title: Preferential adsorption behavior of methylene blue dye onto surface hydroxyl group enriched TiO2 nanotube and its photocatalytic regeneration.
abstract: The present manuscript focus on the synthesis of surface hydroxyl group enriched titanium dioxide nanotube (TNT) by hydrothermal method for preferential adsorption of methylene blue (MB) dye. The mixture of methylene blue (MB) and rhodamine B (RhB) dye was used to study the preferential adsorption nature of TNT. The synthesized TNT were characterized by various techniques such as powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption, and ammonia-temperature programmed desorption (NH3-TPD) analysis. Result demonstrated that enhancement in the surface area of TNT and higher number of hydroxyl group on the surface of TNT. In the binary mixture, the adsorption of MB dye was 12.9 times higher as compared to RhB dye, which clearly indicated the preferential adsorption of MB dye on TNT surface. The preferential interaction of MB on TNT is due to the electrostatic interaction between the cationic MB and negatively charged TNT surface. The preferential adsorption of MB dye was studied by applying Langmuir, Freundlich and Sips isotherm; pseudo-first and second-order kinetic model. Furthermore, the regeneration of dye adsorbed TNT was carried out by eco-friendly photocatalytic process under the irradiation of ultraviolet light.
authors.affiliation: Discipline of Inorganic Materials and Catalysis (DIMC), CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific and Industrial Research (CSIR), G. B. Marg, Bhavnagar 364 002, Gujarat, India; Academy of Scientific and Innovative Research (AcSIR), CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), G.B. Marg, Bhavnagar 364 002, Gujarat, India.
authors.forename: Thillai Sivakumar
authors.initials: TS
authors.lastname: Natarajan
authors.affiliation: Discipline of Inorganic Materials and Catalysis (DIMC), CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific and Industrial Research (CSIR), G. B. Marg, Bhavnagar 364 002, Gujarat, India; Academy of Scientific and Innovative Research (AcSIR), CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), G.B. Marg, Bhavnagar 364 002, Gujarat, India.
authors.forename: Hari C
authors.initials: HC
authors.lastname: Bajaj
authors.affiliation: Discipline of Inorganic Materials and Catalysis (DIMC), CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific and Industrial Research (CSIR), G. B. Marg, Bhavnagar 364 002, Gujarat, India; Department of Environmental Engineering, Kyungpook National University (KNU), 80 University Road, Bukgu, Daegu 702-701, Republic of Korea. Electronic address: tayade@csmcri.org.
authors.forename: Rajesh J
authors.initials: RJ
authors.lastname: Tayade
keywords: Dye adsorption; Hydrothermal; Methylene blue; Photocatalysis; Preferential adsorption; Rhodamine B; TiO(2) nanotube