reacidified

Reacidified is an adjective describing a state in which a substance that has become less acidic (more neutral or basic) is returned to an acidic state. The process, often expressed with the verb to reacidify or the noun reacidification, involves lowering the pH by adding acid or by conditions that increase hydrogen ion activity. Because pH is a continuous scale, reacidification can be to a specific target value or more generally to reestablish acidity after a shift toward neutrality or basicity.

In chemistry and laboratory practice, reacidification is used when a buffered solution or reaction mixture drifts toward neutral or basic pH and requires an acidic environment for the intended reaction or stability of reactants, enzymes, or indicators. In environmental contexts, reacidification can refer to soils or waters becoming acidic again after an initial liming or buffering step, often due to ongoing inputs of acidifying substances such as acid rain or ammonium-based fertilizers.

In industrial and environmental management, controlled reacidification involves dosing acids to maintain a desired pH for processes like coagulation, disinfection, or enzymatic activity, and to prevent unwanted microbial growth or chemical deactivation. In soil science and agriculture, reacidification can result from long-term acid deposition or fertilization practices that release protons during nitrification.

Measurement and precautions: pH meters, indicators, and buffering systems monitor progress, and safety considerations include handling corrosive acids and avoiding overshoot that could harm equipment or ecosystems. The term is pragmatic and usage varies by field.