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NaOH Solution (naoh + solution)
Kinds of NaOH Solution Selected AbstractsDNA Determination in the Presence of Copper in Diluted Alkaline Electrolyte by Adsorptive Stripping Voltammetry at the Mercury Film ElectrodeELECTROANALYSIS, Issue 11 2007Augusto, Mardini Farias, Percio Abstract A stripping method for the determination of single-stranded DNA in presence of copper at the submicromolar concentration levels is described. The method is based on controlled adsorptive accumulation of adenine (from acid-treated DNA) at thin-film mercury electrode followed by linear scan voltammetry measurement of the surface species. Optimum experimental conditions were found to be the use of a 5.0×10,3,M NaOH solution, an accumulation potential of ,0.40,V and a scan rate of 200,mV s,1. The response of adenine,copper is linear over the concentration range 50,250,ppb. For an accumulation time of 15,minutes, the detection limit was found to be 4,ppb. The more convenient relation to measuring the ssDNA in presence of metals and nitrogenated bases were also investigated. The utility of the method is demonstrated by the presence of adenosine-triphosphate (ATP) and amino acids. [source] Gel immobilization of acrylamide-modified single-stranded DNA template for pyrosequencingELECTROPHORESIS, Issue 12 2007Pengfeng Xiao Dr. Abstract A novel two-step process was developed to prepare ssDNA templates for pyrosequencing. First, PCR-amplified DNA templates modified with an acrylamide group and acrylamide monomers were copolymerized in 0.1,M NaOH solution to form polyacrylamide gel spots. Second, ssDNA templates for pyrosequencing were prepared by removing electrophoretically unbound complementary strands, unmodified PCR primers, inorganic pyrophosphate (PPi), and excess deoxyribonucleotides under alkali conditions. The results show that the 3-D polyacrylamide gel network has a high immobilization capacity and the modified PCR fragments are efficiently captured. After electrophoresis, gel spots copolymerized from 10,,L of the crude PCR products and the acrylamide monomers contain template molecules on the order of pmol, which generate enough light to be detected by a regular photomultiplier tube. The porous structure of gel spots facilitated the fast transportation of the enzyme, dNTPs and other reagents, and the solution-mimicking microenvironment guaranteed polymerase efficiency for pyrosequencing. Successful genotyping from the crude PCR products was demonstrated. This method can be applied in any laboratory; it is cheap, fast, simple, and has the potential to be incorporated into a DNA-chip format for high-throughput pyrosequencing analysis. [source] Electrochemical Reduction of Oxygen on Carbon Supported Pt and Pt/Ru Fuel Cell Electrodes in Alkaline SolutionsFUEL CELLS, Issue 4 2003E.H. Yu Abstract A study of O2 reduction in 1 M NaOH solution at gas diffusion electrodes made from carbon supported Pt and Pt/Ru catalysts is reported. Two Tafel regions were observed for both the Pt and Pt/Ru electrodes. Although the same mechanism was suggested for oxygen reduction on both Pt and Pt/Ru catalysts, the O2 reduction activity was lower on Ru. Electrochemical Impedance Spectroscopy (EIS) analysis was carried out at different potentials and showed the significant contribution of diffusion on the reaction process and kinetics. The effect of methanol on O2 reduction was investigated in solutions containing various concentrations of methanol. The electrode performance deteriorated with increasing methanol concentration because of a mixed cathode potential. The methanol tolerance, i. e., the methanol concentration which polarises the O2 reduction reaction for O2 reduction, at the Pt/C electrode with a Pt loading of 1.2 mg cm,2 is 0.2 M methanol in 1 M NaOH. [source] The Synthesis of Novel Porous Functional Materials for use as Nitrosamine Traps,ADVANCED FUNCTIONAL MATERIALS, Issue 11 2004Y. Xu Abstract Two novel porous nitrosamine traps have been synthesized in order to eliminate carcinogens from the environment. A functional mesoporous material, CuO/SBA-15, has been synthesized by using an in-situ coating method, with the addition of a guest salt to the reaction system to modify the porous materials before the particles of SBA-15 were incubated; the synthesis and modification processes were performed in a single step. The resulting mesoporous composites selectively adsorb N -nitrosopyrrolidine (NPYR), a typical volatile nitrosamine, and are potential cigarette additives that can be used for the removal of nitrosamines from cigarette smoke, thereby protecting public health and the environment. In another reaction, silica gel is modified by being coated with magnesia and then corroded by NaOH solution. The magnesia is dispersed onto the silica by impregnating it with a magnesium acetate solution, followed by calcination. After corrosion of the calcined sample with caustic soda, only the silica particles that are completely covered by magnesia remain. This material exhibits a similar ability to SBA-15 and zeolite NaY in its selective adsorption of NPYR. [source] Enhanced bio-hydrogen production from sweet sorghum stalk with alkalization pretreatment by mixed anaerobic culturesINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 8 2010Xiang-Xing Shi Abstract Bio-hydrogen production from sweet sorghum stalk using mixed anaerobic sludge was reported in this paper. Batch tests were carried out to analyze influences of several environmental factors on yield of H2 from sweet sorghum stalk under constant mesophillic temperature (36±1°C). The experimental results showed that, for the raw stalk, the cumulative hydrogen yield was 52.1,ml,g,1·TVS with utilization percentages of sugars, hemi-cellulose and cellulose in the stalk being 89.12, 15.23 and 13.89% respectively; whereas for the stalk pretreated by 0.4% NaOH solution at room temperature for 24,h, the cumulative hydrogen yield was 127.26,ml,g,1·TVS with utilization percentages of sugars, hemi-cellulose and cellulose being 99.17, 53.64, 41.56%, respectively. The hydrogen content in the biogas was about 53% while the methane content was less than 4% throughout the study. Besides hydrogen and methane, the main metabolic products detected were ethanol, propionate and butyrate. The experimental results suggested that the alkalization pretreatment of the substrate plays a crucial role in the conversion of the sweet sorghum stalk wastes into bio-hydrogen by the mixed anaerobic sludge. Copyright © 2009 John Wiley & Sons, Ltd. [source] Highly purified natural rubber by saponificaion of latex: Analysis of green and cured propertiesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010Sureerut Amnuaypornsri Abstract Natural rubber (NR) was purified by saponification of fresh latex from Hevea brasiliensis and soaking process of the coagulum with aqueous NaOH solution. This treatment resulted in the decrease of nitrogen content to the same level as enzymatic deproteinized NR. The saponification of NR latex and soaking of the coagulum gave the rubber having good processability with easy to cure. The saponified rubber showed outstanding physical and dynamic mechanical properties such as high tensile properties, high storage modulus, low tan ,, low heat build-up and low dynamic compression set. The saponified rubber blend with styrene butadiene rubber (SBR) according to the recipe of rubber tire showed also a good performance. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] PEELING AND THE PHYSICAL AND CHEMICAL PROPERTIES OF KIWI FRUITJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 4 2003METIN GULDAS Hand peeling of kiwi fruit has some disadvantages such as difficulty during peeling, increase of loss in weight and nutritional value. Peeling of kiwi fruits with alkali (NaOH) was investigated. Some chemical (acidity, pectin, and chlorophyll) and physical properties (Hunter color value and weight loss) of the fruits were determined after selected alkali peeling methods were used. Peeling methods at 80, 90 or 100C temperatures; in 13, 18 or 23% of NaOH solutions and for 3, 4 or 5 min durations were tested and compared with hand peeling. Weight (fruit tissue) loss in hand peeling was higher than alkali peeling. Peeling with alkali was easier. Nutritional value (ascorbic acid content) of alkali peeled fruits was higher than hand peeled kiwi fruit. Because of less weight loss, better green color and high pectin content the method including 15% of NaOH solution at 95C for 4 min was selected as most advantageous peeling method. [source] Formation of Novel ZSM-5/Porous Mullite Composite from Sintered Kaolin Honeycomb by Hydrothermal ReactionJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 5 2000Hiroaki Katsuki The formation and properties of continuous ZSM-5 film on a porous mullite honeycomb have been investigated. The porous mullite honeycomb coated with ZSM-5 film provides a novel microporous (0.5 nm in diameter),macroporous (0.5,0.6 ,m in diameter) composite. Amorphous silica-glass in the kaolin honeycomb sintered at 1650°C is used as a source for ZSM-5 formation. The honeycomb is hydrothermally treated in NaOH, tetrapropylammonium bromide, and water to prepare a novel honeycomb,zeolite composite by in situ crystallization of ZSM-5 film. This paper describes the effects of hydrothermal conditions,such as reaction temperature, time, and concentration of NaOH solution,on the formation of ZSM-5 film on the honeycomb, and on the mechanical strength and porous properties of the honeycomb composite. [source] Partially hydrolyzed kappa carrageenan,polyacrylonitrile as a novel biopolymer-based superabsorbent hydrogel: Synthesis, characterization, and swelling behaviorsPOLYMER ENGINEERING & SCIENCE, Issue 12 2006M. T. Savoji In this paper, synthesis and swelling behavior of a novel superabsorbent hydrogel based on kappa carrageenan (,C) and polyacrylonitrile (PAN) was investigated. To achieve partially hydrolyzed ,C-PAN hydrogel, physical mixture of ,C and PAN was hydrolyzed by NaOH solution. During alkaline hydrolysis, the nitrile groups of PAN are converted to a mixture of hydrophilic carboxamide and carboxylate groups follow by in situ crosslinking of the grafted PAN chains. The reaction variables affecting on the swelling capacity of the hydrogel were systematically optimized to achieve a hydrogel with swelling capacity as high as possible. Under the optimized conditions concluded, super swelling hydrogel with the ability of water absorption up to 3260 g/g (water/dry hydrogel powder) has been prepared. Swelling measurements of the synthesized hydrogels was carried out in various salt solutions and solutions with different pH. The results indicate that the hydrogels have good pH sensitivity and pH-reversible property between pH 2 and pH 8. POLYM. ENG. SCI. 46:1778,1786, 2006. © 2006 Society of Plastics Engineers. [source] Characteristics of Filiform, Fungiform and Vallate Papillae and Surface of Interface Epithelium-Connective Tissue of the Maned Sloth Tongue Mucosa (Bradypus torquatus, Iliger, 1811): Light and Scanning Electron Microscopy StudyANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 1 2009E. J. Benetti Summary The study of lingual surfaces and the surface of interface epithelium-connective tissue of the tongue of Bradypus torquatus was performed by employing the light and scanning electron microscopy (SEM) techniques. The results revealed that the rostral part of the tongue presents a round apex and covered by filiform and fungiform lingual papillae and a ventral smooth surface. It was observed that the epithelial layer of the dorsal surface possesses the basal, spinosum, granular and cornified epithelial cells. The lamina propria is characterized by a dense connective tissue forming the long, short and round papillae. Numerous typical filiform papillae are located especially in the rostral part intermingled for few fungiform papillae, which were revealed in three-dimensional SEM images. Usually, the fungiform papillae are located in the border of rostral apex of the tongue exhibiting the rounded form. They are covered by keratinized epithelial cells. In the fungiform papillae, several taste pores were observed on the surface. The vallate papillae presented numerous taste buds in the wall of epithelial cells, being that the major number of taste buds is located on the superior half of vallate papilla. The taste pores are surrounded by several laminae of keratinized epithelial cells. The samples treated with NaOH solution and examined by SEM revealed, after removal of the epithelial layer, the dense connective core in original disposition, presenting different sizes and shapes. The specimens stained with Picrosirius and examined by polarized light microscopy revealed the connective tissue, indicating the collagen fibres type I and type III. [source] Leaching characteristics of heavy metals in fly ash from a Chinese coal-fired power plantASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 2 2010Xun Gong Abstract China is the largest coal ash producer in the world. Hydraulic ash transport systems are used in most coal-fired power plants, which lead to serious water pollution due to leaching of trace elements. The investigation on the leaching behavior of trace contaminants from coal ash is critical to environmental risk assessments. Batch leaching tests have been performed on the fly ash collected from each field of the electrostatic precipitator (ESP) of a coal-fired power plant to study the leaching characteristics of Cd, Cr, Pb and V. Leaching solutions included HCl solution of initial pH = 4 and NaOH solution of pH = 10. The liquid/solid (L/S) ratio was about 4:1 in all leaching tests. Fourteen leaching time intervals were selected, ranging from 15 min to 7 days. The results show that under studied experimental conditions, Cr has a relatively higher leachability in the acid-leaching solution, while Pb has a higher leachability in the alkaline solution. With the increase of leaching time, the leachability of Cr in each ash sample increases obviously. Within the same time interval, Cr in the ash sample from the last field of ESP has the highest leachability. The concentration of Cd in FA3 is the highest, but the leachability of Cd for FA3 is not the highest among the three ash samples. The concentration of V in FA1 is the highest; no increased trend with leaching time has been found in the experiment. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Absorption Rate of Carbon Dioxide by K2CO3 -KHCO3 DEA Aqueous SolutionASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 1-2 2005K. Takahshi Gas absorption rates of carbon dioxide from CO2 -air mixtures into K2CO3, K2CO3 -KHCO3, DEA and K2CO3 -KHCO3 -DEA solutions have been measured by using a wetted wall column. The method to determine the enhancement factor of chemical absorption is confirmed by the absorption of carbon dioxide in NaOH solution. The enhancement factor was correlated with the potassium concentration [K+] (= 2[K2CO3 + [KHCO3]), the DEA concentration, and the CO2 -loading ratio of the absorbent. The chemical reaction for CO2, absorption has been expressed by an (m,n)th order irreversible-reaction model, where the reaction orders are m = 1 for CO2, n = 1.35 for DEA, n = 0.6 for K2CO3, and n = 0.6 and 1.35 for K2CO3 and DEA respectively. Experimental values of the enhancement factor were successfully reproduced by the calculations, where the reaction rate constants reflected the effect of loading ratio of the absorbent with carbon dioxide. [source] Effects of excluded volume and polydispersity on solution properties of lentinan in 0.1 M NaOH solution,BIOPOLYMERS, Issue 4 2005Xufeng Zhang Abstract Seven lentinan fractions of various weight-average molecular weights (Mw), ranging from 1.45 × 105 to 1.13 × 106 g mol,1 were investigated by static light scattering and viscometry in 0.1M NaOH solution at 25°C. The intrinsic viscosity [,] , Mw and radius of gyration ,s2, , Mw relationships for lentinan in 0.1M NaOH solution were found to be represented by [,] = 5.1 × 10,3M cm3 g,1 and ,s2, = 2.3 × 10,1M nm, respectively. Focusing on the effects of the Mw polydispersity with the Schulz,Zimm distribution function, the data of Mw, ,s2,, and [,] was analyzed on the basis of the Yoshizaki,Nitta,Yamakawa theory for the unperturbed helical wormlike chain combined with the quasi-two-parameter (QTP) theory for excluded-volume effects. The persistence length, molecular weight per unit contour length, and the excluded-volume strength were determined roughly to be 6.2 nm, 980 nm,1, and 0.1, respectively. Compared with the theoretical value calculated by the Monte Carlo model, the persistence length is longer than that of the single (1 , 3)-,- D -glucan chain. The results revealed that lentinan exists as single-stranded flexible chains in 0.1M NaOH solution with a certain degree of expansion due to the electrostatic repulsion from the interaction between the OH, anions and lentinan molecules. © 2005 Wiley Periodicals, Inc. Biopolymers 78: 187,196, 2005 [source] Tailored Mesoporosity Development in Zeolite Crystals by Partial Detemplation and DesilicationADVANCED FUNCTIONAL MATERIALS, Issue 1 2009Javier Pérez-Ramírez Abstract Partial detemplation of zeolites followed by desilication in alkaline medium is demonstrated as a powerful and elegant approach to design hierarchical zeolites with tailored degree of mesoporosity. This achievement, illustrated for large beta crystals, is based on the fact that the template-containing zeolite is virtually inert to Si leaching upon treatment in aqueous NaOH solutions. Partial removal of the structure-directing agent creates regions in the crystal susceptible to mesopore formation by subsequent desilication, while template-containing regions are protected from silicon extraction. Variation of the calcination temperature in the range 230,550,°C determines the amount of template removed and enables control of the extent of mesopore formation in the zeolite (20,230,m2,g,1) upon alkaline treatment. The functionality of the introduced mesoporosity in the hierarchical beta crystals is demonstrated by the improved performance in the catalytic pyrolysis of low-density polyethylene. The partial detemplation,desilication treatment enhances the tuning options of this demetallation method. [source] Poly(ethylene terephthalate) recycling and recovery of pure terephthalic acid by alkaline hydrolysisADVANCES IN POLYMER TECHNOLOGY, Issue 4 2002G. P. Karayannidis Abstract Poly(ethylene terephthalate) (PET) taken from postconsumer soft-drink bottles was subjected to alkaline hydrolysis after cutting it into small pieces (flakes). The reaction took place in an autoclave at 120,200°C with aqueous NaOH solutions and at 110,120°C with a nonaqueous solution of KOH in methyl Cellosolve. The disodium or dipotassium terephthalate received was treated with sulfuric acid and terephthalic acid (TPA) of high purity was separated. The 1H NMR spectrum of the TPA revealed an about 2% admixture of isophthalic acid together with the pure 98% TPA. The purity of the TPA obtained was tested by determining its acidity and by polymerizing it with ethylene glycol by using tetrabutyl titanate as catalyst. A simple theoretical model was developed to describe the hydrolysis rate. The activation energy calculated was 99 kJ/mol. This method is very useful in recycling of PET bottles and other containers because nowadays TPA is replacing dimethyl terephthalate (the traditional monomer) as the main monomer in the industrial production of PET. © 2002 Wiley Periodicals, Inc. Adv Polym Techn 21: 250,259, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10029 [source] Hydrothermal modification of natural zeolites to improve uptake of ammonium ionsJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 4 2005Yujiro Watanabe Abstract The modification of natural zeolites was carried out under hydrothermal conditions to improve the effectiveness of the uptake of ammonium ions. Natural zeolites originating in Japan, such as mordenite and clinoptilolite with quartz, feldspar and a trace of layered silicate, were treated with 0.1, 0.3, 1.0 and 3.0 M NaOH solutions at temperatures from 25 to 150 °C under autogenous pressure for 7 days. After the hydrothermal treatment, the transformation of the zeolites to phillipsite, hydroxyl-sodalite and analcime was observed, depending on the temperature and NaOH concentration. The amounts of ammonium ions taken up into the hydrothermally-treated zeolites were compared with those of the starting materials. The treated products, containing mainly phillipsite, took up twice the amount of ammonium ions as the starting materials. The maximum uptake of ammonium ions was 1.92 mmol g,1. The number of ammonium ions taken up into phillipsite was equal to the number of Na+ ions released from phillipsite. These results indicate that the uptake of ammonium ions proceeds by an ion-exchange mechanism with Na+ ions. Copyright © 2005 Society of Chemical Industry [source] PEELING AND THE PHYSICAL AND CHEMICAL PROPERTIES OF KIWI FRUITJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 4 2003METIN GULDAS Hand peeling of kiwi fruit has some disadvantages such as difficulty during peeling, increase of loss in weight and nutritional value. Peeling of kiwi fruits with alkali (NaOH) was investigated. Some chemical (acidity, pectin, and chlorophyll) and physical properties (Hunter color value and weight loss) of the fruits were determined after selected alkali peeling methods were used. Peeling methods at 80, 90 or 100C temperatures; in 13, 18 or 23% of NaOH solutions and for 3, 4 or 5 min durations were tested and compared with hand peeling. Weight (fruit tissue) loss in hand peeling was higher than alkali peeling. Peeling with alkali was easier. Nutritional value (ascorbic acid content) of alkali peeled fruits was higher than hand peeled kiwi fruit. Because of less weight loss, better green color and high pectin content the method including 15% of NaOH solution at 95C for 4 min was selected as most advantageous peeling method. [source] Methylation of Chitosan with Iodomethane: Effect of Reaction Conditions on Chemoselectivity and Degree of SubstitutionMACROMOLECULAR BIOSCIENCE, Issue 10 2003Elisabete Curti Abstract N,N,N -trimethylchitosan (TMC) was prepared by reacting purified chitosan with iodomethane, in the presence of sodium hydroxide, water and sodium iodide, at room temperature. The reaction medium was N -methyl-2-pyrrolidone. Different samples of TMC were obtained by adding to the reaction medium a fixed volume (5.5 mL) of aqueous NaOH solutions at different concentrations (15, 20, 30 and 40 wt.-%) and carrying out the reactions for 9 or 24 h. The features observed in the 1H and 13C NMR spectra of these chitosan derivatives, in respect of the chemical shift, number and relative intensity of the signals, depended strongly on the excess of NaOH and H3CI added to the reaction medium, but when the lowest excess was employed, the characteristics of the derivative were not affected by the reaction time to the same extent. The average degree of quaternization of these N -methylated derivatives of chitosan ranged from 10.5% to 44.8%, according to the reaction conditions. Increasing the excess of NaOH, in reactions carried out for 9 h, resulted in TMC samples with progressively higher content of trimethylated sites however, the reaction yields were correspondingly lower and O -alkylation was favored in these cases. 1H NMR spectrum of sample [AX]24h dissolved in D2O (Cp,=,10 g/L). [source] | ||||||||||||||||