<p>The environmental fate of fluoroquinolone antibiotics in arid-region soils remains poorly understood due to the unique physicochemical properties of mineral-dominated loess, characterized by ultra-low organic matter, high clay content, and alkaline pH. This study investigates the sorption-desorption behavior of enrofloxacin (ENR) in loess through batch equilibrium experiments, revealing that sorption follows pseudo-second-order kinetics (R²&gt;0.999) and Freundlich isotherms (R²&gt;0.987), driven by the complex influence of a variety of mineral interactions rather than organic partitioning. Results demonstrate exceptional ENR sequestration (&gt;98% sorption efficiency) via zwitterion-enhanced electrostatic attraction at pH 8.3 and cation bridging with clay minerals, alongside strong desorption hysteresis (HI = 0.52-0.68) limiting reversible release to &lt;6%. Acidic conditions (pH 4.0) amplified sorption 7-fold compared to alkaline states (pH 10.0), while ionic competition experiments uncovered a Hofmeister-like paradox: NH₄⁺ increased sorption by 22% through pH-mediated ENR⁺ formation, whereas Mg²⁺ suppressed retention by 63% via binding and competition as clay-edges. FTIR analysis confirmed binding from inner-sphere complexes (1360 cm^-1 C-N⁺ stretching), highlighting loess’s long-term immobilization capacity. These findings redefine antibiotic retention paradigms for mineral-rich soils, providing actionable strategies to optimize manure fertilization (e.g., minimizing Mg²⁺ inputs) and mitigate groundwater contamination risks in arid agricultural systems. By bridging molecular-scale mechanisms to regional-scale environmental management, this work advances sustainable practices for antibiotic-polluted loess regions under climate stress.</p>