Possible Use of the Algae Lessonia nigrescens as a Biosorbent: Differences in Copper Sorption Behavior Using Either Blades or Stipes

Abstract

Sorption experiments for copper removal were carried out using two different parts of the brown seaweed Lessonia nigrescens (L. nigrescens) as biosorbent. The effect of initial pH, contact time, mass–volume-ratio (M/V) and initial metal concentration was evaluated. The best adsorption capacities were obtained at pH = 3.2 ± 0.2, and to reach equilibrium, 7 days of contact time were necessary for both sections of the seaweed. The maximum experimental uptake achieved was 54.5 mg Cu g−1 by the blades of the alga and 58.5 mg Cu g−1 by the stipes. Both Langmuir and Freundlich models described the equilibrium sorption isotherms very well when using stipes as biosorbent, but the fitting was poor with both models when blades were used as biosorbent. The Ho and McKay pseudo-second order model described the sorption kinetics for stipes and blades satisfactorily.