Removal of Ciprofloxacin from Aqueous Solutions by Waste-Pretreated Ganoderma resinaceum Biomass: Effect of Process Parameters and Kinetic and Equilibrium Studies

This study explores the use of the waste-pretreated biomass of the macro-fungus Ganoderma resinaceum as a biosorbent for removing ciprofloxacin from aqueous solutions. Batch experiments were conducted to evaluate the biosorption performance of G. resinaceum under varying conditions. Key operational parameters—including pH, biosorbent dosage, contact time, and initial ciprofloxacin concentration—were systematically assessed. Equilibrium was reached within 120 min. Equilibrium data were fitted to both Freundlich and Langmuir isotherm models, with the Langmuir model providing a better fit. Under optimal conditions (initial pH of 7.0, 120-min contact time, 1 g/L biosorbent dosage, and ciprofloxacin concentrations ranging from 4 to 20 mg/L), the maximum biosorption capacity was determined to be 18.4 mg/g. Kinetic analysis revealed that the biosorption process followed a pseudo-second-order model. Furthermore, the biomass was characterized before and after biosorption using scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy. The FT-IR analysis of G. resinaceum biomass revealed the presence of hydroxyl, amino, and carbonyl functional groups, which play a crucial role in the binding and biosorption of ciprofloxacin molecules.