Application of Ultrafiltration for Recovery of Bioactive Phenolic Compounds from Rose Wastewater

The purpose of this work was to investigate the posibilties of ultrafiltration with three polyacrylonitrile membranes (molecular weight cut-off 1 kDa, 10 kDa, and 25 kDa) to recover the total polyphenolic compounds, phenolic acids and flavonoids from rose wastewater. The permeate flux, energy demand, contents of total polyphenolic compounds, phenolic acids and flavonoid phenolic compounds were determined during ultrafiltration at volume reduction ratio of 2, 4, 6 and 8, and the rejections and concentration factors were established. The permeate flux decreased with the rise in the volume reduction ratio, and with the decrease in the transmembrane pressure and the molecular weight cut-off of the membranes. Inverse relationship was observed between the permeate flux and the energy demand at the same operating conditions. The rejections and concentration factors of total polyphenolic compounds, phenolic acids and flavonoid phenolic compounds rose with the increase in the volume reduction ratio for all membranes. The 1 kDa membrane had higher concentration and rejection effectiveness than 10 and 25 kDa membranes. Protocatehuic and vanillic acid, determined by using HPLC, increased in the retentate when 1 kDa membrane was used, while gallic acid, catechin, p-coumaric acid, rutin, hesperidin, rosmarinic acid decreased.