A regeneration circuit for regeneration of a dialysis fluid. An inlet and an outlet are arranged to pass a dialysis fluid to and from the regeneration circuit by means of a pump. An adsorbent cartridge is arranged downstream of the pump and comprises an adsorbent made of e.g. activated carbon and an adsorbent made of metal-complexed chitosan and possibly further adsorbents. Downstream of the last adsorbent is arranged a further general adsorbent arranged to adsorb metal ions, such as copper ions, possibly given off by previous adsorbents. Such a general adsorbent is an adsorbent made of uncomplexed chitosan, which adsorb metal ions and does not adsorb physiological electrolytes commonly included in a dialysis fluid, such as sodium, potassium, calcium and magnesium ions.
