Synergic adsorption of acid blue 80 and heavy metal ions (Cu2+/Ni2+) onto activated carbon and its mechanisms

•Synergic adsorption of AB80 and Cu2+/Ni2+ was achieved onto PRAC.•The adsorption of AB80 and Cu2+/Ni2+ were clearly enhanced.•AB80 and Cu2+/Ni2+ adsorption onto PRAC was interpreted by multicomponent isotherms.•Possible mechanisms of the synergic adsorption process were proposed.

A novel synergic adsorption process of acid blue 80 dye (AB80) and heavy metal ions (Cu2+ or Ni2+) on a low-cost activated carbon (PRAC) which was prepared from potato residue was reported. The results indicated that the maximum adsorption capacity of PRAC for AB80 and Cu2+ were 294.7 mg/g and 45.0 mg/g in the AB80-Cu2+ system, respectively. In the mono-component system, the values were 173.0 mg/g and 26.8 mg/g, respectively. Compared with mono-component system, the AB80 and Cu2+ showed good synergistic effect on PRAC. The similarly result was revealed in the AB80-Ni2+ system. For a binary system, the adsorption isotherm of AB80 and heavy metal ions followed the non-modified Sips model, and the adsorption kinetic models followed the pseudo-second order kinetic model. The effect of pH also was discussed, and showed significant role in the binary-component system adsorption. The selectivity in synergic adsorption was discussed. BET, FE-SEM/EDX and XPS were used to characterize PRAC with and without adsorbed dye and heavy metal ions, possible mechanisms of AB80 and heavy metal ions synergic adsorption process were proposed.