NaOH H2O Research Articles

Experimental calibration of silicon and oxygen isotope fractionations between quartz and water at 250 °C by in situ microanalysis of experimental products and application to zoned low δ30Si quartz overgrowths

The interpretation of silicon isotope data for quartz is hampered by the lack of experimentally determined fractionation factors between quartz and fluid. Further, there is a large spread in published oxygen isotope fractionation factors at low temperatures, primarily due to extrapolation from experimental calibrations at high temperature. We present the first measurements of silicon isotope ratios from experimentally precipitated quartz and estimate the equilibrium fractionation vs. dissolved silica using a novel in situ analysis technique applying secondary ion mass spectrometry to directly analyze experimental products. These experiments also yield a new value for oxygen isotope fractionation. Quartz overgrowths up to 235μm thick were precipitated in silica–H2O–NaOH–NaCl fluids, at pH12–13 and 250°C. At this temperature, 1000lnα30Si(Qtz–fluid)=0.55±0.10‰ and 1000lnα18O(Qtz–fluid)=10.62±0.13‰, yielding the relations 1000lnα30Si(Qtz–fluid)=(0.15±0.03)*106/T2 and 1000lnα18O(Qtz–fluid)=(2.91±0.04)*106/T2 when extended to zero fractionation at infinite temperature. Values of δ30Si(Qtz) from diagenetic cement in sandstones from the basal Cambrian Mt. Simon Formation in central North America range from 0 to −5.4‰. Paired δ18O and δ30Si values from individual overgrowths preserve a record of Precambrian weathering and fluid transport. The application of the experimental quartz growth results to observations from natural sandstone samples suggests that precipitation of quartz at low temperatures in nature is dominated by kinetic, rather than equilibrium, processes.

A New Pitzer Parameterization for the Binary NaOH–H2O and Ternary NaOH–NaCl–H2O and NaOH–LiOH–H2O Systems up to NaOH Solid Salt Saturation, from 273.15 to 523.15 K and at Saturated Vapor Pressure

This paper presents a new set of Pitzer ion interaction model parameters for the binary NaOH–H2O system for concentrations up to over 30 mol·kg−1 and temperatures ranging from 273.15 to 523.15 K. Assuming that the electrolyte is only partially dissociated, the model requires the adjustment of (i) the three classical binary interaction parameters β (0), β (1) and C ϕ , (ii) the equilibrium constant of formation of the aqueous complex NaOH0(aq), and iii) one binary (λ NaOH/NaOH) and one ternary (\( \zeta_{{{\text{NaOH}}/{\text{Na}}^{ + } /{\text{OH}}^{-} }} \)) interaction parameter. This approach, which provides much better results than the approach of treating NaOH as a fully dissociated electrolyte, was chosen to extend the description of the system to high temperatures and high concentrations. The temperature functions of the solubility products of anhydrous NaOH(cr) and five hydrated salts, NaOH·nH2O(cr) (where n = 1, 2, 3.11, 3.5, 4α), were determined. In order to evaluate the quality of the new set of parameters, several tests were run on various properties using various literature data. These include the boiling point elevation in the NaOH–H2O system and the phase diagrams of the two ternary systems NaOH–NaCl–H2O and NaOH–LiOH–H2O. Interaction parameters for the two related binary systems NaCl–H2O and LiOH–H2O were taken from previous studies. To ensure consistency, four new mixing parameters were revised (\( \zeta_{{{\text{Na}}^{ + } /{\text{Cl}}^{-} /{\text{NaOH}}}} \) and \( \varPsi_{{{\text{Cl}}^{-} /{\text{OH}}^{-} /{\text{Na}}^{ + } }} \) for the ternary system NaOH–NaCl–H2O and \( \lambda_{{{\text{Li}}^{ + } /{\text{NaOH}}}} \) and \( \varPsi_{{{\text{OH}}^{ - } /{\text{Na}}^{ + } /{\text{Li}}^{ + } }} \) for the ternary system NaOH–LiOH–H2O). Consistent with Pitzer’s equations, our new set of parameters can be used to satisfactorily describe the quaternary Na+–Li+–Cl−–OH−–H2O system to very high concentrations and temperatures.

Pitzer Model Anion–Anion and Ternary Interaction Parameters for the Na2C2O4–NaOH–H2O and Na2C2O4–NaNO3–H2O Systems

Alkaline high-level nuclear wastes in the United States contain large inventories of sodium oxalate (Na2C2O4) immersed in Na+-, $$ {\text{NO}}_{3}^{ - } $$ - and OH−-bearing electrolyte solutions. Dissolution and precipitation of Na2C2O4 will likely influence the treatment of this waste. The Pitzer model has been widely used to model electrolyte solubility during high-level nuclear waste processing. The present study determines the anion–anion (θ) and ternary cation–anion–anion (ψ) Pitzer interaction parameters for oxalate Na2C2O4–NaNO3–H2O and Na2C2O4–NaOH–H2O systems by fitting the Pitzer model with Na2C2O4 solubility data in aqueous NaNO3 and NaOH solutions. The $$ {\text{C}}_{2} {\text{O}}_{4}^{2 - } $$ – $$ {\text{NO}}_{3}^{ - } $$ and $$ {\text{C}}_{2} {\text{O}}_{4}^{2 - } $$ –OH− θ parameters were found to be 0.02369 and −0.005304, respectively. The Na– $$ {\text{C}}_{2} {\text{O}}_{4}^{2 - } $$ – $$ {\text{NO}}_{3}^{ - } $$ and Na– $$ {\text{C}}_{2} {\text{O}}_{4}^{2 - } $$ –OH− ψ parameters were found to be 0.04069 and 0.017044, respectively. The solubility data could be modeled with temperature independent θ and ψ values over the experimental range investigated, which was 20–75 °C for the Na2C2O4–NaNO3–H2O system and 0–50 °C for the Na2C2O4–NaOH–H2O system.

Electrolytic ferrate preparation in various hydroxide molten media

Ferrate(VI) has the potential to be used as an environmentally friendly treatment for wastewater and drinking water. The electrochemical preparation of ferrate can be considered a “green” and simple approach because it typically involves a one-step reaction without harmful or expensive chemicals for the oxidation of Fe(0) to Fe(VI). The electrolyses are performed in three molten systems (i.e. NaOH–H2O, KOH–H2O and NaOH–KOH–H2O). In the first molten system, soluble ferrate was prepared in relatively low yield and current efficiency for continuous addition to wastewater. In the second system, highly stable ferrate that is easily transported and insoluble is produced with high yield. In the third system, the properties and yield of ferrate depend on the Na/K ratio in the melt. The influence of the anode material, current density and temperature on the electrolysis yield and current efficiency during ferrate preparation is discussed.

Solubility Equilibrium of the NaOH–H2O–Na2CrO4–Na2SiO3–NaAlO2 Multicomponent Systems Involved in the Liquid-Phase Oxidation of Chromite

Chromium salts are a group of important chemical raw materials with many applications. While the conventional manufacturing process, i.e. calcium roasting of chromite, has many disadvantages; the novel processes of liquid-phase oxidation, whose main reaction is the oxidation of chromite by oxygen (air) in highly concentrated alkaline solutions, are promising to achieve clean manufacturing. For the oxidation reaction of chromite in NaOH solutions, a significant amount of multicomponent systems consisting NaOH, Na2CrO4, Na2SiO3, and NaAlO2 are generated. It is a prerequisite to clarify the solubility equilibrium of the multicomponent systems for exploring highly efficient separation methods of Na2CrO4 with Na2SiO3 and NaAlO2. In this paper, Na2CrO4 solubility in the ternary system of NaOH–H2O–Na2CrO4 was first measured using the equilibrium analysis method and varying the NaOH concentrations from 100 to 800 g·L–1 and the temperatures from 353.15 to 403.15 K. Aferwards, the solubility of Na2CrO4, NaAlO2, and...

Chemical Processes During Energy‐Saving Preparation of Lightweight Ceramics

Lightweight glass‐ceramic material similar to foam glass was obtained at 700°C–800°C directly from alkali‐activated silica clay and zeolitized tuff without preliminary glass preparation. It was characterized by low bulk density of 100–250 kg/m3 and high pore size homogeneity. Chemical processes occurring in alkali‐activated silica clay and zeolitized tuff were studied using X‐ray diffraction, thermal gravimetry, IR‐spectroscopy, and scanning electron microscopy. Pore formation in both compositions is caused by dehydration of hydrated sodium polysilicates (Na2O·mSiO2·nH2O), formed during alkali activation. Additional pore‐forming gas source in alkali‐activated zeolitized tuff is trona, Na3(CO3)(HCO3)·2H2O, formed during interaction between unbound NaOH and CO2 and H2O from air. Influence of mechanical activation of raw materials on chemical processes occurring in alkaline compositions was also studied.

Solid–liquid equilibria in the ternary system NaBO2–NaOH–H2O thermal behavior of double salts

To increase the energy density of a hydrogen generator system, the NaBH4 concentration has to be maximized; nevertheless, NaBO2 crystallization must be avoided. Sodium borohydride decomposes spontaneously in water to produce hydrogen and by-products: hydrated sodium borate compounds. Sodium hydroxide is added to the solution to limit this self-decomposition, thus stabilizing the system. Therefore, the delimitation of the homogeneous liquid phase domain in the phase diagram quaternary system NaBH4–NaBO2–NaOH–H2O is fundamental. This work introduces a critical analysis of the aqueous boundary binary and ternary phase diagrams presented in the literature, which take part of the complete description of the system. After this critical review, showing numerous inconsistencies about the solid phases presented in the literature, it has been decided to redetermine the isothermal for the NaBO2–NaOH–H2O ternary system in a temperature range of −10 to 50°C. The experimental results of the solubility curves at 50, 25 and 10°C under atmospheric pressure will be presented. The solid phases (borate hydrates, hydroxide hydrates and double salts) in equilibrium with the liquid phase will be also reported.

Determination of the operating parameters of an evaporator crystallizer

This work involves the study of the solid/liquid equilibrium in the NaCl–NaOH–H2O ternary system. The aim is to optimize the operating conditions of an evaporator–crystallizer used in a hydrazine extraction process. The latter is conducted at industrial scale using the Raschig method, a general method for preparing hydrazines for aerospace and pharmaceutical applications. The extraction process includes the use of a Kestner type evaporator–crystallizer to first isolate hydrazine and water by evaporation and then separate two salts: sodium hydroxide, recovered as an aqueous solution, and sodium chloride which crystallizes. However, problems related to the co-precipitation of NaCl–NaOH may be encountered in industry, leading to the clogging of installations. Therefore, it is necessary to ensure that only NaCl crystallizes while maintaining NaOH in liquid state. Knowledge of the equilibrium phases of the NaCl–NaOH–H2O ternary system is thus required, particularly the liquid/solid phase. Phase equilibrium experiments were performed by isoplethic thermal analysis (ITA) and chemical titrations over the temperature range of 313 to 353 K at atmospheric pressure. ITA is an isobaric and isothermal method developed in our laboratory and based on the measurement of the thermal effects associated with transformations in a system (appearance or disappearance of a phase) when its composition is changed. The NaCl crystallization domain was fully determined and the operating parameters of the device were defined precisely as a function of temperature and composition of the Kestner loop.

Zircon solubility and zirconium complexation in H2O+Na2O+SiO2±Al2O3 fluids at high pressure and temperature

Zircon is an important host mineral for many high-field strength elements (HFSE), particularly Zr and Hf. Thus, its solubility in geologic fluids at high pressure and temperature plays an important role in terrestrial cycling of these elements during processes in the Earth's crust and mantle. We performed in-situ high-pressure, high-temperature measurements of zircon solubility in H2O–Na2Si3O7, H2O–Na2Si3O7+Al2O3, H2O–Na2Si2O5, H2O–NaAlSi3O8 fluids, as well as of baddeleyite solubility in H2O–NaOH fluids, by in-situ synchrotron radiation X-ray fluorescence analysis using hydrothermal diamond-anvil cells. Zirconium complexation in fluids in equilibrium with zircon was constrained by in-situ X-ray absorption near-edge structure (XANES) spectroscopy. Zircon solubility is strongly enhanced by addition of Na2Si3O7 to H2O. The degree of enhancement increases with Na2Si3O7 concentration. The Zr content of fluids containing 10wt% Na2Si3O7 reached up to 86±2ppm Zr at 550°C and 400MPa. At 30wt% Na2Si3O7, the maximum Zr concentration was 997±6ppm at 600°C and 440MPa. Zircon solubility in these fluids decreases considerably with pressure and increases slightly with temperature. Addition of Al2O3 decreases the zircon solubility. In H2O–NaAlSi3O8 fluids, the Zr concentrations are in the sub-ppm to ppm range. Zr concentrations in NaOH solutions in equilibrium with baddeleyite reached up to 390±2ppm at 600°C and 930MPa and increase with pressure and temperature. In-situ XANES spectra collected on Zr in H2O–Na2Si3O7, H2O–Na2Si3O7+Al2O3, H2O–NaOH, and H2O–HCl fluids in equilibrium with zircon provide evidence for strong differences in the Zr complexation between these fluids. Comparison of XANES spectra to those of model compounds and ab-initio simulation of XANES spectra revealed [8]Zr for the HCl solution, [7]Zr for the NaOH solution, and [6]Zr for the Na–Al-silicate-bearing solutions. For the latter solutions, formation of alkali zircono-silicate complexes is indicated by the strong dependence of zircon solubility on Na/Al and the similarity of the XANES spectra to spectra simulated based on the local structure around Zr in the alkali zircono-silicates vlasovite and catapleite. Alkali zircono-silicate complexes are responsible for the enhancement of Zr concentrations in Na–Al-silicate-bearing solutions and very likely play an important role for mobilization of HFSE during fluid–rock interaction. Because high alkali/Al can be expected in aqueous fluids at high pressure and temperature due to incongruent dissolution of feldspar and mica, the increase of zircon solubility along the NaAlSi3O8–Na2Si3O7 join points to potentially considerable Zr or HFSE transport by silicate-bearing aqueous fluids in the lower crust and upper mantle.

Crystallization and Agglomeration Kinetics of Hydromagnesite in the Reactive System MgCl2–Na2CO3–NaOH–H2O

The reactive crystallization kinetics of hydromagnesite (4MgCO3·Mg(OH)2·4H2O) for the MgCl2–Na2CO3–NaOH–H2O system has been systematically investigated in a continuously operated mixed-suspension mixed-product removal (MSMPR) crystallizer for the first time. Determination of the effects of reactive temperature and OH– ion on magnesium carbonate hydrates in the above system was conducted through a batch crystallization experiment, and the crystallization temperature of 80 °C for the precipitation of regular spherical-like hydromagnesite was selected for the kinetics study. The relative supersaturation for hydromagnesite is obtained based on the activity coefficients calculated by the Pitzer model. The growth rate, nucleation rate, and agglomeration kernel are determined on the basis of the agglomeration population balance equation, and their kinetic equations are then correlated in terms of power law kinetic expressions. The orders of volume growth rate and linear growth rate with respect to the relative s...

Solid State Spectroelectrochemistry of Redox Reactions in Polypyrrole/Oxide Molecular Heterojunctions

To understand the mechanism of bias-induced resistance switching observed in polypyrrole (PPy) based solid state junctions, in situ UV-vis absorption spectroscopy was employed to monitor oxidation states within PPy layers in solution and in PPy/metal oxide junctions. For PPy layers in acetonitrile, oxidation led primarily to cationic polaron formation, while oxidation in 0.1 M NaOH in H(2)O resulted in imine formation, caused by deprotonation of polarons. On the basis of these results in solution, spectroelectrochemistry was used to monitor bias-induced formation of polarons and imines in PPy layers incorporated into solid state carbon/PPy/Al(2)O(3)/Pt junctions. A positive bias on the carbon electrode caused PPy oxidation, with the formation of polaron and imine species strongly dependent on the surrounding environment. The spectral changes associated with polarons or imines were stable for at least several hours after the applied bias, while a negative bias reversed the absorbance changes back to the initial PPy spectrum. These results indicate that PPy can be oxidized in nominally solid state devices, and the formation of stable polarons is dependent on the tendency for deprotonation of the polaron to the imine. Since PPy conductivity depends strongly on the polaron concentration, monitoring its concentration is critical to determining resistance switching mechanisms. Furthermore, the importance of ion mobility and OH(-) generation through H(2)O reduction at the Pt contact are discussed.

Synthesis and characteristics of novel layered silicates HUS-2 and HUS-3 derived from a SiO2–choline hydroxide–NaOH–H2O system

Three kinds of layered silicates, HUS-2, HUS-3, and HUS-4, were synthesized using amorphous silica, sodium hydroxide, and choline hydroxide as a structure-directing agent (SDA). Structural analyses by powder X-ray diffractometry and solid-state magic-angle-spinning (MAS) NMR spectroscopy revealed that HUS-2 had a layered structure, which was composed of four-, five-, and six-membered rings. Its framework topology was partially similar to that of a HEU-type zeolite including bre (10T)-type composite building units. Structural refinement by the Rietveld method showed that the choline cations that were used as an SDA were incorporated into the interlayers. Double silicate layers were included in each unit cell. The interlayer distance was estimated to be ca. 0.36 nm. The presence of hydrogen bonding between adjacent terminal O atoms was clearly revealed by 1H MAS NMR spectroscopy and through the electron-density distribution obtained by the maximum entropy method. Although the crystal structure of the layered silicate HUS-3 could not be analysed, the HUS-3 was transformed into a CDO-type zeolite by calcination, indicating that the structure of HUS-3 was partially similar to that of a CDO-type zeolite precursor. The crystal structure of HUS-4 was similar to that of PLS-1 synthesized using tetramethylammonium hydroxide. We also demonstrated that the layered silicates HUS-2 and HUS-3 exhibited high catalytic activities as base catalysts in a Knoevenagel condensation reaction.

ChemInform Abstract: Synthesis and Enhanced Photocatalytic Activity of a Hierarchical Porous Flowerlike p—n Junction NiO/TiO2 Photocatalyst.

AbstractFlowerlike NiO/TiO2 composite particles are prepared from β‐Ni(OH)2 (obtained from Ni(NO3)2, en, and NaOH in H2O, autoclave, 100 °C, 2.5 h) dispersed in a Ti(OBu)4/EtOH solution followed by evaporation and calcination at 400 °C for 5 h.

Halocyclization of 3-allylthio-5H-[1,2,4]triazino[5,6-b]indole

The synthesis of 3-allylthio-5H-[1,2,4]triazino[5,6-b]indole has been carried out by the reaction of 3-mercapto-5H-[1,2,4]triazino[5,6-b]indole with allyl bromide in the NaOH–H2O–DMSO system and in a one-pot synthesis from isatin-β-thiosemicarbazide. Halocyclization of allylthio-5H-[1,2,4]-triazino[5,6-b]indole synthesized the 3-halomethyl-3,10-dihydro-2H-[1,3]thiazolo[3',2':2,3][1,2,4]-triazino[5,6-b]indolium halides.

Extraction optimization of organic compounds by demixing observed in the H2O–NaOH–piperidine ternary diagram

Three isothermal sections of the isobaric ternary system H2O–NaOH–C5H10NH were determined by Isoplethic Thermal Analysis at 293, 313, and 323 K. Miscibility gaps were completely delimited and each critical point was calculated. This system is then characterized by a prevalent miscibility gap, three crystallization domains and two triphasic invariant domains. The relevant exploitation of this diagram so permits us to deduce the demixing temperature leading to the optimal transfer of the organic compounds in the light phase and also the composition of the organic phase recovered after this second step of extraction. Moreover, the addition of calculated quantities of sodium hydroxide aqueous solution allows to be in optimized conditions for the next distillation operations.

Диаграммы растворимости тройных систем при NaBH4–NaOH–H2O, KBH4–KOH–H2O, NaBO2–NaOH–H2O И KBO2–KOH–H2O

A study of the solubility in the ternary systems NaBH4–NaOH–H2O, KBH4–KOH–H2O, NaOH–NaBO2–H2O и KOH–KBO2–H2O is of special fundamental and practical interest. The first two systems are used as a fuel and as a hydrogen source in hydrogen power engineering that includes the low-temperature fuel cells; borohydrides are converted into metaborates. Hence, the last two systems represent the discharged by-product. The performance of such mixtures is determined by the solubility of their components, negative temperatures being especially critical. Therefore, in the present work the solubility in the ternary systems was studied by means of isothermal saturation at – 10°C. The compositions of the equilibrium liquid and solid phases and compositions of the eutonic and peritonic equilibria, and the coordinates of the homogeneous solution ranges have been determined. The best solubility of the solid components is characteristic of systems NaBH4–NaOH–H2O and KBO2–KOH–H2O.

Mitochondrial DNA Damage Initiates a Cell Cycle Arrest by a Chk2-associated Mechanism in Mammalian Cells

Previous work from our laboratory has focused on mitochondrial DNA (mtDNA) repair and cellular viability. However, other events occur prior to the initiation of apoptosis in cells. Because of the importance of mtDNA in ATP production and of ATP in fuel cell cycle progression, we asked whether mtDNA damage was an upstream signal leading to cell cycle arrest. Using quantitative alkaline Southern blot technology, we found that exposure to menadione produced detectable mtDNA damage in HeLa cells that correlated with an S phase cell cycle arrest. To determine whether mtDNA damage was causatively linked to the observed cell cycle arrest, experiments were performed utilizing a MTS-hOGG1-Tat fusion protein to target the hOGG1 repair enzyme to mitochondria and enhance mtDNA repair. The results revealed that the transduction of MTS-hOGG1-Tat into HeLa cells alleviated the cell cycle block following an oxidative insult. Furthermore, mechanistic studies showed that Chk2 phosphorylation was enhanced following menadione exposure. Treatment of the HeLa cells with the hOGG1 fusion protein prior to menadione exposure resulted in an increase in the rate of Chk2 dephosphorylation. These results strongly support a direct link between mtDNA damage and cell cycle arrest.

The effect of H2O and PEG on the morphologies of ZnO nanostructures synthesized under microwave radiation

ZnO nanoparticles and nanorods were synthesized from Zn(NO3)2·6H2O and NaOH in H2O and in different molecular weights (MWs) of polyethylene glycol (PEG) using 180 W microwave radiation. The phase was detected using X-ray diffraction (XRD) and selected area electron diffraction (SAED). The diffraction pattern was in accordance with that obtained by simulation. Scanning and transmission electron microscopy (SEM and TEM) revealed the presence of nanoparticles with an average size of 12.7 ± 2.7 nm in water; these gradually changed into nanorods in PEG with different MWs. Four Raman vibrations were detected, with the strongest intensity at 439 cm−1, specified as the optical phonon E2H high frequency mode. Luminescence emission was detected at 366–374 nm, caused by the recombination of free excitons in the products. Emission intensity was highest for the product synthesized in PEG600.

Crystalline mesoporous silicates from layered precursors

Structurally well ordered and crystalline (molecularly ordered) mesoporous silica materials have been prepared from layered silicate precursors. The materials were derived from crystalline layered silicate, Na-RUB-18, by performing secondary hydrothermal synthesis (i.e., restructuring) in the presence of cetyltrimethylammonium (CTA) surfactant molecules. The mesoporous silica materials show retention of molecular ordering (crystallinity) in their framework depending on the method used to remove surfactant molecules. Crystalline RUB-18–surfactant mesophases were first obtained by hydrothermal treatment of Na-RUB-18 in CTA–NaOH–H2O systems at 150 °C for 48 or 120 h. Benign template removal viasolvent extraction in acidified ethanol retained a significant level of crystallinity or molecular ordering in the resulting mesoporous material. H2O2-mediated oxidation of the surfactant at room temperature was also found to be an effective method for generating porous surfactant-free materials with significant crystallinity. Template removal viacalcination generated porous materials that exhibited no crystallinity. The textural properties of the mesoporous materials (surface area: 150–260 m2 g−1, and pore volume: 0.2–0.3 cm3 g−1) depend on the mode of surfactant removal, and follow the trend: calcined > extraction > oxidation. The level of mesostructural ordering was not significantly affected by the surfactant removal method. The morphology of the layered silicate, i.e., plate-like particles, was unchanged during the transformation to mesostructured materials.

Comparative studies of etching mechanisms of CR-39 in NaOH/H2O and NaOH/ethanol

The bulk etch rate for CR-39 in NaOH/ethanol was faster than those in aqueous solution of NaOH (NaOH/H2O). Furthermore, a layer of precipitate always accumulates on the surface of CR-39 detector during etching in NaOH/ethanol, which is absent during etching in NaOH/H2O. In the present work, mass spectrometry results have shown that the same etched products are present in the etchants of NaOH/H2O and NaOH/ethanol after etching of CR-39. This shows that CR-39 has the same etching mechanism in both etchants. These etched products support the etching mechanism of scission of the carbonate ester bond in CR-39 by the hydroxide ion through basic hydrolysis of ester. The difference in the bulk etch rates can be explained in terms of the solubility of the etched products in the etchants. FTIR analyses of the solute formed from the etchants show the formation of allyl alcohol and carbonate during etching in both etchants. The FTIR spectra of the precipitate formed at the surface of CR-39 detectors during etching in NaOH/ethanol has also shown that sodium carbonate is present in the precipitate. Finally, XRD analyses of the solute formed from the etchants show the formation of sodium bicarbonate and sodium carbonate in the etchant of NaOH/H2O after etching and the formation of the mineral natrite and thermonatrite in the etchant of NaOH/ethanol as well as in the layer of precipitate on the surface of the CR-39 detector formed during etching in NaOH/ethanol.