Removal of an Emerging Pharmaceutical Pollutant (Ibuprofen) from Aqueous Solution Using Magnetized Spent Coffee Ground Biochar - Chitosan Composite: Optimization, Isotherms, and Adsorption Kinetics
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Date
2025-10
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Addis Ababa University
Abstract
Pharmaceutical pollutants, such as ibuprofen, are persistent environmental contaminants that threaten both flora and fauna. This study focused on synthesizing and characterizing a magnetized composite of spent coffee grounds biochar and chitosan for removing ibuprofen from synthetic wastewater. The composite adsorbent was developed using a co-precipitation method, varying the ratios of spent coffee grounds biochar to chitosan at 27:75, 50:50, and 75:25. Surface functional groups, morphology, specific surface area, elemental composition, and crystal structure were analyzed using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Brunauer-Emmett-Teller (BET) analysis, Energy Dispersive X-ray Spectroscopy (EDX), and X-ray Diffraction (XRD). Operational parameters for adsorption included initial ibuprofen concentration, pH, contact time, and adsorbent dosage. A statistical experimental design, specifically the Response Surface Methodology Central Composite Design, explored the interactions among these parameters to identify optimal conditions for ibuprofen removal. Analysis of Variance (ANOVA) was used for statistical evaluation. The BET, FTIR, SEM, XRD, and EDX analyses demonstrated that the magnetized composite had a high surface area of 524.65 m²/g, essential functional groups (C–H, C=O, N–H, Fe–O) for ibuprofen binding, a porous and agglomerated morphology, dominant magnetite crystalline peaks alongside an amorphous organic matrix, and an elemental composition rich in Fe, O, and C, confirming successful integration into a uniform composite structure. The maximum ibuprofen removal efficiency achieved was 96.7% under optimal conditions: a pH of 4.5, an adsorbent dosage of 2.0 g/L, an initial ibuprofen concentration of 5 mg/L, and a contact time of 80 minutes. All selected parameters significantly influenced the performance of the synthesized composite adsorbent. The reusability of the composite under optimal conditions showed minimal variation in removal efficiency after five cycles of adsorption-desorption experiments were conducted. In conclusion, the composite adsorbent exhibited notable properties, enabling it to successfully remove ibuprofen from wastewater, making it an appropriate technique for environmental remediation.
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Spent Coffee Ground Biochar, Ibuprofen, Adsorption, Optimization, Kinetic Study.