This paper reports the removal of a basic dye (rhodamine-B) by the activated carbon prepared from Parthenium biomass by sulphuric acid treatment method (SWC). The effectiveness of the prepared adsorbent has been studied as a function of agitation time, adsorbent dosage, initial dye concentration and pH. The removal of rhodamine-B by SWC followed second order kinetic model. The second order model best describes adsorption kinetic data. Adsorption data were modeled using both Langmuir and Freundlich classical adsorption isotherms. The adsorption capacity Q(0) was 18.52 mg/g at initial pH 7 for the particle size 0.3-1 mm. The equilibrium time is about 60 min for the studied initial dye concentrations. Maximum dye removal (99.2%) was obtained at pH 7 using an adsorbent dose of 16.0 g/L for 50 mg/L dye concentration in the aqueous solution. FT-IR spectra of the adsorbents were recorded to explore the number and position of functional groups available for the binding of dye onto studied adsorbents. The presence of O-H, C=O and C-O groups was identified in the adsorbent. SEMs of the native and exhausted (SWC) were recorded to explore the morphology of the adsorbent.