Removal of Reactive Red 198 from aqueous solution by Potamogeton crispus

► Adsorption capacity of alkali pretreated biomass was higher than native and acid pretreated biomass. ► Biomass functional groups were changed after chemical pretreatment. ► With increasing of biomass particle size, adsorption capacity was decreased. ► Hydrolysed RR198 adsorption capacity of biomass of decreased against to non-hydrolysed RR198. Native, acid and alkali pretreated dried Potamogeton crispus ( P. crispus) was used for adsorption of Reactive Red 198 from aqueous solution. Effects of physicochemical environment on adsorption were investigated. The surface charge of the native, acid and alkali treated biomass were determined to be zero at pH 4.6, 3.8 and 4.1 ± 0.1, respectively. Adsorption capacity of native biomass was increased with alkali treatment against native and acid pretreated biomass. The maximum adsorption capacities ( q max) at 20 °C of native, acid and alkali pretreated biomass were determined as 14.3, 26.8 and 44.2 mg g −1, respectively. FT-IR analysis shows that P. crispus has many functional groups such as COO, S O, C–N, N–H. These functional groups can react with dye molecule in solution. Pseudo-second-order and intraparticle diffusion kinetic models are applicable adsorption of RR198 by P. crispus since adsorption of RR198 is complex and involves more than one mechanism.