Removal of crystal violet dye from aqueous solution using adsorbent prepared from oak tree fruit waste

Abstract

The increase in the world's population and the decrease in natural resources, including water, have caused mankind to look for ways to treat the wastes from various industries and reuse them. In this study, the effectiveness of the adsorbent prepared from oak tree fruit waste (activated carbon (AC)) has been investigated in order to remove crystal violet (CV) industrial dye from aqueous solution. The prepared adsorbent was characterized using the diffuse reflectance infrared Fourier transform (DRIFT), scanning electron microscopy (SEM), BET surface area measurement, energy dispersive X-ray (EDX) and powder X-ray diffraction (PXRD) analysis and applied as an effective adsorbent for removal of CV dye as an organic dye from an aqueous solution. Optimum conditions were obtained using 1.4 g adsorbent, 10 mg L−1 CV dye, 38 min contact time and pH 7.5 with 98% dye removal. Equilibrium data were evaluated using Langmuir, Freundlich and Tempkin isotherm. The Langmuir model best described the absorption of CV dye, indicating that it is monolayer and homogeneous (R2 = 0.996). The maximum absorption capacity under optimal conditions was 23.86 mg/g. Kinetic data were analyzed using pseudo-first-order, pseudo-second-order, and elovich equations, and the pseudo-second-order model showed the best fit for kinetic studies (R2 = 0.993).