title: Synthesis and characterization of modified carrageenan microparticles for the removal of pharmaceuticals from aqueous solutions.
abstract: In the present study, carrageenan microparticles were synthesized using spray-drying method and used as biosorbents for the removal of pharmaceutical compounds. The cross-linking reaction of iota-carrageenan (iCAR) and kappa-carrageenan (kCAR) with glutaraldehyde (GLA) at different concentrations (2.5% or 5% (w/w), mass of GLA per mass of CAR) was studied (iCAR/GLA2.5, iCAR/GLA5, kCAR/GLA2.5, kCAR/GLA5). The physicochemical properties of the novel cross-linked polymers were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). Swelling studies were in accordance with the polymer properties, showing the lowest swelling degree (19%) by using the iCAR/GLA5 microparticles. The optimal kCAR/GLA5 microparticles were successfully employed for the removal of Metoprolol (MTPL) from aqueous samples. The adsorption capacity of the adsorbents was investigated using a batch adsorption procedure and the kinetics and thermodynamics of the adsorption process were further investigated. It was found that the adsorption isotherms agree well with the Langmuir-Freundlich model. The maximum adsorption capacity (Qm) was achieved in pH 6, whereas an increase of Qm was observed increasing the temperature (from 109 at 20°C to 178 mg/g at 40°C). Kinetic studies showed that the adsorption process on iCAR/GLA5 microparticles followed pseudo-second-order rate mechanism. Finally, a new phenomenological model of the adsorption process was proposed in order to extract information on the relevant sub-processes.
authors: Laboratory of Polymer Chemistry and Technology, Department of Chemistry, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki, Greece.
authors: Stavroula G
authors: SG
authors: Nanaki
authors: Laboratory of Polymer Chemistry and Technology, Department of Chemistry, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki, Greece; Laboratory of General and Inorganic Chemical Technology, Department of Chemistry, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki, Greece.
authors: George Z
authors: GZ
authors: Kyzas
authors: Laboratory of Environmental Pollution Control, Department of Chemistry, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki, Greece.
authors: Areti
authors: A
authors: Tzereme
authors: Laboratory of Environmental Pollution Control, Department of Chemistry, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki, Greece.
authors: M
authors: M
authors: Papageorgiou
authors: Laboratory of General and Inorganic Chemical Technology, Department of Chemistry, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki, Greece.
authors: Margaritis
authors: M
authors: Kostoglou
authors: Laboratory of Polymer Chemistry and Technology, Department of Chemistry, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki, Greece.
authors: Dimitrios N
authors: DN
authors: Bikiaris
authors: Laboratory of Environmental Pollution Control, Department of Chemistry, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki, Greece. Electronic address: dlambro@chem.auth.gr.
authors: Dimitra A
authors: DA
authors: Lambropoulou
mesh_terms: D000327:Adsorption; D001704:Biopolymers / Q000737:chemistry; D002351:Carrageenan / Q000138:chemical synthesis* / Q000737:chemistry; D005976:Glutaral / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008790:Metoprolol / Q000302:isolation & purification; D008863:Microspheres; D004364:Pharmaceutical Preparations / Q000302:isolation & purification*; D012996:Solutions; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D014961:X-Ray Diffraction
chemical_list: D001704:Biopolymers; D004364:Pharmaceutical Preparations; D012996:Solutions; D014874:Water Pollutants, Chemical; D002351:Carrageenan; D008790:Metoprolol; D005976:Glutaral
keywords: Adsorption; Carrageenan; Kinetic modeling; Metoprolol; Pharmaceuticals; β-Blockers