title: Mixed titanium, silicon, and aluminum oxide nanostructures as novel adsorbent for removal of rhodamine 6G and methylene blue as cationic dyes from aqueous solution.
abstract: Mixed oxide nanoparticles containing Ti, Si, and Al of 8-15 nm size range were synthesized using a combined sol-gel - hydrothermal method. Effects of composition on the structure, morphology, and optical properties of the nanoparticles were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), microRaman spectroscopy, and diffuse reflectance spectroscopy (DRS). Dye removal abilities of the nanoparticles from aqueous solutions were tested for different cationic dyes. While all the mixed oxide nanoparticles revealed high and fast adsorption of cationic dyes, the particles containing Ti and Si turned out to be the best. The adsorption kinetics and equilibrium adsorption behavior of the adsorbate - adsorbent systems could be well described by pseudo-second-order kinetics and Langmuir isotherm model, respectively. Estimated thermodynamic parameters revealed the adsorption process is spontaneous, driven mainly by the electrostatic force between the cationic dye molecules and negative charge at nanoparticle surface. Highest dye adsorption capacity (162.96 mg MB/g) of the mixed oxide nanostructures containing Ti and Si is associated to their high specific surface area, and the presence of surface Si-O(δ-) groups, in addition to the hydroxyl groups of amorphous titania. Mixed oxide nanoparticles containing 75% Ti and 25% Si seen to be the most efficient adsorbents for removing cationic dye molecules from wastewater.
authors.affiliation: Instituto de Física, Universidad Autónoma de Puebla, Apdo. Postal J-48, Puebla, Pue., 72570, Mexico. Electronic address: upal@ifuap.buap.mx.
authors.forename: Umapada
authors.initials: U
authors.lastname: Pal
authors.affiliation: Instituto de Física, Universidad Autónoma de Puebla, Apdo. Postal J-48, Puebla, Pue., 72570, Mexico.
authors.forename: Alberto
authors.initials: A
authors.lastname: Sandoval
authors.affiliation: Instituto de Física, Universidad Autónoma de Puebla, Apdo. Postal J-48, Puebla, Pue., 72570, Mexico.
authors.forename: Sergio Isaac Uribe
authors.initials: SIU
authors.lastname: Madrid
authors.affiliation: Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, 4 sur 104, 72000, Puebla, Mexico.
authors.forename: Grisel
authors.initials: G
authors.lastname: Corro
authors.affiliation: Department of Applied Science & Engineering, Indian Institute of Technology Roorkee, Saharanpur Campus, Uttar Pradesh, 247001, India.
authors.forename: Vivek
authors.initials: V
authors.lastname: Sharma
authors.affiliation: Department of Applied Science & Engineering, Indian Institute of Technology Roorkee, Saharanpur Campus, Uttar Pradesh, 247001, India.
authors.forename: Paritosh
authors.initials: P
authors.lastname: Mohanty
mesh_terms: D000327:Adsorption; D000537:Aluminum Oxide / Q000737:chemistry*; D004396:Coloring Agents / Q000737:chemistry*; D052918:Environmental Restoration and Remediation / Q000379:methods*; D007700:Kinetics; D053768:Metal Nanoparticles / Q000737:chemistry*; D008751:Methylene Blue / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D012235:Rhodamines / Q000737:chemistry*; D012825:Silicon / Q000737:chemistry*; D013816:Thermodynamics; D014025:Titanium / Q000737:chemistry*; D062065:Wastewater / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D000537:Aluminum Oxide; D004396:Coloring Agents; D008751:Methylene Blue; D012235:Rhodamines; D012825:Silicon; D014025:Titanium; D062065:Wastewater; C026188:rhodamine 6G; C009495:titanium dioxide
keywords: Dye-adsorption; Mesoporous materials; Mixed metal oxide; Sol-gel synthesis