title: Preparation of magnetic, macro-reticulated cross-linked chitosan for tetracycline removal from aquatic systems.
abstract: A novel adsorbent, magnetic, macro-reticulated cross-linked chitosan (MRC) was synthesised for the removal of tetracycline (TC) from water using a source of biogenic waste (gastropod shells) as a pore-forming agent. The insertion of crosslinks into the chitosan frame was confirmed by FTIR analysis, while the stability of the MRC was demonstrated via a stability test performed in an acidic solution. The enhanced porosity of the MRC was confirmed by the evaluation of its porosity, a swelling test and the determination of its specific surface area. The time-concentration profile of the sorption of TC onto the MRC demonstrated that equilibrium was attained relatively quickly (120 min), and the data obtained fitted a pseudo second order (r(2)>0.99) kinetic equation better than a pseudo first order or reversible first order kinetic equation. The optimisation of process variables indicated that the sorption of TC onto the MRC was favoured at a low solution pH and that the presence of organics (simulated by the addition of humic acid) negatively impacted the magnitude of TC removal. The area of coverage of TC on the MRC (2.51 m(2)/g) was low compared to the specific surface area of the MRC (47.95 m(2)/g). The value of the calculated energy of adsorption of TC onto the MRC was 100 kJ/mol, which is far above the range of 1-16 kJ/mol stipulated for physical adsorption.
authors.affiliation: Department of Chemistry, Adekunle Ajasin University, Akungba Akoko, Nigeria. Electronic address: bioladoja@yahoo.com.
authors.forename: N A
authors.initials: NA
authors.lastname: Oladoja
authors.affiliation: Department of Chemistry, The Federal University, Wukari, Nigeria.
authors.forename: R O A
authors.initials: RO
authors.lastname: Adelagun
authors.affiliation: School of Chemical Engineering, Universiti Sains Malaysia, Penang, Malaysia.
authors.forename: A L
authors.initials: AL
authors.lastname: Ahmad
authors.affiliation: Environmental and Chemical Processes Research Laboratory, Department of Chemical Sciences, Redeemer's University, Nigeria.
authors.forename: E I
authors.initials: EI
authors.lastname: Unuabonah
authors.affiliation: Department of Chemistry, Adekunle Ajasin University, Akungba Akoko, Nigeria.
authors.forename: H A
authors.initials: HA
authors.lastname: Bello
mesh_terms: D000327:Adsorption; D048271:Chitosan / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D060328:Magnetic Phenomena; D009930:Organic Chemicals / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D013752:Tetracycline / Q000737:chemistry / Q000302:isolation & purification*; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
chemical_list: D003432:Cross-Linking Reagents; D009930:Organic Chemicals; D014874:Water Pollutants, Chemical; D048271:Chitosan; D013752:Tetracycline
keywords: Chitosan; Cross-linked chitosan; Magnetite; Pore forming agent; Tetracycline