Removal of Tetracycline Antibiotic Using Green Synergistic Extractive Extraction from Aqueous Solution

Tetracycline antibiotic (TCA) is a broad-spectrum antibiotic that is extensively utilized in agriculture and human therapy. However, its extensive use poses significant environmental risks. Extractive extraction stands out as one of the effective methods available for TCA removal from aqueous solutions. The use of a single extractant in extractive extraction requires a high extractant concentration due to its low loading capacity. Therefore, this study aims to formulate a synergistic extractant diluted in green diluent (i.e., cooking palm oil). The synergistic extractant provides a high loading capacity and leads to improved extraction performance. The batch equilibrium experiment was performed to evaluate the extraction and stripping performance, where UV-Vis spectroscopy analysis was used to measure the change in TCA concentration in the aqueous solution before and after phase separation. The results show that nearly 98% of TCA (100 mg/L) can be extracted from the aqueous solution with 0.4 M bis-2-ethylhexyl phosphoric acid (D2EHPA)/0.0004 M tributyl phosphate (TBP). This combination achieves the highest synergistic coefficient value of 20.40, indicating a strong synergistic effect between the mixture of extractants. Additionally, about 98% of TCA can be stripped using 0.03 M hydrochloric acid (HCl). Hence, the formulated synergistic extractant, consisting of a mixture of D2EHPA and TBP, demonstrates significant potential for TCA removal from pharmaceutical wastewater.