Addition Of Sodium Carbonate Research Articles

Leaching behaviour of chromium during vanadium extraction from vanadium slag

In order to recover chromium from vanadium slag, the leaching behaviour of chromium during vanadium extraction was studied. The effects of the several parameters that included roasting temperature, roasting time, types of additives as well as addition mass of additives were investigated. The results indicated that chromium can be leached at the same time during vanadium leaching from vanadium slag. In comparison, under the same conditions, the leaching of vanadium is easier than that of chromium. The leaching rate of vanadium and chromium can be beyond 96 and 91%, respectively, under the experimental condition of roasting temperature of 700°C, roasting time of 2 h, 30% (mass fraction) sodium chloride and 20% (mass fraction) sodium carbonate addition to the vanadium slag, leaching temperature of 95°C, and leaching time of 3 h.

Effect of sodium ion concentration profile during softwood kraft pulping on delignification rate, xylan retention and reactions of hexenuronic acids

The objective of this investigation was to study how different concentration profiles of sodium ions influence the delignification rate, hexenuronic acid formation/degradation and xylan retention under kraft cooking conditions. The concentration of sodium ions was varied in time between 0.52 and 3.00 mol/kg solvent, taking two different routes by the controlled addition of sodium carbonate. The reaction rates of hexenuronic acid were found to increase when the sodium ion concentration was at the higher level. Furthermore, the results implied that the kinetics of hexenuronic acid reactions responds rapidly to changes in sodium ion concentration. Delignification and the removal rates of xylan decreased rapidly after the sodium ion concentration was increased. However, when the sodium ion concentration was decreased, the response to the change was delayed. These findings indicate that effects of ionic strength on the rate of delignification and removal of xylan arise as a consequence of changes in solubility and on mass transport phenomena rather than from the rates of chemical reaction. Furthermore, the results suggest that non-dissolved xylan located in the fibre wall matrix may also sorb on cellulose surfaces relatively early on in the cook if the concentration of sodium ions is at high level.

Analyzing the impact of different excipients on drug release behavior in hot-melt extrusion formulations using FTIR spectroscopic imaging

The drug release performance of hot-melt extrudate formulations is mainly affected by its composition and interactions between excipients, drug and the dissolution media. For targeted formulation development, it is crucial to understand the role of these interactions on the drug release performance of extrudate formulations. Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopic imaging was used with an in-situ flow-cell device to analyze the impact of different excipients on drug release from extrudates. The compositions differed in the type of polymer (copovidone and Soluplus®), the salt or acid form of ibuprofen and the addition of sodium carbonate. For comparison, conventional USP (United States Pharmacopeia) Apparatus 2 dissolution studies were performed. FTIR imaging revealed that differences in the drug release rate were mainly due to drug–polymer interactions. Ibuprofen acid showed interactions with the matrix polymer and exhibited a slower drug release compared to non-interacting ibuprofen salt. Addition of sodium carbonate to the ibuprofen acid containing formulations enhanced the drug release rate of these systems by interfering with the drug–polymer interactions. In addition, drug release rates also depended on the polymer type, showing faster drug release rates for extrudate formulations containing copovidone compared to Soluplus®. FTIR imaging revealed that the stronger the drug–polymer interaction in the formulations, the slower the drug release. The addition of sodium carbonate improved release as it reduces drug–polymer interactions and allows for the formation of the more water-soluble ibuprofen salt.

Effect of esterification condensation on the Folin–Ciocalteu method for the quantitative measurement of total phenols

The Folin–Ciocalteu method is widely applied for the determination of the total phenolic contents in natural products. This method is significantly affected by the addition of sodium carbonate. The currently applied Folin–Ciocalteu methods may have been modified without any validation in the quantitative standards and the order of processes. In this study, serial experiments were performed to investigate the effect of phenolic calibrations based on the classic Folin–Ciocalteu method. Esterification condensations were observed in the assays with prior basification for gallic acid and catechin used as quantitative standards. The phenolic contents obtained in the samples differed depending on when basification occurred compared with the gallic acid calibration. The bias of the classic Folin–Ciocalteu method derived from cross-linkage of molecules was first defined in this study. The performance of the Folin–Ciocalteu method is optimised and validated again.

X-ray photoelectron spectroscopy analysis of cotton treated with the TBCC/H2O2/NaHCO3 system

N-[4-(triethylammoniomethyl)benzoyl]caprolactam chloride (TBCC) was used as a bleach activator for activation of hydrogen peroxide (H2O2) in aqueous solution with the addition of sodium carbonate (NaHCO3). The TBCC/H2O2/NaHCO3 system was applied for treatment of cotton greige fabric at 60℃ in comparison with the conventional H2O2/NaOH system for treatment of cotton greige fabric at 95℃. Experimental results showed that the TBCC/H2O2/NaHCO3 system was effective for improving the degree of whiteness, reducing the fiber damage, and improving the water absorbency of cotton fabric. For understanding the treatment performance of the TBCC/H2O2/NaHCO3 system, X-ray photoelectron spectroscopy (XPS) was applied to analyze the surface elemental composition of cotton greige fabric before and after treatment. C 1s XPS spectra and quantitative analysis revealed that the TBCC/H2O2/NaHCO3 system improved the water absorbency of cotton fabric by removing hydrophobic matters as well as by oxidizing coloring matters and cellulose. The hexane extractions and scanning electron microscopy images indicated that the TBCC/H2O2/NaHCO3 system most likely removed the hydrophobic matters from cotton fabric in a “layer-by-layer” mode, which limited the cellulose backbones exposed for XPS analysis but allowed water to penetrate into cotton fibers.

Enhancing total nitrogen removal from wastewater of a science and industrial park using entrapped biomass

This study employed entrapped biomass technology to augment the conventional activated sludge process with anoxic–oxic (AO)/anaerobic–anoxic–oxic (A2O) functions for the removal of total nitrogen (TN) from wastewater of a science and industrial park in Taiwan. The entrapped biomass unit was fabricated in the format of carrier plates on which microbial cells were entrapped. Due to mass transport limitations, anoxic and anaerobic conditions were created within the bioplates that enabled denitrification to occur. The treatment basin incorporated an equivalent amount of 1300–2400 mg MLSS/L of activated sludge on the bioplates at packing ratios of 10–30% (volume ratio of bioplates to basin) operating with the addition of sodium carbonate for alkalinity and methanol for the electron donor. The results showed nearly 90% of ammonia nitrogen being converted to nitrate and 63% of TN removal, in comparison with typically 10% of TN removal in traditional activated sludge process of domestic wastewater plants.

Effects of a sodium carbonate (Na2CO3) additive on the conversion of phenethyl phenyl ether (PPE) in high-temperature water

The use of high-temperature water (including near/super-critical water) has been studied as a promising reaction method for the valorization of lignocellulose biomass (lignin). The dissociation of lignin usually begins with the cleavage of ether bonds which are the weakest chemical linkages in a lignin structure. Of the ether bonds, the most prevalent type is a β-ether bond; phenethyl phenyl ether (PPE) is regarded as a suitable model compound for studying the cleavage of this bond. This study investigates the conversion of PPE in high-temperature water, with sodium carbonate (Na2CO3) serving as an additive to promote ionic pathways. The addition of sodium carbonate greatly enhanced the conversion of PPE and produced phenol as the primary product. It was proposed that phenol was obtained through the dissociation of a Na+–PPE adduct, which progressed via heterolytic ether cleavage and α-hydrogen abstraction.

A novel nanofiltration process for the recovery of vanadium from acid leach solution

The effects of pH, feed concentration and operation pressure on the recovery of vanadium from acid leach solution of stone coal using nanofiltration membrane technology were investigated. The rejection and permeate flux of vanadium with two kinds of membranes in nanofiltration process were also studied. After pre-treatment of leach solution to remove calcium by the addition of sodium carbonate, the vanadium in the final concentrated solution can be up to 30g/L from 1.429g/L in the feed under the optimum conditions of pH6–6.5 and operation pressure of 2069kPa at room temperature during nanofiltration process with the rejection of vanadium more than 95%. The final concentrated solution can be directly used to produce the V2O5 by traditional method, and the permeate stream can be recycled to leaching. The conceptual flow sheet for the extraction of vanadium from acid leach solution using nanofiltration membrane has been developed.

Comparison of methods for distinguishing sodium carbonate activated from natural sodium bentonites

A lot of natural Ca/Mg-bentonites are turned into Na-bentonites. By adding sodium carbonate to a Ca/Mg-bentonite in the presence of some water Na+ enters the interlayer and Ca/Mg-carbonates precipitate outside. Natural Na-bentonites and activated Na-bentonites are rather similar. Therefore, in the present study methods are tested to distinguish both. This is relevant not only for customs but also for research and development. For activation different amounts of sodium carbonate are added. The dosage ranges from a few % of the CEC to slightly above the CEC corresponding to 1–5mass% Na2CO3. Also the water content may vary from the dried state at which the actual activation (cation exchange) does not take place up to the presence of excess water leading to a complete reaction. Altogether four cases had to be considered separately (Na2CO3 above CEC+excess water or dry and Na2CO3 much below the CEC+excess water or dry). If water was absent (cation exchange was not complete) the sodium carbonate phases could be detected by XRD, IR, or with STA–MS measurements. This result was expected but surprisingly, STA–MS–CO2 measurements were found to be applicable even in the most difficult case (sodium carbonate addition below CEC and excess of water=reaction complete). In the case of some samples activated with 2mass% sodium carbonate only, a weak STA–MS–CO2-peak was observed at about 100°C. Unprocessed materials are free of any carbonates which decompose around 100°C. Therefore, this 100°C peak indicates alkaline activation. This method was applied to five real products with unknown activation and two of which were found to be activated. The pH of the activated materials was only slightly higher than that of a natural Na-bentonite. The measured difference of 0.3 pH units is not considered to be sufficient to unambiguously conclude alkaline activation.

Effect of calcium, sulphate and gypsum on copper-activated and non-activated sphalerite surface properties

This work presents results of an experimental study on the depression of sphalerite by the precipitation of calcium sulphate dihydrate (gypsum, CaSO4·2H2O), and the role of the addition of sodium carbonate (Na2CO3) in restoring hydrophobicity. Zeta potential, microflotation, contact angle measurement and scanning electron microscopy were used. The zeta potential results show that sphalerite and gypsum were negatively charged over the pH range studied (5–10), and therefore no interaction between the two species was observed; however, when sphalerite was activated with 5mg/L of Cu at pH 9, the mineral developed a positive charge, thus enabling the electrostatic interaction with gypsum particles which resulted in gypsum covering a significant fraction of the mineral surface. The contact angle measurements show that the simultaneous presence of Ca2+ and SO42- ions decreased the hydrophobicity that the mineral had developed due to copper activation in the absence of these two species (19.6° and 28.7°, respectively). The presence of 10mg/L of CaSO4·2H2O in equilibrium with the saturated solution (0.0205mol/L CaSO4), further decreased the contact angle to 9.7°. In turn, the addition of 1g/L of Na2CO3 and 15min of conditioning substantially restored the hydrophobicity of the sphalerite by a mechanism consisting of gypsum dissolution and calcium consumption via calcium carbonate precipitation, which disperses in the bulk solution. This last practice resulted in a contact angle of 23.4°.

Succinic Acid Production from Corn Cob Hydrolysates by Genetically Engineered Corynebacterium glutamicum

Corynebacterium glutamicum wild type lacks the ability to utilize the xylose fractions of lignocellulosic hydrolysates. In the present work, we constructed a xylose metabolic pathway in C. glutamicum by heterologous expression of the xylA and xylB genes coming from Escherichia coli. Dilute-acid hydrolysates of corn cobs containing xylose and glucose were used as a substrate for succinic acid production by recombinant C. glutamicum NC-2. The results indicated that the available activated charcoal pretreatment in dilute-acid hydrolysates of corn cobs could be able to overcome the inhibitory effect in succinic acid production. Succinic acid was shown to be efficiently produced from corn cob hydrolysates (55 g l(-1) xylose and 4 g l(-1) glucose) under oxygen deprivation with addition of sodium carbonate. Succinic acid concentration reached 40.8 g l(-1) with a yield of 0.69 g g(-1) total sugars within 48 h. It was the first report of succinic acid production from corn cob hydrolysates by metabolically engineered C. glutamicum. This study suggested that dilute-acid hydrolysates of corn cobs may be an alternative substrate for the efficient production of succinic acid by C. glutamicum.

Spectral Analysis of Catalytic Oxidation and Degradation of Bromophenol Blue at Low pH with Potassium Dichromate

Abstract This research investigated the efficacy of potassium dichromate (K2Cr2O7), ultraviolet (UV) solar irradiation and UV in combination with two diprotic acid i-e sulphuric and oxalic acid (UV chromate/carbonate), for decolorizing bromophenol blue (BPB). The results suggested that alone UV and solar exposure was the poor decolorizer of the dye waste water. Up to 10% color removal with alone UV and solar treatment were achieved which indicated that, only solar and UV were not effective for dye removal even though UV was slightly more effective as compared to solar one. The decline reaction rate was observed as a result of increased concentration of dye. Increase in concentration of dichromate showed two peaks at 592 and 515 which showed that bromophenol degraded into two smaller components through complex formation. Addition of sodium carbonate as a catalyst in dye chromate-oxalate system found to be effective in degradation of BPB with reduced time period. The reaction was rapid and almost maximum of the dye converted into CO2. Research outcome suggests that chromate-oxalate system is very effective techniques for reducing color of dye waste water for safety of aquatic environment. Reaction pathway of oxidation of BPB is discussed in the relevant section of the paper.

Effect of Inorganic Ions on the Oxidative Efficiency of Ti(IV)-Catalyzed H2O2/O3 Process in the pH Range of 1.0 to 6.0

The oxidative efficiency of Ti(IV)-catalyzed H2O2/O3 (Ti(IV)/H2O2/O3) for acetic acid (HAc) degradation was investigated in the initial pH range of 1.0 to 6.0, and the effects of some common inorganic ions were also discussed in detail. The results showed that the effects of SO4 2− and NO3 − on the efficiency of Ti(IV)/H2O2/O3 were negligible. However, adding Br− greatly reduced the removal rate of HAc. The presence of Cl− also reduced the efficiency of Ti(IV)/H2O2/O3, but its negative effect became negligible in the initial pH range of 4.5 to 5.5. The presence of H2PO4 − could improve the removal rate of HAc, and addition of sodium carbonate had no influence on the efficiency of Ti(IV)/H2O2/O3 in the initial pH range of 4.5 to 5.5.

A novel method for determination of patulin in apple juices by GC–MS

A reliable gas chromatography–mass spectrometry with a QuEChERS procedure has been developed and validated for detection and determination of patulin in apple juice. This procedure includes initial extraction step with acetonitrile, partitioning step by addition of magnesium sulphate, sodium carbonate and sodium chloride, and clean-up step using dispersive solid-phase extraction by addition of a mixture of magnesium sulphate and primary secondary amine sorbent. In order to increase GC adoptability of patulin, derivatisation step was performed using N,O-bis-trimethylsilyl trifluoroacetamide. Method recoveries of patulin from apple juice samples ranged from 79.9% to 87.9%. Limit of detection (LOD) and quantification (LOQ) were 0.4 and 1.3μg/L, respectively. Relative standard deviations were lower than 9.5%. The developed method has been successfully applied to the analysis of patulin in apple juice samples.

The response of typical South African raw waters to enhanced coagulation

Drinking water treatment plants in South Africa rely almost entirely on surface water sources, which are often compromised due to high return flows and indirect reuse. The typical treatment plants focus on the removal of physical and microbial contaminants which include turbidity, colour, chemical compounds and microorganisms. A relatively new concern to this list is natural organic matter (NOM) which has become a major concern in potable water treatment due to its recent regulation. In this study, eight different raw water samples from the various water types found in the country were seasonally collected and treated for the removal UV absorbance at a wavelength of 254 nm (UV254) using enhanced coagulation (EC). The efficacy of EC, which can be employed as a practical technology in the removal of both turbidity and NOM, was evaluated in remaining UV254 from these raw water sources. Jar tests were conducted, with ferric chloride used as the coagulant (due to its extensive use as a coagulant in the water treatment industry in South Africa) and specific pH values (initial water pH, 7.0, 6.0, 5.5, 5.0 and 4.5) were chosen as target values guiding the six different coagulant dosages for the jar tests. The pH of the low-alkalinity (<60 mg/L CaCO3) raw waters were adjusted and raised by the addition of sodium carbonate. The response parameters of the tests were turbidity (NTU), pH and UV254. Algorithms for finding the optimum coagulant dosage for UV254 removal were developed and consistently applied to all the results. Results showed large variations in the nature of NOM across the country from specific ultraviolet absorbance values. From the UV254 values, the concentrations of NOM also varied greatly geographically than temporally. The general trend observed in the EC results suggested that the pH should always be dropped to between 4.5 and 7.0 to lower the amounts of UV254 and turbidity to reasonable levels.

Performance Study of Composite Clay Instead of a Single Plastic Clay

Zimujie is the common clay which has a very important position in ceramic production. It is facing with the depletion as the non-renewable resources in recent years.It is necessary to study a substitute to solve this problem . Research shows that : When the ratio of Changbai Mountain kaolin clay, Longyan clay, Suzhou clay and the northeast black mud is respectively 65.22wt%, 8.70wt%, 4.35wt%, 21.73wt% to formate the composite clay with 0.4wt% sodium carbonate addition agent, performance of the composite clay is very similar to zimujie.Therefore, it can be applied in the ceramic casting as the substitute of the single Zimujie clay.

Improvement of Heat-gelation Ability of Surimi from Frozen Blue Mackerel by the Addition of Sodium Carbonate

Improvement of Heat-gelation Ability of Surimi from Frozen Blue Mackerel by the Addition of Sodium Carbonate

Roles of double salt formation and NaNO3 in Na2CO3-promoted MgO absorbent for intermediate temperature CO2 removal

Absorption and desorption of carbon dioxide on Na2CO3-promoted MgO have been studied at temperatures compatible with warm gas cleanup (300–470°C) from a pre-combustion syngas. The absorbents are synthesized through the formation and activation of the precipitate resulting from the addition of sodium carbonate to an aqueous solution of magnesium nitrate. The absorbent, which comprises MgO, Na2CO3 and residual NaNO3 after activation, forms the double salt Na2Mg(CO3)2 on exposure to CO2. The thermodynamic properties of the double salt, obtained through computational calculation, predict that the preferred temperature range for absorption of CO2 with the double salt is significantly higher compared with MgO. Faster CO2 uptake can be achieved as a result of this higher temperature absorption window. Absorption tests indicate that the double salt absorbent as prepared has a capacity toward CO2 of 15wt.% (3.4mmol CO2/g absorbent) and can be easily regenerated through both pressure swing and temperature swing absorption in multiple-cycle tests. Thermodynamic calculations also predict an important effect of CO2 partial pressure on the absorption capacity in the warm temperature range. The impurity phase, NaNO3, is identified as a key component in facilitating CO2 absorption by these materials. The reason for reported difficulties in reproducing the performance of these materials can be traced to specific details of the synthesis method, which are reviewed in some detail.

Calcium zincate derived heterogeneous catalyst for biodiesel production by ethanolysis

The transesterification reaction of sunflower oil with ethanol to produce fatty acid ethyl esters (FAEEs) was studied by using calcined calcium zincate as solid base catalyst. The effect of experimental parameters, such as catalyst loading, ethanol:oil molar ratio, free fatty acid and water contents, and stability in the ethanolysis of sunflower oil in the presence of calcium zincate thermally treated at temperatures as low as 400°C are reported. Thus, by using a 3wt.% of catalyst at 78°C, FAEE yields higher than 95wt.% after 3h of reaction time, can be reached. The addition of FFA (until 1.1° of acidity) does not affect the catalytic activity, with yields values higher than 95wt.%, but water brings about a negative effect. However, the catalyst has demonstrated to be less resistant to the reutilization in the ethanolysis process due to the leaching of calcium species, but addition of sodium carbonate to the catalyst before the catalytic process allows obtaining, after washing with water, a biodiesel with concentrations of Ca and Na lower than 5ppm.

ChemInform Abstract: Platinum on Carbon‐Catalyzed Hydrodefluorination of Fluoroarenes Using Isopropyl Alcohol‐Water‐Sodium Carbonate Combination.

We have developed a platinum on carbon-isopropyl alcohol-catalyzed and widely applicable defluorination method for fluoroarenes, and the addition of water and sodium carbonate efficiently accelerated the reaction. The defluorination readily occurred under the reaction conditions in comparison with the dehalogenation of other aromatic halides (fluorine>chlorine>bromine≫iodine).