Magnetic nickel cobalt sulfide/sodium dodecyl benzene sulfonate with excellent ciprofloxacin adsorption capacity and wide pH adaptability

In this study, a novel magnetic nickel cobalt sulfide/sodium dodecyl benzene sulfonate (FSNCS/SDBS) adsorbent was synthesized successfully by a facile protocol and was developed to remove ciprofloxacin (CIP) for water purification. The FSNCS/SDBS adsorbent is featured with excellent CIP adsorption capacity of 625 mg·g −1 (much higher than reported most adsorbents), wide pH adaptability (little changed CIP adsorption capacity in pH 6–11), and good magnetic property. The effects of pH and ionic strength on CIP adsorption were investigated. The calculative thermodynamic parameters indicated that CIP adsorption by FSNCS/SDBS was spontaneous and exothermic. CIP adsorption followed pseudo-second-order kinetics and an isotherm best fit with the Langmuir adsorption mode. The adsorption mechanism of CIP onto FSNCS/SDBS was proposed and demonstrated, which included the electrostatic interaction, π–π interaction, coordination with metal and hydrogen bonding.