The adsorption of Acid Blue 92 onto three low cost and ecofriendly biosorbents viz., cow dung ash, mango stone ash and
parthenium leaves ash and commercial activated carbon have discussed in this work. The ash of all the mentioned bio-wastes
was prepared in the muffle furnace at 500oC and all the adsorbents were stored in an air thermostat. Experiments at total dye
concentrations of 10~100 mg/L were carried out with a synthetic effluent prepared in the laboratory. The parameters such as
pH and dye concentration were varied. Equilibrium adsorption data followed both Langmuir and Freundlich isotherms. The
results indicate that cow dung ash, mango stone ash and parthenium leaves ash could be employed as low-cost alternatives to
commercial activated carbon in wastewater treatment for the removal of dye.