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Nano-Based Wastewater Treatment Technology
Published in M. H. Fulekar, Bhawana Pathak, Environmental Nanotechnology, 2017
Neutralization involves adjusting the pH of a liquid to approach the ‘neutral’ pH of 7.0 (neither acid nor base). Generally, neutralization involves the use of an acid (pH less than 7) to lower the pH of a tank of basic (or alkaline) liquid (pH greater than 7), or the use of a base (or alkali) to raise the pH of a tank of acidic liquid. In the water treatment industry, wastewater is generated from the regeneration of the resins used in cation, anion and mixed bed ion exchange systems. The chemicals used to regenerate the resins have extreme pH levels. For example, sulphuric acid, with a pH of 1–2, is used for regeneration of cation resin and sodium hydroxide, with a pH of 13–14, is used for regeneration of the anion resin. After the regeneration process, the water containing these chemicals must be disposed of. Due to its extreme pH, the wastewater cannot be sent directly to drain, as this will typically violate local regulations regarding the pH of wastewater discharge.
Water Quality Monitoring
Published in Béla G. Lipták, Analytical Instrumentation, 2018
pH is a measurement of the degree of hydrogen ion activity in a sample (Section 46). It is defined as the negative logarithm of the concentration of active hydrogen ions in gram moles per liter. Typical pH values range from zero (high acidity) to 14 (high alkalinity). A pH of 7 indicates a neutral solution. Rapid changes in pH can signal a discharge or spill, since the pH of open bodies of water would normally change only gradually.
Field Troubles
Published in Ramnarayan Padmanabhan, Centrifugal Pump Clinic, 2017
The pH of a liquid is a measure of the relative acidity or alkalinity of this liquid. A solution with a pH of 7 is neutral. pH values above 7 (up to 14) indicate alkalinity, and values below 7 (down to 0) indicate acidity.
Investigation of mechanical, metallurgical and corrosion characteristics of friction stir welded dissimilar AA 5052-H32 and AA 6061-T6 joints
Published in Journal of the Chinese Institute of Engineers, 2023
S. Balamurugan, K. Jayakumar, C. Nandakumar
Salt spray corrosion analysis was chosen for the corrosion investigation based on a literature review. For experimental corrosion investigation of the dissimilar AA5052-H32 and AA6061-T6 alloys, the ASTM B117 standard was used as a standard practice. The corrosion test specimens of 40 mm × 10 mm x 5 mm (lxbxt) dimensions were extracted after the FSWed regions and base metal and are shown in Figure 15. Initially, the test samples were treated to a neutral level. A neutral medium refers to a pH of 7. The pH of distilled water remains constant at 7. However, small contaminants in the distilled water may cause it to fluctuate significantly.