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Maftuleac, Alexei; Dranca, Ion; Lupaşcu, Tudor

doi:10.1023/a:1019972125701

Cited by 8 publications

(3 citation statements)

References 5 publications

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Section: Introductionmentioning

confidence: 99%

“…These impurities should be removed during water processing, either by coagulation or flocculation. The study of the particles in suspension in the rivers from the Republic of Moldova showed that the main inorganic component in water is montmorillonite,13 which has a negative charge with an electrokinetic potential of some tens of millivolts 14. Therefore, the aim of the present study was to correlate the efficiency of the montmorillonite separation from aqueous suspensions, on the one hand, with the structure of some hydrophobically modified polycations and, on the other hand, with the working conditions (polycation dose, stirring time, temperature, and pH).…”

Section: Introductionmentioning

confidence: 99%

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Flocculation of montmorillonite by some hydrophobically modified polycations containing quaternary ammonium salt groups in the backbone

Drăgan¹,

Maftuleac

Dranca

et al. 2002

J of Applied Polymer Sci

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ABSTRACT:The flocculating efficiency of some hydrophilic/hydrophobic cationic polyelectrolytes on montmorillonite suspension in water was investigated as a function of both the polycation structure and the flocculation parameters: polycation/montmorillonite contact time, suspension pH, polycation dose, and temperature. Cationic polyelectrolytes with quaternary ammonium salt groups in the backbone and hydrophobic side chains (hexyloxypropyl, PCA 5 H 1 and PCA 5 H 2 ; and decyloxypropyl, PCA 5 D 1 , respectively) were used as flocculants. The flocculation was time dependent. A negative influence of the stirring time and of the abrupt variation of pH from basic to acidic on the separation efficiency was evidenced. The increase of the polycation dose from 0.58 mg polycation/g montmorillonite up to 1.74 mg/g montmorillonite showed a positive influence on the sedimentation of montmorillonite particles for all the polycations taken into account. The influence of the polycation structure was reflected in the lower turbidity found in the case of the polycation PCA 5 D 1 compared with that of PCA 5 H 1 , at the same concentration; this reflects the positive influence of the hydrophobicity increase on the suspension separation. A common characteristic for all the polycations is that, for more than about 60 min of settling, the lowest turbidity was found at 25°C and the highest at 5°C. The turbidity found at 15°C was in between, both before and after 60 min of settling time.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Flocculation of montmorillonite by some hydrophobically modified polycations containing quaternary ammonium salt groups in the backbone

Drăgan¹,

Maftuleac

Dranca

et al. 2002

J of Applied Polymer Sci

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“…By using DSC, Zhang and Dahn(98) demonstrate that the reaction of the impregnated carbons with air is accelerated by the presence of moisture adsorbed by the impregnated carbon. According to kinetics analysis, this acceleration is caused by an increase in the frequency factor that is determined to result from a decrease in the particle size of the impregnant through a series of steps initiated by the adsorbed water.Maftuleac et al(99) report that dehydration of montmorillonite samples produces endothermic effects in the region °C that may appear as single or double peaks depending on the nature of exchange cations. By studying different exchange forms (Na, Ca, Al, Fe), the authors conclude that the shape of endo effects depends on the state of the active centers of the mineral.Balek et al (100) have studied interaction of various organic compounds with TIXOTON (Ca-bentonite activated by sodium carbonate) by emanation thermal analysis (ETA) supplemented by TG and XRD.…”

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confidence: 99%