scholarly journals One-Time Acidification of Slurry: What Is the Most Effective Acid and Treatment Strategy?

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1319
Author(s):  
Veronika Overmeyer ◽  
Anita Kube ◽  
Joachim Clemens ◽  
Wolfgang Büscher ◽  
Manfred Trimborn
Keyword(s):  
Sulfuric Acid ◽  
Organic Acids ◽  
Ph Value ◽  
Treatment Strategies ◽  
Storage Conditions ◽  
Ph Values ◽  
Mineral Acids ◽  
Ph Increase ◽  
Anaerobic Storage

Acidification of slurry is a common practice to reduce ammonia and methane emissions. Sulfuric acid is usually used for this process. However, this has been criticized due to the high sulfur input into soils. Therefore, the objective of this study is to show the effectiveness of a one-time acidification with alternative acids also in combination with other treatment strategies. The amount of acid as well as the change of pH value during storage were investigated. For most variants, a strong pH increase occurred within the first ten days after acidification. Mineral acids (sulfuric or hydrochloric acid) resulted in a lower pH increase compared to organic acids (lactic, acetic, and citric acid). Under anaerobic storage conditions, the pH remained significantly lower. The addition of glucose before acidification resulted in lower pH values during the first week, but in the long term, the conversion of glucose to carbonate led to higher pH values. A previous separation process was able to reduce the amount of acid. Although the pH increase was not that strong in the first days after acidification, it was much faster and stronger afterwards due to the lower buffer capacity in the separated slurry. A long-term pH reduction was achieved by acidification to pH 3.0, but this was associated with an increased amount of acid. On the basis of the results, a combination of organic acids with anaerobic storage can be recommended as an alternative to sulfuric acid.

Long-term stability of ready-to-use 1-mg/mL midazolam solution

2020 ◽  
Vol 77 (9) ◽  
pp. 681-689
Author(s):  
Sixtine Gilliot ◽  
Morgane Masse ◽  
Frédéric Feutry ◽  
Christine Barthélémy ◽  
Bertrand Décaudin ◽  
...  
Keyword(s):  
High Performance ◽  
Detection Method ◽  
Degradation Products ◽  
Storage Conditions ◽  
Target Concentration ◽  
Long Term Stability ◽  
Ph Values ◽  
Particle Contamination ◽  
The Stability

Abstract Purpose Midazolam is a benzodiazepine derivative commonly used in intensive care units to control sedation. Its use requires dilution of a 5-mg/mL commercial solution to a target concentration of 1 mg/mL. A study was conducted to evaluate the stability of diluted ready-to-use 1-mg/mL midazolam solutions over 365 days when stored in cyclic olefin copolymer vials or polypropylene syringes. Methods A specific stability-indicating high-performance liquid chromatography coupled with UV detection method was developed for midazolam hydrochloride and validated for selectivity, linearity, sensitivity, precision, and accuracy. Three storage conditions were tested: –20°C ± 5°C, 5°C ± 3°C, and 25°C ± 2°C at 60% ± 5% relative humidity. Half of the vials were stored upside down to test for the absence of interaction between midazolam and the stopper. Particle contamination, sterility, and pH were assessed. Results The limit of stability was set at 90% of the initial concentration. After 1 year’s storage at –20°C and 5°C, concentrations remained superior to 90% under all storage conditions. At 25°C, stability was maintained up to day 90 in syringes (mean [SD], 92.71% [1.43%]) and to day 180 in upright and upside-down vials (92.12% [0.15%] and 91.57% [0.15%], respectively). No degradation products were apparent, no variations in pH values were detected, and containers retained their sterility and conformity with regard to any specific contamination during the study. Conclusion The evaluated 1-mg/mL midazolam solution was stable over a 1-year period when stored at a refrigerated (5°C) or frozen (–20°C) temperature in both vials and syringes; with storage at 25°C, the stability duration was lower. The preparation of ready-to-use midazolam solutions by a hospital pharmacy is compatible with clinical practice and could help to decrease risks inherent in dilution in care units.

scholarly journals Changes in the Physicochemical Quality Characteristics of Cabbage Kimchi with respect to Storage Conditions

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Su-Yeon You ◽  
Ji-Su Yang ◽  
Sung Hyun Kim ◽  
In Min Hwang
Keyword(s):  
Organic Acids ◽  
High Performance ◽  
Room Temperature ◽  
Gradual Increase ◽  
Storage Period ◽  
Storage Conditions ◽  
Quality Characteristics ◽  
Analytical Technique ◽  
Ph Values ◽  
Organic Acid Content

In this study, the changes in pH, organic acid content, acidity, and salinity of kimchi prepared at 0 days, stored 1–8 weeks at 4 and 10°C, and stored at room temperature for two days were analyzed. Organic acids content was analyzed by using analytical technique of high-performance liquid chromatography (HPLC). This method was also validated using quality assurance parameters of linearity, limits of detection and quantification (LOD and LOQ), precision, and spike recovery experiments. In the analysis of organic acids content (mg/kg), it was found that the kimchi stored for 1–8 weeks at 4 and 10°C showed gradual increase in the organic acids content during storage period. The order of organic acids was lactic acid > acetic acid > citric acid > malic acid > succinic acid > oxalic acid > fumaric acid. The pH values of kimchi stored at 4°C, 10°C, and 25°C were 4.1, 3.6–3.7, and 4.1, respectively.

Effects of Microorganisms Growth on the Long-Term Stability of Cement and Bitumen

1992 ◽  
Vol 294 ◽  
Author(s):  
Marie F. Libert ◽  
R. Sellier ◽  
G. Jouquet ◽  
M. Trescinski ◽  
H. Spor
Keyword(s):  
Organic Acids ◽  
Nuclear Waste ◽  
Long Term Stability ◽  
Mineral Acids ◽  
Ph Conditions ◽  
Waste Repositories ◽  
Coating Matrix ◽  
Geological Formations ◽  
Growth Of Fungi

ABSTRACTCement is used as a coating matrix for nuclear waste or as an engineered barrier of waste repositories situated in geological formations.The effect of mineral acids excreted by bacteria (Thiobacillus) or organic acids produced by fungi, on the biodegradation of cement is discussed. Organic acids are quantitatively and qualitatively determined during growth of fungi over a two-year period. Even with high pH conditions, pH of the cement ≈ 11, growth of microorganisms occurs.Biodeterioration of cement is expressed in terms of bioleaching velocity of calcium and is observed by electron microscopy.

scholarly journals Change of acidity of the environment in the process of decomposition of apatitis sulfuric acid

2019 ◽  
Vol 81 (1) ◽  
pp. 325-328
Author(s):  
R. F. Sabirov ◽  
A. F. Makhotkin ◽  
Yu. N. Sakharov
Keyword(s):  
Sulfuric Acid ◽  
Phosphoric Acid ◽  
Ph Value ◽  
Raw Materials ◽  
Batch Reactor ◽  
Glass Electrode ◽  
Monocalcium Phosphate ◽  
Rapid Decomposition ◽  
Ph Values ◽  
Phosphoric Acids

An experimental study of the decomposition process of Kovdorsky apatite with certain particle sizes, in a 1 dm3 batch reactor with stirring of the reaction mixture, initial phosphoric acid concentration 17% by weight, in the system: Apatite-H3PO4 – H2SO4-H2O. Sulfuric acid was introduced in stoichiometric amount at the beginning of the process. The process was carried out at a ratio L:S 2.5:1, at a temperature of 78– 82 °C. The process was monitored by the method of joint determination of sulfuric and phosphoric acids by titrimetric analysis of the composition of the reaction mixture in the presence of methyl orange, and then phenolphthalein. Determined the concentration of phosphoric acid, the concentration of excess or deficiency of sulfuric acid and the concentration of monocalcium phosphate gel were determined. The acidity of the reaction mixture was recorded according to the indications of a Ph-meter (pH-105 MA with a combined glass electrode – ESK-10603). In the system: Apatite-H3PO4-H2SO4-H2O, when analyzing the obtained experimental values of these parameters, it was shown that during the process the pH of the reaction mixture rises to pH 6.3 for about 30 minutes, and then decreases to pH 4.5–5. Comparison of the dependence of pH values on the concentration of sulfuric acid in an aqueous solution of phosphoric acid and the pH values of the reaction mixture with the corresponding concentrations of sulfuric and phosphoric acids shows that the pH value of the reaction mixture is determined by the presence in the mixture between weft product - monocalcium phosphate gel. The process of decomposition of apatite in the system Apatite-H3PO4-H2SO4-H2O proceeds in several stages. At the beginning, a rapid decomposition of phosphate raw materials with phosphoric acid and a corresponding change in the pH of the reaction mixture, associated with the accumulation of monocalcium phosphate in solution, takes place. Then there is a slow decomposition of monocalcium phosphate with sulfuric acid and a corresponding decrease in pH to 4.5–5. The pH value at the end of the process is determined by the physicochemical properties of phosphoric acid present in the reaction mixture. At all stages of the process there is a constant increase in the concentration of phosphoric acid associated with the decomposition of monocalcium phosphate gel.

Influence of Fly Ash and Silica Fume on Anti-Corrosion Characteristics of Mortar in Sulfuric Acid

2011 ◽  
Vol 261-263 ◽  
pp. 306-312
Author(s):  
Hong Guang Min ◽  
Zhi Gang Song ◽  
Yan Tao Li ◽  
Yi Jie Shen
Keyword(s):  
Sulfuric Acid ◽  
Fly Ash ◽  
Silica Fume ◽  
Partial Correlation ◽  
Ph Value ◽  
Immersion Test ◽  
Replacement Ratio ◽  
Acid Consumption ◽  
Binder Ratio

A long term immersion test of mortar in sulfuric acid is carried out to investigate the effects of fly ash (FA) and silica fume (SF) on anti-corrosion characteristics. The mortar specimens have water to binder ratios (W/B) ranging from 0.5 to 0.7 and are divided into two series. Series one uses admixture of FA with replacement ratio from 0~0.3 and series two uses admixture of SF with replacement ratio from 0~0.1. The specimens are soaked in sulfuric acid with a pH value of 3.50 for 150 days. The portable pH meter is used to monitor the pH changing of the soak solution. The titrating sulfuric acid with concentration of 0.125mol/l is added to maintain the original pH value of the solution and then sulfuric acid consumption of specimens is recorded. A partial correlation analysis of experiment results shows that the effects of FA and SF on mortar resistance to sulfuric acid would change with the water binder ratio.

scholarly journals Effect of low oxygen storage conditions on volatile emissions and anaerobic metabolite concentrations in two plum fruit cultivars

2010 ◽  
Vol 37 (No. 4) ◽  
pp. 145-154 ◽  
Author(s):  
J. Goliáš ◽  
P. Hic ◽  
J. Kaňová
Keyword(s):  
Organic Acids ◽  
Storage Conditions ◽  
Relative Difference ◽  
Oxygen Storage ◽  
Harvest Time ◽  
Long Term Effects ◽  
Low Oxygen ◽  
Metabolite Concentrations ◽  
Low Oxygen Concentration

By harvest time, small amounts of acetaldehyde were accumulated in the flesh of plums, such as 0.31 mg/l for the cv. Stanley and 1.03 mg/l for the cv. Valjevka. This relative difference in concentrations remained constant throughout the whole period of storage in a regular atmosphere. The long-term effects of higher concentrations of CO<sub>2</sub> are the same as for very low oxygen concentrations; and significant amounts of ethanol accumulate in the tissue. Out of a total number of 42 different odour compounds identified in the juice, there were 11 alcohols, 6 aldehydes, 17 esters, 2 terpenes, 3 organic acids, and 1 lactone. Very low oxygen atmospheres slow down the production of esters and aldehydes, but have little effect on the production of lactones and terpenes. It was shown that a very low oxygen concentration, without much CO<sub>2</sub> (Fluctuating anaerobiosis treatment), does not encourage the production of significant amounts of ethanol and acetaldehyde in the fruit flesh, but does significantly slow the biosynthesis of aromatic volatiles.

scholarly journals Application of Different Organic Acids on Phosphorus Solubility from Rock Phosphate

2018 ◽  
Vol 2 ◽  
pp. 43-48 ◽  
Author(s):  
Aftab Jamal ◽  
Azam Khan ◽  
Muhammad Sharif ◽  
Hifsa Jamal
Keyword(s):  
Citric Acid ◽  
Humic Acid ◽  
Oxalic Acid ◽  
Organic Acids ◽  
Rock Phosphate ◽  
Ph Value ◽  
Ph Values ◽  
P Concentration ◽  
Extractable P ◽  
Oxalic Acids

An incubation experiment was conducted on P solubilization from rock phosphate (RP) through different organic acids such as oxalic acid, citric acid, acetic acid, humic acid and sulphur in the laboratory of the Department of Soil and Environmental Sciences, KP Agricultural University Peshawar during fall 2011. The experiment was laid in a complete randomize design. There were three replications with six treatments. The organic acids were used at the rate of 2 % for 50 g RP in 250 ml conical flasks. These samples were kept in an incubator at 250c for four months and analysed for Mehlic-3 extractable P and pH values after 20 days interval. Statiscal analyses were made and maximum P concentration of 1.52% was observed in the treatment of oxalic acid mixed with RP followed by the treatments of RP mixed with humic acid with P concentration of 0.368% (Fig. 1). Rapid increases in P solubility from RP by mixing with oxalic acids were noted up to 60thdays of incubation period and then remained stable after this period. Solubilization of P from RP by mixing with other organic acids was inconsistent. The pH in treatment of citric acid mixed with RP was noted as 5.64, followed by the treatments of oxalic acid with pH values of 6.31. A dramatic increase in pH value of 9.33 was observed in the treatment of RP mixed with humic acid. It is because the humic acid contains sodium salt and sodium hummate causes increase in its pH values.

scholarly journals Experimental method for the assessment and characterization of hazardous waste for long-term storage

2021 ◽  
Vol 3 (1) ◽  
pp. 19-28
Author(s):  
Gina Alina Catrina ◽  
◽  
Bogdan Stanescu ◽  
Agnes Serbanescu ◽  
Georgiana Cernica ◽  
...  
Keyword(s):  
Redox Potential ◽  
Experimental Method ◽  
Hazardous Waste ◽  
Ph Value ◽  
Ph Values ◽  
Long Term Storage ◽  
Chemical Conditions ◽  
Term Storage

Long-term landfilling of hazardous waste should be a careful choice for any producer or generator of waste, as the behavior of the waste is different due to the physical-chemical conditions or following contact with other hazardous waste. In this study, the research undertaken was aimed at developing an experimental method for the assessment and characterization of hazardous waste for long-term storage. The method consists in the assessment of the behavior of heavy metals from waste, under different leaching conditions. To study various hazardous wastes, fly ash from the incineration of medical waste and slag from aluminum casting were chosen. Contact time, pH and redox potential are important parameters in the leaching process. The solubility of metals increases at pH values between 2 - 5 pH units and decreases at pH values between 6-12 pH units. The highest solubility of metals (As, Cr, Cu, Ni, Pb and Zn) in the tested waste was obtained after 48 hours at pH values between 2 - 5 pH units. Also, the values of the redox potential decrease almost linearly as the pH value increases. The developed method is a useful tool to assess the behavior of hazardous waste for long-term storage in landfills for this category of wastes.

scholarly journals Effect of calcium chloride on the pH values of several formulations of calcium hydroxide mixed with chlorhexidine digluconate

2013 ◽  
Vol 1 (4) ◽  
pp. 344
Author(s):  
Hemanoely Marins-de-Azevedo ◽  
Rodrigo Vargas Conti Montenario ◽  
Mariana Pires Crespo ◽  
Milton Carlos Kuga ◽  
Camila Almeida Nascimento
Keyword(s):  
Calcium Hydroxide ◽  
Calcium Chloride ◽  
Ph Value ◽  
Distilled Water ◽  
Chlorhexidine Digluconate ◽  
Ph Values ◽  
Term Analysis

This study evaluated the effect of the addition of 5% calcium chlorite (CaCl2) on pH values in calcium hydroxide pastes (CH), with or without 2% chlorhexidine digluconate (CHX) used as vehicle, in several periods analysis. Polyethylene tubes were filled with CH mixed with water (G1), 2% CHX solution (G2) or gel (G3), or CHX solution  or gel with 5% CaCl2 (G4 and G5, respectively). All tubes were individually immersed in distilled water. After 12, 24 hours, 7, 14 and 28 days, pH value was evaluated directly in water which the tubes were stored. Data were submitted to ANOVA and Tukey tests (α=0.05). In 24 hs and 14 days, pH values were similar to all groups. In 12 hs, the G1 presented lower pH value than other groups except to G4 (p < 0.05), and G4 presented lower pH value than G5 (p < 0.05). In 7 days, G1 presented lower pH value than G4 and G5 (p < 0.05). In 28 days, G1 and G5 presented lower pH values than G2 and G4 (p < 0.05) and among other groups there are no statistical differences (p > 0.05). The pH values increased in long-term analysis to all CH pastes. The association of 5% calcium chloride with 2% CHX solution as vehicle of CH paste provided a pH value increase in relation to CH mixed with distilled water. The CHX gel interfered negatively on pH value in comparison to CHX solution when mixed with CaCl2.

Effect of Storage Conditions on Biaxial Flexure Strengths of MTA

2008 ◽  
Vol 396-398 ◽  
pp. 429-432
Author(s):  
Hideo Sato ◽  
Naoko Kubota ◽  
Seiji Ban ◽  
Youichi Yamasaki
Keyword(s):  
Ph Value ◽  
Mineral Trioxide Aggregate ◽  
Storage Conditions ◽  
Flexure Strength ◽  
Liner Material ◽  
Pulp Capping ◽  
Ph Values ◽  
Dental Pulp Capping ◽  
Flexure Test ◽  
Biaxial Flexure

The aim of this study was to determine the biaxial flexure strength of a commercially available dental pulp capping or cavity liner material, mineral trioxide aggregate (MTA). MTA and a conventional pulp capping material, calcium hydroxide, were used in this study. Each material was prepared into a disk-shaped specimen. Those specimens were stored in 100% humidity atmosphere at 23 or 37°C for 3 or 24 h. Six specimens in each condition were used for the biaxial flexure test using a piston-on-three-ball according to ISO-6872. Surface pH values were determined. The biaxial flexure strengths of MTA after setting in 24h were larger than those of Dycal (p <0.01). pH value of MTA was higher than that of Dycal. These results indicated that MTA was clinically usage material.

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