title: Removal of tetracycline antibiotic from contaminated water media by multi-walled carbon nanotubes: operational variables, kinetics, and equilibrium studies.
abstract: Multi-walled carbon nanotubes (MWCNTs) were purified and oxidized by a 4 mol L(-1) mixture of H2SO4:H2O2 and then were used as adsorbent for tetracycline (TC) adsorption from aqueous solutions. The purified MWCNTs were characterized using Fourier transform infrared spectroscopy, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and N2 adsorption/desorption isotherms. The adsorption of TC onto the MWCNT was investigated as a function of the initial pH of the solution, adsorbent dosage, and background electrolyte cations and anions. The results of the one-way analysis of variance (ANOVA) showed that Fe(3+) ion significantly affected and decreased TC adsorption onto the MWCNT (P-value < 0.05), while other studied cations and anions did not affect TC adsorption (P-value>0.05). Nonlinear pseudo-first-order, pseudo-second-order, general order, and Avrami fractionary-order kinetic models were used to investigate the kinetics of TC adsorption. The fractionary-order kinetic model provided the best fit to experimental data. In addition, the adsorption isotherms data were well described by nonlinear equation of the Liu isotherm model with the maximum adsorption capacity of 253.38 mg g(-1). The results of this study indicate that the oxidized MWCNTs can be used as an effective adsorbent for TC removal from aqueous solutions.
authors.affiliation: Environmental Technologies Research Center (ETRC), Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran and Department of Environmental Health Engineering, School of Public Health, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran E-mail: shirmardim@yahoo.com.
authors.forename: Ali Akbar
authors.initials: AA
authors.lastname: Babaei
authors.affiliation: Institute of Chemistry, Federal University of Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9500, Porto Alegre, RS, Brazil.
authors.forename: Eder C
authors.initials: EC
authors.lastname: Lima
authors.affiliation: Environmental Technologies Research Center (ETRC), Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran and Department of Environmental Health Engineering, School of Public Health, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran E-mail: shirmardim@yahoo.com.
authors.forename: Afshin
authors.initials: A
authors.lastname: Takdastan
authors.affiliation: Environmental and Occupational Hazards Control Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran and Department of Environmental Health Engineering, School of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Nadali
authors.initials: N
authors.lastname: Alavi
authors.affiliation: Environmental Technologies Research Center (ETRC), Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran and Department of Environmental Health Engineering, School of Public Health, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran E-mail: shirmardim@yahoo.com.
authors.forename: Gholamreza
authors.initials: G
authors.lastname: Goudarzi
authors.affiliation: Environmental Technologies Research Center (ETRC), Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran and Department of Environmental Health Engineering, School of Public Health, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran E-mail: shirmardim@yahoo.com; Student Research Committee, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Vosoughi
authors.affiliation: Department of Environmental Health Engineering, School of Public Health, Yasuj University of Medical Sciences, Yasuj, Iran.
authors.forename: Ghasem
authors.initials: G
authors.lastname: Hassani
authors.affiliation: Environmental Technologies Research Center (ETRC), Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran and Department of Environmental Health Engineering, School of Public Health, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran E-mail: shirmardim@yahoo.com; Student Research Committee, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Shirmardi
mesh_terms: D000327:Adsorption; D000900:Anti-Bacterial Agents; D006861:Hydrogen Peroxide; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D037742:Nanotubes, Carbon / Q000737:chemistry*; D010084:Oxidation-Reduction; D017550:Spectroscopy, Fourier Transform Infrared; D013752:Tetracycline / Q000737:chemistry*; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D014876:Water Pollution; D018508:Water Purification; D014961:X-Ray Diffraction
chemical_list: D000900:Anti-Bacterial Agents; D037742:Nanotubes, Carbon; D014874:Water Pollutants, Chemical; D014867:Water; D006861:Hydrogen Peroxide; D013752:Tetracycline