Authors:Z. Šereš, J. Gyura, M. Eszterle, and Gy. Vatai
The produced sugar, as the final product in sugar production technology, has to contain as low non-sucrose compounds with coloured matters as possible. Ultrafiltration and nanofiltration could be one of the solutions for a more effective separation of non-sucrose compounds from intermediate products from which sucrose directly crystallises. The separation of non-sucrose compounds by ultra- and nanofiltration is investigated on syrup solution with 40% d.m. content, which is an intermediate product in the phase of sucrose crystallisation. Further, this paper investigates variables in the ultrafiltration and nanofiltration of syrup solutions, such as variations in pore sizes of the polymer membranes, syrup temperatures, syrup flow rates and transmembrane pressures. During ultrafiltration, under the investigated conditions; permeate flux is about 10 times less than water flux (150 m-2h-1) on the first membrane and 8 times less than water flux (285 m-2h-1) on the second membrane, while the nanofiltration permeate flux is 15 times less than water flux (320 m-2h-1). The permeate flux decreases due to the adsorption of non-sucrose compounds by the filter membranes and the resultant increase in resistance to mass transfer. The colour content is about 58% lower by ultrafiltration using membranes. There is no great difference in colour separation between the used ultrafiltration membranes with different pore sizes. Nanofiltration was shown to separate 76% of coloured matter from syrup. In all the examined cases, permeate turbidity could be reduced by 75-80%, according to feed.
In our investigations the membrane filtration of quality wines (Tokaji Hárslevelű and Egri Bikavér) — based on diafiltration principles, applying nanofiltration membranes — has been studied. For the diafiltration experiments a relatively dense nanofiltration membrane NF 45 has been used, while for simple wine concentrations a membrane developed for organic components rejection NF200 has been investigated. The mixture of the retarded wine compounds was considered the main product of the process. The permeate that crossed the membrane was handled as the by product. Separated wine samples and the original wines have been subjected to gas chromatographic analysis: according to the results the partition of the main components and aroma compounds of the samples was approximately equal between the main and by-product. Membrane separation has been applied in accordance with a “prelaborated” experimental plan, when completing it the effect of operational parameters on the effectiveness of the process has been evaluated and analysed. By mathematical modelling of the phenomenon empirical and quasiempirical relations were set up, and solutions for the practical realization of the procedure were searched for. Our new model describes the filtration efficiency with our new index in the function of the operational parameters’ influence. The significance of the relation is, that the knowledge of the wine-constants might promote the expedient choice of the membrane, which is a primary aspect in planning and creating the process optimal.
Authors:Jesus Molina, Gyula Vatai, Eszter Fogarassy, and Erika Bekassy-Molnar
. (2001) Nanofiltration used desalination and-concentration in dye production,
Journal of Membrane Science
Semiat, R., Iris, S., David, H. (2001) Technique for evaluating silica scaling and its
Authors:F. Chitry, R. Garcia, L. Nicod, J. Gass, C. Madic, and M. Lemaire
A new method is proposed for the separation of gadolinium(III) and lanthanum(III) in aqueous medium by nanofiltration combined
with a complexation step. First DTPA was chosen as ligand for a selective Gd(III)/La(III) complexation. Having investigated
the influence of three factors (pH, temperature and amount of ligand) for the selective complexation of DTPA towards Gd(III)
and La(III), the system is then combined with a nanofiltration separation process to remove 92% of initial Gd(III) and only
12% of initial La.
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.
Authors:S. Mondal, M. Berihun, M. Kovacs, G. Vatai, and A. Koris
Microscopic organisms play a vital role in the field of green technology. Among the genera fungi, the group of entomopathogens includes Beauveria bassiana, which has been found to have multifunctional applications. In this present research, we have attempted to partially purify chitinase from two strains of Beauveria bassiana (F881 and F911), each cultured in minimal media with 1% (w/v) colloidal chitin as well as in Sabouraud's dextrose media with 1% (w/v) colloidal chitin. The purification process was done with a setup of ceramic membranes, which comprises two stages, ultrafiltration (50 nm pore size membrane) and nanofiltration (MWCO 5 kDa). Furthermore, with the analysis of yield of enzymatically hydrolyzed NAG (N-acetyl glucosamine), resistance and fouling of the membrane were also studied.
Authors:Péter Bor, József Csanádi, Gábor Veréb, Sándor Beszédes, Zita Šereš, Zsuzsanna László, Cecilia Hodúr, and Szabolcs Kertész
To meet the requirements defined by environmental protection regulations effective wastewater treatment is required to process effluents before discharging them into sewers or living waters. While membrane separation offers a quite advantageous method to reduce the organic load of wastewaters, membrane fouling is still limiting its application in wastewater treatment.
In this study, the possibility of membrane fouling reduction by increased shear rates on the surface of the membrane was investigated. 7 and 10 kDa MWCO ultrafiltration and 240 Da nanofiltration membranes were studied, with the use of a laboratory mode Vibratory Shear Enhanced Processing. This work mostly focused on studying the effects of module vibration and recirculation feed flow rate on permeate flux, specific energy demand and membrane rejections. Using the same operation parameters, vibration and non-vibration mode experiments were carried out with high and low recirculation flow rate to have a deeper understanding of the shear rate effects. It can be concluded that higher shear rate had a positive effect on the process: increased shear rate resulted in higher flux, higher overall rejection values, as well as a significantly decreased specific energy demand. By calculating and comparing the shear rates in experiments with different operating parameters, both vibration and nonvibration mode, both low and high recirculation flow rate, we have reached the conclusion that vibration causes a significantly higher shear rate increase than setting the recirculation flow rate high.
Authors:E. Márki, I. Vas-Vincze, L. Tóvári, and Gy. Vatai
One of the most important enriching materials at the processing of alimentary pastes is the egg, which usage is limited because of its water content. Removing water from liquid whole egg with membrane processes, such as ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) was applied for raising the solid content at a temperature of 25 °C at constant flow rate. The separation procedures were carried out on laboratory scale equipments. The initial solid content of the liquid whole egg was 24 refractive (Ref%). The effects of different recirculation flow rates and transmembrane pressure differences were investigated on the permeate flux of the liquid egg. The product had up to 30, 35.5 and 36 Ref% solids in case of UF, NF and RO, respectively. From the resistance data it is obvious, that the polarization layer resistances (RP) determine the values of the permeate flux. The total solid content of permeate was 0.3 and 0.1 Ref% in case of nanofiltration and reverse osmosis, respectively. On the basis of experiments main data of a continuous pilot scale system were calculated and simplified cost estimation was performed using recent economic data of year 2011.