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The sagger, primarily composed of aluminum-silicon, serves as an essential vessel in the sintering process of ternary lithium battery anode materials (LiNi x Co y Mn 1-x-y O 2 , LNCM). However, the acidic oxide SiO 2 in the sagger material readily reacts with Li 2 O in the cathode material, forming substances such as LiAlO 2 or LiAlSiO 4 , resulting in volume expansion, which makes the sagger spalled and damaged. In this study, β-Al 2 O 3 –MgAl 2 O 4 multiphase materials with excellent alkali resistance were prepared using the high-temperature solid-state method. The effects of anhydrous sodium carbonate content and heat treatment temperature on the properties of the composites were investigated, and the thermal shock resistance of the specimens was evaluated by the water-rapid-cooling method, as well as the LNCM corrosion resistance of the specimens was evaluated by the static crucible method. The results showed that the overall performance of the specimens was the best at a anhydrous sodium carbonate content of 6 wt%, with a compressive strength of 57.50 MPa and a flexural strength of 42.49 MPa after firing at 1600 °C for 4 h. The strength retention of the specimens was 33.21 % after one thermal shock at a thermal shock temperature of 900 °C. The specimens showed excellent resistance to erosion as there were no obvious erosion traces on the surface of the specimens after undergoing five cycles of erosion. [ABSTRACT FROM AUTHOR]

Slaked lime was used to synergize with sodium carbonate to activate the slag. Experimental studies were carried out to investigate the effect of the proportion of activator on its workability and mechanical properties. The hydration products, microstructure changes, and strength enhancement mechanism were also explored by isothermal conduction calorimetry (ICC), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscope (SEM) tests. The results show that with the increase of slaked lime doping, the compressive strength increases and then decreases, the fluidity gradually decreases, and the setting time decreases and then increases. The maximum 7- and 28-day compressive strengths were 24.1 and 30.2 MPa at 6% slaked lime dosage, which were 4.8 times higher than those at 0% dosage. This is mainly due to the fact that the reaction products of slaked lime and sodium carbonate can promote the alkali activation reaction, in addition to the fact that higher Ca2+ in the system is favorable to promote C─ (A)─ S─ H generation. However, when the dosage of slaked lime is greater than 8%, the hydrated gel in the system decreases and precipitates more square flakes of Ca(OH)2 , which reduces the interlayer bonding of the hydrated gel, thus reducing the strength. The slaked lime admixture can effectively promote the internal Si and Al dissolution and condensation of slag, improve the rate of hydration reaction, and promote the generation of hydration gel C─ (A)─ S─ H, so that the alkali-activated slag matrix is denser and the strength is improved. [ABSTRACT FROM AUTHOR]

The loss of quality of wolframite concentrates determines the need to improve their processing method that ensures maximum conversion of tungsten into water-soluble wolframate and a reduction in water-soluble impurities. The results of thermodynamic modeling of the sintering of wolframite concentrate with sodium and potassium carbonates indicate a greater efficiency of K2CO3: The reagent consumption required for complete conversion of tungsten into solution decreases from 170% from stoichiometric sintering with Na2CO3 to 110% for K2CO3, as well as the proportion of soluble silicates up to 0.1%. In addition, sintering with K2CO3 is accompanied by the formation of compounds with a higher melting point, preventing melting and coating formation during the process. Mathematical sintering models were obtained by the method of probabilistically deterministic planning of this experiment. Optimal parameters have been determined: The extraction of tungsten into a solution of more than 95% is achieved by sintering with K2CO3 in an amount of 105–110% according to the stoichiometric requirements for the formation of K2WO4, K2MoO4, and K2SO4 at temperatures of 1073–1123 K for 100–120 min. Pilot tests have confirmed the effectiveness of the process. The possibility of sintering a cinder of wolframite concentrate with K2CO3 without the introduction of recycled materials has been established. Sintering under optimal conditions ensures the transition of tungsten to water-soluble tungstate by 97.5%. [ABSTRACT FROM AUTHOR]

Biofuel can be generated by different organisms using various substrates. The green alga Chlorococcum humicola OQ934050 exhibited the capability to photosynthesize carbonate carbon, maybe via the activity of carbonic anhydrase enzymes. The optimum treatment is C:N ratio of 1:1 (0.2 mmoles sodium carbonate and 0.2 mmoles sodium nitrate) as it induced the highest dry mass (more than 0.5 mg.mL−1). At this combination, biomass were about 0.2 mg/mL−1 carbohydrates, 0.085 mg/mL−1 proteins, and 0.16 mg/mL−1 oil of this dry weight. The C/N ratios of 1:1 or 10:1 induced up to 30% of the Chlorococcum humicola dry mass as oils. Growth and dry matter content were hindered at 50:1 C/N and oil content was reduced as a result. The fatty acid profile was strongly altered by the applied C.N ratios. The defatted leftovers of the grown alga, after oil extraction, were fermented by a newly isolated heterotrophic bacterium, identified as Bacillus coagulans OQ053202, to evolve hydrogen content as gas. The highest cumulative hydrogen production and reducing sugar (70 ml H2/g biomass and 0.128 mg/ml; respectively) were found at the C/N ratio of 10:1 with the highest hydrogen evolution efficiency (HEE) of 22.8 ml H2/ mg reducing sugar. The optimum treatment applied to the Chlorococcum humicola is C:N ratio of 1:1 for the highest dry mass, up to 30% dry mass as oils. Some fatty acids were induced while others disappeared, depending on the C/N ratios. The highest cumulative hydrogen production and reducing sugar were found at the C/N ratio of 10:1. [ABSTRACT FROM AUTHOR]

Background: The sources of milk play a significant role on overall milk quality. Therefore, the current study was intended to evaluate the quality (physiochemical, compositional, and microbiological) and detect the adulterants in milk. Methods: A total of 200 milk samples were collected during mid of October to mid of December 2022 from four sources viz. Farmgate (50), Milkman (50), Bazar (50), and Branded packet milk (50). Milk samples were examined for various physiochemical, compositional, microbiological properties, and existence of adulterants. Data were analyzed by one way ANOVA and differences were determined by least significant difference test using RStudio. Results: Physiochemical analysis found significant variation in titratable acidity, protein, fat, salt, Solids-Not-Fat, and Total-Solids content among the sources (p<0.05), while lactose content was found non-significant. The highest (0.17%) and the lowest (0.13%) values for acidity were found in samples obtained from Milkman and Branded packet milk, respectively. Milk sample collected from Farmgate was found significantly higher in protein, fat, lactose, Solids-Not-Fat, and Total-Solids content than the other sources. In microbiological analysis, significant lower Total Viable Count, Total Coliform Count, and Escherichia coli Count were observed in Branded packet milk compared to the milk from Farmgate, Milkman, and Bazar source (p<0.001). In adulteration examinations, only neutralizers (sodium carbonate and bicarbonate) and nitrates were found positive in milk sample collected from Milkman, Farmgate, and Bazar, and their frequency was varied significantly (p<0.001). Overall, the milk obtained from Farmgate was better in terms of nutrient composition and physiochemical properties than the other sources but in respect to microbiological quality, Branded packet milk was found more hygienic. Conclusion: The study found that the variance in milk sources led to changes in the microbial load, physical appearance, and nutritional content of milk. The present study investigated that the addition of different adulterants and variation in time interval (milking to selling) are the main reasons for the deterioration of milk. [ABSTRACT FROM AUTHOR]

Groundwater quality was evaluated with a special emphasis on fluoride (F−) and iron (Fe) concentration, hydrogeochemical facies and suitability in terms of potability and irrigation (n = 32) was assessed in the mixed Ferricrete and Calcrete bearing region under 11 Gram-Panchayats in Gangarampur Block situated in South Dinajpur District of state of West Bengal in India in 2020. F− and Fe concentrations were beyond safe limits for drinking water (> 1.0 mg L−1) in 81.3% and 59.4% samples, respectively. Maximum recorded F− concentration was 4.6 mg L−1 while the lowest was 0.7 mg L−1 while Fe was 0.2–3.9 mg L−1. Nitrate (NO3−) concentration (13.4‒39.4 mg L−1) was found to be high vis a vis the reported levels of NO3 in some other regions of West Bengal but was always lower than the prescribed safe limit (45 mg L−1) for drinking water. Non-carcinogenic risk posed by F− exposure breached the Hazard Quotent limit in almost all samples for children (< 20 years) and adults (20–70 years) in the study area. A newly modified vulnerability assessment method was introduced and found 3 GPs amongst 11 GPs in the study area were highly vulnerable while 3 and 1 GPs respectively came under low and very low vulnerable areas. In the domain irrigation water quality, 62.5, 34.4, 25, 18.75 and samples were not found suitable for irrigating crops in terms of Permeability Index, Soluble Sodium Percentage, Residual Sodium Carbonate and Kelly's Index, respectively. [ABSTRACT FROM AUTHOR]

This study investigates the relationship between groundwater quality and agricultural productivity across six experimental stations in Morocco: Doukkala, Bahira, Tassaout, Beni Amir, Beni Moussa and Tadla. To assess groundwater suitability for irrigation, a comprehensive suite of indices was employed, including the permeability index (PI), Kelly index (KI), sodium strength percentage (SSP), sodium adsorption ratio (SAR), residual sodium carbonate (RSBC), magnesium hazard (MH), Langelier saturation index (LSI), Ryznar stability index (RSI), aggression index (AI), Larson and Skold index (LS), and Puckorious saturation index (PSI). Results indicated significant variations among the stations. Doukkala showed moderate permeability and low salinity risk but high sodium levels (SSP 50.14, SAR 6.87). Bahira had similar trends with slightly higher PI and KI values. Tassaout demonstrated lower values across all indices, suggesting better groundwater quality. Beni Amir and Beni Moussa exhibited decreasing trends in indices, with Beni Moussa having the lowest values overall. Notably, Beni Amir had the most negative RSBC value, indicating a high sodium hazard and potential soil structure issues, while Tadla had the least negative RSBC value, indicating favorable conditions. Water in Beni Amir and Beni Moussa, with MH values of 56.37 and 56.84 respectively, was deemed unsuitable for irrigation, whereas Doukkala, Bahira, Tassaout, and Tadla, with MH values below 50, were considered suitable. The study concludes that groundwater quality varies significantly across regions, impacting agricultural productivity, with some regions posing higher risks due to sodium and magnesium hazards. [ABSTRACT FROM AUTHOR]

Residual arsenic in copper matte is a source of arsenic contamination in subsequent processes in the smelting section of copper pyrometallurgy. In order to solve the impact of arsenic in copper matte on the subsequent process of smelting, this study removes arsenic from copper matte by adding an arsenic removal agent to the molten copper matte. The results show that the most difficult arsenic phase in copper matte is the residual arsenic in copper-arsenic alloys, based on which sodium carbonate was selected as the arsenic removal agent. The arsenic content in the copper matte was reduced by 98% under the optimal experimental conditions of a reaction temperature of 1250 °C, 4% sodium carbonate addition, and a reaction time of 60 min. The experimental results of the reaction mechanism show that sodium carbonate plays two main roles in the process of removing the intractable residual arsenic in copper matte. One is that sodium carbonate has a low melting point, which enhances the fluidity of the reactants. The other is that it can provide oxygen to the reaction system and convert arsenic in the copper-arsenic alloy into gaseous arsenic and arsenate. This study can provide new ideas for controlling arsenic pollution in copper pyrometallurgy. [ABSTRACT FROM AUTHOR]

This is an article in the field of metallurgical engineering. Aiming at the limitation of low reactivity of barite and few chemical processing methods, a new soda ash conversion method is proposed. Firstly, the effect of barite reaction particle size, temperature, and sodium carbonate concentration on the production rate of barium carbonate by the hydrochloric acid hydrolysis method is explored. The results show that the sodium carbonate concentration has the greatest impact on the reaction conversion rate. At limited experimental conditions, when sodium carbonate is used when the concentration reaches 28.57%, the highest formation rate of barium carbonate reaches 90.05%. Secondly, in the subsequent reaction, ammonium chloride is selected to re-convert the barite conversion product to prepare ammonium carbonate. The barium carbonate produced by this method has a higher yield and purity. The new process breaks through the traditional misconception that barium sulfate does not react with soda ash. The process is simple and feasible, and ammonia and carbon dioxide can be recycled and reused, making the entire process a large cycle process, in line with the concept of green environmental protection, and recrystallization. The preparation of barium carbonate from stone provides a new production process.

A novel method for synthesizing dumbbell-shaped (Gd1−xTbx)2O(CO3)2·H2O (GOC:xTb3+) phosphors using sodium carbonate was investigated. An amount of 1 mmol of stable fluorescent powder can be widely prepared using 3–11 mmol of Na2CO3 at a pH value of 8.5–10.5 in the reaction solution. The optimal reaction conditions for the phosphors were determined to be 7 mmol for the amount of sodium carbonate and a pH of 9.5 in the solution. Mapping analysis of the elements confirmed uniform distribution of Gd3+ and Tb3+ elements in GOC:xTb3+. The analysis of fluorescence intensity shows that an optimal excitation wavelength of 273 nm is observed when the concentration of Tb3+ is between 0.005 and 0.3. The highest emission intensity was observed for GOC:0.05Tb3+ with a 57.5% maximum quantum efficiency. The chromaticity coordinates show that the color of GOC:Tb3+ is stable and suitable for fluorescence recognition. Latent fingerprint visualization reveals distinctive features like whorls, hooks, and bifurcations. Therefore, the sodium carbonate method offers an effective alternative to traditional urea chemical reaction conditions for preparing GOC:Tb3+. [ABSTRACT FROM AUTHOR]

Legumes, rich in protein, fiber, and micronutrients, are increasingly popular in pulse-based and gluten-free foods despite global consumption stagnating at 21 g/day due to taste, low protein digestibility, anti-nutrients, and long cooking times. Bean resistance to cooking causes textural defects like the hardshell and hard-to-cook phenomena. The pectin–cation–phytate hypothesis explains why soaking beans in sodium salts reduces cooking time by enhancing pectin solubility in water. Gradoli Purgatory beans (GPB), from Italy′s Latium region, were malted, reducing phytic acid by 32% and oligosaccharides by 63%. This study evaluated the hardness of cooked GPB seeds in various conditions, including decorticated or malted states, using a modified standard method. Cooking at 98 °C for 7–75 min on an induction hob with a water-to-seed ratio of 4 g/g was tested. Soaking was applied before cooking for conventional seeds only, followed by texture analysis. Conventional GPBs were adequately cooked if their cotyledons disintegrated upon pressing, requiring a force peak of 250 to 220 N and cooking times of 52 to 57 min. Malted, decorticated, and split GPBs cooked similarly to raw decorticated and split ones, with times of 32 and 25 min, respectively. Faster cooking was due to bean coat removal and splitting, not chemical changes. Sodium or potassium carbonate/bicarbonate at 1–2 g/L improved cooking efficiency, with 2 g/L of sodium carbonate reducing cooking time to 13 min. Higher concentrations caused non-uniform cooking. Cooking malted, decorticated, and split GPBs in sodium-carbonated water reduced greenhouse gas emissions from 561 to 368 g CO2e/kg, meeting the demand for eco-friendly and nutritionally enhanced plant protein sources. [ABSTRACT FROM AUTHOR]

Improvement of wear, corrosion, and heat-resistant properties of coatings to expand the operational capabilities of metals and alloys is an urgent problem for modern enterprises. Diffusion titanium, chromium, and aluminum-based coatings are widely used to solve this challenge. The article aims to obtain the corrosion-electrochemical properties and increase the microhardness of the obtained coatings compared with the initial Ti-6Al-4V alloy. For this purpose, corrosion resistance, massometric tests, and microstructural analysis were applied, considering various aggressive environments (acids, sodium carbonate, and hydrogen peroxide) at different concentrations, treatment temperatures, and saturation times. As a result, corrosion rates, polarization curves, and X-ray microstructures of the uncoated and coated Ti-6Al-4V titanium alloy samples were obtained. Histograms of corrosion inhibition ratio for the chromium–aluminum coatings in various environments were discussed. Overall, the microhardness of the obtained coatings was increased 2.3 times compared with the initial Ti-6Al-4V alloy. The corrosion-resistant chromaluminizing alloy in aqueous solutions of organic acids and hydrogen peroxide was recommended for practical application in conditions of exposure to titanium products. [ABSTRACT FROM AUTHOR]

The study object was slag from the Balkhash copper smelter, obtained by re-melting anode mud containing nonferrous metals. The process flow for processing these slags includes sintering with Na2SO4, Na2CO3, and coal, followed by soda-alkaline leaching of the sinter and extraction of metals from the solution into marketable products. Since sintering is the main operation providing high selectivity, the composition of the products of this process was studied. The main transformations during sintering were determined, and the optimal parameters were identified. The structures of slags and sintered materials obtained during the experiments were studied by electron-probe microanalysis. Sintering was performed at 600–800 °C. The best results for sulphidization of slag components were obtained at 800 °C; a further increase in temperature leads to the smelting of sinter particles and slows down sulphidization. The optimal quantities of additives, based on the weight of the slag, are Na2SO4—45%, Na2CO3—15%, and reducing agent—41%, with a sintering time of 2 h. These conditions enable the sulphidization of non-ferrous metals in the slag to the entire depth of the polymetallic globules. The distinct concentration of harmful impurities (Ni, As, and Sb) was observed in the fine structure of the polymetallic globules. [ABSTRACT FROM AUTHOR]

Recycling lithium (Li) from spent lithium-ion batteries (LIBs) due to the depletion of natural resources and potential toxicity is becoming a progressively favourable measure to realize green sustainability. Presently, the prevalent recycling technique relying on pyrometallurgy lacks the capability to extract lithium. Meanwhile, conventional hydrometallurgical processes frequently employ robust acidic solutions like sulfuric acid and precipitation agents such as sodium carbonate. Unfortunately, this approach tends to result in the extraction of lithium at the end of a lengthy process chain, leading to associated losses and creating challenges in managing complex waste. This study addresses a cost-effective and environmentally friendly early-stage lithium recovery from the thermally conditioned black mass. In this sense, a thermally conditioned black mass is subjected to the carbonization process in a water solution to transform the water-insoluble Li phase into soluble lithium bicarbonate (LiHCO3) and carbonate (Li2CO3) facilitating its selective separation from other elements. Response surface methodology (RSM)—a statistical tool integrated with central composite design (CCD) is employed to optimize the parameters for Li recovery. Temperature, solid–liquid (S/L) ratio, leaching time and CO2 flow rate are considered as variable factors in modelling the optimum recycling process. A quadratic regression model is developed for Li recovery and based on ANOVA analysis, (S/L) ratio, temperature and time are identified as statistically significant factors. Experimental results demonstrate a maximum leaching efficiency of lithium with optimized parameter set, achieving a recovery rate of 97.18% with a fit response of 93.54%. [ABSTRACT FROM AUTHOR]

Background: Tungiasis is a cutaneous parasitosis caused by the female flea Tunga penetrans. Two-component dimeticone (NYDA) is the only treatment for tungiasis recommended by the World Health Organization; however, this topical drug is not available in Kenya. In Western Kenya, sodium carbonate is commonly used in the treatment of tungiasis. This study evaluated the 7-day cure rates for tungiasis by comparing sodium carbonate and NYDA treatments in Homa Bay County, Kenya. Methodology/Principal findings: This was a randomized, observer-blinded, parallel-treatment cohort trial. Twenty-three eligible children with 126 flea infections were matched and randomized. All participants received both treatments, with one treatment on each foot. We recorded all health conditions/information, including inflammation scores and adverse events. Observations were performed on days 3, 5, and 7 using a digital microscope to confirm dead or live fleas based on the viability signs. Twenty-three children aged 3–13 years were analyzed. The proportion of dead fleas on day 7 was higher after NYDA treatment than after 5% sodium carbonate treatment (87% versus 64%, respectively, P = 0.01) NYDA. Median survival was 5 days for both treatments; NYDA had significantly higher trend of flea non-viability rate than 5% sodium carbonate (P<0.01). There were no significant differences in the inflammation score or pain/itchiness between the two treatments. On the last day, 14 children indicated their preference for NYDA in future treatment of tungiasis, whereas nine children preferred the 5% sodium carbonate solution. Conclusions/Significance: NYDA was significantly more effective than 5% sodium carbonate for tungiasis treatment. Both treatments were safe but the children preferred NYDA more. Future studies with more participants and an extended observation period are warranted to confirm our findings. The findings suggest that NYDA should be made more available in tungiasis endemic area. Trial registration: UMIN-CTR; UMIN 000044320 Author summary: Jigger infestation is caused by fleas. Most of the recommended treatments for jiggers are unaffordable; thus, local people experience difficulty with the usage. This study contribute to the understanding of the efficacy of two treatments against jigger infestation in the community: a local practice (soda ash solution) and a standard treatment (silicone oil). The study participants were 23 children aged 3–13 years with 126 fleas in Homa Bay County, Kenya. We administered the treatment only on day 1 and followed up on days 3, 5, and 7. At 7 days, the soda ash solution killed 64% of the fleas whereas the silicone oil killed 87% of the fleas. Thus, the safety of both treatments was confirmed. As this is the first step in investigating the efficacy and safety of the soda ash solution, we need to conduct further studies with more participants to compare both treatments. [ABSTRACT FROM AUTHOR]

This study investigated the sustainability aspect of the fly ash (FA)-based one-part geopolymers (OPGS) with various combinations and amount of alkali activators (AA). The three groups of OPG were: the M-OPG activated with solely sodium metasilicate-anhydrous (Na2SiO3), the MH-OPG with Na2SiO3 and sodium hydroxide (NaOH), and the MC-OPG with Na2SiO3 and sodium carbonate (Na2CO3). The compressive strength, embodied carbon, embodied carbon index, embodied energy and embodied energy index were identified. Test result shows that the M-OPG and MC-OPG with the AA/FA ratio of 0.20 attained 83 MPa and 75 MPa of compressive strengths, respectively. The MH-OPG with AA/FA ratio of 0.15 attained 72 MPa of compressive strength. The embodied carbon and embodied energy of the OPGs were mainly contributed by the Na2SiO3-anhydrous. The values were lowered when the Na2SiO3-anhydrous were partially substituted with NaOH or Na2CO3. Increasing the AA content increased the embodied carbon and energy. The embodied carbon index (3.80 kg CO2/m³/MPa) and embodied energy index (14.72 MJ/m³/MPa) of the MC-OPG with AA/FA ratio of 0.20 were the lowest. The outcome of this study supports the utilisation of Na2CO3 to partially substitute Na2SiO3 for the development of OPGs. [ABSTRACT FROM AUTHOR]

This research undertakes a comparative study between compacted phosphate-based (CPG) and alkaline-based (CAG) geopolymeric materials. The obtained materials underwent comprehensive evaluation through mechanical, physical, and chemical analyses. CPG exhibited superior mechanical strength, demonstrating an exponential growth with curing age in contrast to CAG. Both materials exhibited stable density over time, with CPG displaying a notably higher density attributed to its enhanced reactivity in an acidic medium. Dimensional variations revealed stable dimensions for CPG and subtle shrinkage for CAG, potentially associated with an observed efflorescence phenomenon. Visual assessments during water immersion highlighted the enhanced stability of CPG. Chemical analyses confirmed the persistence of mineralogical phases, such as quartz and illite, and the emergence of an amorphous geopolymeric network in both CPG and CAG samples. CPG materials featured aluminum phosphate phases, reinforcing structural integrity, while CAG materials exhibited sodium carbonate phases, introducing impurities, elucidating the superior performance of CPG over CAG. For the formation kinetics, CPG exhibited a faster reaction time than CAG, as evidenced by the evolution of pH, densification rate, and FTIR band over curing time. [ABSTRACT FROM AUTHOR]

• We study the chemistry of the core and ocean of Enceladus based on different core compositions. • We study the hydrothermal products from the ocean-core interaction in the context of the chemistry of the plume of Enceladus. • We evaluate the chemistry of the ocean based on its possible pH values and the saturation indices of mineral products. • We find that the actual composition of the core poses a somewhat wide range of possible compositional scenarios. Measurements made by the Cassini spacecraft instruments were able to reveal the composition of the geysers of the Saturn moon, Enceladus, among which salts (sodium chloride, sodium bicarbonate and/ or sodium carbonate) and traces of silica could be the result of hydrothermal processes from the interaction of an inner liquid ocean with the core of Enceladus. The chemistry of the ocean should be closely connected to the chemistry of the core. Even though. the actual composition of the core is unknown, Enceladus has been characterised as a moon with a silicate core and different authors have estimated the properties of the ocean. A core with a silicate composition alone, does not necessarily justify most of the observed species of the plume. Given the many uncertainties, in the current work, we study the possible chemistry of the core and the ocean in the context of a four-layered Enceladus (dry core, hydrated core, ocean and crust) with three different compositional scenarios for the core: primordial (represented by an ordinary chondrite), composite (represented by a carbonaceous chondrite with an igneous inclusion) and non primordial (epresented by a given peridotite). The scenarios comprise a set of minerals that interact with a primordial ocean (either pure or enriched water) at a given temperature and pressure, producing a series of secondary minerals and compounds, some of them, coincident with the chemical species observed in the geysers. Specifically, we make a chemical speciation for each proposed compositional scenario with the software PhreeqC, however our analysis is limited to the study of interactions that reach a given equilibrium. In particular, output values like the potential of hydrogen of the ocean or the saturation indices of mineral products may give us hints about the chemistry of the ocean and the core. We find that, based on the species observed in the plume, the actual composition of the core (and the ocean as well) poses a somewhat wide range of possible compositional scenarios and each of our proposed scenarios and their products justify, to some extent, the observations of the plume. [ABSTRACT FROM AUTHOR]

The study was conducted to determine the suitability of surface water from Oued El Gourzi for irrigation in the Fesdis area, Algeria, during irrigation season of July 2022. The suitability was assessed by analysing eight water samples collected from various sites along the Oued. A range of physicochemical parameters were examined, including EC, pH, Mg2+, Na+, Ca2+, K+, HCO3 - and Cl-, alongside other indices such as sodium absorption ratio (SAR), soluble sodium percentage (SSP), residual sodium carbonate (RSC), permeability index (PI) and magnesium adsorption ratio (MAR) using standard procedures. The Richards classification shows that these waters are characterised by high salinity and low alkalinity hazard (C3-S1). According to the Wilcox classification, the majority of these waters are of doubtful quality, with only 25% exhibiting good quality for irrigation. Based on the RSC and MAR, all water samples are deemed safe and suitable for irrigation. However, PI values suggest that all sampling sites are of marginal quality for irrigation (class II). In terms of sodium and chloride concentration, all water samples were deemed unsuitable for irrigation. Based on these results, the waters pose risks for irrigation, particularly due to salinity, necessitating the implementation of special management practices and the selection of salt-tolerant crops. [ABSTRACT FROM AUTHOR]

In order to improve the utilization value of Perilla leaf polyphenol related food and food additives, and increase the edible added value of Perilla leaf, the polyphenol content of extracts from Perilla leaf was determined. The influence of Folin-Ciocalteu reagent dosage, sodium carbonate dosage, color developing temperature, color developing time and other factors on the determination of polyphenol content were investigated by single factor control variable method, and the determination conditions were optimized by response surface analysis. The experimental results showed that when the determination wavelength was 760 nm, the dosage of Folin-Ciocalteu reagent was 1.0 mL, the dosage of sodium carbonate reagent was 3.2 mL, the color development temperature was 30 °C, and the reaction time was 45 min, the optimal conditions for the determination of polyphenol content showed a good linear relationship with absorbance, and the regression equation was Y=0.0157X-0.0627, R2=0.9991. The stability, precision and reproducibility of the method met the requirements. The average recovery was 95.62% and the relative standard deviation (RSD) was 4.28%. The method was suitable for the determination of polyphenols in Perilla leaves, and the average content of polyphenols in Perilla leaves was 7.439 mg/g, RSD=4.34%. This study can provide data support for the development and researched of Perilla leaf polyphenols and food additives. [ABSTRACT FROM AUTHOR]

The original non-conventional technique of preparing expanded bottle utilizing recycled bottle waste and a combination between glycerin in association with Na2SiO3 and Na2CO3, as liquid and respectively, solid expanding agents, was experimentally tested on an 800 W-electromagnetic wave oven and shown in this article. The work objective was obtaining a cellular glass with physio-mechanical and thermal features almost identical to those achieved by conventional techniques at industrial-scale. Thus, the heat conductivity was in the range of 0.060-0.072 W·m-1 ·K-1, while the compression resistance increased at 6.5-7.2 MPa. Also, the experimental results confirmed the remarkable power efficiency of the non-conventional process, the power use value being diminished to an extremely reduced measure (0.74-0.83 kWh*kg-1). In conclusion, the cellular product made by the unused technique worldwide proved to be suitable for application in special constructions. [ABSTRACT FROM AUTHOR]

Soil erosion poses a significant challenge to environmental management, threatening ecosystem health and sustainable development. Urgent action is required to implement effective erosion control measures within comprehensive environmental management strategies. This study investigates the effectiveness of sand crusts induced by Na2CO3-activated materials in mitigating soil erosion during various rainfall and windstorm events. The study evaluates the erodibility of Na2CO3-activated crusts under varying wind speeds (30, 60, 90, and 120 km/h) and rainfall intensities (30, 60, 90, and 120 mm/h) across 1 to 15 events. Surface strength is measured using penetrometer tests, and the microstructure of the formed crusts is examined through X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and energy-dispersive X-ray spectroscopy (EDS). The results underscore the effectiveness of Na2CO3-activated crusts in erosion control, with treated soil showing significantly reduced erosion compared to untreated soil under both wind and rainfall conditions. Penetrometer tests revealed a significant increase in surface strength, and microstructural analysis identified the formation of albite, anorthite, and brucite crystals, as well as various forms of calcite and portlandite phases in the treated soil. This study endorses Na2CO3-activated materials as a superior method for mitigating wind and rainfall erosion, highlighting their remarkable efficacy, eco-friendly properties, abundance of raw materials, straightforward implementation, and cost-effectiveness.

At present, the National Metrology Institute of Japan provides six national primary pH buffers under the Japan Calibration Service System. Each batch of these buffers is certified by the primary pH method using a Harned cell. On the basis of these primary buffers, the designated laboratories supply the secondary and working pH standards using a high-precision pH meter. This paper provides an estimate of the batch-to-batch reproducibility of the primary pH standard production based on the history of the certification of primary carbonate buffers in NMIJ. This buffer, which was chosen as the subject of the study because of the relative difficulty of its measurements (and thus a greater dispersion of results), is nominally the 0.025 mol kg−1 equimolal solution of disodium carbonate and sodium hydrogen carbonate. As its pH value is significantly affected by the purity of the reagents used, the evaluation of their source materials is made by both pH measurements and acidimetric gravimetric back titrations. Considering the experimentally determined pH reproducibility of ca. 0.010, potential risks to the pH accuracy are discussed when using recipe-based carbonate pH standards. [ABSTRACT FROM AUTHOR]

In the present work, the development of geopolymeric materials with Na or K based on industrial kaolin samples, with variable kaolinite content and alkaline silicates, is studied. XRF, XRD, FTIR and SEM-EDS have been used as characterization techniques. Three ceramic kaolin samples, two from Algeria and one from Charente (France), have been considered. In particular, chemical and mineralogical characterization revealed elements distinct of Si and Al, and the content of pure kaolinite and secondary minerals. Metakaolinite was obtained by grinding and sieving raw kaolin at 80 μm and then by thermal activation at 750 °C for 1 h. This metakaolinite has been used as a base raw material to obtain geopolymers, using for this purpose different formulations of alkaline silicates with NaOH or KOH and variable Si/K molar ratios. The formation of geopolymeric materials by hydroxylation and polycondensation characterized with different Si/Al molar ratios, depending on the original metakaolinite content, has been demonstrated. Sodium carbonates have been detected by XRD and FTIR, and confirmed by SEM-EDS, in two of these geopolymer materials being products of NaOH carbonation. [ABSTRACT FROM AUTHOR]

In this study, the fresh and hardened performance and durability of one-part ground granulated blast furnace slags (GGBFS) activated by solid CaO and Na2CO3 were discussed, and their hydration process and microstructure development were analyzed accordingly. Results showed that when the water-to-binder ratio was 0.32, the alkali-activated slag (AAS) paste exhibited lower flowability, higher yield stress and plastic viscosity. As the content of CaO and Na2CO3 increased, the yield stress, plastic viscosity, and compressive strength of AAS after hardening all increased. For the durability of the hardened sample, AAS with high content of activator have higher shrinkage strain and chloride ion flux. The microscopic analysis results indicated that AAS containing CaO and Na2CO3 exhibited more intense hydration heat release and rapid microstructure development in the early stage, thereby promoting the improvement of strength. The use of CaO and Na2CO3 to activate GGBFS has enormous application potential in solid waste utilization and carbon emission reduction, which can reasonably replace traditional Portland cement (PC) as a new generation of sustainable cementitious materials. [ABSTRACT FROM AUTHOR]

In this study, lithium was recovered from spent lithium-ion batteries through the crystallization of lithium carbonate. The influence of different process parameters on lithium carbonate precipitation was investigated. The results indicate that under the conditions of 90 °C and 400 rpm, a 2.0 mol/L sodium carbonate solution was added at a rate of 2.5 mL/min to a 2.5 mol/L lithium chloride solution, yielding lithium carbonate with a recovery rate of 85.72% and a purity of 98.19%. The stirring rate and LiCl solution concentration significantly impact the particle size of lithium carbonate aggregates. As the stirring rate increases from 200 to 800 rpm, the average particle size decreases from 168.694 μm to 115.702 μm. Conversely, an increase in the LiCl solution concentration reduces the lithium carbonate particle size, with an average particle size of only 97.535 μm being observed at a LiCl solution concentration of 2.5 mol/L. It was also observed that nickel and cobalt ions become incorporated into the crystal lattice of lithium carbonate, thereby affecting the growth and morphology of lithium carbonate. [ABSTRACT FROM AUTHOR]

Cotton stalks are residual biomass resulting from cotton bud harvesting, and they are composed primarily of lignocellulosic material. This material could be a source of functional polyphenols. To investigate this prospect, this study was undertaken with the view to examining whether an ethanol-based organosolv treatment could be suitable for producing extracts enriched in polyphenolic compounds. To this end, alkali catalysis was employed, and two catalysts, sodium hydroxide and sodium carbonate, were tested. The initial approach based on treatment severity showed that both catalysts may be equally effective in the recovery of polyphenols, yet in most cases studied, no clear trend between treatment severity and total polyphenol yield was recorded. The following study, based on response surface methodology, provided optimized conditions for both treatments, sodium hydroxide and sodium carbonate, where the recommended catalyst concentrations were 0.67 and 4%, respectively. Under a constant temperature of 90 °C and residence time of 300 min, the treatments with sodium hydroxide and sodium carbonate afforded total polyphenol yields of 18.4 ± 1 and 15.6 ± 1.9 mg CAE g−1 DM, respectively, which showed no significant statistical difference (p > 0.05). However, high-performance liquid chromatography analyses revealed that the sodium carbonate-catalyzed treatment produced extract particularly enriched in two hydroxycinnamate derivatives, ferulic and p-coumaric acid. This extract also exhibited increased antioxidant activity. The outcome of this study strongly suggests cotton stalks as a bioresource of functional substances, while mild alkali-catalyzed ethanol organosolv treatment appears to be a very promising technique for effectively delivering hydroxycinnamate-enriched extracts. [ABSTRACT FROM AUTHOR]

To develop a better process for synthesizing sodium percarbonate and getting separation of the sodium salt, the equilibrium of the ternary system Na2SO4–H2O2–H2O and Na2CO3–H2O2–H2O at 5 °C was determined using the isothermal method, and the appropriate synthesis conditions for sodium carbonate from a theoretical perspective was discussed. The Na2SO4–H2O2–H2O system phase diagram contains one co-saturated point of Na2SO4·0.5H2O2·H2O and Na2SO4·10H2O. The Na2CO3–H2O2–H2O system phase diagram contains three crystal zones: Na2CO3·10H2O crystallization field, 0Na2CO3·1.5H2O2·H2O crystallization field and Na2CO3·2H2O2·H2O crystallization field. According to the phase diagram, the suitable raw material ratio of sodium percarbonate synthesis was obtained, to get the maximum of product yield, the optimal mass ratio of Na2CO3 to 30% H2O2 is 0.609. [ABSTRACT FROM AUTHOR]

Corrosion-related damage incurs significant capital costs in many industries. In this study, an anti-corrosive pigment was synthesized by modifying calcium carbonate with sodium alginate (SA), and smart self-healing coatings were synthesized by reinforcing the anti-corrosive pigments into a polyolefin matrix. Structural changes during the synthesis of the anti-corrosive pigment were examined using scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. Moreover, thermal gravimetric analysis confirmed the loading of the corrosion inhibitor, and electrochemical impedance spectroscopic analysis revealed a stable impedance value, confirming the improved corrosion resistance of the modified polyolefin coatings. The incorporation of the anticorrosive pigment into a polyolefin matrix resulted in improved pore resistance properties and capacitive behavior, indicating a good barrier property of the modified coatings. The formation of a protective film on the steel substrate reflected the adsorption of the corrosion inhibitor (SA) on the steel substrate, which further contributed to enhancing the corrosion resistance of the modified coatings. Moreover, the formation of the protective film was also analyzed by profilometry and elemental mapping analysis. [ABSTRACT FROM AUTHOR]

Locally sourced agricultural residues are a promising feedstock for the production of reinforcement fibers for wastepaper-based packaging papers. An eco-friendly high yield process to generate fibers from wheat straw using high pressure steam and sodium carbonate is presented. The wheat straw was impregnated with up to 16% of sodium carbonate and steam treated for 10 min at temperatures from 148 °C to 203 °C. The pulps were characterized concerning their chemical composition and test sheets with 100% straw fibers and with 15% and 30% straw fibers blended with recycled pulp were prepared. Fiber yields ranged from 70% to 45%, wherein more severe treatment conditions contributed to increased paper strength but lower yields. At comparable fiber yields, treatments featuring a higher chemical input, coupled with lower treatment temperatures, resulted in improved paper strength. By blending recycled pulp with up to 30% of straw fibers with a beating degree of roughly 45 °SR, the burst, compression and tensile strength was enhanced by up to 66%, 74% and 59%, respectively. As the enhancement effect decreases with a high steam treatment intensity and a high proportion of wheat straw, a moderate treatment and limited use of wheat straw may be the best choice. [ABSTRACT FROM AUTHOR]

The hydration mechanism and strength development of alkaline salt-activated cementitious materials primarily rely on the alkaline activators and mineral admixtures employed. However, the impact of increased Mg2+, Al3+, and Si4+ resulting from the addition of MgO and steel slag (SS) on the hydration mechanism of these systems remains undetermined. This study delves into the hydration mechanism and mechanical properties of a Na2CO3-MgO-activated regenerated micropowder-slag-based cementitious material system. Mechanical properties were assessed by measuring dry shrinkage and compressive strength at various ages, up to 28 days. The reaction mechanism was scrutinized using X-ray diffraction and a thermogravimetric analysis. The main reaction products contributing to the strength development are C-S-H, C-(A)-S-H gel, and hydrotalcite. Other carbonate-containing phases make smaller contributions. The findings reveal that when SS usage is at 10%, it yields higher early strength compared to ordinary samples. Samples incorporating MgO and SS achieved strengths similar to or surpassing those of the control samples. A noteworthy observation is the synergistic excitation effect between sodium carbonate (NC) and MgO, leading to the generation of a significant amount of gelling substances. These substances fill the pores of the structure, resulting in the formation of a dense microstructure. Consequently, the enhanced interaction between NC and MgO contributes to the overall strength development of the cementitious material. [ABSTRACT FROM AUTHOR]

The original non-conventional technique of preparing expanded bottle utilizing recycled bottle waste and a combination between glycerin in association with Na2SiO3 and Na2CO3, as liquid and respectively, solid expanding agents, was experimentally tested on an 800 W-electromagnetic wave oven and shown in this article. The work objective was obtaining a cellular glass with physio-mechanical and thermal features almost identical to those achieved by conventional techniques at industrial-scale. Thus, the heat conductivity was in the range of 0.060-0.072 W·m-1·K-1, while the compression resistance increased at 6.5-7.2 MPa. Also, the experimental results confirmed the remarkable power efficiency of the non-conventional process, the power use value being diminished to an extremely reduced measure (0.74-0.83 kWh·kg-1). In conclusion, the cellular product made by the unused technique worldwide proved to be suitable for application in special constructions.

Residual arsenic in copper matte is a source of arsenic contamination in subsequent processes in the smelting section of copper pyrometallurgy. In order to solve the impact of arsenic in copper matte on the subsequent process of smelting, this study removes arsenic from copper matte by adding an arsenic removal agent to the molten copper matte. The results show that the most difficult arsenic phase in copper matte is the residual arsenic in copper-arsenic alloys, based on which sodium carbonate was selected as the arsenic removal agent. The arsenic content in the copper matte was reduced by 98% under the optimal experimental conditions of a reaction temperature of 1250 °C, 4% sodium carbonate addition, and a reaction time of 60 min. The experimental results of the reaction mechanism show that sodium carbonate plays two main roles in the process of removing the intractable residual arsenic in copper matte. One is that sodium carbonate has a low melting point, which enhances the fluidity of the reactants. The other is that it can provide oxygen to the reaction system and convert arsenic in the copper-arsenic alloy into gaseous arsenic and arsenate. This study can provide new ideas for controlling arsenic pollution in copper pyrometallurgy.

More than 60% of the world's sedimentary rocks are mudrocks (Potter et al., 1980; Schieber, 1998; Potter, 2003; the term mudrock is favored here over mudstone because the latter term was used to characterize a limestone texture; Dunham, 1962). From a palaeontological perspective these are, compared to sandstones and limestones, heavily undersampled. The main reason for this is that mudrocks decay in surface exposures to small chips, which develop with sun/heat and rain into an awkward pulp. The decay of the mudstone concomitantly destroys all macrofossils which are not durable. This comprises fossils with an aragonitic or delicate calcitic shell unless they are preserved as pyritic or internal calcitic molds or preserved within calcareous concretions. Therefore, most of the fossils are not recorded in surface exposures. In addition, sedimentologic investigations of mudrocks are hampered because (i) compaction makes sedimentary structures hardly recognizableand (ii) good thin sections of mudrocks are exceedingly difficult to manufacture. For micropalaeontological investigations, mudrocks rich in organic material are especially difficult to process. Standard treatments with boiling water, sodium carbonate solution, or peroxide H2O2 generally fail to dissolve much of the sediment so that the fine fraction (and in mudrocks we usually need the 63μm-fraction) largely consists of clay particle aggregates. Yet there are methods to dissolve these aggregates. Otherwise, picking the microfossils would become extremely laborious. In this paper, some guidelines for successful palaeontological work in mudrocks are outlined. These are based on the author's personal experience. Examples from Jurassic mudrocks of Switzerland/Europe show that such excavations can be very rewarding. [ABSTRACT FROM AUTHOR]

Zanthoxylum armatum DC. is an important oil plant and economic crop, but the natural reproduction rate is extremely low due to the existence of dormancy in its seeds, so it is of great significance to explore methods to promote its seed germination. In this study, an orthogonal test was applied to study the effects of different factors on the seed germination indexes with four factors and four levels of different sodium carbonate degreasing time, different incubation temperature, different kinetin soaking concentration, and seed soaking time. Through this study, analysis of variance, correlation, and clustering was applied. The results demonstrated that all experimental groups showed significant improvement in different germination indexes compared with the control. Among which, group 7 treated with sodium carbonate degreasing for 12 h, kinetin soaking concentration of 50 mg/L for 48 h, and under the culture condition of constant temperature at 25°C showed the best performance in germination rate, germination vigor, vitality index, germination index, root length, and shoot length. In addition, the shoot fresh weight and dry weight, root dry weight and fresh weight of group 7 were also significantly increased compared with the control. The results of this study provided a certain theoretical basis for the efficient seed germination of Zanthoxylum armatum DC. in the future. [ABSTRACT FROM AUTHOR]

An overview of the composition of wolframite ores of the Akchatau deposit and the technologies for processing concentrates using NaOH and Na2CO3 by hydro- and pyrometallurgical methods is given, and the disadvantages associated with both the technology and the equipment are noted. To develop a technology for processing Akchatau wolframite concentrates, samples of ore materials were taken, the chemical and mineralogical composition of the samples was studied, and enrichment was carried out to obtain rich concentrates. The kinetics of the sintering of the wolframite concentrate with soda was investigated, the dependences of the degree of transformation of the tungsten minerals into sodium tungstate were obtained, and the rate constants, the order of the reaction, and the values of the apparent activation energy were calculated. The results of sintering an enlarged sample of wolframite concentrate with soda in a muffle furnace are presented. After the subsequent leaching, studies were carried out to purify the obtained solutions of sodium tungstate from the impurities while eliminating the operations of the neutralizing solutions through the use of electrodialysis with an MK-40 cation-exchange membrane. The scheme of processing the wolframite ores of Akchatau is proposed. [ABSTRACT FROM AUTHOR]

With a suitable milling system, it is achievable to produce wholegrain flours that match the granulation and technological properties of refined flours while maintaining a complete nutritional profile. This process also minimizes the generation of additional industrial waste. This study aimed to characterize wholemeal flours with a fine granulation size of less than 160 µm: wheat (MWF), rye (MRF), spelt (MSF), barley (MBF), buckwheat (MBWF), and sorghum (MSGF). For comparison, the plain wheat flour type 530 (T530) was analyzed. The flours were assessed in terms of their chemical compositions and alpha amylase activities (the Falling Number assay), pasting properties (amylograph and a Rapid Visco Analyser (RVA)), water absorption using a farinograph, and technological quality based on their water (WRC) and sodium carbonate solvent retention capacity (SRC) profiles. Among the micronized wholemeal flours, wheat flour (MWF) exhibited the highest nutritional value, greatest water absorption, and highest final gelatinization temperature, but had the lowest energy value, carbohydrate content, water SRC, and sodium carbonate SRC. Wholemeal rye flour (MRF) displayed the lowest nutrient content and the highest amylolytic activity, water absorption, and sodium carbonate SRC. The plain wheat flour type 530 (T530) had the lowest water absorption. Special buckwheat flour (MBWF) showed the highest energy value due to its elevated carbohydrate content, along with the lowest sugar and TDF contents, amylolytic activity, and pasting temperature. [ABSTRACT FROM AUTHOR]

Nanocrystalline, ionically modified hydroxyapatites mimicking bone apatite were synthesized. The powders obtained by the wet method were enriched with the main "foreign ions" naturally occurring in bone tissue: carbonates, sodium and magnesium ions. Various parameters of the wet method synthesis were modified: pH, the concentration of reagents, the temperature during the precipitation, and ageing time. The materials were subjected to physicochemical analysis with the use of various analytical methods, such as powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), inductively coupled plasma optical emission spectroscopy (ICP-OES) and Fourier transform infrared spectroscopy (FT-IR). All the obtained materials were also biologically tested in vitro for their potential cytotoxicity and biocompatibility. The morphology, crystallite sizes and crystallinity indices were investigated and the content of hydrogen phosphates, carbonates, magnesium and sodium were analysed. The concentration of reagents and temperature affect the size and shape of crystallites, while pH and ageing time affect the amount of doped ions and the biocompatibility of materials. Optimal conditions for the synthesis of highly biomimetic and biocompatible materials have been identified. • We synthesized and analysed apatites enriched in magnesium, sodium and carbonates, and mimicking biological apatite. • For synthesis, we used the standard wet method with different process conditions. • We determined the effect of the synthesis conditions on the morphology and composition of the obtained biomimetic apatites. • For analysis, we used various analytical methods, i.e. PXRD, TEM, ICP-OES and FT-IR. • The biological activity in vitro of the materials was also studied. [ABSTRACT FROM AUTHOR]

Calcined soda production is one of the important parts of the industry. One of the main problems in the production of soda is the waste of raw materials. Disposing of some raw materials as waste not only causes economic damage but also has a negative impact on the environment. Absorption is the main process in the production of calcined soda. By finding the optimal consumption of the chemical components involved in absorption process, it will be possible to reduce the amount of raw materials released into the waste. In this work, initially, the kinetic model of the absorption process was found using the stoichiometric matrix method. Based on the stoichiometric matrix, the main components (NH3, CO2, NH4HCO3, NaCl) participating in the chemical reaction were identified. Using the found kinetic model, a computer model of the absorption process was simulated in the MATLAB program. Based on the simulated computer model, a diagram of changes in the concentration of components in the absorption process over time was obtained. The use of the considered mathematical model as part of the absorption process control system allows: (1) Reduce the loss of the amount of gases used in the absorption process; (2) Provide the required concentration of liquid saturated with ammonia; (3) Determine the required temperature regime along the entire length of the absorber. [ABSTRACT FROM AUTHOR]

The addition of carbonate minerals to seawater through an artificial Ocean Alkalinization Enhancement (OAE) process increases the concentrations of hydroxide, bicarbonate, and carbonate ions. This leads to changes in the pH and the buffering capacity of the seawater. Consequently, OAE could have relevant effects on marine organisms and in the speciation and concentration of trace metals that are essential for their physiology. During September and October 2021, a mesocosm experiment was carried out in the coastal waters of Gran Canaria (Spain), consisting of different levels of total alkalinity (TA). Different concentrations of carbonate salts (NaHCO3 and Na2CO3) previously homogenized were added to each mesocosm to achieve an alkalinity gradient between -0 to 2400 µmol L-1. The lowest point of the gradient was 2400 µmol kg-1, being the natural alkalinity of the medium, and the highest point was 4800 µmol kg-1. Iron (Fe) speciation was monitored during this experiment to analyse whether total dissolved iron (TdFe), dissolved iron (dFe), soluble iron (sFe), dissolved labile iron (dFe'), iron-binding ligands (LFe) and their conditional stability constants (K'FeL), could change because of OAE and the experimental conditions in each mesocosm. Observed iron concentrations were within the expected range for coastal waters, with no significant increases due to OAE. However, there were variations in Fe size fractionation during the experiment. This could potentially be due to chemical changes caused by OAE, but such effect being masked by the stronger biological interactions. In terms of size fractionation, sFe was below 1 nmol L-1, dFe concentrations were within 0.5-4.0 nmol L-1, and TdFe within 1.5-7.5 nmol L-1. Our results show that over 99% of Fe was complexed, mainly by L1 and L2 ligands with k'Fe'L ranging between 10.92±0.11 and 12.68±0.32, with LFe ranging from 1.51±0.18 to 12.3±1.8 nmol L-1. Our data on iron size fractionation, concentration, and iron-binding ligands substantiate that the introduction of sodium salts in this mesocosm experiment did not modify iron dynamics. As a consequence, phytoplankton remained unaffected by alterations in this crucial element. [ABSTRACT FROM AUTHOR]

This study was the first-ever attempt to apply MIL-68 (Ga) in developing an analytical method. The method extracts and preconcentrates some parabens from mouthwash and hydrating gel samples. The variable extraction parameters were optimized, and the figures of merit were documented. Avogadro software was used besides discussing intermolecular interactions to clarify the absorption process. ComplexGAPI software was also exploited to assess the greenness of the method. After the derivatization of the parabens using acetic anhydride in the presence of sodium carbonate, sodium chloride was added to the solution and vortexed to dissolve. A few milligrams of MIL-68 (Ga) were added into the solution and vortexed. Centrifugation separated the analyte-loaded absorbent, which was treated with mL volume of methanol through vortexing for desorption aim. A few microliters of 1,2-dibromoethane were merged with the methanolic phase and injected into a sodium chloride solution. One microliter of the extracted phase was injected into a gas chromatograph equipped with a flame ionization detector. High enrichment factors (200–330), reasonable extraction recoveries (40–66%), wide linear ranges (265–30,000 µg L−1), and appreciable coefficients of determination (0.996–0.999) were documented. The applicability of dispersive solid phase extraction for extracting polar analytes, imposing no additional step for performing derivatization, the capability of MIL-68 (Ga) for the absorption of both derivatized and non-derivatized parabens, the use of only 10 mg absorbent, and one-pot synthesis besides no high temperature or long reaction time in the sorbent provision are the highlights of the method. [ABSTRACT FROM AUTHOR]

Background and purpose: In the production of pulp, materials such as sodium hypochlorite, chlorine dioxide, ozone, hydrogen peroxide, etc. are used in the bleaching process. In addition, the above-mentioned materials can be used as oxidizing materials to increase the surface charge of fibers, and can help the paper to be more resistant. Therefore, this research was conducted to investigate the effect of fiber oxidation with hydrogen peroxide and sodium hypochlorite on the characteristics of NSSC and OCC pulps as vigin and recycled pulps, respectively. Materials and methods: The pulps required for this research, unbleached NSSC pulp and OCC pulp were obtained from Mazandaran wood and paper factory. First, the consistency, initial freeness and brightness of the pulp were measured. Also, the required chemicals were all of industrial grade, hydrogen peroxide (in liquid form 52%) from Chlor Pars Tabriz Company and sodium hypochlorite (in liquid form 16.4%) from Kleran Semnan Company and sodium silicate from Bawand Shimi Qazvin Company, caustic soda (Liquid soda) with a purity of 47% for bleaching with peroxide was obtained from Arvand Abadan Petrochemical, and soda ash (solid soda) with a purity of 90% for bleaching with hypochlorite was obtained from Chloran Pars, Semnan. In order to control the destructive effects of transition metals, all pulps were treated with 0.2% DTPA, in 2% consistency, time 30 minutes, temperature 90 degrees Celsius and pH=5.5-5, before bleaching. At the end of this step, the pulp is thoroughly washed with distilled water and used for the next steps. For the oxidation of both types of pulp, 3, 4, 5% hydrogen peroxide and sodium hypochlorite were used for oxidation of NSSC pulp using the above ratios (similar to peroxide) and for OCC pulp, 0.5, 1 and 1.5% hypochlorite ratios were used. Then the structural characteristics of the fibers such as pulp freeness, kappa number, WRV, viscosity, carboxyl groups were investigated and finally, the pulps were evaluated by FT-IR spectroscopy. Results: The results showed that with the increase in the consumption of hypochlorite, freeness increased in the oxidized NSSC pulps, but the trend of freeness decreased in the oxidized OCC pulp. This issue shows the situation regarding the use of peroxide. Also, the oxidation of pulp by sodium hypochlorite compared to peroxide has resulted in the release of more lignin, and in this sense, the effectiveness of OCC pulp has been higher compared to NSSC pulp. The amount of water retention value in the pulp fibers in the NSSC pulp treatments has increased compared to the control pulp, and in the case of the OCC treatments, it has not changed significantly compared to the control treatment, and only in one case (OC-Na1) has a significant decrease. With the increase of peroxide consumption in the oxidation process of both types of NSSC and OCC pulp, despite the increase in viscosity, there is no significant difference between different consumption levels. In addition, with the increase in the level of hypochlorite consumption, a significant increase in the viscosity of the aforementioned pulps is observed. The amount of carboxyl groups of pulps treated with peroxide increased in both types of NSSC and OCC pulps compared to the control sample. Compared to peroxide, hypochlorite has been more effective in creating carboxyl groups in both types of pulp. The evaluation of FT-IR spectroscopy also shows that the oxidation treatment with peroxide and hypochlorite has increased the carboxyl groups on both types of pulp compared to the control samples. Conclusion: The effectiveness of hypochlorite compared to peroxide in the creation of carboxyl groups in both types of pulp was more, which seems that the increase of carboxyl groups on the cellulose chain occurred more on C6 by peroxide and more on C2 and C3 by hypochlorite. The oxidation process increases the viscosity of paper pulp by increasing the carboxyl groups and due to the creation of a higher molecular weight. In addition, the increase of carboxyl groups due to higher chemical activity has made them able to absorb higher water and thus higher WRV. [ABSTRACT FROM AUTHOR]

Background: An ammonia gas explosion poses immediate health hazards such as respiratory tract burns, skin and eye irritation, and potential death within seconds. It also causes long-term negative impacts on biodiversity, affecting aquatic life and vegetation. An explosion in the Firuzabad sodium carbonate factory in Iran led to massive ammonia gas leakage and the poisoning of several employees. This study evaluates the risks of ammonia gas release caused by the explosion and the rescue team’s response in the same factory. Materials and Methods: This study was conducted in 2020 in Firuzabad City, Iran. The investigation was based on case reports and data analysis obtained via field observations, document reviews, interviews, and experiments. Technical and specialized information on explosion were analyzed by ALOHA software. Results: Based on data analysis, red, orange, and yellow zones around the explosion area were identified. The red zone had an ammonia emission range of 1.2 km with an explosive power of 10 kW, causing potential death in 60 seconds. Orange zone had a range of about 1.7 km, an explosive power of 5 kW, and the potential for second-degree burns and respiratory damage within 60 seconds of release. The yellow zone covered an area of about 3.3 km. Interviews and field observations provided information on the risk-based response process, response equipment, medical treatment, hazardous materials, handling and response equipment, personal protective equipment, mutual aid, and resource typing. Conclusion: The results of this study show that the immediate evacuation of the area, employment of the rapid warning system, the triage of the injured, the presence of an emergency operation plan to control hazardous and toxic materials disasters, the performance of the rapid response team and multi-specialty teams were among the existing challenges of the operation team. Background of this study confirms the potential hazards associated with ammonia gas emissions from explosions in sodium carbonate plants.

Sauropus androgynus is a precious medicinal herb containing a lot of chlorophyll, used to create a characteristic green color for food products. In this study, chlorophyll was extracted from S. androgynus by stirring fresh grinded leaves at 500 rpm at room temperature for 25 min with a solvent of 40% ethanol and added different salts, such as NaCl, Na2CO3, ZnSO4 to compare stability over time. In parallel with this experiment, S. androgynus blanched with 1% NaCl solvent was added with distinct metal salts to compare the effect of blanching solvent on chlorophyll pigment content and stability. The results showed that under normal extraction conditions at room temperature within 25 min with the addition of 1% of Na2CO3 salt based on the dry matter of materials, the chlorophyll content reached the highest value of 1.351 ± 0.032 mg/g dry matter (d.m.). Samples are sealed, protected from light, and stored at room temperature for 54 days and 124 days at 4 °C, toward the application of food color.

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This paper reports a comprehensive recovery of valuable metals from spent Al2O3-based catalysts using sodium carbonate roasting and water leaching. In all experimental parameters, roasting is one of the most critical influences on the leaching effect. During the roasting of sodium carbonate, insoluble NiAl2O4 and α-Al2O3 are converted to soluble NaAlO2, which can be leached by water. Then, Al, Ni, and V were recovered by leaching solution and residue, respectively. The experimental results showed that Al and V leaching rates were 99.64% and 99.24%, respectively, under the optimal leaching conditions. Moreover, the simple metal composition in the leachate and residue is more favorable for metal recovery than the direct recovery of Al and Ni from the spent Al2O3-based catalyst. Adding Ba(OH)2, which is stoichiometric with V, to the leachate allows the recovery of V first. Subsequently, Al(OH)3 precipitation was obtained by adding the appropriate amount of hydrochloric acid dropwise, and γ-Al2O3 was obtained by calcination. The residue was acid-leached using sulfuric acid again, and after the reaction, Ni(OH)2 was recovered by adding excess NaOH. Ni(OH)2 was heated to a certain temperature to obtain NiO. The recoveries of Al and Ni were 98.68% and 96.31%, respectively, during the whole experiment. [ABSTRACT FROM AUTHOR]

In this study, fennel (Foeniculum vulgare) seeds were used as a precursor for obtaining nanostructured activated carbons by chemical activation with various reagents. The obtained activated carbons were characterized using nitrogen adsorption–desorption isotherms, ash content, Boehm titration and pH of water extracts. It was shown that the choice of activator had an important effect on the physicochemical and sorption properties of the obtained activated carbons. The specific surface area of the obtained adsorbents ranged from 345 to 1052 m2/g. Chemical activation of the starting material with potassium carbonate made it possible to obtain activated carbons with the strongest developed specific surface area and the best sorption capacity against the tested pollutants. 1 g of this carbon is able to adsorb 1215 mg of iodine and 454 mg of methylene blue. The least effective adsorbent turned out to be the carbon obtained by chemical activation of fennel seeds with sodium carbonate, whose sorption capacity toward the pollutants from aqueous solutions was 77 mg/g and 317 mg/g for methylene blue for iodine, respectively. The alkaline pH of the solution promotes effective adsorption of methylene blue on the surface of the obtained adsorbents. The reaction of the dye molecules adsorption on the activated carbons occurs according to the pseudo-second-order model. The Langmuir isotherm best described the process under study. In addition, it was shown that chemical activation of fennel seeds leads to carbon adsorbents with acidic surface character. The negative values of Gibbs free energy indicate the spontaneous character of the process. The study has shown that fennel seeds can be successfully used to obtain low-cost and effective nanostructured carbon adsorbents with good sorption capacity toward organic and inorganic contaminants, from the aqueous phase. [ABSTRACT FROM AUTHOR]

This work systematically investigated the influence of catalyst reuse and reaction time on the yield and quality of organic liquid products (OLP) obtained in a cracking pilot plant at 450 °C and 1.0 atm. The distillation of OLP produced 04 (four) distilled fractions (gasoline, kerosene, and green diesel). The biofuels-like fractions are liquid mixtures with high content of hydrocarbons (alkanes, alkenes, and aromatics) with potential application as substitutes for fossil fuels in internal combustion motors. The quality of the biofuels was certified by physical-chemical analysis and FT-IR and GC-MS analysis. The experimental results showed the feasibility of applying the spent sodium carbonate twice in the catalytic cracking of vegetable oils. The physical-chemical properties (density, viscosity, acid value, saponification value, and flash point) of OLP decrease as the reaction time increases. The distillation of OLP yields 62.35% (wt.), producing green-like gasoline, kerosene, and diesel fractions rich in hydrocarbons. Therefore, biofuel-like fractions produced by distillation of OLP have a great potential for replacing partially petroleum-derived fuels. [ABSTRACT FROM AUTHOR]