Alkali treated Foumanat tea waste as an efficient adsorbent for methylene blue adsorption from aqueous solution Azadeh Ebrahimian Pirbazari a,b,n , Elham Saberikhah a,b , Moslem Badrouh a,b , Mohammad Saeed Emami a,b a Faculty of Fouman, College of Engineering, University of Tehran, P.O. Box 43515-1155, Fouman 43516-66456, Iran b Faculty of Caspian, College of Engineering, University of Tehran, P.O. Box 43841-119, Rezvanshahr 43861-56387, Iran article info Article history: Received 15 April 2014 Received in revised form 16 July 2014 Accepted 23 July 2014 Keywords: Tea waste Alkali treated Methylene blue Isotherm Kinetic Thermodynamic abstract The adsorption of methylene blue (MB) from aqueous solution by alkali treated Foumanat tea waste (ATFTW) from agriculture biomass was investigated. The adsorbent was characterized by Scanning Electron Microscopy (SEM), Fourier Transform-Infrared Spectroscopy (FT-IR) and nitrogen physisorption. FTIR results showed complexation and ion exchange appear to be the principle mechanism for MB adsorption. The adsorption isotherm data were fitted to Langmuir, Sips, Redlich-Peterson and Freundlich equa- tions, and the Langmuir adsorption capacity, Q max was found to be 461 mgg 1 . It was found that the adsorption of MB increases by increasing temperature from 303 to 323 K and the process is endothermic in nature. The removal of MB by ATFTW followed pseudo-second order reaction kinetics based on Lagergren equa- tions. Mechanism studies indicated that the adsorption of MB on the ATFTW was mainly governed by external mass transport where particle diffusion was the rate limiting step. & 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/). Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/wri Water Resources and Industry http://dx.doi.org/10.1016/j.wri.2014.07.003 2212-3717/& 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/). n Corresponding author at: Faculty of Fouman, College of Engineering, University of Tehran, P.O. Box 43515-1155, Fouman 43516-66456, Iran. Tel.: þ98 1327234927; fax: þ98 1327237228. E-mail address: aebrahimian@ut.ac.ir (A. Ebrahimian Pirbazari). Water Resources and Industry ] (]]]]) ]]]–]]] Please cite this article as: A. Ebrahimian Pirbazari, et al., Alkali treated Foumanat tea waste as an efficient adsorbent for methylene blue adsorption from aqueous solution, Water Resources and Industry (2014), http://dx.doi.org/10.1016/j.wri.2014.07.003