pH, commonly used for water measurements, is a measure of acidity and alkalinity, or the caustic and base present in a given solution. It is generally expressed with a numeric scale ranging from 0-14. The value 7 represents neutrality. The numbers on the scale increase with increasing alkalinity, while the numbers on the scale decrease with increasing acidity. Each unit of change represents a tenfold change in acidity or alkalinity. The pH value is also equal to the negative algorithm of the hydrogen-ion concentration or hydrogen-ion activity.
How is pH Measured?
When pH measurements are crucial for controlling processes, an electrochemical pH sensor is most commonly used. This sensor is typically a combination type, which contains both a measuring electrode and reference electrode. The measuring cell detects changes in the pH value while the reference provides a stable signal for comparison. A high impedance device, known as a pH meter, is used to display the millivolt signal in pH units.
How are pH Measurements Used?
pH measurements are widely used to control processes, ensure product quality and safety.
- pH neutralization of effluent in industrial manufacturing environments
- Cooling tower and boiler control
- Environmental monitoring
- Odor scrubbers
- Food and beverage quality control and safety
- Upstream protection of filtration membranes
- Water pre-treatment for manufacturing processes
- Swimming pool control
- Pulp and paper manufacturing
- Pharmaceutical research & development and manufacturing
- Blood-gas analysis in medical devices