Kinetics, Isotherm and Optimum Condition for the Adsorption of Methyl Red Dye Using Hydroxyapatite

The aim of the experiment is to remove dyes from wastewater using adsorption technique. The hydroxyapatite was used as an adsorbent to remove methyl red dye. The adsorption process was carried out with four different experiments. The first one is changing the contact time, and the optimum contact time was found to be 90 minutes with a 97 percent removal. The second experiment was carried away by changing the pH of the medium and using the optimum contact time obtained from the previous experiment. The optimum pH in the second experiment was found to be 4 with a 91.6 percent removal. The third interpretation was analysed by changing the initial concentration of the dye and using the optimum contact time and pH obtained from the two previous experiments. The optimum initial concentration of the dye in the third experiment was found to be 0.1 ppm with a 94.6 percent removal. Finally, the fourth analysis by using the optimum time, pH and initial concentration obtained from the three previous experiments, but the adsorbent dose was changing. It was found that the optimum adsorbent dose was found to be 2 g/l with 94.6% percent removal. According to the two parameter isotherms, the adsorption process followed Freundlich isotherm model, and Halsey isotherm as they had the higher R2 values, which shows that the adsorbent surface is heterogenous. The kinetics of the adsorption process was found to be pseudo second order. The mechanism of the adsorption process was studied by intraparticle diffusion and which indicated the ionic state of the dye.