From green biowaste to water treatment applications: Utilization of modified new biochar for the efficient removal of ciprofloxacin

Abstract

Water pollution caused by antibiotics is a serious environmental problem in recent years. Using biochar to remove such pharmaceutical pollutants has recently emerged as a promising option. After H3PO4 modification, a new waste-based biochar (MPCWSB500) from sour cherry stalk was successfully synthesized to remove ciprofloxacin (CFX) from aquatic media, and modification of feedstock has significantly improved the adsorption capacity of biochar. MPCWSB500 is suitable for both batch and continuous treatment systems. The CFX sorption was systematically studied using various kinetics and isotherm models. The surface characteristics of the modified biochar and the possible CFX−biochar interactions were investigated by BET, FT−IR, and SEM−EDX analysis. Short operation time, high sorption capacity (410.06 mg g−1), and nearly 100% removal efficiency were recorded as significant findings at optimum experimental conditions (pH: 6.3, contact time: 40 min, MPCWSB500 dose: 15 mg). Furthermore, the modified biochar exhibited more than 95% CFX removal efficiency in continuous mode at all flow rates (1–10 mL min−1). Its sorption performance was minimally affected by the presence of Cl−, K+, Na+, and NO3− ions in the adsorption medium. In addition, up to 5 sorption-desorption cycles, biochar regeneration and recycling produced satisfactory results. The proposed biochar was also successfully used to remove CFX from simulated hospital wastewater and synthetic urine samples. These features are all important advantages for its real applications. Overall, our research offers a practical approach for removing CFX from the polluted aquatic environment.