Adsorptive removal of ciprofloxacin by a chitosan modified Fe pretreatment biochar composite from aqueous solution

Abstract

With the increased use of antibiotic medications, more and more ciprofloxacin (CIP) is contaminated into the environment, which could endanger both humans and ecosystems. In this work, chitosan modified Fe pretreated biochar (CS-FBC), which was produced utilizing a straightforward and reduced synthesis process, was tested for its effectiveness in the removal of CIP from an aqueous solution. CS-FBC was analyzed using XPS, XRD, BET, SEM, FTIR, and a zetasizer. In addition, we investigated how ciprofloxacin removal was influenced by a number of variables, including initial concentration, time, pH, and temperature. The findings of the experiment showed that the adsorption impact was very rapid and could reach 80% over the first 60 minutes of the overall adsorbent. The kinetic model of CS-FBC adsorbed CIP in solution was discovered to be comparable to the pseudo-second-order kinetic model, suggesting that it may be connected to chemical adsorption. By matching the adsorption properties, a maximum peak value of 76.72 mg g⁻¹ at 35 °C was found, and the fitting was found to match better with the Langmuir isotherm model. Investigations into the adsorption thermodynamics revealed that the process was temperature dependent and instantaneous. By raising the amount of NaCl, the adsorptive power might be reduced to an extent. However, the adsorption action was seldom affected by amounts of less than 0.01 M NaCl. Furthermore, in addition to hydrogen bonding and hydrophobic interaction, the adsorption process for CS-FBC on CIP also involves electrostatic interaction and π–π electron-donor–acceptor (EDA) interaction. The adsorption rate could still be maintained at 61.25% after 7 experiments. The removal effect of CS-FBC on CIP can prove that CS-FBC is a green, economical, and sustainable adsorbent with a low preparation cost.