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

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.

Spirulina sp. biomass dried/disrupted by different methods and their application in biofilms production.

Arthrospira Spirulina biomass is a source of intracellular compounds with great commercial interest, such as phycocyanin and phenolic compounds. In this work, different cell disruption methods of the microalgae biomass dried in spouted bed and in conventional tray were performed, aiming lead to the better extraction yields of these compounds. The samples of both drying techniques with the most suitable cell disruption were used to biofilms production. FTIR, DSC, and SEM for all samples were performed. The samples dried in spouted bed with cell disruption by milling and by microwave showed the best results for the powder products, with phycocyanin contents of 75.0 and 85.4 mg g-1, and total phenolic compounds of 41.6 and 41.9 mg g-1, respectively. However, the tray drying/milling produced the biofilms with the best characteristics (tensile strength of 3.69 MPa and water vapor permeability of 1.67 × 10-11 g m s-1 m-2 Pa-1) and the highest thermal stability.