Membrane performance and application of ultrafiltration and nanofiltration to ethanol/water extract of Eucalyptus bark

Life cycle assessment of tannin extraction from spruce bark

“…In the P3 scenario, the extract volume reduces during ultrafiltration by a factor of 1.76, as described by Pinto et al (2014), and the concentrate is further evaporated to the required tannin concentration level.…”

“…However, lack of a bark flushing might result in a lower recovery of extractives for PHWE than for ASE extraction. For the P3 scenario, the volume of the extract water solution after ultrafiltration is assumed to decrease by a factor of 1.76 (Pinto et al 2014). The efficiency of ultrafiltration process can vary, mainly depending on the membrane type and transmembrane pressure.…”

“…The efficiency of ultrafiltration process can vary, mainly depending on the membrane type and transmembrane pressure. According to Pinto et al (2014), as much as 93% of the extracted condensed tannins can be recovered. For simplicity, we assume that no tannins are lost after ultrafiltration, yielding a somewhat over-positive but recoverable estimate of the process performance.…”

“…2, right panel) indicates that the percentage of evaporation decreases compared to the P1 scenario, e.g., the relative contribution of GWP is reduced from 86% to 77%. In addition, ultrafiltration can promote the enrichment of tannins in products, according to Pinto et al (2014), which might increase the effectiveness of the extract as an antifungal agent. However, there might be some tannin loss after ultrafiltration, which would lead to a yields reduction.…”

“…Another way to purify tannins is to apply different membrane filtration methods commonly used to separate desirable compounds from a compounds mixture with a low energy requirement (Nawas et al 2006). In fact, Pinto et al (2014) reported that ultrafiltration can increase the concentration of tannins in the extracts of Tasmanian bluegum bark (Eucalyptus globulus Labill.) by about 20 to 30 per cent.…”