title: Removal of methylene blue by adsorption on aluminosilicate waste: equilibrium, kinetic and thermodynamic parameters.
abstract: An aluminosilicate waste (AW) was investigated as adsorbent for methylene blue (MB) dye. AW was characterized by petrography, X-ray diffractometry, X-ray fluorescence, scanning electron microscopy, thermogravimetry and zeta potential measurements. It was found that AW contains kaolinite, and other minor components such as quartz, muscovite, smectite, siderite, pyrite and organic compounds. The chemical composition of AW is mainly SiO2(49%) and Al2O3(23%) and it has negative superficial charge above pH 1.73. Adsorption of MB dye was studied in a batch system under different conditions of initial dye concentration, contact time and temperature. The isothermal data from batch experiments were fitted to Langmuir and Freundlich equations, with a better fit shown by the Langmuir isotherm equation. Also, pseudo-first-order, pseudo-second-order and intraparticle diffusion models were considered to evaluate the rate parameters. The experimental data fitted the pseudo-first-order kinetic model best. Thermodynamic parameters were calculated, showing the adsorption to be an endothermic yet spontaneous process, with the activation energy of +37.8 kJ mol-1. The results indicate that AW adsorbs MB efficiently, and can be employed as a low-cost alternative in wastewater treatment for the removal of cationic dyes.
authors.affiliation: Departamento de Química, Universidade Estadual do Centro-Oeste, Guarapuava 85040080, Brazil E-mail: cpoliciano@hotmail.com.
authors.forename: Carlos Alberto
authors.initials: CA
authors.lastname: Policiano Almeida
authors.affiliation: Departamento de Química, Universidade Estadual do Centro-Oeste, Guarapuava 85040080, Brazil E-mail: cpoliciano@hotmail.com.
authors.forename: Tânia Marina Palhano
authors.initials: TM
authors.lastname: Zanela
authors.affiliation: Instituto Federal de Educação, Ciência e Tecnologia de Santa Catarina, Campus de Jaraguá do Sul, Jaraguá do Sul 89251000, Brazil.
authors.forename: Clodoaldo
authors.initials: C
authors.lastname: Machado
authors.affiliation: Departamento de Geociências, Universidade Federal de Santa Catarina, Florianópolis 88040900, Brazil.
authors.forename: Juan Antônio
authors.initials: JA
authors.lastname: Altamirano Flores
authors.affiliation: Departamento de Geociências, Universidade Federal de Santa Catarina, Florianópolis 88040900, Brazil.
authors.forename: Luiz Fernando
authors.initials: LF
authors.lastname: Scheibe
authors.affiliation: Centre for Sustainable Water Engineering, Department of Engineering Science, The University of Oxford, Oxford OX1 3PJ, UK.
authors.forename: Nicholas P
authors.initials: NP
authors.lastname: Hankins
authors.affiliation: Departamento de Química, Universidade Federal de Santa Catarina, Florianópolis 88040-900, Brazil.
authors.forename: Nito Angelo
authors.initials: NA
authors.lastname: Debacher
mesh_terms: D000327:Adsorption; D000537:Aluminum Oxide / Q000737:chemistry*; D004396:Coloring Agents / Q000737:chemistry*; D004058:Diffusion; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008751:Methylene Blue / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D008962:Models, Theoretical; D012822:Silicon Dioxide / Q000737:chemistry*; D013696:Temperature; D013816:Thermodynamics; D014865:Waste Disposal, Fluid / Q000379:methods; D062065:Wastewater; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D000537:Aluminum Oxide; D004396:Coloring Agents; D008751:Methylene Blue; D012822:Silicon Dioxide; D062065:Wastewater; D014874:Water Pollutants, Chemical