EFFECTS OF VERY LOW pH SULFURIC ACID EXPOSURE ON COMMON SEWER PIPE LININGS

2001 ◽  
Vol 2001 (16) ◽  
pp. 686-697
Author(s):  
Randall C. Conner
Keyword(s):  
Sulfuric Acid ◽  
Low Ph ◽  
Acid Exposure ◽  
Sewer Pipe

Sulfuric Acid Attack on Concrete Sewer Pipe

1970 ◽  
Vol 96 (5) ◽  
pp. 1167-1182
Author(s):  
Alvin H. Meyer ◽  
William B. Ledbetter
Keyword(s):  
Sulfuric Acid ◽  
Sewer Pipe ◽  
Acid Attack

scholarly journals Exposing Sustainable Mortars with Nanosilica, Zinc Stearate, and Ethyl Silicate Coating to Sulfuric Acid Attack

2018 ◽  
Vol 10 (10) ◽  
pp. 3769 ◽  
Author(s):  
Victoria García-Vera ◽  
Antonio Tenza-Abril ◽  
Marcos Lanzón ◽  
José Saval
Keyword(s):  
Compressive Strength ◽  
Sulfuric Acid ◽  
Mass Loss ◽  
Water Absorption ◽  
Zinc Stearate ◽  
Acid Exposure ◽  
Ethyl Silicate ◽  
Acid Attack ◽  
Water Absorption Coefficient ◽  
Silicate Coating

Obtaining durable materials that lengthen the service life of constructions and thereby contribute to sustainability requires research into products that improve the durability of cementitious materials under aggressive conditions. This paper studies the effects of sulfuric acid exposure on four mortar types (control mortar, mortar with nanosilica, mortar with zinc stearate, and mortar with an ethyl silicate coating), and evaluates which of them have better performance against the acid attack. After 28 days of curing, the samples were exposed to a sulfuric acid attack by immersing them in a 3% w/w of H2SO4 solution. Physical changes (mass loss, ultrasonic pulse velocity, open porosity, and water absorption), and mechanical changes (compressive strength) were determined after the sulfuric acid exposure. A scanning electron microscope (SEM) was used to characterize the morphology of the surface mortars after the exposure. The control mortar had the highest compressive strength after the acid attack, although of the four types, the zinc stearate mortar showed the lowest percentage of strength loss. The zinc stearate mortar had the lowest mass loss after the acid exposure; moreover, it had the lowest capillary water absorption coefficient (demonstrating its hydrophobic effect) both in a non-aggressive environment and acid attack.

Comparative Analysis of Acid Resistance between Susceptible and Multi-Antimicrobial-Resistant Salmonella Strains Cultured under Stationary-Phase Acid Tolerance–Inducing and Noninducing Conditions

2003 ◽  
Vol 66 (5) ◽  
pp. 732-740 ◽  
Author(s):  
R. T. BACON ◽  
J. N. SOFOS ◽  
P. A. KENDALL ◽  
K. E. BELK ◽  
G. C. SMITH
Keyword(s):  
Stationary Phase ◽  
Antimicrobial Agents ◽  
Acid Stress ◽  
Acid Tolerance ◽  
Acid Resistance ◽  
Low Ph ◽  
Acid Exposure ◽  
Acid Adaptation ◽  
Acid Shock ◽  
Resistant Strains

This study compared acid resistance levels among five antimicrobial-susceptible strains of Salmonella and five strains that were simultaneously resistant to a minimum of six antimicrobial agents. The induction of a stationary-phase acid tolerance response (ATR) was attempted by both transient low-pH acid shock and acid adaptation. For acid shock induction, strains were grown for 18 h in minimal E medium containing 0.4% glucose (EG medium) and exposed to sublethal acid stress (pH 4.3) for 2 h, and subsequently, both shocked and nonshocked cultures were acid challenged (pH 3.0) for 4 h. Acid adaptation was achieved by growing strains for 18 h in tryptic soy broth containing 1.0% glucose (TSB+G), while nonadapted cultures were grown for 18 h in glucose-free tryptic soy broth (TSB−G). Acid-adapted and nonadapted inocula were acid challenged (pH 2.3) for 4 h. Initial (0 h) mean populations of nonchallenged Salmonella were 8.5 to 8.7, 8.4 to 8.8, and 8.2 to 8.3 log CFU/ml for strains grown in EG medium, TSB−G, and TSB+G, respectively. After 4 h of acid challenge, mean populations were 3.0 to 4.8 and 2.5 to 3.7 log CFU/ml for previously acid-shocked susceptible and resistant strains, respectively, while corresponding counts for nonshocked strains were 4.3 to 5.5 log CFU/ml and 3.9 to 4.9 log CFU/ml. Following 4 h of acid exposure, acid-adapted cultures of susceptible and resistant strains had mean populations of 6.1 to 6.4 log CFU/ml and 6.4 to 6.6 log CFU/ml, respectively, while corresponding counts for nonadapted cultures were 1.9 to 2.1 log CFU/ml and 1.8 to 2.0 log CFU/ml, respectively. A low-pH–inducible ATR was not achieved through transient acid shock, while an ATR was evident following acid adaptation, as adapted populations were 4.2 to 4.8 log units larger than nonadapted populations following acid exposure. Although some strain-dependent variations in acid resistance were observed, results from this study suggest no association between susceptibility to antimicrobial agents and the ability of the Salmonella strains evaluated to survive low-pH stress.

scholarly journals pH-Regulated Gene Expression of the Gastric Pathogen Helicobacter pylori

2003 ◽  
Vol 71 (6) ◽  
pp. 3529-3539 ◽  
Author(s):  
D. Scott Merrell ◽  
Maria L. Goodrich ◽  
Glen Otto ◽  
Lucy S. Tompkins ◽  
Stanley Falkow
Keyword(s):  
Helicobacter Pylori ◽  
Transcriptional Repression ◽  
Bacterial Genome ◽  
Low Ph ◽  
Acid Exposure ◽  
Protein Accumulation ◽  
Bacterial Cells ◽  
Gastric Pathogen ◽  
H Pylori ◽  
Regulated Gene Expression

ABSTRACT Colonization by the gastric pathogen Helicobacter pylori has been shown to be intricately linked to the development of gastritis, ulcers, and gastric malignancy. Little is known about mechanisms employed by the bacterium that help it adapt to the hostile environment of the human stomach. In an effort to extend our knowledge of these mechanisms, we utilized spotted-DNA microarrays to characterize the response of H. pylori to low pH. Expression of approximately 7% of the bacterial genome was reproducibly altered by shift to low pH. Analysis of the differentially expressed genes led to the discovery that acid exposure leads to profound changes in motility of H. pylori, as a larger percentage of acid-exposed bacterial cells displayed motility and moved at significantly higher speeds. In contrast to previous publications, we found that expression of the bacterial virulence gene cagA was strongly repressed by acid exposure. Furthermore, this transcriptional repression was reflected at the level of protein accumulation in the H. pylori cell.

The influence of low pH environments on ion regulation in the larval stages of the anuran amphibian, Rana clamitans

1984 ◽  
Vol 62 (11) ◽  
pp. 2171-2177 ◽  
Author(s):  
D. G. McDonald ◽  
J. L. Ozog ◽  
B. P. Simons
Keyword(s):  
Developmental Stages ◽  
Early Stage ◽  
Low Ph ◽  
Acid Exposure ◽  
Control Group ◽  
Rana Clamitans ◽  
Acid Uptake ◽  
Ion Regulation ◽  
Larval Amphibians ◽  
Circumneutral Ph

Epithelial ion regulation by larval Rana clamitans (developmental stages III to XX) and early stage juveniles (stage XXV) was examined in soft water (Ca2+ = 300 μequiv./L) at circumneutral pH and during exposure to low pH (nominally 4.0). In tadpoles and juveniles, the acute acid exposure initially caused substantial increases in transepithelial net ion losses and in net acid uptake, and a slight inhibition of active ion transport. In tadpoles, these disturbances had largely disappeared by 7 h of acid exposure but they persisted in early stage juveniles with no apparent sign of recovery. Prior acclimation of tadpoles to a sublethal pH (12 days at pH 5.0) did not reduce the ionoregulatory disturbance at pH 4.0 and the acclimated animals were less able to restore those losses at circumneutral pH compared with a control group. It is concluded that larval amphibians show many similarities with fish in ionoregulatory responses to acid exposure including an inability to adapt to low pH, but the magnitude and duration of disturbances are generally less. This suggests that larval amphibians may be more able to resist acid exposure than many acid-intolerant fish species such as the salmonids.

Chelating extraction of vanadium(V) from low pH sulfuric acid solution by Mextral 973H

2018 ◽  
Vol 190 ◽  
pp. 123-135 ◽  
Author(s):  
Ying Zhang ◽  
Ting-An Zhang ◽  
David Dreisinger ◽  
Weihua Zhou ◽  
Feng Xie ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Acid Solution ◽  
Sulfuric Acid Solution ◽  
Low Ph

INFLUENCE OF ACID SULFATE WEATHERING ON CHEMICAL AND MINERALOGICAL PROPERTIES OF AN ACID SULFATE SOIL OF MANITOBA

1988 ◽  
Vol 68 (3) ◽  
pp. 629-644 ◽  
Author(s):  
G. J. ROSS ◽  
K. C. IVARSON ◽  
R. G. EILERS
Keyword(s):  
Sulfuric Acid ◽  
Low Ph ◽  
Formula Unit ◽  
Acid Sulfate Soil ◽  
Dominant Effect ◽  
Acid Sulfate ◽  
Mineralogical Characteristics ◽  
Exchangeable Al ◽  
Structural Breakdown ◽  
Major Chemical

The chemical and mineralogical characteristics of a Gleyed Sombric Brunisol (Keld Series) of the Grandview area of Manitoba were analyzed in detail to determine the influence of acid sulfate weathering. The Keld soil has developed in till derived from underlying soft Cretaceous pyrite-containing shale of the Ashville Formation. The major chemical features of this soil are low pH (3.3) and high amounts of exchangeable Al (15 cmol(+) kg−1) of the Cg and Bg horizons. In addition, amounts of As are high (18–25 mg kg−1) throughout the profile. This element seems to be associated with iron oxides but not with jarosite-type minerals. Pyrite and gypsum were found in the IICkg horizon but jarosite-type minerals, consisting mainly of natrojarosite with ≈ 40% jarosite, were detected in the Cg horizon only. Aluminium-substituted goethite is present in the Bmgj horizon. Smectite, which is partly beidellitic and has an average layer charge density of 0.32 equivalents per formula unit, is the dominant clay mineral in the soil profile and is inherited from the underlying shale along with associated kaolinite and mica. The oxidation and decomposition of pyrite and the formation of sulfuric acid, jarosite-type minerals and aluminum substituted goethite are typical of acid sulfate weathering reactions. The dominant effect of acid sulfate weathering on the clay minerals is their extensive structural breakdown towards the surface of the profile. This is also indicated by the high amounts of Si and Al extracted from weathered mineral residues in the surface horizons. The IICkg horizon of the keld profile is in the pre-sulfuricization stage, the Cg horizon expresses the active sulfuricization stage, and the Bg, Bmgj, and Ah horizons represent the postsulfuricization stage. Key words: Keld series, acid sulfate weathering, natrojarosite, As levels

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