title: Visible light photo catalytic inactivation of bacteria and photo degradation of methylene blue with Ag/TiO2 nanocomposite prepared by a novel method.
abstract: Water purification is one of the worldwide problem and most of the conventional methods are associated with a number of drawbacks. Therefore it is the need of the day to develop new methods and materials to overcome the problem of water purification. In this research work we present a simple and green approach to synthesize silver decorated titanium dioxide (Ag/TiO2) nanocomposite with an efficient photo catalytic activities. Phytochemicals of the Cestrum nocturnum leaf extract were used to synthesize silver nanoparticles (AgNPs), Titanium dioxide (TiO2) and Ag/TiO2 nanocomposite. To confirm the formation, crystal structure, particle size and shape of green synthesized nanoparticles and nanocomposite, they were characterized by UV-visible spectroscopy (UV-vis), X-ray diffraction spectroscopy (XRD), high resolution transmission electron microscopy (HRTEM), Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). The AgNPs, TiO2 and Ag/TiO2 were evaluated for photo degradation of methylene blue (MB) and photo inhibition of Bacteria. The bio-synthesized Ag/TiO2 nanocomposite was observed to have strong catalytic activities for photo reduction of MB and photo inactivation of bacteria as compared to bare AgNPs and TiO2. In the presence of Ag/TiO2, 90% of MB was degraded only in 40min of irradiation. Alternatively the bare AgNPs and TiO2 degraded less than 30% and 80% respectively of MB even in more than 100min of irradiation. Similarly the Ag/TiO2 has very strong photo inhibition efficiency towards Escherichia coli and Pseudomonas aeruginosa. The zone of inhibition of irradiated Ag/TiO2 nanocomposites against E. coli and P. aeruginosa was 19mm and 17mm respectively which was two times higher than in dark. These promising photocatalytic activities of nanocomposite may be due to the highly decorated AgNPs over the surface of TiO2.
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China; Institute of Chemical Sciences, Gomal University D.I.Khan, KP, Pakistan.
authors.forename: Kamran
authors.initials: K
authors.lastname: Tahir
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China.
authors.forename: Aftab
authors.initials: A
authors.lastname: Ahmad
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China. Electronic address: bsli@mail.buct.edu.cn.
authors.forename: Baoshan
authors.initials: B
authors.lastname: Li
authors.affiliation: Institute of Chemical Sciences, Gomal University D.I.Khan, KP, Pakistan.
authors.forename: Sadia
authors.initials: S
authors.lastname: Nazir
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China.
authors.forename: Arif Ullah
authors.initials: AU
authors.lastname: Khan
authors.affiliation: Department of Physics, Gomal University D.I.Khan, KP, Pakistan.
authors.forename: Tabassum
authors.initials: T
authors.lastname: Nasir
authors.affiliation: Department of Chemistry, University of Science and Technology Bannu, 28100, KP, Pakistan.
authors.forename: Zia Ul Haq
authors.initials: ZUH
authors.lastname: Khan
authors.affiliation: Institute of Chemical Sciences, Gomal University D.I.Khan, KP, Pakistan.
authors.forename: Rubina
authors.initials: R
authors.lastname: Naz
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China.
authors.forename: Muslim
authors.initials: M
authors.lastname: Raza
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D008027:Light; D053768:Metal Nanoparticles / Q000737:chemistry; D008751:Methylene Blue / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects / Q000528:radiation effects*; D053761:Nanocomposites / Q000737:chemistry*; D010782:Photolysis; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D012834:Silver / Q000737:chemistry*; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; C009495:titanium dioxide; D012834:Silver; D014025:Titanium; D008751:Methylene Blue
keywords: Ag/TiO(2) nanocomposite; Cestrum nocturnum; Green deposition method; Photo catalytic activity; Photo inhibition of bacteria