The aim of this work was to develop bio-sourced membranes suitable for heavy metals extraction under acidic solutions. For this purpose cross-linked gelatin membranes were synthetized and tested to carry out copper (II) ions extraction from aqueous acidic solutions as a model. Gelatin membranes were cross-linked with three different compounds: terephthalaldehyde (TPA), ferulic, acid (FA) or glutaraldehyde (GTA) in vapor phase. Both gelatin-TPA and gelatin-FA membranes showed a weak resistance in aqueous medium though gelatin-GTA membranes were very stable and resistant to acidic conditions. A preliminary study of copper (II) permeation showed that gelatin-GTA membranes were very permeable whereas they are slightly affected by the acidity of the aqueous medium and very efficient for the transfer of copper (II) ions at low concentrations. (C) 2017 Elsevier B.V. All rights reserved.