Adsorption of Organic Dyes from Aqueous Solution by Surfactant Modified Corn Straw

The modification of adsorbent with a cationic surfactant is an effective and inexpensive method to enhance sorption capability of adsorbent. In this study, raw corn straw, modified with a cationic surfactant, tetradecyltrimethyl ammonium bromide was used as adsorbent for dye removal from aqueous solution. The modification caused surface properties of the adsorbent altered from hydrophilic to hydrophobic. To comprehend the modification, the physical property of adsorbents was characterized by BET surface analysis, FTIR-spectra and SEM images. The adsorption of two organic dyes namely blue21 and yellow20 on the modified adsorbent has been investigated in three batch adsorption experiments. Firstly, kinetic study was performed. It was found that the equilibrium time was at 180 min and the kinetic data obeyed pseudo-second order kinetic model. Secondly, the effect of the pH solution was investigated. It was found that the adsorption capacity decreased at a low level with increase in the solution pH. Finally, the adsorption isotherms experiment was conducted and the equilibrium adsorption data was fitted into Langmuir and Freudlich isotherms and the system followed only the Freulich equation. From the above result, the corn straw modified by cationic surfactant is an effective adsorbent for removal of the organic dyes from aqueous solution.