Adsorption of natural organic matter by carbon nanotubes

Multiwalled carbon nanotubes (CNTs) were thermally treated and were employed as adsorbents to study their characterizations and adsorption performance of natural organic matter (NOM) in aqueous solutions. The physiochemical properties of CNTs such as structure and nature of the carbon surface were changed after thermal treatment, which made CNTs adsorb more NOM. The amount of adsorbed NOM onto CNTs increased with a rise in initial NOM concentration and solution ionic strength but decreased with a rise in solution pH. A comparative analysis on the NOM adsorption between CNTs and granular activated carbon (GAC) was also conducted. Under the same conditions, the treated CNTs have the best NOM adsorption performance, followed by the raw CNTs and then the GAC, suggesting that the CNTs are efficient NOM adsorbents and possess good potential applications to maintain water of high quality. Further research works on testing the toxicity of CNTs and CNT-related nanomaterials are needed in order to promote safe and optimized applications of CNTs in water treatment.

[1]  W. Weber,et al.  Adsorption of Humic Substances: The Effects of Heterogeneity and System Characteristics , 1983, Journal AWWA.

[2]  Chungsying Lu,et al.  Removal of nickel(II) from aqueous solution by carbon nanotubes , 2006 .

[3]  Chungsying Lu,et al.  Adsorption of trihalomethanes from water with carbon nanotubes. , 2005, Water research.

[4]  Irving Langmuir,et al.  The constitution and fundamental properties of solids and liquids. Part II.—Liquids , 1917 .

[5]  B. Girgis,et al.  A study of the factors affecting the removal of humic acid by activated carbon prepared from biomass material , 2004 .

[6]  P. Ajayan,et al.  Self-organized Ribbons of Aligned Carbon Nanotubes , 2002 .

[7]  T. Karanfil,et al.  Competitive interactions among components of humic acids in granular activated carbon adsorption systems : Effects of solution chemistry , 1996 .

[8]  T. Karanfil,et al.  Adsorption of organic macromolecules by granular activated carbon. 1. Influence of molecular properties under anoxic solution conditions , 1996 .

[9]  José L. Figueiredo,et al.  Adsorption of dyes on activated carbons: influence of surface chemical groups , 2003 .

[10]  G. Newcombe,et al.  Influence of characterised natural organic material on activated carbon adsorption: I. Characterisation of concentrated reservoir water , 1997 .

[11]  Bingqing Wei,et al.  Lead adsorption on carbon nanotubes , 2002 .

[12]  Cailu Xu,et al.  Adsorption of fluoride from water by aligned carbon nanotubes , 2003 .

[13]  Vernon L. Snoeyink,et al.  Activated carbon adsorption of humic substances , 1981 .

[14]  Jaeweon Cho,et al.  MEMBRANE FILTRATION OF NATURAL ORGANIC MATTER: INITIAL COMPARISON OF REJECTION AND FLUX DECLINE CHARACTERISTICS WITH ULTRAFILTRATION AND NANOFILTRATION MEMBRANES , 1999 .

[15]  T. Hyeon,et al.  New nanoporous carbon materials with high adsorption capacity and rapid adsorption kinetics for removing humic acids , 2003 .

[16]  C. Johnston,et al.  Quantitative Fourier Transform Infrared spectroscopic investigation humic substance functional group composition , 1999 .

[17]  Riichiro Saito,et al.  Raman spectroscopy on isolated single wall carbon nanotubes , 2002 .

[18]  Chungsying Lu,et al.  Effects of Acetic Acid on the Regrowth of Heterotrophic Bacteria in the Drinking Water Distribution System , 2005 .

[19]  Newcombe,et al.  Adsorption of NOM onto Activated Carbon: Effect of Surface Charge, Ionic Strength, and Pore Volume Distribution. , 1999, Journal of colloid and interface science.

[20]  Chungsying Lu,et al.  Sorption of divalent metal ions from aqueous solution by carbon nanotubes: A review , 2007 .

[21]  I. Langmuir.  THE CONSTITUTION AND FUNDAMENTAL PROPERTIES OF SOLIDS AND LIQUIDS , 1917 .

[22]  Araceli Rodríguez,et al.  Multiwalled Carbon Nanotubes for Liquid-Phase Oxidation. Functionalization, Characterization, and Catalytic Activity , 2006 .

[23]  J. Rose,et al.  Water chlorination: essential process or cancer hazard? , 1995, Fundamental and applied toxicology : official journal of the Society of Toxicology.

[24]  Darren J. Martin,et al.  THE BIOCOMPATIBILITY OF CARBON NANOTUBES , 2006 .

[25]  M. Rood,et al.  Adsorption equilibrium of organic vapors on single-walled carbon nanotubes , 2005 .

[26]  Chungsying Lu,et al.  Effects of oxalic acid on the regrowth of heterotrophic bacteria in the distributed drinking water. , 2004, Chemosphere.

[27]  Z. Luan,et al.  ADSORPTION OF 1, 2-DICHLOROBENZENE FROM WATER TO CARBON NANOTUBES , 2003 .

[28]  R. T. Yang,et al.  Carbon nanotubes as superior sorbent for dioxin removal. , 2001, Journal of the American Chemical Society.

[29]  C. Ko,et al.  Highly efficient microwave-assisted purification of multiwalled Carbon nanotubes , 2004 .

[30]  G. Amy,et al.  Molecular weight distribution, carboxylic acidity, and humic substances content of aquatic organic matter: implications for removal during water treatment. , 1986, Environmental science & technology.

[31]  Chungsying Lu,et al.  Adsorption of zinc(II) from water with purified carbon nanotubes , 2006 .

[32]  H. Boehm.,et al.  Some aspects of the surface chemistry of carbon blacks and other carbons , 1994 .

[33]  Cailu Xu,et al.  Adsorption of cadmium(II) from aqueous solution by surface oxidized carbon nanotubes , 2003 .