Abstract
The wastes of Myoporum laetum and Livistona chinensis leaves were utilized for removal of malachite green dye (MG) from solution. The highest removal for dye was observed with M. laetum biomass at pH: 6, temperature: 35 degrees C, biomass dose: 0.3 g L-1 and contact time: 120 min. The different concentrations of MG (5-35%) were highly removed by M. laetum (99.28% to 79.31%, respectively) as compared with L. chinensis (95.48-69.67%, respectively) at the optimum conditions. The sorption data were represented by Langmuir, Freundlich and Temkin isotherms. Adsorption was established well with isotherms of Langmuir and Freundlich. The study of thermodynamic suggested that the adsorption reaction was endothermic and the sorption of dye onto the biomass proceed in the forward direction and greatly promising process. The removal of dye was characterized by FT-IR analyses and the results confirmed that the groups responsible for the process of dye binding were hydroxyl or amino, and carboxylate or amide. The M. laetum cell wall showed a great porosity which permits the passage of dye molecules. The M. laetum biomass was more efficient than that of L. chinensis. The efficiency of the plant waste for a decolorizing solution containing dye, their abundance in nature and less processing requirements may lead to the emergence of low-cost adsorbents.