The Removal of Basic Dyes from Wastewater onto Dead Water Hyacinth

摘要

Water hyacinth (WH), an aquatic plant macrophyte, was investigated for its ability to perform as a suitable adsorbent for basic dyes from aqueous solution. Kinetics adsorption experiments were conducted to evaluate the adsorption characteristics of the system. Results showed that WH can remove basic dyes effectively from aqueous solution. The loading of basic dyes onto WH was found to increase significantly with increasing the initial dye concentration, but the residual concentration of the dye in solution also increased. A complete removal of dye from solution was only achieved at the lower range of initial dye concentration. The adsorption rate was fast and more than half of the adsorbed dye was removed in the first 15 minutes at room temperature, which makes the process practical for industrial application. The overall rate of dye uptake was found to be controlled by external mass transfer at the beginning of adsorption, and then gradually changed to intraparticle-diffusion control at a later stage. The initial period where external mass transfer is the rate controlling step was found to increase with increasing initial dye concentration and decrease with increasing temperature. The increase in temperature was also found to increase the rate of adsorption and reduce the time required to reach equilibrium.