Column Study on Adsorption-Desorption Behavior of Pharmaceutical Pollutants from Synthetic Water by Immobilized Chlorella Sorokiniana Algae

Abstract

The release of pharmaceutical contaminants, especially antibiotics, into the ecosystem is a major environmental concern. This study evaluates the effectiveness of the adsorption and desorption process for ciprofloxacin and rifampicin, two common antibiotics due to their known adverse environmental effects. The adsorption process was conducted using a moving column filled with immobilized Chlorella Sorokiniana algae. The study aimed to understand the effect of flow rate on column efficiency and the formation of the breakthrough curve under different operating conditions. The column was set up with a diameter of 4 cm and a length of 90 cm, and the drug solution was pumped at various flow rates (1, 5, and 10 ml/min). Samples were collected from the column outlet at specific time intervals, and the drug concentration was analyzed using a UV-Vis device. The results showed that increasing the flow rate decreased the time required to reach the drug's breakthrough point, with a steeper curve and faster column saturation. After adsorption was complete, the drug removal process was performed using a suitable solvent (5% nitric acid) to ensure drug recovery and analyze the process performance. The results showed an increase in the removal rate during the first 60 minutes, followed by a decrease with time. Mathematical models (Yoon-Nelson, Adams-Bohart, and Thomas), were applied to simulate the adsorption curves and determine the column capacity and removal efficiency. They also helped estimate the effect of flow rate on column dynamics. The models indicated that the column can remove a high percentage of the drug at low flow rates. This study provides a qualitative improvement in the design of moving columns for use in treating wastewater containing pharmaceuticals. The study provides realistic operational data from which precise, detailed adsorption processes can be designed by determining optimal flow rates and other operating conditions to achieve high efficiency. The results can be generalized to other pharmaceuticals. Therefore, it can be considered a practical framework for applying adsorption and dissolution processes in industrial and laboratory settings, leading to the development of management strategies for pharmaceutical-contaminated water to minimize its environmental impacts.