Abstract
In this study, batch adsorption of acid violet 49 (AV49) dye onto thermally activated groundnut shell (AGS) was investigated in aqueous solution. The adsorbent was characterized using Fourier transform infrared, scanning electron microscope equipped with energy dispersive spectroscopy, X-ray diffractometer, BET surface area, and CHNSO analyzer. The effects of solution pH, initial AV49 dye concentration, adsorbent quantity, salinity, and contact time on the removal efficiency of AV49 dye were investigated. The factors influencing dye removal were optimized using the response surface optimization technique. It was observed that the adsorption of AV49 dye onto AGS followed the pseudo-second-order kinetic model with the coefficient of determination (R-2) of 0.999 and a root mean square error of 2.28. The isotherm equation parameters were estimated along with an R-2 for Langmuir and Freundlich isotherms. Based on the R-2 values, it was observed that the experimental data are in close agreement with Langmuir isotherm as compared with Freundlich. The AGS achieved a maximum adsorption capacity of 167, 169, and 172 mg/g at temperatures, 301, 313, and 323 K, respectively. The experimental data revealed that AGS can be used as an adsorbent for the removal of AV49 dye from aqueous solution.