Optimal Acid Research Articles

Studies on Applying Acid Compositions to Treat the Western Siberian Field Bottomhole Formation Zone

Effective development of oil deposits includes the measures to restore and improve the porosity and permeability properties (PPP) of reservoir units, which inevitably deteriorate during the operation of the field. For this purpose, various technologies of bottomhole formation zone acid treatment (BFZAT) are used. These approaches are sufficiently developed and usually do not require additional laboratory adaptation. Specific requirements for technologies that include acid effect on the formation are required for interventions on low-permeability reservoirs (LPR), where the influence of the mineralogical composition of rocks and their porosity and permeability properties on the efficiency of BFZAT is the most significant. Therefore, during interventions development for LPR using acid methods, it is necessary to correctly assess the capabilities of a particular method (composition) in relation to specific conditions. This can be achieved by conducting standard laboratory tests (determination of rock carbonation and mass loss in 12% hydrochloric acid) and additional experiments to determine the mass of the secondary sediment, as well as the optimum reaction time at the formation temperature. The research objective is a laboratory research on the selection of acid compositions for bottomhole formation zone treatment for a number of low-permeability reservoirs in Western Siberia. Standard and special laboratory studies have allowed suggesting the most optimum acid compositions adapted to “rigid” formation conditions.

Deep oxidation of ethanol over SiO2-supported MoV heteropoly acids modified with palladium

Silica-supported catalysts with Mo (MoV) heteropoly acids (HPAs) and their palladium-modified analogs were prepared and applied in deep oxidation of ethanol. The catalysts were characterized by elemental analysis MP-AES, nitrogen physisorption, FTIR, DR UV–vis spectroscopy, ESR, H2-TPR, NH3-TPD, and X-ray photoelectron spectroscopies. In the oxidation of ethanol, the supported MoV (Pd/MoV) catalysts were as active as common transition metal oxide catalysts (at space velocity 20 l g−1 h−1, the T50 temperature varied in the range from 126 to 179 °C). The Pd-modified Mo (MoV) catalysts showed slightly higher activity than the non-modified ones, but substantially improved selectivity towards the formation of undesirable reaction byproducts: formation of CH3CHO was decreased and CO was not formed at all. Thus, Pd/HPA/SiO2 materials, with their optimum acidity and high oxidation/reduction abilityare promising catalysts for the deep oxidation of alcohols.

Selective removal of copper and nickel ions from synthetic process water using predispersed solvent extraction

AbstractSelective predispersed solvent extraction and the stripping of copper and nickel ions from synthetic process water containing calcium ions was investigated, and the effect of four experimental parameters on extraction efficiency was studied. The extraction process was performed in two stages. In the first stage, maximum copper extraction was targeted with nickel extraction minimized. During the second stage, nickel was extracted from the remaining copper‐free aqueous solution and optimum experimental conditions for maximum nickel recovery were determined. In order to investigate the effect of experimental parameters (extractant concentration, phase volume ratio (PVR), equilibrium pH, and calcium concentration) on the nickel extraction, response surface methodology (RSM) was used. It was found that equilibrium pH, extractant concentration, and calcium concentration were the most significant factors on nickel extraction. While the first two factors had a positive effect, the latter one negatively affected the response. In order to selectively extract copper, the optimum range for the maximum extraction of copper with minimum nickel extraction was determined, which for any level of calcium concentration is an extractant concentration of 0.2–0.3 % (w/v), phase volume ratio of 2, and equilibrium pH of 2.5. Once copper ions were selectively removed from the process water, the optimum conditions for maximum nickel concentration were determined at three levels of calcium concentrations. Stripping experiments were also carried out, and the optimum acid concentrations of 10 and 5 g/L were determined for the stripping of copper and nickel, respectively.

Influence of sucrose addition and acid treatment of silica-supported Co-Ru catalysts for Fischer-Tropsch synthesis

This article highlights the formulation and evaluation of Co-Ru catalysts on silica used in Fischer-Tropsch synthesis. An acid treatment of the support associated with the addition of sucrose as a chelating agent was employed. The six formulated catalytic systems were characterized (TG, XRD, N2 adsorption, H2-TPR, H2 chemisorption) and evaluated in a fixed bed tubular reactor (H2/CO:2:1, 2 MPa, space velocity 4.5 × 10−2 LN.gcat−1·h−1) at five different temperatures (185 °C, 200 °C, 215 °C, 230 °C, 260 °C). The combination of both methods enhanced the cobalt dispersion, which is accompanied by an increase in C5+ hydrocarbon productivity. However, an optimum acid treatment is required to avoid large cobalt particle formation that leads to low CO conversion.

Preparation of Oligosaccharides by Degradation of Polysaccharides from Chinese Jujube and Its Biological Activity

This study examined the degradation of polysaccharides to oligosaccharides in Chinese jujube fruits. Using a response surface model, the degradation conditions of polysaccharides under acid hydrolysis and enzymatic hydrolysis were optimized in laboratory conditions. A degradation rate of 66.9% was obtained under optimum acid hydrolysis conditions: 0.6 mol/L hydrochloric acid, 3% substrate concentration, and 1 h reaction time. A degradation rate of 41.4% was obtained under optimum enzyme hydrolysis conditions: 4.0 mL cellulose solution (10 mg/mL), 0.3 mL substrate solution (20 mg/mL), 0.7 mL citric acid buffer solution (pH 5), and 7.3 h reaction time. Using the stimulation effect for strain J-4 intestinal probiotic proliferation, the biological activity of oligosaccharides was determined. The results showed that the oligosaccharides from enzyme hydrolysis encouraged intestinal probiotic proliferation.

Intrinsic affinity of acid-activated bentonite towards hydrogen and carbon dioxide

The effect of acid activation on bentonite affinity toward carbon dioxide (CO2) and hydrogen (H2) was investigated at ambient conditions. Characterization through X-ray diffraction and fluorescence, thermal gravimetric analysis, nitrogen adsorption-desorption isotherms, Fourier Transform Infrared spectroscopy and differential scanning calorimetry allowed correlating newly induced textural and structural features with adsorptive properties. Optimum acid treatment improved the specific surface area and porosity. The resulting decrease in dehydration temperature indicates decay in hydrophilic character. The affinity improvement towards hydrogen was due to Brønsted acidity suppression and surface basicity attenuation, which are essential requirements for adsorption on aluminosilicates (AS) via weak Lewis Acid-Base interactions, but excessive acid attack was detrimental. Low Si/Al surfaces should be suitable for CO2 capture, while moderately acid-treated clays should be interesting candidates as hydrogen adsorbents. This allows envisaging promising prospects for low-cost AS-based materials intended for selective CO2-free capture and storage of hydrogen without energy and safety constraints.

БУРОВЫЕ ШЛАМЫ И ПОВЫШЕНИЕ УРОЖАЙНОСТИ СЕЛЬСКОХОЗЯЙСТВЕННЫХ КУЛЬТУР

The laboratory vegetative chronic experiments, on the example of spring wheat, showed that reclaimed drill cuttings can be used for deoxidizing (liming) acidic soils, increasing the biomass yield in growing agricultural crops. Doses of drill cuttings providing long-term maintenance of optimum acidity of investigated soils are defined.

Fumaric Acid Production by Rhizopus oryzae ATCC® 20344™ from Lignocellulosic Syrup

Powdered activated carbon-treated lignocellulosic syrup prepared from energy cane bagasse was evaluated as a potential feedstock in the production of fumaric acid by Rhizopus oryzae ATCC® 20344™. Energy cane bagasse was pretreated with dilute ammonia and enzymatically hydrolyzed with commercially available enzymes, Cellic® CTec2 and HTec2. The collected hydrolysate samples were subjected to powdered activated carbon adsorption for the removal of non-sugar compounds (i.e., organic acids, furaldehydes, total phenolic compounds) and concentrated to a final 65°Bx syrup (mostly xylose and glucose sugars). The use of lignocellulosic syrup, the effect of nitrogen source, medium additives, and initial pH in the seed culture medium on fungal morphology were investigated. The carbon to nitrogen (C/N) ratio in the acid production medium was also optimized for maximum yields in fumaric acid production. Optimum seed culture medium conditions (2.0 g/L urea, 3.0 pH) produced the desired compact, smooth, and uniform fungal pellets. Optimum acid production medium conditions (400 C/N ratio, 0.2 g/L urea) resulted in a fumaric acid production of 34.20 g/L, with a yield of 0.43 g/g and a productivity of 0.24 g/L/h. These results were comparable to those observed with the control medium (pure glucose and xylose). The present study demonstrated that lignocellulosic syrup processed from dilute ammonia pretreated energy cane bagasse has potential as a renewable carbon source for fumaric acid fermentation by Rhizopus oryzae ATCC® 20344™.

Fermenting Saudi Wasted Dates by Using <i>Lactobacillus casei</i> (ATCC 393), <i>Acidophilus</i> (CICC 6088) and the Mixed-Culture Bacteria to Produce Lactic Acid

The Kingdom of Saudi Arabia produces over one million metric tons annually, which returns a 20% of wasted dates annually. Lactic acid and its derivatives are widely used in food, pharmaceutical and textile industries. There has been an increase in lactic acid production because it is used as a raw material to produce polylactic acid, a polymer that is used as a special medical and environmental friendly biodegradable plastic. This study aimed to use wasted dates to produce lactic acid by single culture Lactobacillus casei (ATCC 393), Lactobacillus acidophilus (CICC 6088) and the mixed culture using batch fermentation. The investigation results showed that the maximum concentration of lactic acid for ATCC 393, CICC 6088 and the mixed culture are 87, 84 and 84 g/l respectively. For single CICC 6088 and the mixed culture, the total percentage of glucose and fructose utilized was found to be 100%; 76%, respectively, whereas in the case of the single culture ATCC 393, the total percentage of glucose and fructose were 100% and 72%, respectively. With regard to lactic acid concentration, and sugar consumption, the results revealed that the single culture ATCC 393 produced the optimum lactic acid of 87 g/l for 48 hr with initial sugar concentration of 90 g/l.

Strategies for characterizing compositions of industrial pulp and paper sludge

The large quantities of waste sludge produced by the pulp and paper industry present significant environmental challenges. In order to minimize the amounts of waste, the pulp sludge should be utilized for productive applications. In order to find feasible solutions, the sludge need to be characterized. In this study, the potential of using acid pretreatment and ashing method to determine the chemical compositions of the sludge is investigated. This study shows that acid pretreatment could be used to dissolve and determine the composition of CaCO3 in the pulp sludge. CaCO3 removal also facilitates the measurement of fiber and ash (clay) contents by using the ashing method. The optimum acid concentration used to completely dissolve CaCO3 was determined using a titration method. Using this method, the measurement of the chemical composition of the sludge sample revealed that it consisted primarily of CaCO3 (55% w/w), clay (25%, w/w), and fibers (18%, w/w). Based on these chemical compositions, potential utilization for the sludge could be determined.

Effects of alkali metal oxides on crystallization behavior and acid corrosion resistance of cordierite-based glass-ceramics

MgO-Al2O3-SiO2-TiO2 glass-ceramics with 3mol% alkali metal oxides were prepared, and the 3mol% alkali metal oxides were induced by 3mol% Na2O only, 1.5mol% Na2O+1.5mol% Li2O, and 1.5mol% Na2O+1.5mol% K2O, respectively. Effects of alkali metal oxides on the crystallization behavior and acid corrosion resistance of the MgO-Al2O3-SiO2-TiO2 glass-ceramics were investigated. The results showed that μ-cordierite precipitated in the glass matrix firstly, and it changed into α-cordierite with the crystallization temperature increasing. Using K2O substitution of Na2O hindered the precipitation of cordierite, while the addition of Li2O promoted the precipitation of μ-cordierite at low temperatures. When the main crystalline phase was μ-cordierite, the acid resistance of the glass-ceramics was significantly improved compared with the base glass. With the main crystalline phase changing from μ-cordierite to α-cordierite, the acid resistance of the glass-ceramics became worse, which was related to the honeycomb structure of α-cordierite. When 1.5mol% Na2O was replaced by Li2O, the glass samples crystallized at 880°C showed the optimum acid resistance with the minimum weight loss ~0.096%.

Solvent-free “green” amidation of stearic acid for synthesis of biologically active alkylamides over iron supported heterogeneous catalysts

Stearoyl ethanolamine was synthesized by amidation of stearic acid with ethanolamine in solventless conditions. Iron containing heterogeneous catalysts supported on SiO2, Al2O3, Beta (BEA), ZSM-12 (MTW) and Ferrierite (FER) were used in this work. Sn-modified Ferrierite and H-Ferrierite were also studied for comparison. Fe-modified catalysts synthesized using solid state ion-exchange and evaporation impregnation methods, were thoroughly characterized with X-ray powder diffraction, scanning electron microscope, FTIR with pyridine, nitrogen adsorption, energy dispersive X-ray microanalysis and Mössbauer spectroscopy. The highest conversion was obtained with Fe-H-FER-20 at 140°C in 1h giving 61% conversion and 98% selectivity towards the desired amide. The catalytic performance in terms of turnover frequency per mole of iron was achieved with the catalyst exhibiting the largest amount of Fe3+ species, optimum acidity and a relatively low Brønsted to Lewis acid site ratio.

Association of nutritional parameters and survival in parenteral nutrition-supported (PN) gastrointestinal cancer patients.

10078 Background: PN is a major tool in managing nutritional challenges in cancer patients. However, a clear set of clinical and biochemical indices to determine PN application in cancer patients has not been developed. We assessed the association between PN related nutritional parameters and survival in a large group of gastrointestinal (GI) cancer patients. Methods: 1197 consecutive GI cancer patients who received PN support between 08/01/08 – 08/01/13 were reviewed. Height, weight, plasma glucose (baseline and within 48 hours after PN initiation), surgical history, and pharmacy data including PN contents (dextrose, amino acids, and fat) and non-PN dextrose or fat in drug administration were recorded. Body mass index (BMI), Ideal body weight (IBW), PN and non-PN Calorie, and nitrogen were calculated for analysis. Data were entered into a multivariate analysis controlling for age, gender, cancer site, and medical comorbidities. Results: Median BMI was 25.4. 70% of the patients had unsteady weight ( > 2.5% change) before PN initiation. The magnitude of weight change was inversely related to survival (HR 1.02), P < 0.001). Patients with BMI > 25 and < 7.5% weight change prior to PN initiation had the most favorable survival. Glycemic instability (maximum plasma glucose variation > 100mg/dL) was independently related to shorter survival (HR 1.53, P < 0.001). Total calorie by IBW (kcal/kg/day) (HR 0.97, P < 0.001), non-PN calorie % (HR 1.04, P < 0.001), and calorie to nitrogen ratio (kcal:g) (HR 1.02, P < 0.001) were all independently associated with overall survival. Conclusions: Lower BMI, weight instability, and glycemic instability were adversely associated with survival. Higher total PN calorie and amino acid support were associated with better survival. Higher non-PN calorie % was adversely related to survival. Future studies must focus on developing a set of indices incorporating independent prognostic clinical and biochemical factors in determining PN application and monitoring in cancer patients. Optimum calorie and amino acids in PN support for cancer patients also require further investigation.

Design of optimum response surface experiments for the adsorption of acetic, butyric, and oxalic acids on Amberlyst A21

ABSTRACTIn this study the adsorption equilibria of acetic, butyric, and oxalic acids onto Amberlyst A21 were investigated experimentally at 25°C. The process was optimized using response surface methodology (RSM). The time to reach the equilibrium state, effects of adsorbent amount, and initial acid concentrations on adsorption efficiency were investigated. Freundlich, Langmuir, and Temkin isotherms were applied to experimental data. The Freundlich isotherm revealed better results than the others. In addition to the main aim of this research, a statistical/mathematical approach – RSM – was utilized to simulate and determine the optimum conditions of acetic, butyric, and oxalic acids removal by Amberlyst A21 using three selected parameters (adsorbent dose, initial dye concentration, and type of acids). The significance of independent variables and their interactions were tested by the analysis of variance (ANOVA). The optimum acid concentration, amount of adsorbent, type of acid, and removal of acid (%) were found by desirability function to be 0.199 mol/L, 1.999 g, butyric acid, and 84.537%, respectively.

Removal of cesium by countercurrent solvent extraction with a calix[4]crown derivative

ABSTRACTA macrocyclic 1,3-di(1-dodecyloxy)-2,4-crown-6-calix[4]arene (DodCalix[4]C6) was synthesized and characterized. The extraction of Cs(I) and more than 10 typical metals with DodCalix[4]C6/octanol in HNO3 medium was investigated. DodCalix[4]C6 exhibited strong extraction ability and high selectivity for Cs(I) over others except for Rb(I). The optimum acidity in Cs(I) extraction was 3.0 M HNO3. The Cs(I) separation from a simulated highly active liquid waste by five-stage countercurrent extraction was performed. The extraction efficiency of Cs(I) for five-stage extraction was greater than 99%. The effective partitioning of Cs(I) by DodCalix[4]C6/octanol through multistage countercurrent extraction was achieved.

Assessment of Some Heavy Metals in the Dead Sea Mud and Treatment Optimization

ABSTRACTThis paper describes the experimental remediation of the Dead Sea mud and the quantitative determination of some heavy metals. Herein, two chelating agents were employed as extracting aqueous solution: ethylenediaminetetraacetic acid (EDTA) and citric acid. The study focused on the main known heavy metals that were reported previously to be in the Dead Sea mud, which are Co, Ni, Pb, Zn, and Cr. Findings had indicated that citric acid was efficient in the removal of the aforementioned heavy metals. Physicochemical parameters that were expected to affect the removal of metals in the Dead Sea mud were optimized. Those parameters were the chelating agent concentration, mixing time and speed, type of washing water, temperature, and pH. The results showed that the best removal of heavy metals from Dead Sea mud can be achieved under optimum citric acid concentration, 1.5 g/50 mL for treatment of 10 g mud. Optimum mixing speed and time were found to be 800 rpm and 1 hr, respectively. Regarding washing water, it was found that the use of the same water for repeated washing provided better removal percentages. pH values and temperature had effect on removal percentages of the heavy metals from mud. However, working at pH 7 and room temperature would provide convenient results for heavy metal removal.

Production and characterization of three-dimensional graphite nanoplatelets

Discovery of nanographitic structure of remarkable properties such as fullerenes, carbon nanotubes and three-dimensional graphite nanoplatelets (3D-GNPs) opens the door for potential applications in science and technology. In the present work, graphite intercalation compound (GIC) technique with different acids ratio has been optimized for exfoliated graphite nanoplatelets (EGNPs), and the same optimum acids ratio has been used to successfully produce 3D-GNPs of 10 graphene layers and 145-nm lateral size. Raman spectroscopy, SEM, HRTEM and DLS techniques have been used to evaluate the thickness and number of layers of both EGNPs and 3D-GNPs. A new empirical formula based on Raman analysis has been introduced for the first time to evaluate the number of graphene layers, and it has been verified by using SEM, HRTEM and DLS results. This formula has been tested as well by using experimental data from the literature and found to be consistence and trusty used up to 30 graphene layers. Also, lateral size of graphitic structure has been measured and then evaluated by Lotya formula based on DLS data. The suggested empirical formula along with Lotya formula will open the door in the future work for extensive trials of GIC till reach to monographene layer.

Phosphate solubilization and acid phosphatase activity of Serratia sp. isolated from mangrove soil of Mahanadi river delta, Odisha, India.

Phosphorus is an essential element for all life forms. Phosphate solubilizing bacteria are capable of converting phosphate into a bioavailable form through solubilization and mineralization processes. Hence in the present study a phosphate solubilizing bacterium, PSB-37, was isolated from mangrove soil of the Mahanadi river delta using NBRIP-agar and NBRIP-BPB broth containing tricalcium phosphate as the phosphate source. Based on phenotypic and molecular characterization, the strain was identified as Serratia sp. The maximum phosphate solubilizing activity of the strain was determined to be 44.84 μg/ml, accompanied by a decrease in pH of the growth medium from 7.0 to 3.15. During phosphate solubilization, various organic acids, such as malic acid (237 mg/l), lactic acid (599.5 mg/l) and acetic acid (5.0 mg/l) were also detected in the broth culture through HPLC analysis. Acid phosphatase activity was determined by performing p-nitrophenyl phosphate assay (pNPP) of the bacterial broth culture. Optimum acid phosphatase activity was observed at 48 h of incubation (76.808 U/ml), temperature of 45 °C (77.87 U/ml), an agitation rate of 100 rpm (80.40 U/ml), pH 5.0 (80.66 U/ml) and with glucose as a original carbon source (80.6 U/ml) and ammonium sulphate as a original nitrogen source (80.92 U/ml). Characterization of the partially purified acid phosphatase showed maximum activity at pH 5.0 (85.6 U/ml), temperature of 45 °C (97.87 U/ml) and substrate concentration of 2.5 mg/ml (92.7 U/ml). Hence the present phosphate solubilizing and acid phosphatase production activity of the bacterium may have probable use for future industrial, agricultural and biotechnological application.

Template Free Synthesis of Ni-Perovskite: An Efficient Catalyst for Hydrogen Production by Steam Reforming of Bioglycerol

Ni-based perovskite catalysts are prepared by two different methods and used as selective catalyst for hydrogen production from glycerol. The physicochemical properties of the catalysts were studied by X-ray diffraction, H2 temperature-programmed reduction, NH3 temperature-programmed desorption, N2 physisorption and TEM analysis. The effects of perovskite structure on the Ni particle size and acidity were studied, and the possibility of a nontemplate approach is examined. Steam reforming of bio-glycerol was carried out in a fixed bed down flow reactor at atmospheric pressure. The catalysts were compared with the Ni supported alumina; catalysts prepared with and without template were found to contain smaller nickel oxide particles and optimum acidity for good glycerol conversion and hydrogen selectivity. Under optimized reaction conditions, LaNiO3 (E) catalyst exhibited 72% glycerol conversion with 70% hydrogen selectivity. The Ni/Al2O3 catalyst with bigger nickel oxide particle size and moderately strong ...

Tailoring the catalytic activity of metal organic frameworks by tuning the metal center and basic functional sites

Optimum acidity and basicity of amine functionalized metal organic frameworks are important for condensation and cycloaddition reactions.