Sorption of heavy metals in the biomass of alga Palmaria palmata

Sorption of heavy metals by the sea alga Palmaria palmata was investigated in laboratory conditions. The sorption process of the analytes was carried out with constant flow of the solutions through the algae samples. The Langmuir isotherm model was used to describe equilibria. The experiments confirmed that 50 min of exposure of algae with little heavy metal contamination in contaminated waters results in the increase of concentration of these analytes, proportional to their concentration in the tested waters. On the basis of the Langmuir isotherm direction factor, a = (c_(a,max) × K)⁻¹, affinity of heavy metals and algae increases in the following sequence: Mn²⁺ < Zn²⁺ ≈ Cd²⁺ < Cu²⁺, and the competitiveness of sorption of cations naturally present in the algae environment versus Zn²⁺ ions changes according to following sequence: Na⁺ < Ca²⁺ < H⁺, defined for the concentrations referring to the ion unit charge. It was also confirmed, that the presence of sodium and calcium ions in the solutions, within the conductivity range from 200 to 1,000 μS/cm, is not statistically significant for the sorption of heavy metals from these solutions.