Rastreio etnobotânico nas comunas de Caxito, Mabubas e Úcua (Província do Bengo): resultados preliminares

Objectivos do estudo: documentar e valorizar os conhecimentos tradicionais, relativamente a utilização de plantas medicinais; orientar estudos de recolha, classificação e identificação de espécies; potenciar a elaboração de perfis fitoquímicos e ensaios de bioactividade em espécies com potencial farmacológico; avaliar a biodiversidade vegetal na área de estudo potenciando a valorização da flora da região; potenciar a integração de estágios e capacitação de recursos humanos no âmbito do projecto CISA.

Nanofiltration of Cork Wastewaters and Their Possible Use in Leather Industry as Tanning Agents

Cork processing wastewater is a very complex mixture of vegetal extracts and has, among other natural compounds, a very high content of phenolic/tannic colloidal matter that is responsible for severe environmental problems. In the present work, the concentration of this wastewater by nanofiltration was investigated with the aim of producing a cork tannin concentrate to be utilized in tanning. Permeation results showed that the permeate fluxes are controlled by both osmotic pressure and fouling/gel layer phenomena, leading to a rapid decrease of permeate fluxes with the concentration factor. The rejection coefficients to organic matter were higher than 95%, indicating that nanofiltration has a very good ability to concentrate the tannins and produce a permeate stream depleted from organic matter. The cork tannin concentrate obtained by nanofiltration and evaporation had total solids concentration of 34.8 g/l. The skins tanned by this concentrate were effectively converted to leather with a shrinking temperature of 7 degrees C.