Development of chitosan/Spirulina sp. blend films as biosorbents for Cr6+ and Pb2+ removal

• Published in: International journal of biological macromolecules 2020-07, Vol.155, p.142-152
• Main Authors: Gerhardt, Rafael, Farias, Bruna S., Moura, Jaqueline M., de Almeida, Leandro S., da Silva, Adriano R., Dias, Daiane, Cadaval, Tito R.S., Pinto, Luiz A.A.
• Format: Article
• Language: English
• Subjects: Electrostatic interaction; Metal ions; Physical integrity
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2020.03.201

Chitosan film, Spirulina sp. film and its blend were developed as biosorbents to remove Cr6+ and Pb2+ ions from aqueous solutions. The kinetic study and the pH effect on biosorption efficiency were evaluated to comprehend the interactions between the ions and biosorbents. The characterization analyses pointed out that occurred interaction between both biomaterials, which resulted in structural alterations through the blend. The Spirulina sp. film exhibited the highest biosorption capacities for Cr6+ (43.2 mg g−1) and Pb2+ (35.6 mg g−1) ions, however, its physical integrity was not kept in acid medium. The blend film showed results slightly lower (35.8 mg g−1 for Cr6+ and 31.6 mg g−1 for Pb2+), but its physical integrity remained intact in all assays. Chitosan film presented the lower biosorption capacities (15.4 mg g−1 for Cr6+ and 20.9 mg g−1 for Pb2+). Elovich and pseudo–second order models were the most suitable to express the kinetic behaviors for Cr6+ and Pb2+, respectively. Therefore, chitosan/Spirulina sp. blend could be a green alternative for Cr6+ and Pb2+ removal, because this biosorbent showed high biosorption capacity obtained from Spirulina sp. and great physical integrity obtained of chitosan. •Chitosan film, Spirulina sp. film and its blend were successfully developed.•Spirulina sp. film showed the highest biosorption capacities for Cr6+ and Pb2+ ions, but no integrity at acid pH.•Chitosan improved the mechanical properties of the blend film.•Blend film stood out due to its high biosorption capacity and physical integrity.•Electrostatic interactions were the main mechanism regarding biosorption process.