נגישות
menu      
Advanced Search
Syntax
Search...
Volcani treasures
About
Terms of use
Manage
Community:
אסיף מאגר המחקר החקלאי
Powered by ClearMash Solutions Ltd -
Settling and flocculation value of sodium-montmorillonite particles in aqueous media.
Year:
1988
Authors :
Keren, Rami
;
.
Klein, Eva
;
.
Shainberg, Isaac
;
.
Volume :
52
Co-Authors:
Keren, R., Inst. of Soils & Water, The Volcanic Center, P.O.B. 6, Bet Dagan 50250, Israel.
Shainberg, I., Inst. of Soils & Water, The Volcanic Center, P.O.B. 6, Bet Dagan 50250, Israel.
Klein, E., Inst. of Soils & Water, The Volcanic Center, P.O.B. 6, Bet Dagan 50250, Israel.
Facilitators :
From page:
76
To page:
80
(
Total pages:
5
)
Abstract:
The effect of pH, particle size and clay concentration on the flocculation value (FV) and the settling rate of Na- montmorillonite in dilute suspension were studied in solutions of various NaCl concentrations. Flocculation values increased with increasing pH, being 10, 13, 31 and 44 mmol/dm3 of NaCl at pH 5, 7.5, 8.5 and 9.8, respectively. The final gel volume of the samples at all pH values was high (0.35 < gel volume < 0.49 m3/kg), and the corresponding thickness of the water film associated with the clay surface was approx 500 nm. The high gel volume indicates that a three-dimensional 'card-house' structure was formed. The presence of a negative charge on the broken edges at pH 9.8, the high FV (44 mmol/dm3 NaCl) and the high gel volume suggest that an open structure with a face-to-face association predominates. Face-to- face association between two platelets may take place at surfaces having either a lower or higher specific charge density than the average montmorillonite value of 0.117C/m2. At pH equal or below the point of zero charge of the edges, edge-to-edge or edge-to-face association may occur. The time that it takes to establish a boundary between the gel and the supernatant liquid depends on the size of the clay particles; the smaller the particles, the longer is the settling time. The settling rate depends also on the clay concentration. The boundary between the gel and the clear solution was observed after 1 and 4 d for clay concentrations of 0.1% and 0.5%, respectively, but at higher clay concentrations (0.2 and 0.5%) the suspensions remained stable for >7 d. (Authors' abstract)A.W.H.
Note:
Related Files :
CLAY PARTICLE SIZE
HYDROGEN ION CONCENTRATION DEPENDENT FLOCCULATION VALUE
Show More
Related Content
More details
DOI :
Article number:
0
Affiliations:
Database:
Scopus
Publication Type:
Language:
English
Editors' remarks:
ID:
19905
Last updated date:
02/03/2022 17:27
Creation date:
16/04/2018 23:32
Scientific Publication
Settling and flocculation value of sodium-montmorillonite particles in aqueous media.
52
Keren, R., Inst. of Soils & Water, The Volcanic Center, P.O.B. 6, Bet Dagan 50250, Israel.
Shainberg, I., Inst. of Soils & Water, The Volcanic Center, P.O.B. 6, Bet Dagan 50250, Israel.
Klein, E., Inst. of Soils & Water, The Volcanic Center, P.O.B. 6, Bet Dagan 50250, Israel.
Settling and flocculation value of sodium-montmorillonite particles in aqueous media.
The effect of pH, particle size and clay concentration on the flocculation value (FV) and the settling rate of Na- montmorillonite in dilute suspension were studied in solutions of various NaCl concentrations. Flocculation values increased with increasing pH, being 10, 13, 31 and 44 mmol/dm3 of NaCl at pH 5, 7.5, 8.5 and 9.8, respectively. The final gel volume of the samples at all pH values was high (0.35 < gel volume < 0.49 m3/kg), and the corresponding thickness of the water film associated with the clay surface was approx 500 nm. The high gel volume indicates that a three-dimensional 'card-house' structure was formed. The presence of a negative charge on the broken edges at pH 9.8, the high FV (44 mmol/dm3 NaCl) and the high gel volume suggest that an open structure with a face-to-face association predominates. Face-to- face association between two platelets may take place at surfaces having either a lower or higher specific charge density than the average montmorillonite value of 0.117C/m2. At pH equal or below the point of zero charge of the edges, edge-to-edge or edge-to-face association may occur. The time that it takes to establish a boundary between the gel and the supernatant liquid depends on the size of the clay particles; the smaller the particles, the longer is the settling time. The settling rate depends also on the clay concentration. The boundary between the gel and the clear solution was observed after 1 and 4 d for clay concentrations of 0.1% and 0.5%, respectively, but at higher clay concentrations (0.2 and 0.5%) the suspensions remained stable for >7 d. (Authors' abstract)A.W.H.
Scientific Publication
You may also be interested in