Influence of Preparation Method of Spirogyra Sp. Algae on their Sorption Capacity

The influence of the preparation method of samples on the zinc ions sorption parameters in Spirogyra sp. algae was analysed. The Zn²⁺ sorption process from the salt solutions of this analyte was carried out in static conditions. The carried out analyses results show that the method of algae samples preparation for analyses (thermal drying, freeze drying, samples conditioning in demineralised water) and storage period influence their sorption capacity. On the basis of the carried out research of the metal sorption kinetics in live and prepared algae samples, it was found that the equilibrium is achieved after approximately 30 min. In the experiment conditions, 56% of metals are sorbed in live algae during the first 15 min. Approximately 17 and 65% of zinc ions present in the dilution accumulated in thermally dried and freeze dried algae samples respectively after 30 min of the process. It was confirmed that conditioning of the algae samples in demineralised water, prior to the sorption process, increases its efficiency. In order to define sorption capacity of freeze dried Spirogyra sp. algae, the Langmuir isotherm model was applied. It was found out that algae absorb heavy metals in proportion to their content in a solution, in which they were immersed. The sorption capacity of freeze dried Spirogyra sp. algae and zinc, defined with the use of the Langmuir isotherm, shows considerable imprecise result. Evident influence of hydrogen cations on zinc concentrations in algae and in the solution in the state of equilibrium was found out.