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Modification of the Process of Obtaining Pectin by the Methods of Membrane Technology

Davitadze Nazi

Journal of Ecological Engineering

2023

Vol. 24, nr 11

117--126

The proposed approach to the processing of plant materials using membrane methods is new in the field of developing new methods for isolating pectin substances and obtaining not only pectin itself, but also new low-cost high-quality pectin-containing products. The studies were carried out on pressings obtained after squeezing juice from citrus fruits (Georgia): lemon (“Meer”), Washington-Navel orange variety, “Unshiu” mandarin and the largest citrus pomelo fruit (China). From the fruits harvested in April-December, the juice was squeezed out and from the remaining mass, which was crushed, by adding HCl (1:10) pectin isolates were obtained, which were concentrated by ultrafiltration. Soluble pectin was precipitated from the concentrated extract with ethyl alcohol, i.e. converted to an insoluble form. The resulting precipitate was thoroughly washed with alcohol and then dried at T = 55°C. The concentration of isolates was carried out by tangential filtration in dynamic mode on a UPL-06 unit, an AR-0.2 ultrafiltration separating apparatus was used as a membrane, which was located vertically in the unit and was a ready-made module with a filtration area of 2 m2; obtained on the basis of polyamide and phenylone – C 2-B hollow fibers VPU-15PA with a pore size of 500 A. Ultrafiltration was carried out in circulation mode to the maximum possible concentration of the extract. The dependence of the productivity of the process of purification-concentration of pectin extracts from citrus fruit waste without their morphological division, pressure, duration and filtration mode, type and term of fruit harvesting was studied. The work performed has shown that the use of semi-permeable membranes for concentrating pectin extracts allows: to a large extent to remove carbohydrates from the extract, to achieve partial discoloration of the pectin extract; ensure 100% retention of pectin substances by membranes; to achieve a high degree of concentration of the extract and made it possible to obtain a pectin preparation with a purity of 95%. The proposed technology using membrane technology makes it possible to obtain pectin with a purity of 95% or more by purifying it from ballast impurities at the stage of extract concentration.

A Mini-Review on Thin-Film Composite Hollow Fiber Membranes for Forward Osmosis Applications

Al-Musawy Wafaa Kh., Al-Furaiji Mustafa H., Aljumaily Mustafa Mohammed, Rashid Khalid T., Salih Hussein G., Alsalhy Qusay F., Majdi Hasan Sh., Figoli Alberto

Ecological Engineering & Environmental Technology

2023

Vol. 24, iss. 1

287--301

Forward osmosis (FO) is an emerging technology that has been extensively studied in the last decade as an efficient method for desalination and water treatment. FO presents many benefits over traditional desalination technologies such as reverse osmosis and distillation. Nevertheless, there are many decisive challenges; the great significance one is the new modification and advances in the preparation of the TFC membranes that must be achieved to enhance the FO performance. Therefore, preparing a suitable TFC membrane with a low structural parameter, low tortuosity, and high porosity are preferred in preparing the TFC membranes to get higher water flux and lower salt flux. This paper reviewed the recent development and advances in using TFC hollow fiber membranes in FO applications. Within that, the most widely applied monomers to prepare the thin polyamide layer (PA) in TFC membranes and the additives that are added during the preparation of the PA layer and their effect on the performance of the TFC membranes have been discussed. Moreover, an effort is made to generate a TFC membrane properties and performance trend according to the results of the water permeate flux and reverse salt flux of the modified TFC FO membranes and the future perspectives and concluding remarks on the FO membrane are evaluated.

Hollow fiber-based liquid phase microextraction combined with high performance liquid chromatography for determination of flavonoids in Ginkgo biloba and urine

Lu H., Wang X., Liu X., Jiang S.

Chemia Analityczna

2009

Vol. 54, No. 3

309-319

A hollow fibre membrane-based liquid phase microextraction (HF-LPME) method for determination of flavonoids in Ginkgo biloba leaves was developed. Three flavonoids: quercetin, kaempferol, and isorhamnetin were extracted and then analysed by high performance •-:; liquid chromatography. The factors affecting HF-LPME, including concentration of donor ,; and acceptor phases, concentration of NaCl, extraction time, and stirring speed were systematically investigated. Under the optimum conditions, calibration plots of reasonable linearity were constructed in the analyte's concentration range of 10-100 μg L-1. Up to 200-fold enrichment factor for quercetin and up to tens of folds for kaempferol and isorhamnetin ' were obtained. The method was applied to determine the concentrations of flavonoids in urine and was proven to be an convenient sample preparation technique.

Opracowano metodę oznaczania flawonoidów w liściach Ginkgo biloba za pomocą ^ mikroekstrakcji z fazy ciekłej przy użyciu membranowego wydrążonego włókna. Ekstra-howano i analizowano trzy flawonoidy: kwercetynę, kempferol i izorhamnetynę stosując wysokosprawną chromatografię cieczową. Systematycznie zbadano następujące czynniki wpływające na mikroekstrakcję: stężenie donora i akceptora, stężenie NaCl, czas ekstrakcji oraz szybkość mieszania. W optymalnych warunkach uzyskano liniowy wykres krzywej kalibracji w zakresie stężenia analitu od l O do 100 μg L-1. Współczynnik zatężenia wynosił do 200 razy w przypadku kwercetyny i do dziesiątek razy w przypadku kempferolu oraz izorhamnetyny. Opracowaną metodę zastosowano do oznaczania zawartości flawonoidów w moczu. Stwierdzono, że metoda jest odpowiednia do przygotowywania próbek.