scholarly journals Quantitative Analysis of Membrane Fouling Mechanisms Involved in Microfiltration of Humic Acid–Protein Mixtures at Different Solution Conditions

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1306 ◽  
Author(s):  
Chunyi Sun ◽  
Na Zhang ◽  
Fazhan Li ◽  
Guoyi Ke ◽  
Lianfa Song ◽  
...  
Keyword(s):  
Humic Acid ◽  
Ionic Strength ◽  
Interaction Energy ◽  
Membrane Fouling ◽  
Calcium Ion ◽  
Ion Concentration ◽  
Total Interaction Energy ◽  
Quantitative Understanding ◽  
Total Interaction ◽  
Calcium Ion Concentration

A systematical quantitative understanding of different mechanisms, though of fundamental importance for better fouling control, is still unavailable for the microfiltration (MF) of humic acid (HA) and protein mixtures. Based on extended Derjaguin–Landau–Verwey–Overbeek (xDLVO) theory, the major fouling mechanisms, i.e., Lifshitz–van der Waals (LW), electrostatic (EL), and acid–base (AB) interactions, were for the first time quantitatively analyzed for model HA–bovine serum albumin (BSA) mixtures at different solution conditions. Results indicated that the pH, ionic strength, and calcium ion concentration of the solution significantly affected the physicochemical properties and the interaction energy between the polyethersulfone (PES) membrane and HA–BSA mixtures. The free energy of cohesion of the HA–BSA mixtures was minimum at pH = 3.0, ionic strength = 100 mM, and c(Ca2+) = 1.0 mM. The AB interaction energy was a key contributor to the total interaction energy when the separation distance between the membrane surface and HA–BSA mixtures was less than 3 nm, while the influence of EL interaction energy was of less importance to the total interaction energy. The attractive interaction energies of membrane–foulant and foulant–foulant increased at low pH, high ionic strength, and calcium ion concentration, thus aggravating membrane fouling, which was supported by the fouling experimental results. The obtained findings would provide valuable insights for the quantitative understanding of membrane fouling mechanisms of mixed organics during MF.

The action of rennets on the caseins: I. Rennin action on β-casein-B in solution

1971 ◽  
Vol 38 (3) ◽  
pp. 269-280 ◽  
Author(s):  
L. K. Creamer ◽  
O. E. Mills ◽  
E. L. Richards
Keyword(s):  
Ionic Strength ◽  
Conformational Changes ◽  
Calcium Ion ◽  
Ion Concentration ◽  
Disk Electrophoresis ◽  
C Terminus ◽  
Rate Of Hydrolysis ◽  
Calcium Ion Concentration ◽  
Hydrolysis Of ◽  
Electrophoresis Technique

SummaryA study of the hydrolysis of β-casein-B by crystalline rennin or rennet extract at pH 6·5, using a disk electrophoresis technique, showed that 3 bonds in β-casein are appreciably more sensitive than the others to rennin proteolysis, and that these bonds are probably located near the C-terminus of the protein. The most susceptible bond is hydrolysed, at 10°C, about 200 times faster than any other bond, whilst at 37°C it is hydrolysed 60 times faster. A study of the hydrolysis of this bond showed that its rate of hydrolysis at 37°C and pH 6·5 is decreased by either increased ionic strength or increased calcium ion concentration at constant ionic strength. Conformational changes in the substrate are probably responsible for these effects.

Coagulation of renneted bovine casein micelles: dependence on temperature, calcium ion concentration and ionic strength

1983 ◽  
Vol 50 (3) ◽  
pp. 331-340 ◽  
Author(s):  
Douglas G. Dalgleish
Keyword(s):  
Ionic Strength ◽  
Calcium Ion ◽  
Maximum Rate ◽  
Bond Formation ◽  
Ion Concentration ◽  
Ionic Interactions ◽  
Maximal Rate ◽  
Casein Micelles ◽  
Hydrophobic Bond ◽  
Calcium Ion Concentration

SummaryThe rates of coagulation of completely renneted casein micelles have been measured as functions of ionic strength, temperature, and concentration of Ca2+. At 25 °C and below, the rate constants for the coagulation were found to be low, but increased with temperature so that at 60 °C the particles were coagulating at almost maximum rate permitted by diffusion. This maximal rate at 60 °C was achieved at nearly all of the ionic strengths and concentrations of Ca2+ used. At lower temperatures the rate constant decreased with increasing ionic strength, the dependence being more marked at lower temperatures. Increasing concentration of Ca2+ also increased the rate at low and moderate temperatures. The implications of these results are discussed in terms of specific and non-specific ionic interactions and of hydrophobic bond formation.

Model of short-term regulation of calcium-ion concentration

SIMULATION ◽  
1979 ◽  
Vol 32 (6) ◽  
pp. 193-204 ◽  
Author(s):  
George G. Járos ◽  
Thomas G. Coleman ◽  
Arthur C. Guyton
Keyword(s):  
Calcium Ion ◽  
Ion Concentration ◽  
Short Term ◽  
Calcium Ion Concentration

Zeta-Potential Investigation and Experimental Study of Nanoparticles Deposited on Rock Surface To Reduce Fines Migration

SPE Journal ◽  
2013 ◽  
Vol 18 (03) ◽  
pp. 534-544 ◽  
Author(s):  
M.. Ahmadi ◽  
A.. Habibi ◽  
P.. Pourafshary ◽  
S.. Ayatollahi
Keyword(s):  
Zeta Potential ◽  
Interaction Energy ◽  
Fine Particles ◽  
Rock Surface ◽  
Production Engineering ◽  
Release Process ◽  
Fines Migration ◽  
Total Interaction Energy ◽  
Total Interaction ◽  
Potential Test

Summary Fines migration is a noticeable problem in petroleum-production engineering. Plugging of throats in porous media occurs because of detachment of fine particles from sand surfaces. Thus, the study of interactions between fines and pore surfaces and the investigation of governing forces are important factors to consider when describing the mechanism of the fines-release process. The main types of these forces are electric double-layer repulsion (DLR) and London–van der Waals attraction (LVA). It may be possible to alter these forces with nanoparticles (NPs) as surface coatings. In comparison with repulsion forces, NPs increase the effect of attraction forces. In this paper, we present new experiments and simple modeling to observe such properties of NPs. For this purpose, the surfaces of pores were coated with different types of NPs: magnesium oxide (MgO), silicon dioxide (SiO2), and aluminum oxide (Al2O3). A zeta-potential test was used to examine changes in the potential of the pore surfaces. Total interaction energy was then mathematically calculated to compare different states. Total interaction energy is a fitting criterion that gives proper information about the effect of different NPs on surface properties. Consequently, total interaction plots are found to be suitable tools for selecting the best coating material. On the basis of experimental results, the magnitude of change in zeta potential for the MgO NP was 45 mV. Our model demonstrated that the magnitude of the electric DLR in comparison with the LVA of the probe and plate surface was considerably diminished when MgO NPs were used to coat the surface of the plate, which agrees completely with our experimental observation.

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