title: Morphology dependent adsorption of methylene blue on trititanate nanoplates and nanotubes prepared by the hydrothermal treatment of TiO2.
abstract: The adsorption properties of two nanomorphologies of trititanate, nanotubes (TiNT) and plates (TiNP), prepared by the hydrothermal reaction of concentrated NaOH with different phases of TiO2, were examined. It was found that the capacity for both morphologies towards methylene blue (MB), an ideal pollutant, was extremely high, with the TiNP having a capacity of 130 mg/g, higher than the TiNT, whose capacity was 120 mg/g at 10 mg/L MB concentration. At capacity, the well-dispersed powders deposit on the floor of the reaction vessel. The two morphologies had very different structural and adsorption properties. TiNT with high surface area and pore volume exhibited exothermic monolayer adsorption of MB. TiNP with low surface area and pore volume yielded a higher adsorption capacity through endothermic multilayer adsorption governed by pore diffusion. TiNP exhibited a higher negative surface charge of -23 mV, compared to -12 mV for TiNT. The adsorption process appears to be an electrostatic interaction, with the cationic dye attracted more strongly to the nanoplates, resulting in a higher adsorption capacity and different adsorption modes. We believe this simple, low cost production of high capacity nanostructured adsorbent material has potential uses in wastewater treatment.
authors.affiliation: Department of Chemistry, Xi'an Jiaotong Liverpool University, 111 Renai Road, Dushu Lake Higher Education Town, Suzhou Industrial Park, Suzhou, Jiangsu 215123, China E-mail: graham.dawson@xjtlu.edu.cn.
authors.forename: Graham
authors.initials: G
authors.lastname: Dawson
authors.affiliation: i-lab, Suzhou Institute of Nanotechnology and Nanobionics, Chinese Academy of Sciences, Dushu Lake Higher Education Town, Suzhou Industrial Park, Suzhou, Jiangsu 215123, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.affiliation: China Faculty of Material Science and Chemical Engineering, China University of Geosciences, Wuhan 430074, China.
authors.forename: Luhua
authors.initials: L
authors.lastname: Lu
authors.affiliation: College of Physics and Electronic Information, Huaibei Normal University, Huaibei 235000, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Dai
mesh_terms: D000327:Adsorption; D007700:Kinetics; D008751:Methylene Blue / Q000737:chemistry*; D008956:Models, Chemical; D043942:Nanotubes / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*
chemical_list: C009495:titanium dioxide; D014025:Titanium; D008751:Methylene Blue