Title
Triethoxysilylpropylamine modified alkali treated wheat straw: an efficient adsorbent for methyl orange adsorption
Authors
HOOSHYAR MOGHIM ALIABADI ELHAM SABERIKHAH AZADEH EBRAHIMIAN PIRBAZARI REZA KHAKPOUR and HOUMAN ALIPOUR

Received December 8, 2016
Published Volume 52 Issue 1-2 January-February
Keywords triethoxysilylpropylamine, modification, wheat straw, methyl orange, isotherm, kinetics

Abstract
In this work, alkali treated wheat straw (ATWS) materials were simply modified by triethoxysilylpropylamine (TESPA) to prepare a novel adsorbent. The adsorption of methyl orange (MO) from aqueous solutions onto the modified wheat straw was studied. The adsorbent was characterized by scanning electron microscopy (SEM) and Fourier transform-infrared spectroscopy (FT-IR). FTIR results suggested that electrostatic interaction appears to be the principle mechanism of MO adsorption. The adsorption isotherm data were fitted to Langmuir, Sips and Redlich Peterson equations, and the Langmuir adsorption capacity, Qmax, reached 304.2 mgg−1, while a Qmax value of 75.8 mgg−1 was found for unmodified wheat straw. Also, it was observed that the adsorption of MO increases with increasing temperature from 303 to 323K, and the process is endothermic in nature. The removal of MO by TESPA ATWS followed pseudo-second order reaction kinetics based on Lagergren equations. Mechanism studies indicated that the adsorption of MO onto the TESPA-ATWS was mainly governed by external mass transport, where particle diffusion was the rate limiting step.