Amino-functionalized MIL-88B(Fe)-based porous carbon for enhanced adsorption toward ciprofloxacin pharmaceutical from aquatic solutions

Abstract

The present study focused on the synthesis of novel NH 2 -PC700 adsorbent through the pyrolysis of NH 2 -MIL-88B (Fe) material under different pyrolysis temperatures (500, 700, and 900 °C) and investigated its application for ciprofloxacin adsorption. The obtained adsorbents were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and nitrogen adsorption/desorption isotherm measurements. The parameters of the adsorption experiments that affect the removal efficiency, including solution pH (3–10), contact time (0–240 min), and initial concentration (10–40 mg/L), were also studied in detail. For the adsorption kinetic and isotherm studies, nonlinear models combined with error functions such as adjusted coefficient of determination ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>R</mml:mi> <mml:mi>adj</mml:mi> <mml:mn>2</mml:mn> </mml:msubsup> </mml:math> ), mean relative error (MRE), and squares of the errors (SSE) were used to evaluate the compatibility between kinetic models (pseudo-first-order, pseudo-second-order, Elovich, and Bangham) and isotherm (Langmuir, Freundlich, Temkin, and Dubinin–Radushkevitch) adsorption equations. Besides, the role of amino functionalization for the ciprofloxacin (CFX) adsorption of NH 2 -PC700 adsorbent was also explained. Through the Langmuir model, the maximum CFX adsorption capacity of NH 2 -PC700 was calculated to be 102.5 mg/g, considerably higher than that of NH 2 -MIL-88B (Fe). This outcome suggested that NH 2 -PC700 could be a promising adsorbent for the CFX remediation.