Increasing NaOH Concentration Research Articles

PENGARUH KATALIS BASA (NaOH) PADA TAHAP REAKSI TRANSESTERIFIKASI TERHADAP KUALITAS BIOFUEL DARI MINYAK TEPUNG IKAN SARDIN

Biofuel is an alternative diesel engine fuel is produced from oils/fats of plants and animals (including the fisheries industry waste) through the esterification and transesterifiksi reactions. A transesterification is reaction to form esters and glycerol from trigliserin (fat/oil) and bioalcohol (methanol or ethanol). Transesterification is an equilibrium reaction so that the presence of a catalyst can accelerate the achievement of a state of equilibrium. Process of the transesterification reaction of sardine flour oil waste with NaOH as base catalyst in producing biofuels was conducted.The research purpose has studied the influence of NaOH concentration in transesterification process and examinate its effect on the quality of biofuels production, conversion, and physic quality. The variables that analysed was the effect of NaOH concentration as catalyst (0.5%, 1.0%, 1.5%, and 2.0% from amount of oil and methanol) in the transesterification reaction step. The result showed that the increasing NaOH concentration (0.5 - 1.5%), enhanced the biofuel conversion (%). The highest conversion of biofuels was achieved by using 1.50% NaOH (w/w) with 45.34% biofuels conversion. The major component in the biofuels was methyl palmitate (20.31%). ASTM analysis data also supported that the biofuel product was in agreement with automotive diesel fuel specification.

Removal of cationic dye methylene blue (MB) from aqueous solution by ground raw and base modified pine cone powder

The adsorption capacity of raw and sodium hydroxide-treated pine cone powder in the removal of methylene blue (MB) from aqueous solution was investigated in a batch system. It was found that the base modified pine cone exhibits large adsorption capacity compared with raw pine cone. The extent of adsorption capacity was increased with the increase in NaOH concentration. Overall, the extent of MB dye adsorption increased with increase in initial dye concentration, contact time, and solution pH but decreased with increase in salt concentration and temperature for both the systems. Surface characteristics of pine cone and base modified pine cone were investigated using Fourier transform infrared spectrophotometer and scanning electron microscope. Equilibrium data were best described by both Langmuir isotherm and Freundlich adsorption isotherm. The maximum monolayer adsorption capacity was found to be 129.87 mg g−1 at solution pH of 9.02 for an initial dye concentration of 10 ppm by raw pine cone. The base modified pine cone showed the higher monolayer adsorption capacity of 142.25 mg g−1 compared with raw pine cone biomass. The value of separation factor, R L, from Langmuir equation and Freundlich constant, n, both give an indication of favourable adsorption. The various kinetic models, such as pseudo-first-order model, pseudo-second-order model, intraparticle diffusion model, double-exponential model, and liquid film diffusion model, were used to describe the kinetic and mechanism of adsorption process. Overall, kinetic studies showed that the dye adsorption process followed pseudo-second-order kinetics based on other models. The different kinetic parameters, including rate constant, half-adsorption time and diffusion coefficient, were determined at different physicochemical conditions. A single-stage bath adsorber design for the MB adsorption onto pine cone and modified pine cone has been presented based on the Langmuir isotherm model equation. Thermodynamic parameters, such as standard Gibbs free energy (ΔG 0), standard enthalpy (ΔH 0) and standard entropy (ΔS 0), were also calculated.

Surface modification of PVDF hollow fiber membrane to enhance hydrophobicity using organosilanes

AbstractThis work investigates the membrane modification to enhance hydrophobicity aiming for applications as membrane contactors. The PVDF membranes were activated by NaOH and by plasma activation followed by grafting using three organosilanes. For the NaOH, the contact angle of original membranes (68°) was decreased from 44° to 31° with increasing NaOH concentration from 2.5M to 7.5M at 60°C for 3 h. The contact angle of NaOH treated membranes was increased to 100° after modification with 0.01M FAS‐C8 for 24 h. A needle‐like structure was observed on the membrane surface while there was no significant change in pore size and pore size distribution. Moreover, FTIR and XPS data showed Si peak and composition. The mechanical strength was improved. The surface modified membranes under helium plasma activation followed by grafting with 0.01M FAS‐C8 for 24 h showed higher contact angle, mechanical strength and surface roughness than that obtained by NaOH activation method while other physical properties did not change. The long‐term performance test for 15 days of operation was conducted. The modified membranes exhibited good stability and durability for CO2 absorption. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Increased recovery and improved purity of PHA from recombinant Cupriavidus necator

A simple procedure for recovering biodegradable polymer from bacterial cells has been developed using economical and environmentally friendly solvent or chemicals. Recombinant bacterium, Cupriavidus necator harboring pBBR1MCS-C2 plasmid polyhydroxyalkanoate (PHA) synthase gene was used for the production of copolymer P(3HB-co-3HHx) from crude palm kernel oil (CPKO). NaOH was chosen in this study as it could give high purity and recovery yield. Increase of NaOH concentration had resulted in an increase of the PHA purity, but the recovery yield had decreased. The greater improvement of PHA purity and recovery were achieved by incubating the freeze-dried cells (10–30 g/L) in NaOH (0.1 M) for 1–3 h at 30°C and polishing using 20% (v/v) of ethanol. The treatment caused negligible degradation of the molecular weight of PHA recovered from the bacterial cells. The present review also highlights other extraction methods to provide greater insights into economical and sustainable recovery of PHA from bacterial cells.

Polymorphic transformation of cellulose I to cellulose II by alkali pretreatment and urea as an additive

The effect on crystalline structure transformation from cellulose I to cellulose II polymorph was studied of the cotton linter treated with NaOH with and without urea as an additive, analyzed by wide-angle X-ray diffraction analysis. Cotton linter treated with increasing NaOH concentration showed at 15wt% sudden transformation from cellulose I to cellulose II polymorph. But when urea 5wt% was used as additive along with 15wt% NaOH concentration the magnitude of the transformation reduced largely. The crystallinity index showed a gradual decrease with increasing concentration of NaOH. The crystallinity index showed a gradual decrease with increasing concentration of NaOH with or without addition of urea, nevertheless with addition of urea a further slight more transformation was also observed.

Morphology-controllable Bi2O3 crystals through an aqueous precipitation method and their photocatalytic performance

Abstract This study investigated the formation of bismuth oxide (Bi 2 O 3 ) crystals by an aqueous precipitation method using bismuth nitrate pentahydrate [Bi(NO 3 ) 3 ·5H 2 O] and NaOH. The phase evolution during NaOH titration was also studied. Basic bismuth nitrates were formed during NaOH titration. However, these nitrates dissolved and recrystallized into Bi 2 O 3 when the pH attained a critical range between 13 and 14. A second phase of Bi(OH) 3 was induced when the pH of the solution was over the critical pH range. The morphology of the Bi 2 O 3 crystal strongly depended on precipitation conditions. The NO 3 − ions favored the crystal growth along the [001] direction to obtain needle-like Bi 2 O 3 crystals. Conversely, NaOH tended to be absorbed on the (001) face and suppressed the preferred growth in the [001] direction because of the shielding effect. The crystal changed from needle-like to plate or polyhedral shape with increasing NaOH concentration. The optical absorption properties were also modified accordingly, resulting in the change of color from yellow to pale orange because of size and shape effects. Finally, Bi 2 O 3 crystals with plate and polyhedral morphologies were found to show relatively higher photocatalytic activity than the needle-like crystals due to the better development of the active crystal faces with suppression of the preferred crystal growth habit.

오징어 및 명태껍질 유래 콜라겐의 추출 및 물리화학적 특성

The collagens from squid (Todarodes pacificus ) skin and Alaska pollack ( Theragra chalcogramma) skin were extracted and their physicochemical properties were investigated. The yield was improved with the increase of NaOH concentration and was increased Neutrase than Alcalase in enzymatic hydrolysates. Protein and collagen contents from Alaska pollack skin were 38.3 ∼62.7% and 13.1∼28.9%, respectively. All enzymatic hydrolysates also showed high antioxidant activities as NaOH concentration decrease. Composition of their amino acids was mainly glycine and proline. The spectrum of FT-IR of the collagen showed wavenumber at 1,631 cm-1 , 1,549 cm -1 , 1,234 cm -1 and 3,322 cm -1 representing the regions of amide Ⅰ, amide Ⅱ, amide Ⅲ and amide A, respectively. The decomposition temperature for the collagen was in the range of 300℃ and showed relatively good enough for their thermal stabilities.

Pressure leaching of bismuth sulfide concentrate containing molybdenum and tungsten in alkaline solution

The leaching results of bismuth sulfide concentrate containing molybdenum and tungsten in air-H2O2-NaOH system, pressure-O2-Na2CO3 system and pressure-O2-NaOH system were investigated. The results show that the extraction of molybdenum, tungsten and sulfur goes up with the increase of NaOH concentration, oxygen partial pressure and reaction time. The extraction of molybdenum and tungsten also rises up with temperature, but the leaching ratio of sulfur increases initially to a peak of 98% at 150°C and then decreases with the increase of temperature. Under the optimal conditions, the extraction of molybdenum, tungsten and sulfur is more than 95.6%, 93.8% and 96.0%, respectively, and the main phases of residue are Bi2O3 and Fe2O3. Therefore, the method of pressure leaching in alkaline solution is provided as an effective separation of molybdenum, tungsten and sulfur from bismuth and a beneficial pretreatment for consequent process.

Characterization of Raw and Treated Curaua Fibers to be Applied as Reinforcement in Composites

Lignocellulosic fibers present several advantages over synthetic fibers, such as low cost and biodegradability. In this work the tensile mechanical behavior of as-received and surface treated curaua fibers was analyzed. Mercerization and three different enzyme surface treatments were used. The tensile stress data were analyzed using the Weibull statistical distribution, and SEM was used to characterize the surface modifications caused by the treatments. The results show that mercerization causes an increase of the deformation capacity of the fibers. This result was attributed to the removal of hemicellulose, and to an increase of mobility of the internal fibrils. The increase of NaOH concentration at the alkali solution affects both the surface characteristics and the tensile properties. Solutions with more than 5%wt NaOH degraded the fibers. The enzyme treatments increase the tensile mechanical properties, but also increase their brittleness.

Solubility and Modeling of Sodium Aluminosilicate in NaOH–NaAl(OH)4 Solutions and Its Application to Desilication

The solubility of :sodium aluminosilicate (sodalite), a major desilication product (DSP) in the Bayer process, in NaOH and NaOH-NaAl(OH)(4) solutions was determined and modeled from 3.03.2 to 34 4 K Sodium aluminosilicate was synthesized in a batch crystallizer and the effect of temperature, solution concentrations, and aging time Was investigated. Solubility was found to increase with increasing NaOH concentration while the solubility sharply decreases with the addition of Al(OH)(3), reaches a minimum at about 0.8 mol.L-1, and then increases A mixed-solvent electrolyte (MSE) model for the solubility of sodalite was developed with the help of the OLI platform via regression to obtain the model parameters. In addition, the desilication kinetics of NaOH-NaAl(OH)(4) solutions by using sodalite as seeds was studied experimentally and modeled with the aid of a second order kinetic model. The activation energy of desilication over the temperature range 323.2-363.2 K was found to be 92 +/- 14 kJ.mol(-1). Under the optimal operation conditions, 80% silica was removed after 2 h.

Barium zirconate titanate nanoparticles synthesized by the sonochemical method

A new route for preparing barium zirconate titanate nanoparticles (BaZr0.3Ti0.7O3 (BZT)) has been developed by ultrasonication of BaCl2·2H2O, ZrOCl2·8H2O and TiCl4 precursors in a high concentration of NaOH aqueous solution. The as-prepared powders were identified by X-ray diffraction (XRD) as cubic perovskite BZT. The phase formation was confirmed by FT-IR and Raman spectroscopy. The increase of NaOH concentration resulted in BZT powders with smaller particle size and less BaCO3 contamination. The microstructure of BZT powders prepared in 20 M NaOH examined by scanning electron microscopy (SEM) showed nanosized spherical morphology with the average particle sizes of 51±6 nm.

Development of Al2O3 carrier-Ru composite catalyst for hydrogen generation from alkaline NaBH4 hydrolysis

A recyclable and reusable Ru/Al2O3 catalyst is prepared for hydrogen generation from the hydrolysis process of alkaline sodium borohydride (NaBH4) solution. The hydrogen generation rate by the hydrolysis and methanolysis of alkaline NaBH4 was explored as a function of NaOH concentration. Meantime, the byproducts derived from the spent alkaline NaBH4 solution were characterized by X-ray diffraction (XRD), scanning electro microscope/energy dispersive spectrometer (SEM/EDS) and NMR (Nuclear Magnetic Resonance). The effect of NaOH concentration on the hydrogen generation from the hydrolysis of NaBH4 significantly depends on the type of catalysts. With increasing NaOH concentration, the hydrogen generation rates decrease when using ruthenium (Ru) composite as a catalyst. The hydrogen generation rate of the methanolysis of NaBH4 is significantly inhibited in the presence of NaOH as compared with the hydrolysis of NaBH4. The durability test of the Ru/Al2O3 catalyst shows that the hydrogen generation rate decreases with recycling and reuse. The XRD and NMR analysis results show that the borate hydrate (NaBO2 H2O) was derived from the hydrolysis of 20 wt% and 30 wt% NaBH4.

FRACTIONAL SEPARATION AND STRUCTURAL FEATURES OF HEMICELLULOSES FROM SWEET SORGHUM LEAVES

Six hemicellulosic samples were isolated from cell wall material of dewaxed sweet sorghum (Sorghum bicolor (L.) Moench) leaves by sequential extractions with distilled water, alkali, and organic alkali solvent. The samples were treated with water, 1% NaOH, and 60% ethanol. The organic alkali samples were treated with 1%, 3%, 5%, and 8% NaOH, which yielded 8.3%, 5.4%, 1.0%, 5.6%, 2.5%, and 4.9% hemicelluloses based on the dry initial sweet sorghum leaves, respectively, and resulted in a total release of 81% of all hemicelluloses originally present in the cell wall. The results indicated that water-soluble hemicelluloses contained noticeable amounts of glucose, arabinose, galactose, and xylose, and had a relatively lower molecular weight (17300 g/mol). The four alkali-soluble hemicellulosic fractions, rich in xylose, were more linear, and had higher molecular weights (48500-128000 g/mol) than those of the alkali organic-soluble hemicellulosic fraction. With an increase of NaOH concentration from 1% to 8%, the ratio of arabinose to xylose decreased from 0.29 to 0.01, which implied that the hemicelluloses obtained by the higher concentration of alkali appeared to be more linear. Based on the sugar analysis, Fourier transform infrared (FT-IR), and nuclear magnetic resonance (NMR) results, 4-O-methylglucuronoarabinoxylans were the major constituents of the hemicellulosic polymers.

Effects of sodium hydroxide exposure on esophageal epithelial cells in an in vitro ovine model: implications for esophagus tissue engineering

BackgroundEsophagus tissue engineering holds promises for esophageal replacement after severe caustic injuries. The aim of this study was to determine whether viable esophageal epithelial cells could be isolated from an esophagus exposed to varying concentrations of alkali with regard to number, viability, and morphology during in vitro culture. MethodsOvine esophagi were exposed to phosphate-buffered saline 2.5%, 15%, or 25% sodium hydroxide (NaOH). The effect of NaOH concentrations on epithelial damage was assessed histologically. Esophageal epithelial cells were then isolated, and cell count and viability were investigated. Finally, cell number, viability, and morphology of esophageal epithelial cells were determined for 24 days of in vitro culture. ResultsHistologic analysis showed a progressive destruction of the epithelium proportional to increasing NaOH concentrations. Esophagi treated with phosphate-buffered saline and 2.5% NaOH showed significantly higher viable cell counts after isolation and culture in comparison with those treated with 15% to 5% NaOH. ConclusionThe evidence presented in this study indicates that epithelial biopsies from an esophagus exposed to low concentrations (2.5%) of NaOH will still yield large numbers of viable cells suitable for tissue engineering applications. In cases of exposure to higher concentrations (15%-25%), alternative cell sources for epithelial regeneration, such as stem cells, will be necessary for tissue engineering applications.

Structural factors and physical properties of needle-punched nonwovens based on Co-PET/PA bicomponent fibers via alkali treatment

Needle-punched nonwovens are widely used in industrial fields. However, they are limited to some applications such as high-efficiency filters, high-performance synthetic leathers, and high-absorption wipes because of their low surface area and large pore size. In this study, needle-punched nonwovens composed of Copolyethylene terephthalate (Co-PET)/Polyamide (PA) sea-island bicomponent fibers were treated in NaOH solution with various conditions for preparing nonwovens composed of ultra-fine fibers. The effect of NaOH concentration and treatment temperature on the structural factors and physical properties of nonwovens was investigated. The morphological structures of Co-PET and PA components were analyzed by scanning electron microscope. After alkali treatment, fiber diameter was significantly reduced from 23.65 to 3.95 μm, specific surface area of nonwovens increased more than five times, calculated and experimental mean pore diameter decreased by 83.6 % and 20.8 %, respectively. By increasing NaOH concentration and treatment temperature, pore diameter was reduced, thereby decreasing the air permeability of nonwovens. Meanwhile, tensile strength increased and tearing strength decreased as NaOH concentration and treatment temperature were increased in both machine and cross direction, respectively. The treatment temperature of alkali treatment was significantly influenced by the physical properties of nonwovens.

Carboxymethyl cellulose film from durian rind

Cellulose from durian rind was converted to carboxymethyl cellulose (CMCd) by carboxymethylation using sodium monochloroacetate (SMCA) and various sodium hydroxide (NaOH) concentrations (20–60 g/100 mL). The chemical structure of the cellulose and resulting polymers was then characterized using Fourier transform infrared spectroscopy (FTIR). Then, the properties of the CMCd materials were investigated. The optimum condition for carboxymethylation was found to be 30 g/100 mL NaOH, which provided the highest viscosity and degree of substitution (DS = 0.87). Crystallinity of CMCd was found to decline after synthesis. The L* value of the CMCd decreased with increasing NaOH concentrations (20–40 g/100 mL). The trend of the a* and b* values varied inverses to the L* values. The CMCd films were prepared and tested, and the highest tensile strength (140.77 MPa) and WVTR (220.85 g/day·m2) were found using the 30 g/100 mL NaOH-synthesized CMCd film. The percent elongation at break of the different CMCd films was not to significantly differ.

Microwave assisted greener synthesis of nickel nanoparticles using sodium hypophosphite

Nickel nanoparticle (NiNP) was synthesized by reduction of less toxic nickel acetate tetrahydrate (Ni(CH3CO2)2·4H2O) precursor, using sodium hypophosphite monohydrate (NaPH2O2·H2O) under microwave irradiation. By varying the molar ratio of [Ni+2]/[NaPH2O2]/[NaOH], NiNP of 3.8 to 7.1nm was obtained. Increasing NaOH concentration resulted in morphological change from isolated spherical particles (7.2±1.5nm) to agglomerated nano flowers (72±14nm). Phase analysis and interplanar spacing measurements confirmed the particles as fcc-Ni. Quantitative analysis showed the presence of P and O due to HPO2− radical in reaction product. Addition of small amounts of polyvinylpyrolidone (PVP) or cetyltrimethylammonium bromide (CTAB) resulted in slight increase in particle size.

The solubility of Ca(OH)2 in extremely concentrated NaOH solutions at 25°C

Abstract The solubility of Ca(OH)2 in aqueous NaOH solutions up to 12.50 M at 25°C has been determined. The solubility data obtained for NaOH concentrations lower than 3 M was compared with those published in the literature. The solubility of Ca(OH)2 steadily decreases with the increasing NaOH concentration. The solubility data obtained at a constant ionic strength (I = 1 M Na(Cl,OH)) enabled the determination of the conditional solubility product of Ca(OH)2(s) (lgLCa(OH)2 = − 4.10 ± 0.02). Formation of the hydroxo complex CaOH+(aq) was invoked to describe the variation of [Ca2+]T with [OH−]T. Its conditional stability constant was found to be lgKCaOH+ = 0.97 ± 0.02. The experimental protocol employed was proven to be suitable for accurate solubility determinations in rapidly equilibrating systems comprising of highly concentrated, alkaline solutions and containing analytes in the ppm range.

The Effect of Oxygen and Hydroxide Ion on Electrochemical Leaching Behavior of Tin

The dissolution of tin from waste Pb-free solder was electrochemically investigated in NaOH solution. Two oxidation peaks were observed in a cyclic voltammetry test in 1 kmolm13 NaOH solution at less than 45°C, and the peaks indicate the oxidation of tin to Sn2+ and Sn2+ to Sn4+, whereas only one peak was observed at 75°C resulting from the direct oxidation of tin to Sn4+. The increase in NaOH concentration and the introduction of oxygen enhanced the dissolution of tin in NaOH solution with less than 0.5 kmolm13 whereas that of tin decreased with increasing NaOH concentration further to 1.5 kmolm13 and the decrease in the dissolution of tin was accelerated by introducing oxygen. An optimum waste solder alkaline electrolysis process was found to be at more than 75°C and around 0.5 kmolm13 NaOH based on the cyclic voltammetry and constant current experiment. [doi:10.2320/matertrans.M2012311]

Time-efficient microwave synthesis of Pd nanoparticles and their electrocatalytic property in oxidation of formic acid and alcohols in alkaline media

In this study time-efficient size controlled synthesis of stable Pd nanoparticles was carried out using microwave heating method by the decomposition of palladium chloride with glucose in aqueous medium using poly(ethyleneglycol) as capping agent. The benefit of the synthesis is that it was achieved in only 20 s. The synthesized Pd nanoparticles were characterized by UV–Visible spectroscopy, transmission electron microscopy, X-ray diffraction, and particle size analysis. The relative rates of electro-oxidation of formic acid, methanol and ethanol measured by cyclic voltammetry showed that efficiency of Pd nanoparticles as catalyst followed the order: formic acid < methanol < ethanol. The current–voltage characteristics improved with increase in either electrolyte (NaOH) or fuel concentrations but decreased with further increase in NaOH concentration.