Adsorption Isotherm And Kinetic Studies of Rhodamine B From Aqueous Solution Using Activated Carbon Prepared From Marigold Stems

This study explored the adsorption of rhodamine B by H3PO4 activated carbon prepared from marigold stems. The research aimed to evaluate various factors affecting the adsorption such as the contact time, adsorption isotherm, and pH. Moreover, the kinetics of the absorption of rhodamine B was also determined. The optimum conditions were then applied to the determination of rhodamine B adsorption capacity. The measurements of rhodamine B concentration were carried out by the use of UV-1800 Shimadzu spectrophotometer. It was evident that the optimum adsorption occurred at the equilibrium adsorption time of 90 minutes and pH 3 with the isotherm concentration of 120 mg/L, while the adsorption capacity was of 1.9205 mg/g. The rhodamine B adsorption the activated carbon follows the pattern of Langmuir isotherm. The adsorption kinetics patterns for the adsorption of rhodamine B follows the kinetics of second order with an adsorption rate constant of 3.00 x 10-5 min-1ppm-1. Keywords: activated carbon, adsorption, isotherm, kinetics, marigold stems, rhodamine B.