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During our research concentrations of quality wines were investigated by membrane separation on nanofiltration and reverse osmosis membranes. The practicability of the process was examined by experimental design in our laboratory experiments. The effects of the operating parameters on the efficiency of the methods were analyzed, from which the conclusion was drawn that the sugar content of the wines affects the filtrate capacity considerably. This phenomenon was attributed to the resistance appearing during the process. This resistance is the osmotic pressure which is faced with the driving force. By the mathematical modeling of the process - building up experimental and empirical relations - the answer for the practical implementing was searched for. Our concrete model concentrates on the connection between the changing of the osmotic pressure and the retained molecules by the membrane. Monitoring of this connection is a primary criterion when planning the optimal development of the process.

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Milk and dairy products contain a number of biological materials that are essential for the human body, for example proteins, lipids, vitamins and minerals. In this study the application of membrane filtration based milk partial demineralization is detailed. The main point of the partial demineralization is to reduce the monovalent ions (Na+, K+) but to keep the divalent ions (Ca2+, Mg2+) content. The experiments were carried out using laboratory ultra- and nanofiltration units. Comparing the separation behavior of the membranes it was found that the investigated membranes are suitable for the partial demineralization. The result of the Lowry test showed that the protein concentration is higher in the retentates of all membrane filtrations than in the permeates.

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Abstract

This study aimed to assess the effectiveness of two reverse osmosis membranes (RO99 and X20) plus one nanofiltration membrane (NF270) at concentrating hawthorn fruit and anise seed extracts. Extracting the anise was done using water at a temperature of 37 °C over a period of 100 min. For hawthorn, ethanol-water (56%) was used as the solvent and extraction occurred at 55 °C for 80 min. The transmembrane pressure (TMP), temperature, and recirculation flow rate of the membrane separation process were monitored and set at 35 bar, 30 °C, and 400 l/h respectively. Using a spectrophotometer, the quantification of valuable compounds was examined. After studying the flow levels, it was discovered that the X20 membrane had the tiniest alterations in permeability, followed by RO99 and NF270. Moreover, in terms of efficiency, the X-20 outperformed RO-99 and NF-270 membranes, where TPC was increased (20 and 18-fold) for anise seed and hawthorn fruit extracts respectively, and TFC was increased 8-fold for both of the extracts. While using NF-270, TPC was increased only (11 and 6-fold), and TFC (4 and 2-fold) for anise seed and hawthorn fruit extracts respectively. For the antioxidant activity, the process using X-20 showed an improvement of around 12-fold for anise extracts and 15-fold for hawthorn extracts for antioxidant activity. In terms of brix, the anise extracts saw a 3-fold increase and the hawthorn extracts saw a 4-fold boost after going through the X-20 membrane concentration process. Additionally, the X-20 membrane exhibits the highest retention rates for both anise and hawthorn extracts and is least affected by fouling during the concentration process.

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The problem of wastewater with high content of salt is a frequent problem for the environmental authorities, because the existing municipal and industrial wastewater treatments are incapable to remove effectively inorganic compounds. In this paper an attempt was made to report new results with reverse osmosis (RO) and nano-filtration (NF) membranes to remove salts from fermentation wastewater.The basic target of the experiments was to find an industrial membrane, which can separate salts from fermentation wastewater with a high efficiency and the concentration of the clean water should satisfy the environmental regulation: salt concentration ≤ 2500 mg/L and COD concentration ≤ 1200 mgO 2 /L. RO process exhibited good salt rejection and effective removal of organics. The other aim of this study was to model the osmotic pressure and permeate flux in the wastewater using basic expressions, like van’t Hoff law and Rautenbach equations. The combination of the above models with experiment based constants gave a good tool for modeling salty wastewater.

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Progress in Agricultural Engineering Sciences
Authors:
Szilvia Bánvölgyi
,
Eszter Dusza
,
Fiina K. Namukwambi
,
István Kiss
,
Éva Stefanovits-Bányai
, and
Gyula Vatai

Abstract

Similarly to other industries wineries also increasingly attempt to minimize and utilize waste to protect our environment. The aim of this study was to determine the optimal parameters (temperature, solvent concentration, and time) of extracting total polyphenol content (TPC) from Tokaji Aszú marc using two different extraction solvents: ethanol–water and isopropanol–water (1:4 solid/liquid ratio). The extractions were achieved based on Central Composite Design with Response Surface Method (CCRD–RSM). The optimal extraction parameters in the case of ethanol–water solvent: 60 °C temperature, 59.5% ethanol concentration in solvent, 5 h. At these parameters the probable TPC concentration is 23966.2 uM GAE/L. The optimal extraction parameters in the case of isopropanol–water solvent: 60 °C temperature, 52% ethanol concentration in solvent, 5 h. At these parameters the probable TPC concentration is 7188.44 uM GAE/L. In both cases the binary solvent was better than the mono-solvent. Ethanol–water solvent was more efficient than the isopropanol–water solvent.

Open access

Abstract

In this work, an assessment of effective solvents and extraction methods was carried out to recover the bioactive compounds from hawthorn fruit (Crataegus monogyna Jacq.). Extractions assisted by heat, microwave, and ultrasound were carried out using various organic solvents (methanol, ethanol, and isopropanol). pH differential, Folin–Ciocalteu's, and aluminum chloride methods were used to determine total monomeric anthocyanin (TMA), total phenolic compound (TPC), and total flavonoid content (TFC), consecutively. Ferric Reducing Antioxidant Power (FRAP), 2,2-Diphenyl-1-picrylhydrazyl Hydrate (DPPH), and 2,2′- azino- bis (3-ethylbenzothiazoline-6- sulfonic acid) (ABTS) assays were used to measure the antioxidant activity (AA) of the extracts. The outputs revealed that extraction methods and solvents significantly affect anthocyanin concentration, TPC, TFC, AA, and color values of hawthorn fruit extracts. Due to the highest recovered TMA (0.152 ± 0.002 mg ECy3Gl/g of dry weight), TPC (49.14 ± 0.38 mg gallic acid equivalents/g of dry weight), and TFC (18.38 ± 0.19 mg quercetin equivalents/g of dry weight) contents, the ultrasonic-assisted extraction is superior to heat and microwave-assisted extractions. Accordingly, it was also observed that the methanol solvent is more profound than ethanol and isopropanol. Further, the bioactive compounds' content and the extracts' antioxidant activity are shown to be highly correlated. Thus, hawthorn extracts are considered to have antioxidant properties because of their concentrated bioactive compounds.

Open access