title: Sonocatalytic degradation of humic acid by N-doped TiO2 nano-particle in aqueous solution.
abstract: BACKGROUND
  Un-doped and N-doped TiO2 nano-particles with different nitrogen contents were successfully synthesized by a simple sol-gel method, and were characterized by X-ray diffraction, field emission scanning electron microscopy, Energy dispersive X-ray analysis and UV-visible diffuse reflectance spectra techniques. Then enhancement of sonocatalytic degradation of humic acid by un-doped and N-doped TiO2 nano-particles in aqueous environment was investigated. The effects of various parameters such as initial concentration of humic acid, N-doping, and the degradation kinetics were investigated.
  
  
  RESULTS
  The results of characterization techniques affirmed that the synthesis of un-doped and N-doped TiO2 nano-particles was successful. Degradation of humic acid by using different nano-particles obeyed the first-order kinetic. Among various nano-particles, N-doped TiO2 with molar doping ratio of 6 % and band gap of 2.92 eV, exhibited the highest sonocatalytic degradation with an apparent-first-order rate constant of 1.56 × 10(-2) min(-1).
  
  
  CONCLUSIONS
  The high degradation rate was associated with the lower band gap energy and well-formed anatase phase. The addition of nano-catalysts could enhance the degradation efficiency of humic acid as well as N-doped TiO2 with a molar ratio of 6 %N/Ti was found the best nano-catalyst among the investigated catalysts. The sonocatalytic degradation with nitrogen doped semiconductors could be a suitable oxidation process for removal of refractory pollutants such as humic acid from aqueous solution.
authors.affiliation: Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Hossein
authors.initials: H
authors.lastname: Kamani
authors.affiliation: Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran ; Center for Water Quality Research, Institute for Environmental Research, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Simin
authors.initials: S
authors.lastname: Nasseri
authors.affiliation: Department of Medicinal Chemistry, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Khoobi
authors.affiliation: Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Ramin
authors.initials: R
authors.lastname: Nabizadeh Nodehi
authors.affiliation: Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran ; Center for Solid Waste Research, Institute for Environmental Research, Tehran University of Medical Sciences, Tehran, Iran ; National Institute of Health Research, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Amir Hossein
authors.initials: AH
authors.lastname: Mahvi
keywords: Humic acid; N-doped TiO2; Sonocatalytic degradation
references.citation: Ultrason Sonochem. 2011 Sep;18(5):1057-61
references.pmid: 21454117
references.citation: Ultrason Sonochem. 2012 Jul;19(4):767-71
references.pmid: 22227556
references.citation: J Hazard Mater. 2011 Jun 15;190(1-3):938-44
references.pmid: 21555185
references.citation: Chemosphere. 2001 Feb;42(4):379-87
references.pmid: 11100789
references.citation: J Hazard Mater. 2011 Sep 15;192(3):1267-74
references.pmid: 21741172
references.citation: J Environ Health Sci Eng. 2015 Apr 21;13:35
references.pmid: 25908992
references.citation: PLoS One. 2012;7(7):e27571
references.pmid: 22829863
references.citation: Chemosphere. 2002 Jul;48(4):453-60
references.pmid: 12152748
references.citation: J Hazard Mater. 2009 Aug 30;168(1):253-61
references.pmid: 19282105
references.citation: Ultrason Sonochem. 2007 Jul;14(5):531-7
references.pmid: 17289421
references.citation: J Environ Health Sci Eng. 2014 Apr 15;12:67
references.pmid: 24735555
references.citation: Ultrason Sonochem. 2010 Jan;17(1):145-52
references.pmid: 19535281
references.citation: J Environ Health Sci Eng. 2014 Nov 25;12(1):139
references.pmid: 25485140
references.citation: J Hazard Mater. 2012 Oct 15;235-236:326-35
references.pmid: 22939090
references.citation: J Environ Health Sci Eng. 2014 Dec 19;12(1):146
references.pmid: 25648623
references.citation: J Environ Health Sci Eng. 2013 Aug 02;11(1):24
references.pmid: 24499711
references.citation: Ultrason Sonochem. 2012 May;19(3):642-51
references.pmid: 22000097
references.citation: J Environ Health Sci Eng. 2014 Jun 30;12:101
references.pmid: 25105016