Research paperSorption of Congo red and reactive blue on biomass and activated carbon derived from biomass modified by ionic liquid

•Peanut shell and AC synthesized from peanut shell were modified by Ionic liquid.•Characterization of the materials using FTIR, SEM, BET and TGA.•The materials were used in the adsorption of Congo red and reactive blue dyes.•Ionic liquid modified-materials had better sorption capacities than unmodified ones.

Ionic liquid modified sorbent materials derived from peanut shell were prepared and used in the sorption of Congo red (CR) and reactive blue 4 (RB) dyes from aqueous solution. 1-methyl-3-decahexyl imidazolium ionic liquid (IL) was used to modify peanut shell (NS) and activated carbon (AC) from NS, to produce IL modified peanut shell (ILNS) and IL modified AC (ILAC), respectively. The adsorbents were characterised by fourier transform infrared (FTIR), Brunauer−Emmett−Teller (BET), x-ray diffraction (XRD), thermal gravimetric analysis (TGA) and scanning electron microscopy (SEM). The effects of sorbent dosage, initial solution pH and contact time (min) were evaluated. Adsorption was pH dependent, the modified materials (ILNS and ILAC) showed improved adsorption capacities of 136.4 and 150.0 mg g−1 for CR and 290.0 and 364.4 mg g−1 for RB respectively. Adsorption followed pseudo-second order. Also, adsorption of CR and RB onto ILAC followed the Freundlich isotherm, while ILNS was described by Freundlich and Langmuir.