Intrinsic properties and performances of NF270 and XLE membranes for water filtration

2011 ◽  
Vol 11 (2) ◽  
pp. 186-193 ◽  
Author(s):  
S. N. Diop ◽  
M. A. Diallo ◽  
C. K. Diawara ◽  
D. Cot
Keyword(s):  
Zeta Potential ◽  
Reverse Osmosis ◽  
Low Pressure ◽  
Separation Performance ◽  
Permeability Evolution ◽  
Force Microscopy ◽  
Feed Pressure ◽  
Atomic Force ◽  
Membrane Characterization ◽  
Drinking Water Production

Nanofiltration and low pressure reverse osmosis membranes are well-known in the field of drinking water production and their separation performance is very strongly related to their intrinsic characteristics. The membrane characterization (scanning electron microscopy (SEM), atomic force microscopy (AFM), zeta potential …) was realized on a NF270 and extra-low energy (XLE) membrane. SEM results of virgin NF270 and XLE membranes show that both are about the same thickness whereas that of the active layer of NF270 membrane is weaker than that of the XLE. The AFM measurements show that the roughness of the low pressure reverse osmosis membrane (XLE) is almost 20 times as high as that of nanofiltration (NF270). Zeta potential measurements showed that both membranes are negatively charged in pH (4–12) range. An increase in permeability by increasing feed pressure and temperature was also noted for the two types of membrane; but the permeability evolution for XLE membrane according to the volume factor reduction reveals a fall faster than that of NF270.

Potential of nanofiltration and low pressure reverse osmosis in the removal of phosphorus for aquaculture

2013 ◽  
Vol 67 (4) ◽  
pp. 831-837 ◽  
Author(s):  
C. P. Leo ◽  
M. Z. Yahya ◽  
S. N. M. Kamal ◽  
A. L. Ahmad ◽  
A. W. Mohammad
Keyword(s):  
Zeta Potential ◽  
Reverse Osmosis ◽  
Low Pressure ◽  
Separation Performance ◽  
Feed Concentration ◽  
Water Contact ◽  
Cross Sectional ◽  
High Feed ◽  
Rich Solution ◽  
Aquaculture Wastewater

Aquaculture activities in developing countries have raised deep concern about nutrient pollution, especially excess phosphorus in wastewater, which leads to eutrophication. NF, NF90, NF450 and XLE membranes were studied to forecast the potential of nanofiltration and low pressure reverse osmosis in the removal of phosphorus from aquaculture wastewater. Cross-sectional morphology, water contact angle, water permeability and zeta potential of these membranes were first examined. Membrane with higher porosity and greater hydrophilicity showed better permeability. Membrane samples also commonly exhibited high zeta potential value in the polyphosphate-rich solution. All the selected membranes removed more than 90% of polyphosphate from the concentrated feed (75 mg/L) at 12 bar. The separation performance of XLE membrane was well maintained at 94.6% even at low pressure. At low feed concentration, more than 70.0% of phosphorus rejection was achieved using XLE membrane. The formation of intermolecular bonds between polyphosphate and the acquired membranes probably had improved the removal of polyphosphate at high feed concentration. XLE membrane was further tested and its rejection of polyphosphate reduced with the decline of pH and the addition of ammonium nitrate.

Comparison of atomic force microscopy and zeta potential derived surface charge density

2020 ◽  
Vol 130 (3) ◽  
pp. 36001
Author(s):  
M. Herzberg ◽  
S. Dobberschütz ◽  
D. Okhrimenko ◽  
N. E. Bovet ◽  
M. P. Andersson ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Zeta Potential ◽  
Charge Density ◽  
Surface Charge ◽  
Surface Charge Density ◽  
Force Microscopy ◽  
Atomic Force

scholarly journals Interaction Mechanism between Molybdenite and Kaolinite in Gypsum Solution Using Kerosene as the Flotation Collector

Minerals ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 304 ◽  
Author(s):  
Liqing Sun ◽  
Yijun Cao ◽  
Yinfei Liao ◽  
Zilong Ma
Keyword(s):  
Zeta Potential ◽  
Calcium Ion ◽  
Potential Distribution ◽  
Detrimental Effect ◽  
Adhesion Force ◽  
Interaction Mechanism ◽  
Solution Concentration ◽  
Force Microscopy ◽  
Atomic Force ◽  
Flotation Collector

This paper aims to understand the fundamental interaction mechanism between molybdenite and kaolinite in gypsum solution using kerosene as collector. Micro-flotation tests were conducted to study the effect of gypsum solution on the flotation performance of mixed −74 μm molybdenite and −10 μm kaolinite mineral. The results showed that the recovery of molybdenite decreased from 86% to 74% while the gypsum solution concentration increased from 0 to 800 mg/L, indicating the detrimental effect of kaolinite on molybdenite flotation could be enhanced by gypsum solution. This is mainly caused by the slime coating of kaolinite on molybdenite through dissolved calcium ion of gypsum solution. In order to confirm the slime coating phenomenon, zeta potential distribution, scanning electron microscopy (SEM) and atomic force microscopy (AFM) measurements were used to investigate interaction characteristics and mechanisms. The zeta potential distribution results revealed that mixed samples had the value between signal molybdenite and kaolinite samples in gypsum solution, which proved the coating phenomenon of kaolinite on molybdenite. Moreover, the coating phenomenon was becoming more and more obvious with the gypsum solution concentration. The coating phenomenon of kaolinite on molybdenite surface was also directly observed from SEM results. The AFM results provided further evidence for the possibility of slime coating, as the adhesion force increased with the gypsum solution concentration, which means the aggregates of molybdenite and kaolinite were becoming more stable.

Initial stages of silicate growth on and oxidation of graphite: A model for composites

1998 ◽  
Vol 13 (1) ◽  
pp. 217-222 ◽  
Author(s):  
Dawn A. Bonnell ◽  
Darrin Jiron ◽  
Timothy Flinn
Keyword(s):  
Atomic Force Microscopy ◽  
Oxidation Behavior ◽  
Oxidation Mechanism ◽  
Low Pressure ◽  
Morphological Development ◽  
Site Specificity ◽  
Force Microscopy ◽  
Atomic Force ◽  
Primary Oxidation

The initial stages of silicate growth on graphite are characterized with atomic force microscopy. The morphological development indicates that decomposition of tetra ethyloxysilane at low pressure produces films of 3 nm clusters located at undercoordinated carbon sites. Clusters eventually cover the surface, at which point a second layer grows. In higher pressure deposition multiple layers of clusters grow simultaneously. A comparison of the oxidation behavior of surfaces with defects completely and incompletely terminated with SiOx shows that edge recession is the primary oxidation mechanism and that the site specificity of SiOx is effective in inhibiting oxidation.

Surface characterization of polymer foils

e-Polymers ◽  
2012 ◽  
Vol 12 (1) ◽  
Author(s):  
Zdenka Kolská ◽  
Alena Řezníčková ◽  
Václav Švorčík
Keyword(s):  
Zeta Potential ◽  
Surface Characterization ◽  
Streaming Potential ◽  
Electrolyte Solutions ◽  
Force Microscopy ◽  
Angle Measurements ◽  
Atomic Force ◽  
Contact Angle Measurements ◽  
Polymer Foils

AbstractElectrokinetic potential (zeta potential) for selected 21 polymer foils was studied. The results on zeta potential are supplemented with contact angle measurements (goniometry) and with the results on surface roughness measured by atomic force microscopy (AFM). Zeta potential was determined using two approaches: streaming current and streaming potential at pH=6.0-6.2. Two electrolyte solutions with KCl (concentrations 0.001 and 0.005 mol/dm3) and KNO3 (0.001 mol/dm3) were used in the experiments. Zeta potential was shown to depend on surface chemistry, polarity, roughness and morphology of the polymer foils.

Polyelectrolyte brushes: Water Content, Zeta Potential and Mechanical Properties

2015 ◽  
Vol 1754 ◽  
pp. 53-58
Author(s):  
Joseba Irigoyen ◽  
Jagoba Iturri ◽  
José Luis Camacho ◽  
Edwin Donath ◽  
Sergio Moya
Keyword(s):  
Ionic Strength ◽  
Zeta Potential ◽  
Water Content ◽  
Polymer Brushes ◽  
Polymer Brush ◽  
Trimethylammonium Chloride ◽  
Surface Approach ◽  
Force Microscopy ◽  
Polyelectrolyte Brushes ◽  
Atomic Force

ABSTRACTPolymer brushes of poly[2-(methacryloyloxy)ethyl]trimethylammonium chloride (PMETAC) and poly(sulfo propyl methacrylate) (PSPM) were synthesized by Atomic Transfer Radical Polymerization from planar and colloidal surfaces. Polymer brush growth was followed by QCMD and the water content determined by combined QCMD and elipsometry. From the water content the percentage of water lost during the brush collapse with the ionic strength could be obtained.Highly charged PSPM brushes were indented by Atomic Force Microscopy at different ionic strengths. The force response was fitted to a phenomenological equation analogous to the equation of state of a compressible fluid. Internal energy and brush compressibility were obtained as a function of ionic strength.Spherical brushes of PMETAC and PSPM display an invariance of the zeta potential with ionic strength in the range from 20 mM to 200 mM NaCl, the zeta potential remains almost constant. This invariance can be explained applying a hairy surface approach.

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