrated optical microscope and analyzed with ImageJ software to calculate the track diameters of α-particles. The results demonstrated that MBH is a more efficient and rapid etchant for registering and detecting charged particles with various energies compared with conventional etching solutions (NaOH, KOH, etc.). DAM-ADC with MBH can be used in environmental applications for detecting radon and neutrons.

Preparation and Ferroelectric Properties of Er Doped BaTiO3 Nanotubes

In this paper, erbium-doped barium titanate nanotubes with different concentrations were prepared by combining the anodic oxidation method with the low-temperature hydrothermal method. The TiO2 nanotubes produced by electrolysis using titanium flakes as substrate were put into barium hydroxide octahydrate solution for hydrothermal reaction, and different concentrations of Er-doped barium titanate nanotubes were prepared by adding different concentrations of Er(NO3)3·5H2O to the reaction solution. The samples with different doping concentrations were analyzed for their morphological structure, physical phase composition and ferroelectric properties. All samples were found to have complete barium titanate nanotube structure, and the diffraction peaks of XRD were compared with the standard Cope, and the doped samples were all tetragonal phase chalcogenide structure with no other impurities generated. From the hysteresis loop diagram of the samples measured by the TF-2000 ferroelectric analyzer, it can be found that the residual polarization intensity of the samples showed a characteristic of increasing and then decreasing with the increase of the doping concentration, and the residual polarization intensity was the largest at 0.151 uC/cm2 under the hydrothermal reaction condition of 180°C and 3 h with the Er3+ concentration of 0.0025 mol/L.

Supercooling degree decrease of barium hydroxide octahydrate employing 3D porous silver foam as supporting material

Inorganic hydrated salts possess high latent heat of phase transition and are promising phase change materials (PCMs). However, the issues of supercooling, low thermal conductivity, susceptibility to leakage, and phase separation significantly impediment the practical applications of inorganic hydrated salts. In this study, it is proposed to decrease the inorganic hydrated salt supercooling degree by increasing the surface roughness of the porous material and to load the nucleating agent silver (Ag) onto polydopamine (PDA) modified melamine foam (MF) by electroless plating to obtain 3D porous Ag foams, which are then utilized as support materials. The results demonstrated that the 3D porous Ag foam compounded with barium hydroxide octahydrate (BHO) can ameliorate the shortcomings of leakage and reduce the supercooling degree in the cooling process. The composite not only exhibits high enthalpy of over 248.5 J/g and high thermal conductivity of 1.82 W·m−1·K−1 but also has a low supercooling degree of 0.21 ℃. Furthermore, the composites exhibited superior shape stability and thermal cycling stability. This study provides an effective method for reducing the supercooling degree of inorganic hydration salts.

Feasibility study of Replacing Currently used Freons with Ammonium Chloride and Barium Hydroxide for Freezing System

The machinery used to cool or freeze food uses a lot of energy. Consequently, it is necessary to lower energy use. Additionally, due to their significant global warming potential (GWP), traditional refrigerants must be replaced to help reduce greenhouse gas (GHG) emissions. Therefore, the usage of alternative refrigerants with lower GWPs is necessary. The possibility of the ammonium chloride (NH4Cl(s)) and solid hydrated barium hydroxide (Ba(OH)2.8H2O(s)) based non-freon refrigerant as a substitute refrigerant was evaluated in this study. Demo-tests were conducted using a prototype refrigerator, which is essentially a closed chamber with foam and PVC insulation. Despite reaching the freezing point satisfactorily, the stirring chamber of the prototype had an unpleasant ammonia odor. Due to the lack of equilibrium between the reactant and product, these components were not permanent solutions like freons. Therefore, further research is needed to determine how effective it would be as a refrigerant

Synthesis and performance of tetragonal BaTiO3 fine powders via a facile tartaric acid assisted method

A facile tartaric acid assisted method using metatitanic acid, barium hydroxide and tartaric acid as starting materials is proposed to prepare tetragonal BaTiO3 fine powders. Owing to the ultrafine character of the as-formed BaCO3 with high chemical activity, and its arrangement coating the surface of intermediate TiO2 nanoscale needles, pure cubic phase BaTiO3 homogeneous powders with size of about 50 nm was obtained via calcining treatment at 650℃, which subsequently transformed as tetragonal BaTiO3 uniform powders with size of about 240 nm and high tetragonality (c/a=1.0095) after calcining treatment at 1050℃. The BaTiO3 ceramic prepared from the BaTiO3 uniform powders displayed much improvement performances with high permittivity of about 5980 and low dielectric loss of about 0.014 at room temperature in comparison to the BaTiO3 ceramic prepared respectively from the BaTiO3 synthesized via a traditional solid-state method, and commercial BaTiO3, suggesting it’s compatible in application of MLCCs with high performance.

Shape-stabilized phase change materials of barium hydroxide octahydrate based on Cu‐coated melamine foam

Hydrated salt phase change materials (PCMs) have the advantages of high energy storage density and low cost, and have great application prospects in the field of phase change energy storage. However, the problems of supercooling, phase separation and leakage of hydrated salt PCMs limit their further applications. In this work, we designed and fabricated Cu-coated melamine foam (MF)/barium hydroxide octahydrate (BHO) shape-stabilized phase change materials (SSPCMs) with low supercooling. MF was used as supporting material and Cu as a nucleating agent and thermal conductivity enhancer by loading it onto MF via electroless plating. BHO was then encapsulated into the MF@Cu skeleton through vacuum impregnation to obtain BHO@MF@Cu SSPCMs. The results demonstrated that BHO@MF@Cu SSPCMs not only present very low supercooling degree of 0.12 °C and high thermal energy capacity of 247 J/g, but maintained a latent heat of phase transition of 229.3 J/g with little change in enthalpy after 100 thermal cycles. Moreover, compared to BHO, SSPCMs exhibited high thermal conductivity of 1.687 W m−1 K−1, excellent shape stability, and thermal cycling stability. In summary, BHO@MF@Cu SSPCMs with low supercooling degree were prepared by electroless plating and vacuum impregnation in this study, which provides a new strategy to reduce the supercooling degree of hydrated salt PCMs.

Enhanced sulfate recovery from high salinity reject brine through simultaneous chemical precipitation and electrocoagulation

A modified electrocoagulation method is proposed for the recovery of sulfate from high salinity reject brine. This method is based on recovering sulfate using highly/moderately alkaline solids, namely, calcium oxide (CaO), barium hydroxide (Ba(OH)2), hydroxyethyl cellulose (HEC), and ladle furnace slag (LFS), which are added to high salinity water at specific concentrations, in combination with electrocoagulation at specific current densities. This method does not require a prior chemical precipitation, minimizes the required energy input, and the collected solid products can be further purified using conventional methods of separating sulfate from solid mixtures. The system comprises an electrocoagulation unit with alkaline solids at certain operating and mixing conditions. Rectangular aluminium plates were used as electrodes for the electrocoagulation reactor. A current density of 4.5–22.5 mA/cm2 is applied using a power source. The method involved generating electrons at the anode under moderate to high pH conditions and specific anodic potential. The cathode facilitated the production of hydrogen gas and hydroxyl ions, which effectively improved the dissociation of dissolved sulfate components. Combining the chemical precipitation and electrocoagulation in the presence of CaO in one process, a high sulfate removal was achieved from an initial concentration of 6051 mg/L to 196 mg/L in real reject brine after 4 h of treatment. Furthermore, the sulfate removal efficiency reached up to 88% using HEC, 87% using LFS, and 98% using barium hydroxide. In addition, the barium ions in the treated brine reduced up to 64%. The process led to the precipitation of solid compounds specifically, calcium sulfate (CaSO4) using CaO and LFS, and barium sulfate (BaSO4) using Ba(OH)2 and acid fuchsin (C20H12N3Na2O9S3) using HEC. The modified method resulted in an energy reduction of 40% from 14.1 kW h/kg SO42− to 8.5 kW h/kg SO42− compared with the conventional hybrid process.

Efficient and fast detection of alpha particles using CR-39 detector

The CR-39 track detector was used to create alpha particle tracks using molten hydrated barium hydroxide (MBH). In this experiment, seventeen CR-39 plates with a thickness of 250 μm were used. For determining the bulk etch rate, the rate of the change of track dimeter of fission fragments has been used. The detectors were etched at the suitable etching conditions of MBH, and the track diameters were measured using two suitable image analysis software (Infinity Analyzer and ImageJ). A standard micrometer slit was used to calibrate the images in the field of view of the microscope. The results of this investigation demonstrated that MBH provides significant etching characteristics in addition to shorter etching times and higher etching efficiency for the registration and detection of charged particles of various energies. This work has numerous uses, ranging from plastic nuclear track filters and environmental applications to alpha spectroscopy and neutron detection. Results of sample irradiation, track diameter analysis, sensitivity analysis, and etching efficiency analysis are covered in detail.

Ferroelectric Polarization in BaTiO3 Nanocrystals Controls Photoelectrochemical Water Oxidation and Photocatalytic Hydrogen Evolution.

Ferroelectric (FE) semiconductors such as BaTiO3 support a remnant polarization after the application of an electric field that can promote the separation of photogenerated charge carriers. Here, we demonstrate FE-enhanced photocatalytic hydrogen evolution and photoelectrochemical water oxidation with barium titanate nanocrystals for the first time. Nanocrystals of the ferroelectric tetragonal structure type were obtained by a hydrothermal synthesis from TiO2 and barium hydroxide in 63% yield. BaTiO3 nanocrystal films on tantalum substrates exhibit water oxidation photocurrents of 0.141 mA cm-2 at 1.23 V RHE under UV light (60 mW cm-2) illumination. Electric polarization at 52.8 kV cm-1 normal to the film plane increases the photocurrent by a factor of 2 or decreases it by a factor of 3.5, depending on the field polarity. It also shifts the onset potential by -0.15 or +0.09 V and it modifies the surface photovoltage signal. Lastly, exposure to an electric field increases the H2 evolution rate of Pt/BaTiO3 by a factor of ∼1.5, and it raises the selectivity of photodeposition of silver onto the (001) facets of the nanocrystal. All FE enhancements can be removed by heating samples above the Curie temperature of BaTiO3. These findings can be explained by FE dipole-induced changes to the potential drop across the space charge layer of the material. The ability to use the ferroelectric effect to enhance hydrogen evolution and water oxidation is of potential interest for the development of improved solar energy for fuel conversion systems.

Multi-stage precipitation for the eco-friendly treatment of phosphogypsum leachates using hybrid alkaline reagents

The leachate of waste phosphogypsum (PG) contains substantial amounts of phosphate, sulfate, and fluoride, which poses an immense threat to the safety of the aquatic ecosystem. In this study, a multi-stage precipitation approach is proposed to treat PG leachates using hybrid alkaline reagents including barium hydroxide (Ba(OH)2) and quicklime (CaO). To avoid potential environmental impacts, hazardous environmental contaminants are removed from the PG leachates by adding alkaline reagents in a specific order. The multi-stage precipitation approach achieves nearly 100% removal efficiencies for phosphate, fluoride, and metal ions as well as satisfactory removal efficiencies for sulfate and ammonia nitrogen (93.6% and 94.8% respectively). The compositions of generated mineral precipitates are comprehensively investigated by analytical techniques including X-ray diffraction (XRD), transmission electron microscope (TEM), etc. The main precipitated mineral phases are barite (BaSO4), brushite (CaHPO4·2H2O), and hydroxyapatite (Ca5(PO4)3OH). This is further proven by the geochemical modeling using Visual MINTEQ, in which the precipitation of mineral phases is calculated. Furthermore, a straightforward economic analysis indicates the proposed method has a lower cost of the use of alkaline reagents. Overall, this study establishes an effective and eco-friendly approach for the treatment of waste PG leachates to remove hazardous environmental contaminants and recover valuable precipitates.

Technology for the Nondestructive Reprocessing of Sodium Iodide Technogenic Solutions into a Charge for Single Crystal Growth

Introduction. The production of NaI-based single crystals results in accumulation of great amount of liquid waste. To bring valuable constituents of this waste back, the NaI technogenic solutions are treated to precipitate iodine that is further used in the synthesis of high-pure NaI. However, the least contaminated part of the waste may be brought back into the main technological process without the intermediary stage of iodine destruction, which allows a considerable cost saving.Problem Statement. There have been no data on the effective purification coefficients for NaI solutions subsequently treated with barium hydroxide, sodium carbonate, and by mass crystallization. Requirements to impurity content, which NaI solutions have to comply with in order to be used in the nondestructive treatment have mot been not formulated.Purpose. The purpose of this research is to develop a technology for reprocessing NaI technogenic solutionsinto sodium iodide of high purity without NaI destruction at the intermediate stage.Material and Methods. The materials that have been used for this research are as follows: aqueous solutions of NaI-based crystal production waste, active coal, barium hydroxide, sodium carbonate. The methods that have been employed are the treatment of NaI solutions with barium hydroxide, sodium carbonate, and by mass crystallization. Results. The technology of NaI solution purification by treatment with barium hydroxide and sodium carbonate with further mass crystallization of the purified salt has been developed. This technology is more environment friendly and cheaper than the conventional one that includes obtaining pure iodine. A series of NaI technogenic solutions has been treated in laboratory conditions and on industrial equipment, and the efficiency of their purification by the chemical treatment and mass crystallization hasbeen estimated. The impurity content in the obtained salt and the scintillation parameters of grown NaI : Tl crystals meet the requirements for these products.Conclusions. The technology has been implemented in the manufacturing process at the pilot plant of the Institute for Scintillation Materials of the NAS of Ukraine. It may be used at other enterprises that deal with alkali metal iodide waste treatment.