scholarly journals Aluminium and calcium ions binding to pectin in sugar beet juice: Model of electrical double layer

2014 ◽  
Vol 68 (1) ◽  
pp. 89-97 ◽  
Author(s):  
Tatjana Kuljanin ◽  
Lidija Jevric ◽  
Biljana Curcic ◽  
Milica Nicetin ◽  
Vladimir Filipovic ◽  
...  
Keyword(s):  
Zeta Potential ◽  
Sugar Beet ◽  
Double Layer ◽  
Calcium Ions ◽  
Electrical Double Layer ◽  
Theoretical Basis ◽  
Sugar Industry ◽  
Double Electric Layer ◽  
Average Amount ◽  
Binding Properties

In sugar industry, there is a problem of the presence of undesirable macromolecules such as pectins in sugar beet juice. Separation of these compounds is done mostly by CaO. Calcium may cause undesirable process of alkalization of soil in the near environment of the sugar factory. The theoretical basis of new juice purificatin method based on the application of Al2(SO4)3, CaSO4 and their mixtures are presented. Two model solutions of pectin (0.1 % w/w) are investigated using a method of measuring zeta potential. Pure salts Al2(SO4)3 and CaSO4, showed better binding properties with the pectin than mixtures. Amount of all studied pure salts and mixtures of Al3+ and Ca2+ ions were significantly less (142 - 710 mg/gpectin) than the average amount of CaO used in classical process (about 9 g/gpectin). Mechanism of discharge of pectin macromolecules in the presence of mixtures of these ions using a model of double electric layer are suggested.

scholarly journals The effect of copper ions, aluminium ions and their mixtures on separation of pectin from the sugar beet juice

2013 ◽  
Vol 67 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Tatjana Kuljanin ◽  
Nevena Misljenovic ◽  
Gordana Koprivica ◽  
Lidija Jevric ◽  
Jasna Grbic
Keyword(s):  
Zeta Potential ◽  
Sugar Beet ◽  
Copper Ions ◽  
Sugar Industry ◽  
Waste Water Treatment ◽  
Double Electric Layer ◽  
Colloidal Systems ◽  
Divalent Metal Ions ◽  
Ion Antagonism ◽  
Effect Of Copper

In sugar industry there is a problem of the presence of undesirable macromolecules compounds such as pectin in sugar beet juice. The affinity of calcium ions commonly used in the sugar industry for the removal of pectin from the sugar beet juice is relatively small. Coagulation and precipitation of pectin can be performed by process of discharging that is chemically induced. Compounds with di- and trivalent cations such as pure CuSO4, Al2(SO4)3 or their mixtures can be applied for clarification of pectin colloidal systems. According to data from the order of pectin selectivity to divalent metal ions, Cu2+ ions are the first order of ion binding. Also, aluminum sulfate is commonly used in the waste water treatment. Two model solutions of pectin whose concentration corresponds to the concentration of these macromolecules in sugar beet juice (0.1% w/w) are investigated. Using a method of measuring zeta potential, it was proven for both investigated pectin that fewer quantities of Cu2+ ions compared to the values of Al3+ ions are needed to reach zero zeta potential. In all the investigated coagulants and their mixtures, zeta potential has changed the sign. In experiments with mixtures has been shown that pure salts showed better coagulation properties. The reduced strength of binding of cations in the case of most of the applied mixture of Cu2+ and Al3+ ions, can be explained by the mutual competition of these ions for the adsorption site (COO- groups) on the surface of macromolecules. Mixture with approximately equal shares of ions Cu2+ and Al3+ had the most unfavorable coagulation ability (ion antagonism). Mechanism of discharge as well as the model of double electric layer surrounding pectin macromolecules in the presence of mixtures of Cu2+ and Al3+ ions are suggested. However, due to possible undesirable effects of CuSO4 on food processing, Al2(SO4)3 is proposed instead of traditional coagulant CaO, not only because of lower consumptions of coagulants but owing to protection of the environment.

scholarly journals CaO&CaSO4 and CaO&Al2(SO4)3 as Pectin Precipitants–Model of Overlapping Diffuse Layers

2018 ◽  
Vol 63 (1) ◽  
pp. 239-245
Author(s):  
Tatjana A. Kuljanin ◽  
Vladimir S. Filipović ◽  
Milica R. Nićetin ◽  
Biljana Lj. Lončar ◽  
Bojana V. Filipčev ◽  
...  
Keyword(s):  
Zeta Potential ◽  
Sugar Beet ◽  
Surface Charge ◽  
Binary Mixtures ◽  
Theoretical Basis ◽  
Binary Systems ◽  
Purification Method ◽  
Absolute Value ◽  
Model Solutions ◽  
Diffuse Layers

This work is concerned with the theoretical basis of novel sugar beet juice purification method using binary systems CaO&CaSO4 and CaO&Al2(SO4)3. The Gouy–Chapman–Stern (GCS) model of overlapping of diffuse layers of EDLs on pectin surface and that on Ca2+ and Al3+ ions, theoretically explains this method. The change of the zeta potential was used to quantitatively indicate overlapping of diffuse layers. For the experiment two model solutions of pectin (0.1 % w/w) were prepared, while the concentrations of CaO&CaSO4 and CaO&Al2(SO4)3 in the range of 50–500 g dm-3 were used. The greater decrease in the absolute value of zeta potential indicated greater overlapping of diffuse layers between pectin particles and Ca2+ and Al3+ ions and faster coagulation of pectin. The overlapping degree increased with increased concentration of these binary systems. Pectin with a greater surface charge and multivalent Al3+ from CaO&Al2(SO4), exerted a greater impact on the zeta potential. Optimal quantities of the applied binary mixtures were as follows: 256–640 mg g-1 pectin. This is much lower than CaO commonly used in the conventional process of sugar beet juice purification (about 9 g g-1 pectin).

The electrical double-layer properties of the mica (muscovite)-aqueous electrolyte interface

1981 ◽  
Vol 34 (6) ◽  
pp. 1177 ◽  
Author(s):  
JS Lyons ◽  
DN Furlong ◽  
TW Healy
Keyword(s):  
Zeta Potential ◽  
Double Layer ◽  
Electrical Double Layer ◽  
Negative Charge ◽  
Aqueous Electrolyte ◽  
Streaming Potential ◽  
Electrolyte Interface ◽  
Muscovite Mica ◽  
Silica Alumina ◽  
Flow Apparatus

Electrophoresis and streaming potential data are reported for crushed and sheet muscovite mica respectively. For streaming potential measurements a newly designed radial flow apparatus was used. Measurements on crushed mica show that both aluminium and silicon leach out of the mica. Leached aluminium and silicon may readsorb to confer increased positive and negative charge respectively on the mica. Electrophoresis data indicate that leaching of aluminium occurs more rapidly than of silicon. Aging experiments on sheet mica show leaching effects to be much slower than on crushed mica. Streaming potential measurements on freshly cleaved mica sheets showed that (i) the zeta- potential depended strongly on electrolyte (KCl) concentration; (ii) the zeta-potential was relatively independent of pH and (iii) monovalent cations were adsorbed in the sequence H+ > Cs+ > K+ > Na+ > Li+, whilst Ca2+ adsorbed more strongly than K+. It is proposed that the structure of the electrical double layer at the mica/electrolyte interface results from the distribution of all ions between the diffuse layer, the Stern plane (hydrated) and more critically the lattice holes of the silica-alumina basal plane.

scholarly journals The effect of the electrical double layer on hydrodynamic lubrication: a non-monotonic trend with increasing zeta potential

2017 ◽  
Vol 8 ◽  
pp. 1515-1522 ◽  
Author(s):  
Dalei Jing ◽  
Yunlu Pan ◽  
Xiaoming Wang
Keyword(s):  
Zeta Potential ◽  
Double Layer ◽  
Electrical Double Layer ◽  
Hydrodynamic Lubrication ◽  
Load Capacity ◽  
Hydrodynamic Load ◽  
Slider Bearing ◽  
Electrical Field Strength ◽  
Monotonic Trend ◽  
Electroviscous Effect

In the present study, a modified Reynolds equation including the electrical double layer (EDL)-induced electroviscous effect of lubricant is established to investigate the effect of the EDL on the hydrodynamic lubrication of a 1D slider bearing. The theoretical model is based on the nonlinear Poisson–Boltzmann equation without the use of the Debye–Hückel approximation. Furthermore, the variation in the bulk electrical conductivity of the lubricant under the influence of the EDL is also considered during the theoretical analysis of hydrodynamic lubrication. The results show that the EDL can increase the hydrodynamic load capacity of the lubricant in a 1D slider bearing. More importantly, the hydrodynamic load capacity of the lubricant under the influence of the EDL shows a non-monotonic trend, changing from enhancement to attenuation with a gradual increase in the absolute value of the zeta potential. This non-monotonic hydrodynamic lubrication is dependent on the non-monotonic electroviscous effect of the lubricant generated by the EDL, which is dominated by the non-monotonic electrical field strength and non-monotonic electrical body force on the lubricant. The subject of the paper is the theoretical modeling and the corresponding analysis.

scholarly journals CaSO4 and cationic polyelectrolyte as possible pectin precipitants in sugar beet juice clarification

2015 ◽  
Vol 69 (6) ◽  
pp. 617-625 ◽  
Author(s):  
Tatjana Kuljanin ◽  
Biljana Loncar ◽  
Lato Pezo ◽  
Milica Nicetin ◽  
Violeta Knezevic ◽  
...  
Keyword(s):  
Zeta Potential ◽  
Sugar Beet ◽  
Cationic Polyelectrolyte ◽  
Sugar Beet Pulp ◽  
Average Amount ◽  
Juice Clarification ◽  
Ph Values ◽  
Beet Pulp

Three pectin preparations were isolated from fresh sugar beet pulp during the 150 minutes of extraction, at pH values of 1, 3.5 and 8.5. CaSO4 precipitant was added to 100 cm3 of 0.1% (wt) solution of pectin. Studies were performed with 9 different concentrations of CaSO4 solution (50-450 mg dm-3) with the addition of a cationic polyelectrolyte (cationic PAM) in concentrations of 3 and 5 mg dm-3. The efficiency of pectin precipitation was monitored by measuring the zeta potential of pectin preparations. Optimal amounts of precipitant CaSO4, without the use of a cationic polyelectrolyte, were as follows: 490-678 mg CaSO4/g pectin. After the use of a cationic polyelectrolyte, the optimal amounts of CaSO4 were smaller (353-512 mg/g pectin). These quantities are significantly lower than the average amount of CaO used in the conventional clarification process of sugar beet juice (about 9 g/g pectin of sugar beet juice).

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