nthispresentwork,acommercialcoffeewastewastreatedusingcationicsurfactantscetyltrimethylammo-niumbromide(CTAB)orcetylpyridiniumchloride(CPC)toenhanceitsadsorptioncapacityfortheremovalofmethylorangedye(MO,anionicdye)fromaqueoussolutions.AseriesofexperimentswereundertakeninanagitatedbatchtoassesstheeffectofkeyparameterssuchaspH,contacttime,adsorbentdoseandionicstrength.Maximummethylorangedyeadsorptionontomodifiedcommercialcoffeewaste(MCWs)wasob-servedatpH3.5with0.1g/50mlofadsorbentdose.Modelingstudyshowsthatpseudo-second-orderkineticmodelandLangmuiradsorptionisothermmodelprovidebetterfitnesstotheexperimentaldata.Themaxi-mumadsorptioncapacity(62.5mg/gat25°C)wasobtainedwithCPCmodifiedcommercialcoffeewaste.Cal-culatedthermodynamicparametersG0,H0andS0showedthatadsorptionisspontaneousandexother-mic.TheFT-IRanalysisshowedthatpossiblemechanismscontrollingMOadsorptionontheMCWsincludedelectrostaticinteractionsandhydrophobicinteraction.