Highly porous NiFe-mixed metal oxides derived from calcinated layered double hydroxide for efficient antibiotics removal

Tetracycline (TC), a widely employed broad-spectrum antibiotic with global prevalence, possesses the ability to infiltrate soil matrices and potentially reach groundwater systems, thereby posing a consequential human health risk. To address this concern, a novel NiFe-mixed metal oxides (MMO) composite was synthesized and employed within quartz sand as a strategic measure to regulate the downward migration of TC. In-depth investigations of TC transport behavior in quartz sand, complemented by NiFe-MMO, were conducted via a series of rigorous batch and saturation-filled column experiments. The impacts of NiFe-MMO dosage, ionic strength, cationic types, solution pH, and flow rates on TC transport were systematically and comprehensively scrutinized. Our findings reveal that even minute quantities of NiFe-MMO prompt substantial TC adsorption, facilitated by electrostatic interactions and surface complexation, notably in low-concentration background solutions. Additionally, the presence of Ca²⁺ engenders a bridging effect, further enhancing TC adsorption onto the sand. These significant observations bear far-reaching implications in elucidating the fate of antibiotics within the intricate interplay of soil and groundwater domains. The strategic amalgamation of NiFe-MMO and quartz sand offers innovative prospects for managing TC dissemination, thereby augmenting endeavors toward sustainable environmental protection.