Adsorption Removal Of Polycyclic Aromatic Hydrocarbons And Antibiotics From Aqueous Solution By Magnetic Carbon Nanocomposite Materials

Magnetic carbon nanocomposite materials have been prepared successfully for the adsorption of organic pollutants in the water environment. Polycyclic aromatic hydrocarbons (PAHs) are considered one of the largest groups of polluting compounds, and are known to be carcinogenic, mutagenic and may cause endocrine disruptors. Much more attention has been focused on their possible biological effects on human health. So far, over200PAHs have been found, and16of them are on the priority pollutant list of the US EPA and they have become appreciable environmental concerns around the world. Antibiotics are widely used in health care and agricultural industries for the treatment and prevention of human and animal diseases. The wide spread of antibiotics made the antibiotic resistance genes been observed increasing in many circumstances globally, and the extensive use of pharmaceuticals also resulted in frequent detection of their residues in surface water, groundwater and sediments. Due to the potential for migration into the environment and the possible development of resistance in pathogens, the environmental impact of such antibacterial agents represents a serious concern for the public health. Herein, three different kinds of magnetic carbon nanocomposite were used as adsorbents to adsorption removal of polycyclic aromatic hydrocarbons (anthracene, naphthalene), and ciprofloxacin antibiotics from aqueous solution.1. Multi-wall carbon nanotubes/iron oxide magnetic composite was prepared using chemical co-precipitation. The performance of using the magnetic composite to adsorption anthrancene from aqueous solution was investigated. The effects of environmental factors such as pH, ion strength, humic acid were discussed. The results demonstrate maximum adsorption of anthrancene could be reached under weak acid condition. The ion strength had little effect on anthrancene adsorption. Inhibition of anthrancene adsorption was abserved at low humic acid concentration, however, promotion of anthrancene adsorption at high humic acid concentration. The sorption kinetics was found to follow a pseudo-second-order kinetic model. The removal rate of anthracene was over98%, and the maximum adsorption amount was95.2mg/g. The magnetic adsorbent has good adsorption ability and could be used to anthrancene removal.2. Activated carbon/CoFe2O4magnetic composite was prepared using a simple one-step refluxing method, and characterized by XRD, nitrogen adsorption-desorption isotherms, TG, SEM, and TEM. The performance of using the magnetic composite to adsorption naphthalene from aqueous solution was investigated. The effect of environmental factors such as pH, and ion strength were discussed. The adsorption equilibrium data can be well fitted by the Langmuir model. Kinetics of the naphthalene removal was found to follow a pseudo-second-order rate equation. The solution of pH had minor effect on the adsorption of naphthalene on activated carbon/CoFe204, and ionic strength of0to0.5M NaCl have minor effect on the Nap adsorption, while the salting out effect may increased the removal of Nap with the concentration of NaCl increasing above0.5M. The results demonstrate the maximum adsorption amount was96.90mg/g. The magnetic adsorbent has good adsorption ability, recycleable and easily separated from solution by applying an external magnetic field, thus could be used to naphthalene removal.3. A new magnetic mesoporous carbon composite (Fe3cyC) was synthesized and characterized by XRD, nitrogen adsorption-desorption isotherms, FT-IR, TG, ζ potential, SEM, and TEM. The performance of using Fe3O4/C composite as an adsorbent for removal of antibiotics using ciprofloxacin (CIP) as a model was investigated. The Langmuir adsorption isotherm was applicable to fit the removal process. Kinetics of the CIP removal was found to follow a pseudo-second-order rate equation. The solution pH is critical for the adsorption of CIP on Fe3O4/C, and the maximum adsorption of CIP could be reached under neutral conditions. In addition, the Fe3O4/C adsorbent showed high magnetization and operational stability, and it could be readily separated from solution by applying an external magnetic field. After10recycle runs, over85%of the adsorption capacity was retained. The high performance, low cost, and easily recyclable Fe3O4/C composite may become a promising adsorbent for water treatment.