Abstract

• Removal of Methylene Blue (MB) from aqueous solution is carried out using carbonized material prepared from leaves of Polyalthialongifolia (PL) commonly called as Ashoka. The dried leaves samples were carbonized at 150 C for 2 h. The carbonized sample was heated at 175 C for 1 h in muffle furnace to give the heated Polyalthialongifolia leaves charcoal (HPL). The activated carbon was prepared from Polyalthialongifolia leaves (APL) by chemical activation with ZnCl2 as activation agent.The HPL and APL were characterized by FT IR and SEM. Batch sorption study has been carried out to investigate the effect of various parameters such as initial concentration of dye solution, contact time and amount of biosorbent. It was observed that the dye removal efficiency and adsorption capacity depended upon initial concentration of dye solution, contact time and amount of biosorbent. The equilibrium data were described by Freundlich and Langmuir isotherms. The resulting activated carbons were tested for their ability to sorb methylene blue in aqueous solution. The removal percent of methylene blue by HPL was 79.58 % and that by APL was 70.17 %.From Freundlich isotherm studies, the sorption capacity of HPL was 0.3716 mg g-1 and that of APL was 0.2773 mg g-1 for methylene blue and from Langmuir isotherm studies, the removal capacity of HPL was 232.55 mg g-1 and that of APL was 126.58 mg g-1 for methylene blue.The removal of methylene blue by HPL fits both Langmuir and Freundlich isotherms better than APL. The sorption capacity of Polyalthialongifolia leaves as found from the result suggests it to be a non-conventional and efficient biosorbent for the removal of MB from aqueous solution which can be used for the development of clean and cheap technology for effluent treatment.