Removal characteristics of copper by marine macro-algae-derived chars

The char derived from the fast pyrolysis of macro-algae biomass, a brown alga Undaria pinnatifida, proved to be useful for the removal or recovery of copper from aqueous solutions. Even at a low dose of 0.1 g char/L, a high adsorption capacity was obtained. Physical activation with steam enhanced the adsorption of Cu, but chemical activation with a KOH solution decreased the adsorption capacity. A pseudo-second order kinetic model was used to explain the adsorption kinetics. The physically-activated char showed a Langmuir type of isotherm, and had a maximum adsorption capacity of 125.85 mg Cu/g. Based on the adsorption capacity, even at a low copper concentration, the char derived from the fast pyrolysis of U. pinnatifida is a valuable adsorbent for recovering copper from aqueous solutions.

► Biochars derived from Undaria pinnatifida proved to be useful for the removal of copper.
► Physical activation with steam enhanced the adsorption of Cu.
► The pseudo-second order kinetic model explained well the adsorption kinetic data.