Activated carbon (AC) can be used as an adsorbent to remove pollutants from waste water streams.rn520 kg flower biomass waste is generated daily at a single floriculture industry in Ethiopia. DespiternAC has been produced from different lignocellulosic biomass waste, utilizing Flower wasternbiomass (FWB) as a precursor to produce AC has an advantage of being new raw material, easilyrnavailable, renewable precursor, and can be a way of reducing environmental pollution. This studyrnpresents synthesis of AC from FWB by chemical activation method using ZnCl2 and removal ofrnmethylene blue (MB) using the as-prepared AC. The parameters in the study were impregnationrnratio, carbonization temperature, and carbonization time. Higher BET surface area of 750 mrn2rn-1rn grn, rnpore volume of 1.91 cmrn3 rn-1rngrn and pore diameter of 1.89 nmrn rnwas obtained at 1:1 impregnation ratio, rnÂ°rn500 rnC carbonization temperature, and 1 hr of carbonization time. Effect of adsorption dosage, PH, rninitial dye concentration, and contact time on percentage removal of MB were studied. Maximumrnremoval of MB was recorded at 0.05 g adsorbent dosage, 60 min contact time, PH of 10, and initialrndye concentration of 10 mg Lrn-1rn. Kinetics and isotherm studies showed that the adsorption rnmechanism of MB using FWB based AC follows pseudo second order while both Langmuir andrnFreundlich model well fitted the adsorption data with maximum removal efficiency of 94.2% andrnadsorption capacity of 22.39 mg grn-1rn. FWB can be a good precursor for AC production and can be rnused to remove MB from wastewater.