Experimental Study and Mathematical Modeling of a Nanofiltration Membrane System for the Recovery of Polyphenols from Wine Lees

Abstract

The winemaking process in Spain generates a significant amount of wastes such as wine lees. Currently, the nanofiltration process is a viable technique for the revalorization of compounds from wastes. In this aspect, this technique can be used for the recovery of compounds, such as polyphenols, as well as active principles widely used in industries, such as pharmaceuticals or cosmetics. Polyphenols are found in acceptable amounts in wine lees wastes and it is interesting to study the nanofiltration process viability to recover them. In order to study this possibility, it is necessary to determine the choice of the best membrane to use and the effect of operational parameters such as pressure, temperature, cross-flow rates, and concentration. In addition, it is important to be able to develop a mathematical model that can help in the future design of lees treatment plants. The treatment of red wine lees to concentrate polyphenols has been studied in a laboratory plant using different membranes (RO and NF) at different pressures (4.5, 9.5, and 14.5 bar), different temperatures (293, 303, and 308 K), and two concentrations (2100 and 1100 mg tyrosol eq·L−1). The results have been encouraging to consider nanofiltration as a viable technique for the treatment and revalorization of this waste. The most suitable membrane has been the NF270, in which 96% rejection rates have been obtained, with a flux of 30 L·h−1·m−2. Moreover, in this study, the Spiegler–Kedem model (SKM) was used to calculate mass transfer constants and permeabilities. Suitable adjustments of these parameters were obtained to validate this mathematical model. For this reason, the SKM might be used in future studies to continue in the research work of the treatment of wine lees wastes.

Experimental Study of a Sequential Membrane Process of Ultrafiltration and Nanofiltration for Efficient Polyphenol Extraction from Wine Lees

“…Once again, this adjustment is made by forcing the intersection through the origin, determining the water permeability of the membrane at a fixed temperature of 20 The resulting permeability parameter presents an elevated regression coefficient of 0.997, which indicates a good fit. This value is similar to those reported by other authors [27,[42][43][44], maintaining the same order of magnitude. Values of permeability 8.15 L/bar•m 2 •h were observed and the same operating conditions, whereas other experiments presented values of 7.04 and 8.7 L/bar•m 2 •h at an operating temperature of 25 °C.…”

“…The resulting permeability parameter presents an elevated regression coefficient of 0.997, which indicates a good fit. This value is similar to those reported by other authors [27,[42][43][44], maintaining the same order of magnitude. Values of permeability 8.15 L/bar•m 2 •h were observed and the same operating conditions, whereas other experiments presented values of 7.04 and 8.7 L/bar•m 2 •h at an operating temperature of 25 • C. These differences could be explained by the volumetric flow applied in the experiment, as they were inferior to the experiments conducted in this study.…”

“…Regarding the winemaking industry, the use of membrane technology to extract polyphenols from biproducts has been widely studied, including the purification of grape marc phenolic compounds using a sequential UF and NF process [23]. However, the most significant residues come from pomace, grape seeds and lees [24], which represent the residues on which UF and NF processes can be implemented most effectively and which have been intensively studied by other authors [25][26][27][28]. Due to the nature of wine lees, they do not require the use of any solvents to be directly suitable for membrane filtration, thereby resulting in lower costs for industries.…”

“…The method employed for the quantification of polyphenols involves a colorimetric technique using the Folin-Ciocalteu reagent (FCR), a mixture of phosphomolybdic and phosphotungstic acids that, upon reduction, takes on a bluish tone that can be measured through the absorbance of the sample at a wavelength of 765 nm [38]. Due to the large amount of existing phenolic compounds, the concentration of tyrosol in mg/L is used as reference [27].…”

Recovery of phenolic compounds from wine lees using green processing: Identifying target molecules and assessing membrane ultrafiltration performance

“…Unlike grape pomace, studies carried out in the context of the recovery of polyphenols from wine lees are scarce. Different pressure-driven membrane strategies have been evaluated for a range of membranes (Arboleda Meija et al, 2019;Giacobbo et al, 2013Giacobbo et al, , 2015Giacobbo et al, , 2017López-Borrell et al, 2022;Romero-Díez et al, 2018;Tapia-Quirós et al, 2022b;Tapia-Quirós et al, 2020). The process performance is usually assessed in terms of total polyphenol content or families of polyphenols, but profiling each individual component is not performed.…”