Effect Of Hydrogen Ion Concentration Research Articles

Kinetic Analysis of Gluconacetobacter diazotrophicus Cultivated on a Bench Scale: Modeling the Effect of pH and Design of a Sucrose-Based Medium

Gluconacetobacter diazotrophicus is an endophytic bacterium that has shown important plant growth-promoting properties. During the growth of G. diazotrophicus with high carbon source concentrations, organic acids are produced, and pH decreases, thus inhibiting biomass growth. The objective of this work was to design a sucrose-based medium and perform a kinetic analysis of the batch submerged cultivation of this bacterium in a 3 L stirred-tank bioreactor without pH control. A mathematical model was proposed for representing G. diazotrophicus concentration, considering the inhibitory effect of hydrogen ion concentration. It comprises a biomass growth model, a specific growth rate expression that accounts for the inhibitory effect of hydrogen concentration, and a hydrogen model that represents the relationship between hydrogen and biomass concentrations. The sucrose-based medium proved its suitability for G. diazotrophicus growth. A higher biomass concentration (1.10 g/L) was obtained in a modified LGI-P medium containing 30 g/L sucrose with a three-fold increase in biomass production relative to the initial inoculation. The model allowed a satisfactory description of the experimental data obtained, and it could be used to design a cultivation strategy to maximize biomass production leading to the production of an alternative microbial inoculant for plant growth promotion of economically important crops.

Effect of temperature and pH on keratinophilic fungus Chrysosporium indicum in vitro conditions

Hyphomycetes includes keratinophilic, dermatophytes and non dermatophytes filamentous fungi. Keratinophilic fungi growth is effected by biotic and environmental factors. Evaluation of effect of pH and temperature as physical conditions was observed . In the present investigation the steps have been undertaken to study the effect of temperature and Ph on keratinophilic fungus Chrysosporium indicum in vitro condition. The study of fungus has specific range of favourable pH and temperature. The normal growth of chrysoporium inducing was observed between 250C to 350C, where maximum growth and speculation was observed at 30. There has been a drastic reduction in fungal growth below 100C or 150C and speculation and growth declined at above 350C. So, it is observed that between 25 0C to 350C fungal growth and sporulation occur favorably .Below 100C and above 350C did not favour the growth and reproduction of keratinophilic fungi. Effect of hydrogen ion concentration was observed particularly for Chrysosporium indicum. Favourable hydrogen ion concentration for mycelial growth was 7.00. In present study Chrysosporium indicum fungal hyphae growth was changed with pH and the maximum growth was found at the end of incubation day is about pH 7 to 7.5

Treatment of Industrial wastewater containing dye Sulphur Black 1 in presence of semiconductor Strontium Chromate

The paper reports a work done on photocatalytic degradation of an Industrial dye Sulphur Black 1 with the help of Strontium Chromate photocatalyst. The experiment was controlled by photocalayst, visible light and air. And also studied the effect of hydrogen ion concentration, dye concentration and quantity of catalyst on the photodegradation. The experiment observed by spectrophotometrically at definite time gape

Influence of Hydrogen Ion Concentrations on the Protein Mobility in Native-PAGE Buffers

The study demonstrates the effect of hydrogen ion concentrations (pH) of Tank Buffer (TB) and resolving gel buffer (RGB) in a native-PAGE system on protein samples. A pH range of 7.8 to 9.3 for RGB and 8.3 to 9.3 for TB were used. Proteins in the samples under native-PAGE at varying pH of RGB such as 7.8, 8.3 and 8.8 with pH of TB, 8.3 and 8.8 were resolved well. The total running time for the samples to reach the end of the dye front ranged between 2.30 h to 4.30 h at the above pH combinations. It was observed as 3.30 h as total running time under normal pH conditions (RGB, pH 8.8; TB, pH 8.3). At the same time, buffers at higher pH or the combination of extreme pH (7.8 vs. 9.3) in the buffers were not favored good protein mobility/resolution, and bands were diffused. Longer running time was observed in various combinations of pH of RGB and pH of TB with 18.00 h being a longest with a pH of 8.3 and 9.3 for RGB and TB, respectively. This indicated the importance of pH of electrophoresis buffers for ionization of various proteins for better separation.

Effect of hydrogen ion concentration and adsorbent dosage on the removal of heavy metals from metal scrap effluents using activated carbon from African palm fruit

This study details the production of activated carbon from African palm fruit and subsequent treatment of heavy metals; Cadmium, Copper, Nickel, and Lead in wastewater effluent with the produced activated carbon from a metal scrap market in the heart of Kaduna state, Nigeria, which constitutes high level of pollution in the environment. Hydrogen ion concentration and adsorbent dosage were determined on water treatment quality using Atomic Absorption Spectrophotometer (AAS). The produced activated carbon showed a significant ability in removing heavy metals; Cadmium, Copper, Nickel, and Lead from samples of the wastewater. Higher efficiencies were observed with increase in adsorbent dosage (99.73 ± 0.265, 95.96 ± 0.053, 99.91 ± 0.085, and 95.12 ± 0.035 % at 2.5 g for Cadmium, Copper, Nickel, and Lead, respectively) and at a pH of 6 (99.61 ± 0.182 and 80.31 ± 0.015 % for Cadmium and Lead, respectively) and at a pH of 8 ( 99.79 ± 0.201 and 99.73 ± 0.252 for copper and nickel respectively). This findings show that African palm fruit can be utilized to produce activated carbon used in removal heavy metals from effluent water, representing an effective means of utilizing agricultural residues and also an alternative to the expensive commercial activated carbon. Â

Effect of some physiological factors on citric acidproduction bythreeisolates ofAspergillus niger acid - hydrolyzed sawdust as a carbon source

Introduction: Citric acid (2-hydroxy-propane-1, 2, 3-tricarboxylic acid) was first isolated from lemon juice in 1784. It is a primary metabolic product which is formed in the tricarboxylic acid (Krebs) cycle. It is estimated that the market value of citric acid will exceed two billion dollars in 2019. About 70% of total citric acid produced globally is utilized in food industry, while about 12% is utilized in pharmaceuticals and cosmetic industries and the remainder in other industrial purposes. The industrial production of citric acid is undertaken by fermentation process in the presence of filamentous fungi for large scale of production. Aspergillus niger is the most efficient fungus due to its ability to produce more citric acid per unit time and ferment different inexpensive raw materials. Materials and Methods: Three isolates of the fungus Aspergillus niger (An1, An2, An3) were used throughout this study using different carbon source concentration in the form of sawdust acid hydrolysis supplemented with different concentration of (NH4)2H2SO4 as a nitrogen source. The effect of hydrogen ion concentration and addition of methanol to the fermentation medium was also investigated. Results and Discussion: The results indicated that the optimization of carbon and nitrogen concentration had stimulatingeffect on citric acid production by the three used isolates. Moreover, addition of methanol at concentration of 1% at pH of 3.5 highly increased citric acid production. Conclusion: we concluded that the agriculture waste was a favorable substrate for the production of citric acid especially it is cost effective and easily obtainable.

Comprehensive evaluation on effective leaching of critical metals from spent lithium-ion batteries

Recovery of metals from spent lithium-ion batteries (LIBs) has attracted worldwide attention because of issues from both environmental impacts and resource supply. Leaching, for instance using an acidic solution, is a critical step for effective recovery of metals from spent LIBs. To achieve both high leaching efficiency and selectivity of the targeted metals, improved understanding on the interactive features of the materials and leaching solutions is highly required. However, such understanding is still limited at least caused by the variation on physiochemical properties of different leaching solutions. In this research, a comprehensive investigation and evaluation on the leaching process using acidic solutions to recycle spent LIBs is carried out. Through analyzing two important parameters, i.e. leaching speed and recovery rate of the corresponding metals, the effects of hydrogen ion concentration, acid species and concentration on these two parameters were evaluated. It was found that a leachant with organic acids may leach Co and Li from the cathode scrap and leave Al foil as metallic form with high leaching selectivity, while that with inorganic acids typically leach all metals into the solution. Inconsistency between the leaching selectivity and efficiency during spent LIBs recycling is frequently noticed. In order to achieve an optimal status with both high leaching selectivity and efficiency (especially at high solid-to-liquid ratios), it is important to manipulate the average leaching speed and recovery rate of metals to optimize the leaching conditions. Subsequently, it is found that the leaching speed is significantly dependent on the hydrogen ion concentration and the capability of releasing hydrogen ions of the acidic leachant during leaching. With this research, it is expected to improve understanding on controlling the physiochemical properties of a leaching solution and to potentially design processes for spent LIBs recycling with high industrial viability.

Electrocatalitic Detection of Hydrazine Using Chemically Modified Electrodes with Cobalt Pentacyanonitrosylferrate Adsorbed on the 3–Aminopropylsilica Surface

Cobalt pentacyanonitrosylferrate on the aminopropylsilica silica gel surface (SiCoNP) was previously prepared following two steps. The electrochemical behavior of SiCoNP modified electrode showed two redox couples, the first and second redox couples were observed at anodic potential (Epa)1 = 0.36 and 0.60 V vs. Ag/AgCl attributed to the oxidation of Co(II) to Co(III) and Fe(II)(CN)5NO/Fe(III)(CN)5NO, respectively. The modified carbon paste electrode with SiCoNP was tested in the hydrazine electrooxidation. In the hydrazine electrooxidation, the H+ release was observed and the two metal centers are involved in this process. The proposed mechanism has been described and based on studies of the effect of hydrogen ion concentration in the redox process of bivalent compound formed. Thus a large increase in hydrogen ion concentration promotes the formation of an intermediate electroactive species with an anodic peak at 0.56 V. The nature of this species is not well established but may be related to protonation of cyanide or NO groups present. The modified graphite paste electrode presented a limit of detection of 2.38×10-4 mol L-1 and amperometric sensitivity of 1.37×10-6 A.mol-1.L.

Unraveling the Nature of Interaction between Substituted Phenol and Amiodarone

A comprehensive study of the interaction between nitrophenols (π-acceptors) and amiodarone (AM) was performed using electronic absorption spectra. The key point is to clarify the erroneous interpretation of the interaction between nitrophenols and one of the basic organic drugs. Matching of the experimental UV-vis spectra and the theoretical ones obtained by DFT calculations revealed that the tertiary amino group of AM reacts with the phenol compounds under investigation via proton-transfer but not charge-transfer (C.T.) mechanisms, unlike what is commonly known about this type of interaction. The interaction was carried out in solutions of different basic pH values to study the effect of hydrogen ion concentration on the reaction. The results show that the reaction is a simple acid-base reaction. As a result, this reaction cannot be used by analytical chemists for determination of one of the studied compounds due to its very low selectivity. TD-DFT as well as geometry optimization of the nitrophenols were calculated with the B3LYP functional, using aug-cc-pvDZ and LanL2DZ as basis sets for ionic and neutral compounds, respectively. The theoretical spectra of possible interactions between AM and nitrophenols result in the same spectra of ionized nitrophenols alone, indicating no possibility for the formation of charge-transfer complexes.

Kinetics of xylose in hydrolysate using dilute sulphuric acid as catalyst

In the technology of manufacturing fuel alcohol from biomass as feedstock, hydrolysis using dilute acid as catalyst is one way to produce fermentable saccharide. In this process, the yield of xylose is always low because of the degrading during the acid environment. In this paper, the degrading kinetics of xylose in the hydrolysate was investigated under the conventional process conditions of the hydrogen ion range from 0.05 to 0.2 mol L−1 and the temperature range from 150 to 200°C. Through the numerical calculation method, the kinetic parameters were estimated and the activation energy of xylose in the degrading reaction was obtained. The kinetic equations that correlated the effect of hydrogen ion concentration on the rate constants of the degrading reaction were established. Comparisons between calculated results and the experimental results have proved that the established kinetic model can satisfactorily predict the degradation behaviours of xylose in the acidic hydrolysate.

Kinetics of xylose in hydrolysate using dilute sulphuric acid as catalyst

In the technology of manufacturing fuel alcohol from biomass as feedstock, hydrolysis using dilute acid as catalyst is one way to produce fermentable saccharide. In this process, the yield of xylose is always low because of the degrading during the acid environment. In this paper, the degrading kinetics of xylose in the hydrolysate was investigated under the conventional process conditions of the hydrogen ion range from 0.05 to 0.2 mol L−1 and the temperature range from 150 to 200°C. Through the numerical calculation method, the kinetic parameters were estimated and the activation energy of xylose in the degrading reaction was obtained. The kinetic equations that correlated the effect of hydrogen ion concentration on the rate constants of the degrading reaction were established. Comparisons between calculated results and the experimental results have proved that the established kinetic model can satisfactorily predict the degradation behaviours of xylose in the acidic hydrolysate.

Studies on the oxygen atom transfer reactions of peroxomonosulfate: Oxidation of glycolic acid

AbstractThe kinetics of oxidation of glycolic acid, an α‐hydroxy acid, by peroxomonosulfate (PMS) was studied in the presence of Ni(II) and Cu(II) ions and in acidic pH range 4.05–5.89. The metal glycolate, not the glycolic acid (GLYCA), is oxidized by PMS. The rate is first order in [PMS] and metal ion concentrations. The oxidation of nickel glycolate is zero‐order in [GLYCA] and inverse first order in [H+]. The increase of [GLYCA] decreases the rate in copper glycolate, and the rate constants initially increase and then remain constant with pH. The results suggest that the metal glycolate ML+ reacts with PMS through a metal‐peroxide intermediate, which transforms slowly into a hydroperoxide intermediate by the oxygen atom transfer to hydroxyl group of the chelated GLYCA. The effect of hydrogen ion concentrations on kobs suggests that the structure of the metal‐peroxide intermediates may be different in Ni(II) and Cu(II) glycolates. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 41: 160–167, 2009

Effect of Hydrogen Ion Concentration and Electrostatic Polarity on Food Powder Coating Transfer Efficiency and Adhesion

Two kinds of soy protein isolate, rice protein, whey protein isolate, albumen, bovine collagen hydrolysate, NaCl, and corn starch were used in this study. Solutions were prepared by mixing the powder and distilled water (1:8 ratio) and either H(2)SO(4) or NH(4)OH to obtain pH 3, 5, 7, 9, and 11. The solutions were dried to produce powders with different hydrogen ion concentrations and the powders were ground. Powders were coated nonelectrostatically and using negative and positive polarity corona electrostatically. There was no solution pH effect on transfer efficiency or adhesion for most powders. However, transfer efficiency and density of both of the soy protein isolates and corn starch changed with solution pH. Solution pH may have affected the density, which affected the transfer efficiency for these powders. Adhesion and cohesiveness of one of the soy protein isolates and corn starch also changed with solution pH. Solution pH may have affected the cohesiveness, which affected the adhesion for these powders. Negative and positive coronas produced the same results for most powders, with no solution pH effect, except for one of the soy protein isolates, rice protein, and corn starch. These powders accumulated on the electrode wires during negative corona electrostatic coating, reducing transfer efficiency and adhesion. This polarity effect was intermittent, implying it is due to tribocharging.

Studies of the Rate Constant of Levodopa Methyl Ester Hydrolysis by LC

This paper investigates the hydrolysis kinetics of levodopa methyl ester in 0.05–1.5 M HCl between 37 and 75°C. An isocratic HPLC assay was developed for simultaneous determination of levodopa methyl ester and levodopa in the hydrolysate of levodopa methyl ester. A series of hydrolysis rate constants were obtained and the effects of hydrogen ion concentration and temperature on the reaction were evaluated. It was found that pH was a key factor at low temperature, but that when the temperature was raised, temperature became in turn the most influent factor on the hydrolysis. From the measured pseudo-first order reaction rate constants, the activation energy for levodopa methyl ester hydrolysis in 0.5, 1.0 and 1.5 M HCl were calculated to be 71.24, 74.32 and 76.57 kJ mol−1, respectively.

Effect of hydrogen-ion concentration on stability of 1 : 1 complex of iron(III) with salicylic acid and its different derivatives

The stability constant of 1 : 1 Fe I I I complex of salicylic acid and ten other derivatives of the ligand was determined by spectrophotometric method developed in this laboratory at different pH values, after taking careof hydrolysis of Fe I I I . It was found that during complex formation both hydroxyl and carboxyl group releases the hydrogen ion.

THE SORPTION OF COBALT FROM AQUEOUS SOLUTIONS BY POTASSIUM NICKEL HEXACYANOFERRATE COMPLEX

ABSTRACT The inorganic complex, potassium nickel hexacyanoferrate, KNiFC, was used for the separation of cobalt from diluted nitric acid aqueous solutions using the batch technique. The effect of hydrogen ion concentration on the distribution coefficient of cobalt has been studied in the pH range 2–5.5. The effect of particle size and temperature on the sorption isotherm and rate of uptake of cobalt were investigated. The increase of temperature was found to enhance the sorption equilibrium and rate of uptake. The diffusivity of cobalt ions into different particle sizes of KNiFC was calculated. The effect of the presence of cesium ions on the rate of uptake of cobalt is presented.

Removal of Cr 6+ and Ni 2+ from aqueous solution using bagasse and fly ash

Raw bagasse and fly ash, the waste generated in sugar mills and boilers respectively have been used as low-cost potential adsorbents. Raw bagasse was pretreated with 0.1N NaOH followed by 0.1N CH 3COOH before its application. These low-cost adsorbents were used for the removal of chromium and nickel from an aqueous solution. The kinetics of adsorption and extent of adsorption at equilibrium are dependent on the physical and chemical characteristics of the adsorbent, adsorbate and experimental system. The effect of hydrogen ion concentration, contact time, sorbent dose, initial concentrations of adsorbate and adsorbent and particle size on the uptake of chromium and nickel were studied in batch experiments. The Sorption data has been correlated with Langmuir, Freundlich and Bhattacharya and Venkobachar adsorption models. The efficiencies of adsorbent materials for the removal of Cr(VI) and Ni(II) were found to be between 56.2 and 96.2% and 83.6 and 100%, respectively. These results were obtained at the optimized conditions of pH, contact time, sorbent dose, sorbate concentration of 100 mg/l and with the variation of adsorbent particles size between 0.075 and 4.75 mm. The order of selectivity is powdered activated carbon>bagasse>fly ash for Cr(VI) removal and powdered activated carbon>fly ash>bagasse for Ni(II) removal.

Effect of hydrogen ion concentration and buffer composition on ligand binding characteristics and polymerization of cow's milk folate binding protein.

The ligand binding and aggregation behavior of cow's milk folate binding protein depends on hydrogen ion concentration and buffer composition. At pH 5.0, the protein polymerizes in Tris-HCl subsequent to ligand binding. No polymerization occurs in acetate, and binding is markedly weaker in acetate or citrate buffers as compared to Tris-HCl. Polymerization of ligand-bound protein was far more pronounced at pH 7.4 as compared to pH 5.0 regardless of buffer composition. Binding affinity increased with decreasing concentration of protein both at pH 7.4 and 5.0. At pH 5.0 this effect seemed to level off at a protein concentration of 10(-6) M which is 100-1000 fold higher than at pH 7.4. The data can be interpreted in terms of complex models for ligand binding systems polymerizing both in the absence or presence of ligand (pH 7.4) as well as only subsequent to ligand binding (pH 5.0).

Equilibrium and kinetic studies of the sorption of cesium by potassium nickel hexacyanoferrate complex

Sorption of cesium from nitric acid medium by potassium nickel hexacyanoferrate, KNiFC, was investigated using the batch technique. The effect of hydrogen ion concentration on the distribution coefficient of cesium has been studied in the pH range 1–5.5. The effect of particle size, the temperature on the sorption equilibrium and rate of uptake of cesium were investigated. The temperature effect on both sorption equilibrium and rate of uptake was found to be limited. The kinetic study shows that the sorption is controlled by particle diffusion mechanism. The diffusitivity of cesium ions into different particle sizes of KNiFC, the activation energy, and the entropy change of the sorption process were calculated. The effect of the presence of cobalt ions on the equilibrium and the rate of uptake of cesium is presented.

Responses to different levels of esophageal acidification during waking and sleep.

The purpose of this study was to assess the effect of hydrogen ion concentration of intraesophageal infusions during sleep on acid clearance time and latency to swallow and arousal responses from sleep. We studied 10 normal volunteers during sleep via polysomnography and concomitant esophageal pH monitoring. Sleep prolonged the acid clearance time of both pH 3.0 and 1.2. Swallow and arousal latencies were both progressively decreased with decreasing pH of the infusate (P < 0.05, 0.07, respectively). We concluded that intraluminal hydrogen ion concentration creates an afferent warning stimulus that produces prompt airway-protective responses.