03222naa a2200397 a 450000100080000000500110000800800410001902400590006010000130011924501860013226000090031852019800032765000210230765000160232865000190234465000120236365000240237565300190239965300170241865300270243565300220246265300210248465300220250565300250252770000160255270000170256870000260258570000170261170000190262870000230264770000170267070000270268770000170271470000230273177300700275420819522018-01-23       2017    bl uuuu     u00u1 u    #d7 ahttp://dx.doi.org/10.1016/j.scitotenv.2017.07.0452DOI1 aCÔA, F.  aCoating carbon nanotubes with humic acid using an eco-friendly mechanochemical methodbApplication for Cu(II) ions removal from water and aquatic ecotoxicity.h[electronic resource]  c2017  aIn this work, industrial grade multi-walled carbon nanotubes (MWCNT) were coated with humic acid (HA) for the first time by means of a milling process, which can be considered an eco-friendly mechanochemical method to prepare materials and composites. The HA-MWCNT hybrid material was characterized by atomic force micros- copy (AFM), scanning electron microscopies (SEM and STEM), X-ray photoelectron spectroscopy (XPS), termogravimetric analysis (TGA), and Raman spectroscopy. STEM and AFM images demonstrated that the MWCNTs were efficiently coated by the humic acid, thus leading to an increase of 20% in the oxygen content at the nanotube surface as observed by the XPS data. After the milling process, the carbon nanotubes were short- ened as unveiled by SEM images and the values of ID/IG intensity ratio increased due to shortening of the nano- tubes and increasing in the number defects at the graphitic structure of carbon nanotubes walls. The analysis of TGA data showed that the quantity of the organic matter of HA on the nanotube surface was 25%. The HA coating was responsible to favor the dispersion of MWCNTs in ultrapure water (i.e. −42 mV, zeta-potential value) and to improve their capacity for copper removal. HA-MWCNTs hybrid material adsorbed 2.5 times more Cu(II) ions than oxidized MWCNTs with HNO3, thus evidencing that it is a very efficient adsorbent material for removing copper ions from reconstituted water. The HA-MWCNTs hybrid material did not show acute ecotoxicity to the tested aquatic model organisms (Hydra attenuata, Daphnia magna, and Danio rerio embryos) up to the highest concentration evaluated (10 mg L−1). The results allowed concluding that the mechanochemical method is effec- tive to coat carbon nanotubes with humic acid, thus generating a functional hybrid material with low aquatic tox- icity and great potential to be applied in environmental nanotechnologies such as the removal of heavy metal ions from water.  aCarbon nanotubes  aHumic acids  aNanotechnology  aToxidez  aTratamento da água  aÁcido húmico  aBall milling  aDespoluição da água  aFunctionalization  aMechanochemistry  aNanoecotoxicology  aNanotubos de carbono1 aSTRAUSS, M.1 aCLEMENTE, Z.1 aRODRIGUES NETO, L. L.1 aLOPES, J. R.1 aALENCAR, R. S.1 aSOUZA FILHO, A. G.1 aALVES, O. L.1 aCASTRO, V. L. S. S. de1 aBARBIERI, E.1 aMARTINEZ, D. S. T.  tScience of the Total Environmentgv. 607-608, p. 1479-1486, 2017.