Obtenção de lignina a partir do caroço do bagaço da azeitona oriundo da extração do azeite

Abstract

The production of 1 liter of olive oil is responsible for generating about 4 kg of pomace that, due to the high amount of phenolic compounds present in its composition, may cause damage to the environment when disposed of improperly. For this reason, ways to use olive pomace are being studied, aiming, besides the creation of new technological applications, to reduce the environmental impact of incorrect disposal. Among the components of the lignocellulosic biomass of olive pomace is lignin, and the pit is the main source of this compound. Lignin has a phenolic nature and is characterized as non-toxic, renewable and biodegradable, and has the function of providing rigidity, strength and flexibility to the cell wall, also helping in the protection against attacks by microorganisms and in the transport of water and nutrients. Its main application, after the separation of cellulose, is burning for energy generation. However, its abundance and the presence of functional groups that influence its characteristics and bring benefits to different applications, allow the expansion of studies focused on the research of methods of valorization of this compound in processes of greater added value as a substitution of phenol in phenol-formaldehyde resins, dispersant in pesticides, additive in concrete, addition in animal feed, incorporation into thermosetting resins, application in biodegradable films, among others. Knowing the presence of 26.5 to 39% of lignin present in the olive pit, it was sought to combine the redirection of waste from olive oil production with obtaining lignin to add value from new applications. Therefore, the objective of this study was to obtain the lignin from the olive pomace from olive oil extraction. The results showed that the olive pomace kernel has a solid fraction rich in lignin and showed increased efficiency of pulping using NaOH concentration of 11%. The bands presented by the FT-IR spectrum proved the presence of lignin in the extracted material and the thermogravimetric analysis allowed the observation of points of thermal stability of lignin as well as its degradation behavior in the presence of heat. Therefore, it is possible to perform the isolation of lignin from the olive pomace kernel, but further analysis of the obtained product would be necessary in order to obtain more knowledge about its structure.