What pH is ammonia adjusted to with borate buffer during distillation?

During the distillation process involving ammonia, the pH is typically adjusted to around 9.0 using a borate buffer. The significance of this pH level lies in its role in optimizing the ammonia distillation process. At a pH of 9.0, ammonia is in its un-ionized form, which enhances volatility and allows for more efficient recovery during distillation.

When the pH is maintained at this level, it helps to ensure that most of the ammonia present in the solution can be distilled effectively, as this is where ammonia's presence is maximized in its gaseous state. Distilling at this pH also helps to minimize the formation of interfering compounds and maintain the integrity of the analytical results.

Choosing a lower pH, such as 7.0 or 8.0, would lead to insufficient ammonia volatility, while a higher pH, such as 9.5, could introduce potential issues with stabilization and could lead to errors in the final ammonia concentration measurements. Hence, the adjustment to around 9.0 is crucial for the accuracy and efficiency of the distillation process in wastewater analysis involving ammonia.