scholarly journals Immobilization of Cd, Zn, and Pb from Soil Treated by Limestone with Variation of pH Using a Column Test

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Sung-Wook Yun ◽  
Chan Yu
Keyword(s):  
South Korea ◽  
Water Systems ◽  
Metal Mobility ◽  
Acid Solutions ◽  
Test Results ◽  
Column Test ◽  
Acidic Solutions ◽  
Ph Values ◽  
Metal Mines ◽  
Site Restoration

Decades of mining in South Korea have resulted in the contamination of large amounts of soil by metals. The most feasible approach to site restoration requires the use of a stabilization agent to reduce metal mobility. This study examined the leaching characteristics of limestone used as a stabilization agent when subjected to solutions of differing pH. In a laboratory-scale column test, solutions with pH values of 3.5, 4.6, and 5.6, representing acidic to nonacidic rainfall, were applied to soil mixed with limestone. Test results indicate that metal components can be released with the addition of acidic solutions, even if the soil is highly alkaline. Cd and Zn, in particular, exhibited abrupt or continuous leaching when exposed to acid solutions, indicating the potential for contamination of water systems as metal-laden soils are exposed to the slightly acidic rainfall typical of South Korea. Treatment using stabilization agents such as limestone may reduce leaching of metals from the contaminated soil. Stabilizing metal-contaminated farmland is an economical and feasible way to reduce pollutants around abandoned metal mines.

MGP NAPL interception with organophyllic media: flow-through column test results

2006 ◽  
Vol 14 (2) ◽  
pp. 489-493
Author(s):  
Michael J. Gefell ◽  
Erin C. Rankin ◽  
William R. Jones
Keyword(s):  
Test Results ◽  
Column Test ◽  
Flow Through

Durability of Red Mud Based Geopolymer Paste in Acid Solutions

2016 ◽  
Vol 866 ◽  
pp. 99-105 ◽  
Author(s):  
Smita Singh ◽  
M.U. Aswath ◽  
R.V. Ranganath
Keyword(s):  
Mechanical Properties ◽  
Acetic Acid ◽  
Fly Ash ◽  
Red Mud ◽  
Acetic Acid Solution ◽  
Strength Loss ◽  
Acid Solutions ◽  
Test Results ◽  
Acid Attack ◽  
Geopolymer Paste

The present investigation is on the effect of red mud on the mechanical properties and durability of the geopolymer paste in sulphuric and acetic acid solution. Red mud and fly ash were used to form the geopolymer paste along with the alkalies. The variation of red mud in the paste composition was from 0% to 90%. Cylindrical shaped specimens of 1 inch diameter and 1 inch height were prepared. The specimens were immersed in 5% sulphuric acid and 5% acetic acid for 1, 7, 14, 28, 56 and 84 days and tested for weight loss, visual deformation, strength loss and colour of the solvent, based on the procedure specified by ASTM C 267 – 01. SEM/EDX Tests were performed on the geopolymer specimens. Test results show that initially, the strength of the geopolymer increased upon the addition of red mud. The strength was maximum when the percentage of red mud was 30%. The maximum strength obtained was 38 MPa for the paste containing 30% red mud using 10M alkali solution as against 31.69 MPa, when only fly ash was used. Geopolymer paste containing 30% and 50% red mud showed better resistance to acid attack. The strength loss was minimum for the samples containing 30% red mud in both inorganic and organic acid i.e. sulphuric and acetic acid.

Resistance of Acid-Adapted Salmonellae to Organic Acid Rinses on Beef†

1995 ◽  
Vol 58 (9) ◽  
pp. 973-976 ◽  
Author(s):  
J. S. DICKSON ◽  
M. R. KUNDURU
Keyword(s):  
Organic Acid ◽  
Parent Strain ◽  
Good Growth ◽  
Acid Solutions ◽  
Bacterial Populations ◽  
Acid Adaptation ◽  
Ph Values ◽  
Atcc Strain ◽  
Lean Beef ◽  
Acidic Conditions

Four strains of salmonellae, including three bovine isolates and an ATCC strain, were adapted to growth in acidic conditions by sequential transfer in tryptic soy broth with reduced pH values. The cultures were transferred until good growth (approximately log107 CFU/ml) was obtained within 24 h at 37°C at pH 5.0. Lean beef tissue was inoculated by immersion into either the acid-adapted or the homologous parent strain of each bacterium. The inoculated tissue was rinsed for 10s in 1.5% or 3.0% lactic acid solutions at 23°C or 55°C. Reductions in bacterial populations were compared between the parent and acid-adapted strains to determine if the acid-adapted strains were more resistant to the organic acid rinses. Acid-adapted strains had either equal or greater sensitivity to organic acid rinses than their homologous parent strains, indicating that acid adaptation did not result in bacteria which were resistant to organic acid rinses. Acid-adapted strains had significantly lower D55°C− values than their homologous parent strains.

Spin-Gitter-Relaxationszeit-T1-Untersuchungen an Hyaluronsäure. / Spin-Lattice-Relaxationtime-T1 Measurements of Hyaluronic Acid

1979 ◽  
Vol 34 (7-8) ◽  
pp. 508-511 ◽  
Author(s):  
H. Hofmann ◽  
O. Schmut ◽  
H. Sterk ◽  
H. Kopp
Keyword(s):  
Hyaluronic Acid ◽  
Acid Solutions ◽  
Spin Lattice ◽  
Ph Values

Reductions with [3H]NaBH4 proof that the decrease in viscosity of hyaluronic acid solutions caused by lowering the pH does not depend on a depolymerisation of hyaluronic acid. At the same time investigations at different pH-values, show a sigmoide increase of the Spin-Lattice-Re­laxationtime T1. This increase depends on a progressive aggregation of the hyaluronic acid mole­cule. The effect seems to be induced by the decrease of ionization of the carboxylgroups, by acidi­fication of the solution.

scholarly journals Influence Of Volcanic Scoria On Mechanical Strength, Chemical Resistance And Drying Shrinkage Of Mortars

2014 ◽  
Vol 61 (3) ◽  
pp. 143-150 ◽  
Author(s):  
A. Al-Swaidani ◽  
S. Aliyan ◽  
N. Adarnaly ◽  
B. Hanna ◽  
E. Dyab
Keyword(s):  
Mechanical Strength ◽  
Sulphuric Acid ◽  
Chemical Resistance ◽  
Control Sample ◽  
Acid Resistance ◽  
Drying Shrinkage ◽  
Strength Development ◽  
Acid Solutions ◽  
Test Results ◽  
Blended Cements

Abstract In the study, three types of cement have been prepared; one CEM I type (the control sample) and two blended cements: CEM II/A-P and CEM II/B-P (EN 197-1), each of them with three replacement levels of volcanic scoria: (10 %, 15 %, 20 % wt.) and (25 %, 30 %, 35 % wt.), respectively. Strength development of mortars has been investigated at 2, 7, 28 and 90 days curing. Evaluation of chemical resistance of mortars containing scoria-based cements has been investigated through exposure to 5 % sulphate and 5 % sulphuric acid solutions in accordance with ASTM C1012 & ASTM 267, respectively. Drying shrinkage has been evaluated in accordance with ASTM C596. Test results showed that at early ages, the mortars containing CEM II/B-P binders had strengths much lower than that of the control mortar. However, at 90 days curing, the strengths were comparable to the control mortar. In addition, the increase of scoria significantly improved the sulphate resistance of mortars. Further, an increase in scoria addition improved the sulphuric acid resistance of mortar, especially at the early days of exposure. The results of drying shrinkage revealed that the CEM II/B-P mortar bars exhibited a greater contraction when compared to the control mortar, especially at early ages. However, drying shrinkage of mortars was not influenced much at longer times.

Synthesis and Dispersity of YBCO Powder Produced by Oxalic Acid Precipitation Method

2015 ◽  
Vol 645-646 ◽  
pp. 145-150 ◽  
Author(s):  
Ai Qin Wang ◽  
Hui Hui Han ◽  
Min Li ◽  
Jing Pei Xie ◽  
Qing Jie Wu ◽  
...  
Keyword(s):  
Grain Size ◽  
Oxalic Acid ◽  
Technological Parameter ◽  
Oxalic Acid Solution ◽  
Acid Precipitation ◽  
Precipitation Method ◽  
Test Results ◽  
Ph Values ◽  
Mean Grain Size ◽  
The Mean

The YBCO powder was prepared by oxalic acid precipitation method and consequent annealing. The correlation between pH values of oxalic acid solution and the precipitation percentage of precursors were analysed based on thermodynamics analysis. The differential scanning calorimetryanalysis (DSC) was used to confirm the synthetic technological parameter. The phases of powder in each process were investigated by XRD. The microstructures of each powder were tested by SEM and TEM. The mean grain size was calculated by the scherrer’s equation. The test results indicated that the YBCO powder with high purity, less impurities, smaller particle, but severe agglomeration, was Y123 when annealing at 900°C. However, adding dispersants could effectively solve the severe agglomeration. The size of YBCO particles was nanosized and coincided with the calculation.

A rating procedure for solar domestic hot water systems based on ASHRAE-95 test results

Solar Energy ◽  
1991 ◽  
Vol 47 (6) ◽  
pp. 405-411 ◽  
Author(s):  
BVV. Minnerly ◽  
S.A. Klein ◽  
W.A. Beckman
Keyword(s):  
Water Systems ◽  
Hot Water ◽  
Test Results ◽  
Domestic Hot Water

scholarly journals Boron removal from aqueous solutions by a polyethylenimine-epichlorohydrin resin

2018 ◽  
Vol 83 (2) ◽  
pp. 251-264 ◽  
Author(s):  
Sofia Sarri ◽  
Panagiotis Misaelides ◽  
Dimitrios Zamboulis ◽  
Jolanta Warchoł
Keyword(s):  
Aqueous Solutions ◽  
Boron Concentration ◽  
Kinetic Studies ◽  
Alkaline Solutions ◽  
Competitive Sorption ◽  
Boron Removal ◽  
Boron Uptake ◽  
Acidic Solutions ◽  
Ph Values ◽  
Batch Technique

The use of a polyethylenimine?epichlorohydrin resin for the boron removal from aqueous solutions (boron concentration: 100?5000 mg L-1) of non-adjusted and pre-adjusted pH (pHnat, pHinit 8.0, 9.0 and 10.0) aqueous solutions was investigated using a batch technique. The boron concentration in the solutions after sorption was determined photometrically. The results indicated that the pH-dependent boron uptake was related to the protonation/deprotonation of the surface functional groups of the resin and to the boron speciation in solutions of different pH values. The maximum boron sorption capacity observed in solutions of pH 9.0 was 55 mg g-1 exceeding the majority of other commercial or alternative sorbents. Five empirical adsorption equations (Freundlich, Langmuir, Redlich?Peterson, Langmuir?Freundlich and Toth) were applied to the modelling of the boron adsorption equilibrium. The modelling results identified the homogenous boron sorption from acidic and heterogeneous from alkaline solutions. At alkaline pH, the system non-ideality can originate either from the different binding mechanism or from the competitive sorption of different boron species. The homogenous type boron sorption from acidic solutions was further confirmed by kinetic studies

scholarly journals AMINOMETHANSULFONIC AND ALKYLAMINOMETHANSULFONIC BUFFER SYSTEMS

2019 ◽  
Vol 85 (9) ◽  
pp. 3-16
Author(s):  
Ruslan Khoma ◽  
Alim Ennan ◽  
Aleksandr Chebotarev ◽  
Sergey Vodzinskii
Keyword(s):  
Chemical Analysis ◽  
Electron Donor ◽  
Concentration Ratio ◽  
Buffer Capacity ◽  
Water Systems ◽  
Acid Base ◽  
Buffer Action ◽  
Ph Values ◽  
Biochemical Studies ◽  
Medium Acidity

The investigations of acid-base interactions in aminomethanesulfonic acid (AMSA)–potassium aminomethanesulfonate–water and alkylaminomethanesulfonic acid–potassium alkylaminomethane-sulfonate–water systems, where alkyl are methyl (MeAMSA), N-(2-hydroxyethyl) (HEAMSA), n-propyl (n-PrAMSA), n-butyl (n-BuAMSA), tert-butyl (t-BuAMSA), n-heptyl (n-HpAMSA) and benzyl (BzAMSA) were performed in temperature range 293–313 К. Buffer action pH limits were determined and the buffer capacity of these systems was estimated.Based on the evaluation of buffer action pH limits of aminomethansulfonic acids, it has been found that with the help of n-PrAMSA and n-BuAMSA, it was possible to maintain the medium acidity in the range of physiological pH values throughout the range of investigated temperatures.As the temperature rises, the pH of the lower buffer limit increases for AMSA and n-BuAMSA systems, while for HEAMSA, t-BuAMSA, n-HpA-MSA and BzAMSA decreases. The value of the pH of the upper buffer threshold for all tested systems decreases during their heating. With the increase of the electron-donor properties of the N-substituent in the AMSA–MeAMSA–HEAMSA–t-BuAMSA series, the value of their electronegativity decreases to result in lowering of the pH values of the lower buf-fering action limit of these systems. For the more lipophilic N-substituents (n-C4H9, n-C7H15 and C6H5CH2), this regularity is not typical.It has been established that with increasing the CYAMSK/CYAMSA concentration ratio, the buffer capacity of YNHCH2SO3H–YNHCH2SO3K–H2O systems with hydrophilic aminomethansulfonic acids (Y = H, CH3 and HOCH2CH2) increases. For systems with lipophilic n-PrAMSA and t-BuAMSA, their buffer capacity doesn’t change at 0.4 ≤ QKOH/QYAMSA ≤ 1.0.The obtained data on the buffer capacity of the investigated systems is recommended for use in chemical analysis, microbiological and biochemical studies.

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