Purine removal with graphene based materials foreseeing their application in the brewing industry

• Autor(a) principal: Santos, Ana Catarina Almeida
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/30111
• topic: Beer; Purine compounds; Uric acid; Hyperuricemia; Gout; Adsorption; Graphenebased materials; Adsorption kinetics; Adsorption isotherms; Adsoprtion efficiency

Beer exhibit purine compounds which are catabolized into uric acid leading to its serum level increase which may contribute to hyperuricemia and gout. Thus, it is relevant develop an efficient and selective method to remove these compounds from beer. An iron oxide functionalized graphene-based material was prepared through a sustainable approach, characterized and used to remove purine compounds in an aqueous media. Kinetic and equilibrium isotherm studies were applied to purines and aromatic amino acid adsorption to understand the mechanisms of the process, the relationship with the surface features of the adsorbent material and the interactions and to evaluate the selectivity of the material. The Pseudo Second Order was used to adjust the adsorption kinetic of all the studied compounds, showing an adsorption process on the solid-phase interface on the adsorbent material. A maximum removal efficiency of 68.40 and 69.70% was obtained for adenosine and guanosine and 45.90 and 47.16% for adenine and inosine, showing its applicability on their removal process. A maximum adsorption efficiency of 15.35 and 27.16% was obtained for L-Tyrosine and L-Tryptophan, demonstrating a greater selectivity of the material for purine compounds. SIPS model was adjusted to adsorption isotherm of all the studied purine, except for adenosine, where the Freundlich model was used for the adjust, proving the heterogeneity of the external surface of the material. The SIPS model adjusts the adsorption isotherm of L-Tyrosine, while the Freundlich model was used to adjust the isotherm for L-Tryptophan. Despite its applicability to adsorb purines, further studies need to be accomplished to increase its selectivity and then develop a method to remove them from beer, thus improving brewing industries, allowing it to consume by hyperuricemic and gouty patients and decreasing the healthcare economic burden.