Electrical conductivity and ion-exchange kinetic studies of a crystalline type `organic–inorganic' cation-exchange material: polypyrrole/polyantimonic acid composite system, (Sb2O5) (–C4H2NH–)·nH2O

Polypyrrole–titanium(iv)sulphosalicylophosphate composite is a better sensing as well as conducting material than polypyrrole in the semiconducting range.

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Cation-exchange kinetic studies on poly-o-toluidine Ce(IV) phosphate: a nano-composite and electrical conducting material

Journal of Materials Science ◽

10.1007/s10853-011-6162-8 ◽

2011 ◽

Vol 47 (7) ◽

pp. 3241-3247 ◽

Cited By ~ 2

Author(s):

Asif Ali Khan ◽

Tabassum Akhtar

Keyword(s):

Cation Exchange ◽

Kinetic Studies ◽

Conducting Material ◽

Nano Composite ◽

Exchange Kinetic ◽

Electrical Conducting

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Preliminary Study on Enzymatic-Based Cleaning of Cation-Exchange Membranes Used in Electrodialysis System in Red Wine Production

Membranes ◽

10.3390/membranes9090114 ◽

2019 ◽

Vol 9 (9) ◽

pp. 114 ◽

Cited By ~ 2

Author(s):

Bdiri ◽

Bensghaier ◽

Chaabane ◽

Kozmai ◽

Baklouti ◽

...

Keyword(s):

Electrical Conductivity ◽

Contact Angle ◽

Ion Exchange ◽

Cation Exchange ◽

Red Wine ◽

Exchange Capacity ◽

Operating Conditions ◽

Cleaning Efficiency ◽

Wine Production ◽

Ion Exchange Capacity

The use of enzymatic agents as biological solutions for cleaning ion-exchange membranes fouled by organic compounds during electrodialysis (ED) treatments in the food industry could be an interesting alternative to chemical cleanings implemented at an industrial scale. This paper is focused on testing the cleaning efficiency of three enzyme classes (β-glucanase, protease, and polyphenol oxidase) chosen for their specific actions on polysaccharides, proteins, and phenolic compounds, respectively, fouled on a homogeneous cation-exchange membrane (referred CMX-Sb) used for tartaric stabilization of red wine by ED in industry. First, enzymatic cleaning tests were performed using each enzyme solution separately with two different concentrations (0.1 and 1.0 g/L) at different incubation temperatures (30, 35, 40, 45, and 50 °C). The evolution of membrane parameters (electrical conductivity, ion-exchange capacity, and contact angle) was determined to estimate the efficiency of the membrane′s principal action as well as its side activities. Based on these tests, we determined the optimal operating conditions for optimal recovery of the studied characteristics. Then, cleaning with three successive enzyme solutions or the use of two enzymes simultaneously in an enzyme mixture were tested taking into account the optimal conditions of their enzymatic activity (concentration, temperatures, and pH). This study led to significant results, indicating effective external and internal cleaning by the studied enzymes (a recovery of at least 25% of the electrical conductivity, 14% of the ion-exchange capacity, and 12% of the contact angle), and demonstrated the presence of possible enzyme combinations for the enhancement of the global cleaning efficiency or reducing cleaning durations. These results prove, for the first time, the applicability of enzymatic cleanings to membranes, the inertia of their action towards polymer matrix to the extent that the choice of enzymes is specific to the fouling substrates.

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Electrical conductivity of cation-exchange membranes in the hydrogen ion form

Australian Journal of Chemistry ◽

10.1071/ch9661299 ◽

1966 ◽

Vol 19 (7) ◽

pp. 1299 ◽

Cited By ~ 13

Author(s):

R Arnold ◽

DFA Koch

Keyword(s):

Electrical Conductivity ◽

Ion Exchange ◽

Cation Exchange ◽

Ion Mobility ◽

Volume Fraction ◽

Hydrogen Ion ◽

Acid Solutions ◽

Homogeneous Type ◽

Rapid Rise ◽

Initial Rise

Measurements are reported of the conductivities of a number of different cation-exchange membranes in the hydrogen-ion form. The membranes were equilibrated both with water and with sulphuric acid solutions of concentrations up to 6N, and the amounts of water and acid absorbed were also measured. Some of the membranes used were found to undergo an irreversible expansion on heating. When equilibrated with water, equivalent conductivities of the homogeneous- type membranes could be fitted by the equation Δ = A(1- Vp), where Vp is the volume fraction of polymer and A is a constant whose value depends on the concentration of ion-exchange groups but which is little affected by the nature of the membrane. In the presence of acid the conductivity changes depend markedly on the presence of voids. This behaviour can be well described in terms of the model of Sauer, Southwick, Spiegler, and Wyllie, which treats the membrane as an assembly of solid resin and continuous and discontinuous voids. Evaluation of these results in terms of this model enables estimates to be made of the extent and nature of the voids. On adding acid to a membrane there is at first a rapid rise in apparent counter-ion mobility, followed by a fall at higher acid concentrations. The initial rise in apparent mobility is attributed to the entry of acid into discontinuous voids.

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