Influence Of Acetic Acid Concentration Research Articles

Chitosan‑g‑maleic acid for effective removal of copper and nickel ions from their solutions

Pollution of the environment associated with discharging the toxic heavy metals in water makes us focus the light to solve this problem. In continuation of our efforts, we aim in this work to utilize the graft copolymer (chitosan‑g‑maleic acid) to purify water from copper and nickel ions. The graft copolymer has been synthesized using gamma radiation and the grafting conditions have been optimized by studying the influence of acetic acid concentration (0.5–10% V/V), monomer concentration (5–17.5% w/v), chitosan concentration (0.25–2.5% w/v) and absorbed dose (0.5–5 kGy). FT-IR and TGA have been employed to characterize the graft copolymer. The metal ions uptake by the prepared graft copolymer was investigated and the influence of contact time, solution pH, polymer concentration, and metal ion concentration was studied. Adsorption kinetic models (pseudo-first-order, pseudo-second-order, and intra-particle diffusion equations) and adsorption isotherms (Langmuir, Freundlich, and Temkin equations) were also studied. It was found that the adsorption kinetics and isotherm agreed well with pseudo-second-order and Langmuir equations, respectively, indicating that the adsorption was chemisorption. The adsorption capacities of CTS‑g‑MA were 312.4 mg g−1 and 70.1 mg g−1 for Cu2+ and Ni2+, respectively. Effect of co-existence of other cationic ions on the adsorption capacity was also investigated.

Impact of Acetic Acid Concentration, Application Volume, and Adjuvants on Weed Control Efficacy

Acetic acid (CH3COOH) is produced naturally through anaerobic fermentation (vinegar) or synthesized through various industrial chemical methods. The primary components of vinegar are water and acetic acid. Acetic acid can destroy cell membranes, which then can result in plant tissue desiccation and plant death. Therefore, vinegar has the potential as a natural contact herbicide for the control of weeds in organically produced crops. Additional information is needed to determine the influence of acetic acid concentration, application volume, and adjuvants on weed control. Typically, household vinegar contains 5% acetic acid and greater acetic acid concentrations are available commercially. Field research was conducted in southeast Oklahoma (Lane, OK) to determine the effect of acetic acid concentrations, application volumes, and adjuvants on weed control efficacy. The factorial experimental design included three acetic acid concentrations (0, 5 and 20%), two sprayer application volumes (187 and 935 L/ha), three adjuvants (none, orange oil, and canola oil), and one weedy-check. The experiment was repeated twice. Visual weed cover and control ratings were collected 4 days after treatment. The experiment had very high weed densities with multiple grass and broadleaf weed species. The weedy check average weed cover percentages were 98% total weeds, 53% grass, 44% broadleaf weeds, 52% large crabgrass (Digitaria sanguinalis (L.), 25% carpetweed (Mollugo verticillata L.), and 14% cutleaf evening primrose (Oenothera laciniata Hill). Total weed control ranged from 0% control (no acetic acid) to 74% control (20% acetic acid, 935 L/ha, & canola oil). Acetic acid was more effective in controlling broadleaf weeds than in controlling grasses. Optimum total grass and crabgrass weed control occurred with 20% acetic acid applied at 935 L/ha, resulting in weed control that ranged from 44% to 63%. Broadleaf weed control was 84% or greater for plots receiving either 10% acetic acid applied at 935 L/ha or 20% acetic acid applied at 187 or 935 L/ha. In addition, 5% acetic acid applied at 187 L/ha provided good cutleaf evening primrose control (77% to 90%). When averaged across application volumes (187 and 935 L/ha) and adjuvants (none, orange oil, and canola oil), weed control increased for all species as acetic acid concentrations increased from 5% to 20%. When averaged across acetic acid concentrations and adjuvants, weed control increased as application volumes increased from 187 to 935 L/ha. Individual comparisons among adjuvants within acetic acid concentrations and application volumes showed little or no advantage to adding either orange oil or canola oil to vinegar spray solutions.

Preparation of mesoporous silica from a Nigerian talc ore by acetic acid treatment

A study on the preparation of porous silica from a Nigerian talc ore by acetic acid leaching was investigated. The initial and leached talc products were characterized by Energy Dispersive X-ray fluorescence EDXRF , X-ray diffraction XRD , Scanning Electron Microscopy SEM with Energy Dispersive spectroscopy EDS and the N2 adsorption techniques. The influence of acetic acid concentration, reaction temperature and particle size on the ore leaching kinetics were examined. The results of the dissolution rates were found to be significantly influenced by leachant concentration, temperature and decreasing particle size. The dissolution mechanism process followed the diffusion control shrinking core model with the calculated activation energy of 34.53 kJ/mol supporting the proposed mechanism. The leached product has a specific surface area increased to 2.056 m2 /g from the initial ore surface area of 0.15 m2 /g. At optimal leaching conditions, the pore size distribution calculated by Barret-Joyner-Halenda BJH method based on N2 gas isotherms showed the presence of peaks from micropores and mesopores formation, indicating the porous nature of the leached product.

<b>Effect of inhibitors on ethanol production by <i>Pichia stipitis</i> in a complex culture media

Biomass from lignocellulosic material constitutes a promising energy alternative and without competing with food production. However, pretreatments are required for conversion into sugars which release hexoses, pentoses and other sugars, coupled to inhibitors. Current analysis focuses on ethanol production with the three major inhibitors of lignocellulosic biomass pretreatment, namely, acetic acid, furfural and 5-hydroxymetilfurfural (HMF), and investigates the influence of a mixture of these inhibitors on fermentation by Pichia stipits , using commercial xylose as the only carbon source, through a full factorial 2 3 + 3 design of experiments (DOE). Fermentations were conducted in a laboratory scale, at 150 rpm and 72h, in a complex culture media with xylose and different inhibitor concentrations, based on the experimental analysis of sugarcane bagasse and 2.10 7 cell mL -1 of initial concentration of the microorganism. Experimental results showed a significant influence of acetic acid concentration, which must be at the lowest possible level, with no influence of furfural and hydroxymethyl furfural respectively up to concentrations 2.25 and 0.75 g L -1 .

Physicochemical Properties and Amino Acid and Functional Group Profiles of Gelatin Extracted from Bovine Split Hide Cured by Acid

Gelatin is natural substance obtained from the partial hydrolysis of collagen from animal skin, bones and connective tissue. This study examined the influence of acetic acid concentration on characteristics of gelatin extracted from bovine split hide. Bovine split hides were obtained from a local tannery and divided into three groups cured with 0.1, 0.3, or 0.5 M acetic acid for 24 h, followed by gradient extraction at 60, 70 and 80°C for 5 h each. Data were analyzed using a completely randomized design each treatment was replicated thrice. The results showed that the acetic acid concentration significantly affected the yield, ash content, pH and gel strength, but not the moisture, fat and protein content or viscosity of the resultant gelatin. Electrophoresis of gelatin proteins showed bands distribution between 25-40 kDa. The amino acid profile of the extracted gelatin was similar to that of collagen with a high level of hydroxyproline. Infrared spectroscopy showed the presence of O-H, C = O, C = C, C-H and C-O functional groups. The results suggest that gelatin extracted from bovine split hide cured with 0.5 M acetic acid provided the best physicochemical characteristics. Key words: Gelatin, bovine split hide, physical characteristic

Electrospinning of Gelatin/Poly (Vinyl Pyrrolidone) Blends from Water/Acetic Acid Solutions

Electrospinning is a versatile and efficient technique for obtaining polymeric microfibers and nanofibers with great potential for applications in tissue engineering, biosensors, filtration, wound dressings, controlled drug release and enzyme immobilization. Electrospun fibers are obtained by applying an electric field in a polymer solution resulting in non-woven fibrous mats with high surface area relative to volume and high porosity. In this work, the electrospinning of gelatin/poly(vinyl pyrrolidone) (PVP) blends was investigated. The polymers were electrospun from solutions containing different concentrations of water and acetic acid. Solutions were characterized by measuring the pH, electrical conductivity, surface tension and viscosity. The influence of acetic acid concentration in solution properties and its influence in the spinnability were investigated. The resulting non-woven membranes were characterized by using scanning electron microscopy (SEM), thermogravimetric analysis (TG) and cytotoxicity.

The Effects of Acetic Acid Concentration and Extraction Temperature on Physical and Chemical Properties of Pigskin Gelatin

This research was aimed to study the influence of acetic acid concentration and extraction temperature on physical and chemical properties of pigskin gelatin. The experiment used Completely Randomized Design (CRD) with two factors and three replicates of treatment. The first factor was concentration of acetic acid solution consisted of 3 levels (2, 4 and 6%). The second factor was extraction temperature consisted of 3 levels (50, 55 and 60 oC). The result showed that interaction of acetic acid and extraction temperature had no significant effect (P>0.05) on the gel strength, viscocity, protein content and pH value of pigskin gelatin. Pigskin gelatin with acetic acid concentration 2, 4 and 6% and extraction temperature up to 60oC had similar characteristics to the commercial gelatin. The optimum production was obtained from 4% acetic acid and temperature 55oC such as gel strength 134.22g/Bloom; viscocity.7.16 cP; protein content 88.56% and pH value 5.21.

Propene Acetoxylation in the Liquid Phase-influence of Technological Parameters and Pretreatment of the Catalyst Support on the Course of the Process

AbstractThe novel and more safe method for propene acetoxylation has been developed. The reaction is conducted in the liquid environment of acetic acid, which is also the one of the substrates for this process, in the presence of palladium catalyst supported onto activated carbon. The influence of acetic acid concentration, temperature and pretreatment of the carbon catalyst support on the selectivity of transformation to allyl acetate and propene conversion has been investigated. The influence of the parameters has been described using the following factors: the selectivity of transformation to allyl acetate in relation to propene consumed and degree of propene conversion. Preparation of the catalyst and its characteristics has been described. Catalysts were prepared by wet impregnation method and pelletized activated carbon was used as a support. Prepared catalysts were analysed using XRD, SEM-EDX and UV-VIS DRS methods. Carbon support was pretreated before impregnation due to the literature reports. Thus the final catalyst samples were different from one another in terms of quantity and degree of dispersion of active phase on the support surface. Activity of catalyst samples has been tested in propene acetoxylation as the one of reaction parameters.

Effect of the organic loading rate on the performance of anaerobic acidogenic fermentation of two-phase olive mill solid residue

A study of the effect of the organic loading rate (OLR) on the anaerobic acidogenic fermentation of two-phase olive mill solid residue (OMSR) derived from fruits with a low ripening index was carried out in a laboratory-scale completely stirred tank reactor at mesophilic temperature (35 degrees C). Eight experimental runs were carried out at OLRs of 3.2, 5.6, 7.4, 9.6, 11.0, 12.9, 14.0 and 15.1g T-COD/ld, which were equivalent to hydraulic retention times of 50.0, 28.8, 21.8, 16.9, 14.7, 12.4, 11.5 and 10.7d, respectively. The experimental results obtained demonstrated that the optimum value of OLR for the acidogenic fermentation process was 12.9 g T-COD/ld, for which a maximum production of acetic acid was achieved. It was found that inhibition of the process occurred at OLRs higher than 12.9 g T-COD/ld. This was characterized by a significant decrease in the acetic acid concentration in the effluent and an increase in the concentration of other volatile acids that may affect the methanogenic step. The process inhibition was also characterized by the plateau in the curves of the effluent substrate concentration versus the OLR applied. It was found that a first-order kinetics satisfactorily described the influence of non-acetic acid soluble organic matter concentration (S-COD( *)) on the rate of soluble organic matter conversion to acetic acid (R(S-COD)( *)), and the influence of acetic acid concentration (AcH) on the rate of acetic acid production (R(AcH)), while a potential equation type adequately described the influence of acetic acid concentration on the volumetric hydrogen production (R(ACH) ). The kinetic constant for soluble organic matter removal was 0.145 d(-1), while the constant for acetic acid formation was found to be 0.075 d(-1).

Nonaqueous capillary zone electrophoresis of synthetic organic polypeptides.

Poly(Nepsilon-trifluoroacetyl-L-lysine) was used as a model solute to investigate the potential of nonaqueous capillary electrophoresis (NACE) for the characterization of synthetic organic polymers. The information obtained by NACE was compared to that derived from size exclusion chromatography (SEC) experiments, and the two techniques were found to be complimentary for polymer characterization. On one hand, NACE permitted (i) the separation of oligomers according to their molar mass and (ii) the separation of the polymers according to the nature of the end groups. On the other hand, SEC experiments were used for the characterization of the molar mass distribution for higher molar masses. Due to the tendency of the solutes (polypeptides) to adsorb onto the fused-silica capillary wall, careful attention was paid to the rinsing procedure of the capillary between runs in order to keep the capillary surface clean. For that purpose, the use of electrophoretic desorption under denaturating conditions was very effective. Optimization of the separation was performed by studying (i) the influence of the proportion of methanol in a methanoVacetonitrile mixture and (ii) the influence of acetic acid concentration in the background electrolyte. Highly resolved separation of the oligomers (up to a degree of polymerization n of approximately 50) was obtained by adding trifluoroacetic acid to the electrolyte. Important information concerning the polymer conformations could be obtained from the mobility data. Two different plots relating the effective mobility data to the degree of polymerization were proposed for monitoring the changes in polymer conformations as a function of the number of monomers.

Modelling the influence of pH and organic acid types on thermal inactivation of Bacillus cereus spores

A model is proposed to describe the influence pH on the heat resistance of Bacillus cereus spores. In addition to the conventional z value, the effect of pH on the thermal resistance of spores is characterised by a z pH value ( z pH is the distance of pH from a reference pH*, which leads to a 10-fold reduction of D value). The type of organic acid used for acidifying the heating medium, influences the z pH value. For nine organic acids, a linear relationship between the calculated z pH value and its lower acid p K a is observed. This relationship showed that the acid form (dissociated or undissociated) modifies the thermal spore resistance in addition to the H + ion. The influence of acetic acid concentration on the D value at pH 7 shows the protective effect of the dissociated acid form on the heat resistance of spores. The acid concentration in the medium modified the heat resistance of spore and the z pH value.

Influence of acetic acid concentration on the solubilization of chitosan

This article concerns the protonation of chitosan in acetic acid aqueous solution with variable concentration. Comparison with HCl is also drawn. Potentiometry allows the determination of the degree of protonation and the pK0. Conductimetry and viscometry are combined to follow the role of protonation on solubilization of chitosan. Solubilization occurs for a degree of protonation around 0.5 as previously found for HCl.

Mechanistic investigations of the formation of TTF derivatives via the phosphonate way

We studied the influence of acetic acid concentration on the deamination and dephosphonylation of the adduct resulting of the nucleophilic reaction between adequate α-metalated phosphonate and imminium salt. to enhance the yield of such reactions in order to access efficiently a lot of unsymmetrical TTF derivatives. A mechanism is proposed for the formation of TTF, including steps, i1 to i-. The potential concurrent formation of phosphonate 1 and other by-products is also discussed.