A new approach for rhenium(VII) recovery by using modified brown algae Laminaria japonica adsorbent

Brown algae Laminaria japonica was chemically modified with sulfuric acid to obtain a crosslinked brown algae gel (CAS). The CAS gel showed a high affinity for Re(VII) comparing with other biomass gels, and the maximum adsorption capacity was evaluated as 37.20 mg g−1 in case of pH 6, which could be explained by their different adsorption mechanisms. The adsorption equilibrium, kinetics and thermodynamic study for Re(VII) on the CAS gel was discussed in detail by the several models, such as Langmuir, Freundlich, Temkin and Dubinin–Radushkevich model for kinetics analysis, the pseudo first, the second-order, the Elovich and intraparticle diffusion equation for equilibrium analysis. Reutilization of the CAS gel was confirmed up to three adsorption–elution cycles in column-mode operation with no damage of gel, packed in the column. The result also provides a new approach for the recovery of Re(VII) from Re-containing wastewater by using the modified brown algae gel.

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► A low cost brown algae Laminaria japonica biosorbent treated by H2SO4 was developed.
► The novel adsorbent exhibited a high affinity for Re(VII) comparing with other biomass gel.
► Several models were applied to obtain kinetics and equilibrium parameters.
► The recovery of Re(VII) from Re-containing wastewater was possible.