Enhanced adsorption for fluoroquinolones by MnOx-modified palygorskite composites: Preparation, properties and mechanism

Adsorption plays a critical role in eliminating antibiotics in wastewater, so it is urgent to develop an effective adsorbent in the application. Palygorskite exhibits enormous potential in the field of adsorption. In this study, palygorskite was modified by MnOx into a suitable and efficient adsorbent by a simple method, and they were used for the application and comparison of adsorbing fluoroquinolone antibiotics from aqueous solution. The surface chemical properties of adsorbents were characterized by different analytical techniques, and the results were used to analyze the corresponding adsorption interactions. Statistical physics calculations were performed to explain the physical and chemical parameters involved in FQs adsorption mechanism. The highest adsorption efficiency was achieved at pH 3, and the maximum adsorption capacities of MnOx@Pal for CIP, ENR, LFX and LOM were 51.48 mg·g−1, 40.46 mg·g−1, 55.16 mg·g−1 and 52.13 mg·g−1, respectively. Antibiotics adsorption mechanism of adsorbent is mainly due to electrostatic interaction and hydrogen bonding. The adsorbent can be desorbed more easily using NaOH solutions. This adsorbent is expected to be used to treat wastewater contaminated by fluoroquinolone antibiotics.