China
Africa
Explore chapters and articles related to this topic
Qualitative and Quantitative Analysis of Water
Published in Sreedevi Upadhyayula, Amita Chaudhary, Advanced Materials and Technologies for Wastewater Treatment, 2021
pH is a measure of the acidity or basicity and is mathematically defined as negative logarithm of H+ ion concentration. Danish chemist Sorensen introduced the concept of pH. It has values between 1 and 14. Each unit change in pH represents a 10-fold change in H+ ion concentration. When the number of H+ ions equals the number of OH− ions, water is neutral and has a pH of 7. Carbon dioxide forms carbonic acid and reduces pH of water, whereas lime (calcium hydroxide), with a formula of Ca(OH)2, raises pH of water. pH=−logH+orH+=10−pH
Applied Chemistry and Physics
Published in Robert A. Burke, Applied Chemistry and Physics, 2020
The pH scale measures the acidity or alkalinity of a solution. Acids are acidic and bases are alkaline. Acids have a value on the pH scale of 1–6.9. Materials with a pH value of 7 are considered to be neutral; they are neither acidic nor basic. Bases have values on the pH scale from 7.1 to 14. It is not important that emergency responders know how the pH scale measures corrositivity or the specific values of any given acid or base. It is important, however, for responders to know that numerical values less than 7 are acids and those higher than 7 are bases. The acidic side of the scale is a reverse ratio. Usually, the higher the number, the greater the amount that is being measured. With the pH scale on the acidic side, it is reversed. The lower the pH value, the more acidic an acid is. So an acid with a pH of 1 would be much more acidic than an acid with a pH of 2 and so on. This difference in acidity is much greater than the numbers of 1 through 6.9 may represent (Figure 3.139). The ratio and the intervals between the numbers are exponential. For example, an acid with a pH of 6 is 10 times more acidic than an acid with a pH of 6.9. A pH of 5 is 10 times more acidic than a pH of 6 and so on. The result of this exponential ratio is that an acid with a pH of 1 is 1,000,000 times more acidic than an acid with a pH of 6.9. So the difference between individual values on the pH scale is very great and one of the reasons that dilution and neutralization are not as simple as they might sound.
Contamination
Published in Daniel T. Rogers, Urban Watersheds, 2020
An acid increases the concentration of the hydrogen ion H+ when dissolved in water and lowers the pH (potential hydrogen) of the solution. The bare hydrogen ion, H+, is short for the hydronium ion, H3O+, since a bare H+ does not exist in a solution. Conversely, a base increases the concentration of the hydroxide ion OH− when dissolved in water, and raises the pH of the solution (Meyers 2003). Common acids and bases are listed in Table 7.7 (Meyers 2003). We recognize acids and bases by their simple properties, such as taste, and conclude the sour taste of a lemon indicates it must be acidic. Bases tend to taste bitter. On the pH scale, any substance with a pH less than 7 (the neutral point) is acidic and any substance having a pH greater than seven is basic. Acids and bases are widely used in industry, and are present in many widely consumed foods and drinks (see Table 7.7). Stronger acids and bases are used in household cleaners and detergents, especially those used on glassware and in ovens (Meyers 2003).
Water quality assessment of Mansbal Lake in Kashmir
Published in Water Science, 2022
Daawar Bashir Ganaie, Anirudh Malhotra, Irfan Ahmad Wani
pH (power of hydrogen/ hydrogen ion activity or concentration) scale is used to analyze the acidity or basicity of a given solution/liquid. The scale measures the values from 1 to 15, values being below 7 pH are categorized as acidic, while above 7 pH as basic and 7 pH denotes as neutral. Hydrogen ion concentration (pH) is well defined as the decimal logarithm of the reciprocal of the hydrogen ion activity (Covington, Bates, & Durst, 1985). pH that maintains the acidic or basic property, is a vital characteristic of any aquatic ecosystem since all the biochemical activities and retention of physicochemical attributes of the water are greatly dependent on the pH of the surrounding water (Jalal & Sanal Kumar, 2013). In the present study, the pH values ranged between 8.9 pH and 7.6 pH showing alkaline nature of water, indicating the lake was well buffered during this period of study. The highest pH values in all the months were recorded at Kondabal site 2 because of the calcium intrusion and heavy pollution load from the near catchment area. This inconstancy in pH values can be attributed to the influence of the variations in photosynthetic and decomposition rates of organic matter due to high pollution, and this statement also goes well with the findings of (Shah, Pandit, & Shah, 2017).
Deciphering water quality using WQI and GIS in Tummalapalle Uranium Mining area, Cuddapah Basin, India
Published in Water Science, 2020
M. Pramod Kumar, K. Nagalakshmi, N. Jayaraju, T. Lakshmi Prasad, B. Lakshmanna
pH is an estimate of hydrogen ion concentration value in water which is measured on a logarithmic scale, suggests whether the solution is acidic or alkaline in nature. The pH value in the study area varies from 7.28 to 8.61 with an average of 8 indicating the basic (alkaline) nature of the groundwater (Table 2). The spatial distribution map of pH also depicts the alkaline nature of water in most of the study area including Tummalapalle village (Figure 3(a)). The alkaline nature of water is attributed to the presence of bicarbonate, carbonate-rich rock beds (Limestone and dolomite) (Ranjana, 2009; Rasheed, Lakshmi, Patil, & Dayal, 2011).
Fabrication of spirulina based activated carbons for wastewater treatment
Published in Environmental Technology, 2022
Mustafa Rakib, Yeshaswini Baddam, Balakrishnan Subeshan, Ayse B. Sengul, Eylem Asmatulu
pH is the measurement of the acidity or alkalinity of water. This measure determines the concentration of hydrogen ion [H+] and can be expressed mathematically as pH = –log [H+]. The pH scale can calculate values from 0 to 14, where 0 means a highly concentrated strong acid, 14 means a highly concentrated base, and 7 is the neutral pH. Pure water should have a pH of 7 [70]. In 1984, new pH guidelines for drinking water were introduced, and the new range was between 6.5 and 8.5. Until now, this range was considered the usual pH range. Sometimes the ideal pH range for drinking water is recommended between 6.5 and 9.5 [71].