What is the Effect of Changing pH on Pharmaceuticals' Sorption?

The present article aims to determine how the change in pH affects the adsorption efficiency of pharmaceuticals on adsorbents. Natural zeolites of various fractions and activated carbon (granular, powdered) were used as suitable and available adsorbents. A total of 102 drugs were detected at the outflow from the Devinska Nova Ves wastewater treatment plant (WWTP), and their total concentration was 12.2 mu g/l. The results of the first test (pH = 7.0) show that the highest removal of the total drug concentration was observed in powdered activated carbon (PAC > 99%). On the other hand, zeolites achieved the highest removal efficiency of only 52%. Subsequently, the pH of the treated water was adjusted to 2.0, and an increase in the amount of drug removed in each of the sorbents used was observed. In granular activated carbon (GAC), a 35% increase in total drug removal was observed. An increase in elimination was also observed for all zeolite fractions. Subsequently, the sample was adjusted to pH = 12.0, where we can observe the opposite effect. Except for PAC, all substances were removed with minimal efficiency. The elimination decreased by almost 50% for all types of zeolite fraction and GAC.