Green technology: synthesis of iron-modified biochar derived from pine cones to remove azithromycin and ciprofloxacin from water

Abstract

The rise of antibiotic pollutants in water threatens ecosystems and human health. Iron-modified biochar (BC) exhibits adsorption properties and offers a promising approach for effective environmental remediation. The current study explored the potential of iron-loaded biochar synthesized from pine cones for antibiotic removal from water. In this study, pine cones, a sustainable and renewable source, were used to produce iron-modified biochar and employed to remove azithromycin, ciprofloxacin, and their mixture from aqueous solutions. Biochar was synthesized through pyrolysis and modified by the addition of iron salts. The analysis of iron-modified biochar by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) suggested a crystalline structure rich in minerals and functional groups (O–H, C=O, and C≡C) and loaded with iron, having plate-like roughness and distorted morphology along with sharp edges and corners. Antibiotic removal was evaluated by changing physical parameters, including biochar dose, pH, and temperature. The maximum removal percentages of azithromycin, ciprofloxacin, and their mixture were obtained as 87.8%, 91.3%, and 84%, respectively, at low pH, a low Fe-modified biochar dose, and higher temperature. Application of kinetic models suggested that the adsorption of antibiotics on iron-modified biochar is more inclined toward pseudo-second-order (R2 > 0.98) kinetics, indicating a chemisorption nature of the adsorption process. The findings highlight the potential of iron-modified biochar for removing antibiotics from aqueous solutions.

Properties and Possibilities of Using Biochar Composites Made on the Basis of Biomass and Waste Residues Ferryferrohydrosol Sorbent

“…BC4 was produced with a higher yield than BC3. As reported by [ 74 ], the conversion of substrates into iron-containing biochar occurred with an efficiency of 80%. The reduction in efficiency may result from the loss of biochar during the process of chemical coprecipitation.…”

“…However, the authors used modified Ag/Fe nanoparticles on a biochar carrier to remove cephalexin. Similar effectiveness of removing antibiotics such as azithromycin and ciprofloxacin (87.8%, 91.3%) using iron-modified biochar was achieved [ 74 ]. A high efficiency of 72.26% in removing amoxicillin from the solution was achieved by [ 104 ].…”

“…The analysis of FTIR spectra ( Figure 3 ) obtained for biochar and BC1, BC2, BC3 and BC4 composites showed the presence of bands corresponding to the stretching vibrations of the C=O bond (in the region of a wavelength of 1691–1697 cm −1 ) in all analyzed samples, which indicates the potential presence of ketones, quinones and/or carboxylic carbon [ 28 , 74 ]. As [ 88 ] points out, the presence of C=O and other carbonyl or carboxyl groups can provide adsorption sites on the biochar surface.…”

“…The vibrations in this area may correspond to the stretching vibrations of the aliphatic CH 3 and CH 2 bonds [ 94 ]. Weak signals possibly corresponding to deformation vibrations or carbon dioxide in the C≡C plane were observed in the region with a wavelength of 2280 cm −1 [ 74 ].…”